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Analysis of propagation effects from GNSS - gAGE

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1. 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 145 HW2 Combinations of three frequency measur 0 Answer to Question A 3 Repeat the previous exercise for the GPS signals L1 L2 L5 using the files 15dt1260 090 15dt1260 09n and satellite PRNO1 Resolution 1 Using the configuration file neas cfg READ the RINEX and generate the MEAS file with content MEAS YY Doy sec GPS PRN el Az N list C1C L1C C1P L1P C2C L2C C2P L2P C5X L5X 1 2 3 4 5 6 78 9 10 11 12 13 14 15 16 17 18 19 20 gLAB linux input cfg meas cfg input obs 15dt1260 090 input nav l15dt1260 09n pre dec 0 grep GPS gt 15dt meas sec PC LC PC2 LC2 2 From 15dt126 09 meas file generate a file with the following content 1 gt 3 gawk if 6 01 print 4 13 1 55 17 13 1441 55 14 18 7 08 13 14 26 13 17 18 20 05 19 20 l5dt meas gt 15dtPc2Lc2 dat 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 146 HW2 Combinations of three frequency measur 3 Plotting results graph py f 15dtPc2Lc2 dat x1 y 345140 1 PC2 LC2 125 f l5dtPc2Lc2 dat x1 y2 1 PC LC 12 cl r xn 29700 xx 49200 yn 100 yx 100 xl time s yl m iog St order and 1st 2nd order ionosphere free combination noise Peet Although the noise Is lower than i
2. Model components Postfit residuals Orbit and Clock comparison Global Graphic Parameters Title Model components X label time s Y label model m EL fv Column ff ono v 25 i Label Select IONO advance vi Automatic Limits X min X max Y min Y max 10000 20000 30000 40000 50000 60000 70000 80000 90000 Individual Plot s Configuration time s Plot Nr 1 Plot Nr 2 Plot Nr 3 Plot Nr 4 ce lonosphere delays code and Condition MODEL iv y 1 MODEL Blue X Column advances carrier measurements Note Use the gLAB out file In gLAB1 out file this model component was switched off Plot gAGE UP Research group of Astronomy amp Geomatics Technical University of Catalonia 22 J Sanz amp J M Juan Example 1 Measur P2 P1 v s Model Klobuchar gLAB Version 2 0 0 Cesa lonospheric combinations gLAB gAGEUPC MEN HIER http www gage es e at Preferences About m H e ee E e Positioning Analysis gt Templates z 2e Ce di e NEU positioning error Horizontal positioning error Zenith Tropospheric Delay lonospheric combinations amp aad he M eg o 5 e Dilution Of Precision Satellite skyplot Carrier phase ambiguities Measur Multipath Noise va Wy Model components Pre
3. 1 effect due to the different Antenna Phase Centres APC of the L1 L2 L5 signals meters of L1 delay The study of this effect was done in the previous Home Work exercise HW1 30000 35000 40000 45000 time s gA GE UPC J Sanz amp J M Juan 155 oe up o or As tronomy amp Geomatics s chnical University of Catalonia HW2 Combinations of three frequency measur Comment 2 After removing the error due to the APCs the following plot is found see this plot generation in exercise LWP 2 Geometry free and first order iono free comb APC correction applied LI2 125 Elev 10 Nevertheless the noise in the combination in both cases GPS and Galileo is over the expected value for the 279 order ionospheric effect which is less than 2cm see HW3 or R 9 meters of L1 delay 30000 35000 40000 45000 time s gA GE UPC J Sanz amp J M Juan 156 oe up o or As tronomy amp Geomatics s chnical University of Catalonia HW3 Theoretical exercises on 2 order iono Question 1 Show that the second order ionospheric delay on the L1 carrier produced by 10 TECU of STEG is less than 2 millimetres Which values would reach I2 in the Halloween lonospheric Storm October 30 2003 analyzed in exercise 3 Hint Consider the next expression where a single thin ionospheric layer approximation has been taken for the second term B 7427cB pa PR ET N Bcos
4. Question 3 Taking into account the previous results of HW2 and HW3 and thinking of high accuracy geodetic positioning discuss what is more suitable to remove this effect on the first order ionosphere free combination LC To use a model or to remove this effect from a linear combination of three frequency signals Question 4 The previous expressions give the I2 effect in L1 delay units Show the following relation between the I2 delay in the L1 carrier and in the first order ionosphere free combination LC 12 p 4 ro LC 121 m LI yrs yy 4 gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 159 Thank you for your attention e c J Sanz amp J M Juan 160 Research group of Astronomy amp Geomatics Technical University of Catalonia Bibliography R 1 J Sanz Subirana J M Jaun Zoroza M Hern ndez Pajares GNSS Data processing Volume and Volume ll ESA Publications Division 2012 R 2 J Sanz Subirana J M Jaun Zoroza M Hernandez Pajares Tutorial on GNSS Data Processing Laboratory Exercises ESAlnternational Summer School on GNSS 2010 R 3 Hernandez Pajares M J M Juan J Sanz EGNOS Test Bed lonospheric Corrections Under the October and November 2003 Storms IEEE Transactions on Geoscience and Remote Sensing Vol 43 10 pp 2283 2293 2005 R 4 Hernandez Pajares M J M Juan J Sanz Medium Scale Traveling Distu
5. J Sanz amp J M Juan 71 meters of L1 L2 28 Oct 2003 Solar flare 252011212212511 estsetocteot oasen 2122222 12 24 2 222 2 2 2 22 2 22 2 2922 2 001 unu 8 PEETI T niis ML IIT PT MENT 39500 time 5 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia npe E Peet See ka i e PETTEE Ex 3 Solar Flare October 28 2003 du Ukraine Arabia Mall Lied chag Sudan 7 a F EE nd Algeria Libya Egypt ae e Pakistan Ttip zil LE E 3 aum Conga Kenya GARS Tanzania Anges TAS i j Namibia _ Botswana P South Africa J Sanz amp J M Juan India T7 12 Ex 4 Halloween storm P2 P1 analysis Associated with the Solar Flare analysed in the previous exercise a Coronal Mass Ejection occurred which sent a large particle cloud impacting the Earth s magnetosphere about 19 hours later on October 29 Subsequent impacts were still occurring several hours later This material interacted with the Earth s magnetosphere and a Storm Enhancement Density SED appeared in North America and affected later the northern latitudes in Europe Extra large gradients of TEC associated with this phenomenon were also produced degrading the GPS positioning performance DEG EE eve DU The TEC evolution in October 30 2003 i e Day 303 of year 2003 can be seen in the movie TEC 20030ct30 anim gif gA GE UPC
6. PI1 125 PI 12 oe arrier Geometry free and 2nd order iono free comb I5dt126 LI1 125 LI 12 Carriers gt PER EEE EG IPAE UN meters of L1 delay e o o meters of L1 delay e I c e EE EE 40000 60000 70000 80000 70000 80000 18000 30000 20000 30000 40000 20000 60000 50000 Why does this pattern appear in LI1 PI1 see exercise HW1 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 151 HW2 Combinations of three frequency measur C Geometry Free amp First order lono Free combination analysis Questions analyse the suitability of the combinations PI2 and LI2 obtained in the previous exercises to estimate the second order ionosphere effect 1 Make a plot to show the geometry free and first order ionosphere free combination LI2 of Galileo carrier phase measurements E1 E7 E8 Use the files gien327sw 090 and orb15591 sp3 and satellite PRN16 Discuss the results taking into account the theoretical noise figures found at the beginning of this exercise 2 The same question for GPS carrier phase measurements L1 L2 L5 Use the files I5dt1260 090 15dt1260 09n and satellite PRNO1 3 Discuss if the second order ionospheric effect can be depicted from Galileo or GPS data gA GE UPC oe up o Br Astro RR ge chnical University of
7. 2mm the noise Will be over the phenomena threshold 20000 20006 NUES 19009 2 The same question for Galileo data see HW2 meters of L1 delay gA GE UPC ics et re eomatics ge chnical University of Catalon J Sanz amp J M Juan 129 OVERVIE Introduction A The gLAB tool suite Examples of GNSS processing using gLAB Laboratory session organization LABORATORY Session A Starting up your laptop A Basic Introductory lab exercises lono amp Posit SF storm TIDs Medium Laboratory Work Projects LWP1 to LWP4 Advanced Homework e c J Sanz amp J M Juan 130 Research group of Astronomy amp Geomatics Technical University of Catalonia n Home Work igi Aim te 100 EE Different complementary ER Q2 die questions theoretical and AE experimental related to the aem o7 5 LW4 are asked in this 4 m homework section p E l The assessment will be based The aim is to analyze in depth in actual GPS measurements the combinations of three at frequencies L1 L2 and L5 frequency signals as well as Galileo at E1 E5 and E5b frequencies J Sanz amp J M Juan 131 Research group of Astronomy amp Geomatics Technical University of Catalonia HW1 APC effect on the LI2 combination Question 1 Study the effect of the Antenna Phase Centre APC on the LI2 combination in order to analyze the elevation dependent pattern seen in previous of
8. lonospheric correction broadcast Klobuchar lonospheric delays are larger at noon due to the higher insulation Klobuchar model is unable to mitigate the large ionospheric errors during the storm Position domain errors reach up to 40 meters with Klobuchar corrections used 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 62 Ex 1 Assessing lono effects on single freq pos T North error with Klobuchar MEN m error m North error mi 0 East error mi Horizontal positioning error 2 freq lono free North error j T T T T T T East error gt UP error Iono z free T EE error m 10000 20000 30000 40000 50000 60000 70000 80000 90000 time s 0 East error m lonospheric correction broadcast Klobuchar The ionosphere free combination PC of P1 and P2 codes is immune to the ionospheric storm e Although PC is three times noisier than P1 or P2 it provides positioning accurate at the level of a few meters during the storm United States Solor To Kansas 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 63 5 P 1 n 3 P Un ET hh 2 NE n z i i 1 eo ret Ta t TT fi ER oie 3 T i i S im ug j 4 M rw hu vi 4 a T E m rn UE ml E e
9. Sky plots Example 2 gLAB Version 2 0 0 1 Ex5b4 Sky plot madr 2009 11 02 Sesion Sesion 1 Ex5a4 Sky plot alrt 2009 11 02 comparison Mcasur Multipath Noise lonospheric combinations Y uU o UJ Le 2 o ed o gt m X3 Pal i lt v 2 a 3 A u 7m v al 9 wu uw v o A a 9 og pes o dar par l w R na o i y a re GE it N U o o WM gt Be c E Q zs 5 p Li wa ome Be a Qa E u o v v og 2 4 5 vi a m N 2 E v o FY a a Analysis odel components i EV positioning error Dilution Of Precision M Templates N 8 0 fiii zuo e Eius Wu cu west J TANE u S e k 3 U E E ea gt x v D N pe 2 E c a T 1 x 5 An v v 7 o 4 s E pan ki gt a rm v c 5 v S 2 s oe ad a n 0 c amp s E n z c g amp a p E e ve amp 4 El93 ws 2 v Mi o S U UJ r C a v a z a 2 0 mr gt U an v m g 2D las Sic E 7 Z oL Pe 3 P a c o 8 ae lt 2 2 53 o c un 2 c o 3 be e ee de RIA ee eee armerte Se se er a hl de TS retentu ewecc9 s eu e bet et bt TTIE rT ts eges VS st E ee e EEE TYTY re a g E Poja o A fen eee ee 9 te of AE Y D eee S Fe te T 5 TT poso
10. gLAB linux input cfg meas cfg input obs garl3010 030 input nav brdc3010 03n gt gar13010 03 meas gLAB linux input cfg meas cfg input obs garl13020 030 input nav brdc3020 03n gt gar13020 03 meas gLAB linux input cfg meas cfg input obs gar13030 030 input nav brdc3030 03n gt gar13030 03 meas gLAB linux input cfg meas cfg input obs garl3040 030 input nav brdc3040 03n gt gar13040 03 meas gLAB linux input cfg meas cfg input obs garl13050 030 input nav brdc3050 03n gt garl13050 03 meas gLAB linux input cfg meas cfg input obs garl3060 030 input nav brdc3060 03n gt garl13060 03 meas 2 Merge files and refer all the data to Oh of October 28th Doy0301 cat gar130 0 03 meas gawk d 3 301 86400 4 4 d print 6 4 3600 15 13 7 gt PI txt 3 Plot results IONO Halloween Storm 280ct 02Nov garl Lat 40 Lon 119 graph py f PI txt x2 y3 1 ALL P2 P1 iud end f PI txt c 1 04 x2 y4 1 PRN 4 ELEV T NBN IE ee f PI txt c 1 04 x2 y3 so 1 PRNO4 P2 P1 xn O0 xx 144 LIU Canada meters of L1 L2 delay ui pnie States North Atlantic Ocean 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia Ex 5 Halloween storm evolution Zoom at time interval 70 to 78 h graph py f PI txt x2 y3 1 ALL P2 P1 graph py f PI txt x2 y3 1 ALL P2 P1 f PI txt c 1 04 x2 y4 1 94 EL f PI txt c 1 04
11. oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 133 HW1 APC effect on the LI2 combination Answer to Question 2 Knowing the L1 and L2 APCs estimate the L5 APC The APC of L5 signal together with the carrier ambiguity bias can be estimated from carrier measurements along a continuous data arch for the three carriers as follows d L A SIN e bias k Syp a L t a L t asL t aA A sine t bias a sin e t A n y t y t 1 a sine t l gt bias f yt l a sine t xv y A gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 134 HW1 APC effect on the LI2 combination Numerical application to L1 L2 and L5 signals Applying the values a 6 287 a 34 084 a 27 797 0 09002 A 0 11989 to previous equation it follows 6 287 L t 34 084L t 27 797 L t 43 505 sin t bias 27 797 sin e t A SS FO y t y t 27 797sin amp t As 5 0 283m bias 5133 Im y t 27 797sin amp t U i qx oe_imle y A Using the L1 L2 L5 values of file 15dt1260 090 in the time interval 30000 t 49000 sec see details in the notepad gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 135 HW1 APC effect on the LI2 combination b Plot the LI2 combi
12. amp J M Juan 1 2 Research group of Astronomy amp Geomatics Technical University of Catalonia no of Examples of GNSS Data Processing using gLAB Example 1 lonospheric effects on single frequency positioning e his exercise is devoted to analysing the effect of the ionospheric error in single frequency positioning This is done both in the Signal In Space SIS and User Domains A receiver will be positioned in Standard Point Positioning SPP mode a with full modelling b neglecting the ionospheric correction J Sanz amp J M Juan 13 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 1 lono effects on single freq Posit mM O Data set 24h data collected by the IGS permanent receiver ramo Lon Lat on May 4th 2000 Solar radio flux F10 7 B M LUN 1950 1960 1970 1980 1990 2000 2010 a a n EE NU 2 13 00 upci001 78 Time years O 80 180 240 320 400 480 560 640 720 800 880 960 gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 14 Example 1 lono effects on single freq Posit 1 Compute SPP using files ramo1250 000 brdc1250 00n gLAB Version 2 0 0 gL AE saGEUPC E http www gage es gLAB Version 2 0 0 Mu gLAB 7 gAGEUF http www gage es Cesa 8 EEN e Preferences Aba Positionigg Analysis 6 NEU p
13. dL1 dLc Trier ERN RN NET EE ieee ntert m s Q5 Justify the discrepancy between the two plots Answer 5 e The large drift in dL1 dRho curve is due to the satellites GPS and LEO clock drift These large clock variations do not allow to see the atmospheric bending effect 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 104 LWP2 Atmospheric Bending in RO P6 Plot dL2 dRho and dL2 dLc as a function of time Discuss results graph py f bending dat x 7 5 y4 1 dL2 dRho f bending dat x10 y4 1 dL2 dLc x1 m L2 s yl p km t COSMIC 4 Antenna 1 PRN 2 COSMIC 4 Antenna 1 PRNO2 Sor NN Q6 Justify the discrepancy dL2 dRho i ae between the two plots 6800 Answer 6 e The same answer as In previous plot 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 105 Bending Angle oa p METTIIILLLLA L L A Af V ops Kops sd Kio 1 Hope Nope SM ee Oe o SG Oeo Ed Q Ops T OLEO A Af Ap occult Va JG A f GPS LEO Ap im Vape Kope d A f GPS GPS LEO LEO Tangent point Backu 106 LWP2 Atmospheric Bending in RO Comments From phase excess rate measurements the bending angle can be estimated From the bending angle the variations of the refractiv
14. effect on single frequency carrier smoother code e LWP4 To analyse if second order ionospheric effects can be depicted from three frequency GNSS measurements i i I ree comb LI2 125 l Elev 10 deg A minimum knowledge of UNIX e g awk would be desirable 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 48 Laboratory session organization A 3 Advanced Labeled as Homework exercises A set of additional exercises addressed to those students that already have a solid background in GPS data processing These exercises are beyond the scope of this 3h laboratory session and are given for a possible further discussion As in the previous cases the answers to the questions are also included as BACKUP slides A minimum 2 at Ly aA sin bias knowledge of a UNIX e EE awk APC correction term is desirable for these homework exercises gawk BEGIN g 77 60 2 print 6 4 g 13 14 15 16 g 1 meas txt gt PC txt 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 49 OVERVIEW Introduction A The gLAB tool suite Examples of GNSS processing using gLAB Laboratory session organization LABORATORY Session gt Starting up your laptop A Basic Introductory lab exercises lono am
15. input cfg gLAB p1 IFree cfg obs amc3030 030 nav brdc3030 03n input input http www gage es gLAB Version 2 0 0 cQ gAGE UP http www gage es gt AB Preferences About Cesa Positioning Analysis Measurements Troposhere Selection Estimate Troposphere Pseudorange Pseudorange Smoothing epochs Pseudorange Carrier phase Available Frequencies Dual Frequency Receiver Kinematics Static Kinematic Measurement configuration and noise PC vy Fixed StdDev m 1 Elevation StdDev m Select Dual Frequency Parameters gLAB Version 2 0 0 Coordinates Receiver Clock http www gage ax Preferences Save Config M Pr nt CS Cycle Slig de ow Change output ae file name to esse gLAB2 out Print EPOCHSAT Messages amp Print PREFIT Messages g Print POSTFIT Message Il Print FILTER Message Print OUTPUT Message Show Output Ex 1 Assessing lono effects on single freq pos NEU positioning error SPP Full model Execute in a single line or use the gLAB GUI graph py f gLAB out x4 y18 s c 1 OUTPUT 1 North error f gLAB out x4 y19 s c 1 OUTPUT 1 East error f gLAB out x4 y20 s c 1 OUTPUT 1 UP error yn 40 yx 70 x1 time s yl error m i EE m t NEU positioning error SPP Full model
16. 1 and y t 1 The averaging in the Hatch filter can be implemented as AT y t AT 2 aci yr fear gt HET I y t f AT TIER Thence L t A TUE gt Te O 1 e bias 2 1 1 t 559 21 gA GE UPC ics up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 112 LWP3 lono Divergence on Smoothing Divergence Free smoothing DFree With 2 frequency measurements the ionosphere can be removed from a combination of two carriers p 2 Y pab dalh L By 4 FF B B 20 B B gt DFree smoothed code is not affected by iono temporal gradients being the ionospheric delay the same as in the original code F lonosphere Free smoothing IFree Using both code and carrier 2 frequency measurements it is possible to remove the frequency dependent effects using the lionosphere free combination P Le gt Free smoothed code is not affected by either spatial or temporal gradients but is 3 times noisier than the DFree or the in the Single Freq smoothed code 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 113 LWP3 lono Divergence on Smoothing NENNT O 1 Multipath and measurement noise assessment on raw code measurements The C1 code multipath and receiver noise can be depicted using the following combination that removes all frequency dependent a
17. 11 12 13 14 15 16 17 18 19 29 gLAB linux input cfg meas cfg input obs 15dt1260 090 input nav 15dt1260 09n pre dec 0 grep GPS gt 15dt meas sec LI2 elev 2 From 15dt9 meas file generate a file with the following content 1 gt 3 gawk if 6 01 print 4 6 287 14 34 084 18 27 797 20 7 15dt meas gt LI2 dat Note although the elevation is not needed for this exercise and thence the broadcast orbit file 15dt1260 09n it is computed because it will be useful for a further study 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 124 LWP4 Second order lonospheric Effect 3 Plotting results graph py f LI2 dat x1 y2 1 LI2 125 xn 29700 xx 49200 yn 5128 yx 5134 x1 time s yl meters of L1 delay mE Discussion QUETETUTTT ERuss 1 What is the order of magnitude of the second order ionospheric effect 2 Ils the pattern seen in the figure due to the 2nd order ionospheric effect or it is related to other phenomena of L1 delay meters Hint Add the elevation in the previous plot and explore If the pattern could be related to the antenna phase centers of the different signals 20000 35000 40000 45000 time s e GE UPC J Sanz amp J M Juan 125 oe up o Br Astro RR ge chnical University of Catalon LWP4 Second order lonospheric Effect 3 Plotting results with the e
18. 97 921L Op 143 00 C p 11 212 PC2 6 964C 78 318C 72 354C 5 Ope 106 80 C p nll 27 12 gt PII 12 110C 182 385C 170 275C op 249 80 C p y I 2 y A I2 PI2 3 073C 52 033C 48 960C o 71 50 Note h Jn 194fs Sp Sesy 118 fo Js fees 116 5f gAGE UP J Sanz amp J M Juan Research group of Astronomy amp Geomatics Technical University of Catalonia 141 HW2 Combinations of three frequency measur A First order and Second order lono Free combination analysis Questions analyse the suitability of the combinations PC2 and LC2 obtained in the previous exercises to navigate 1 Calculate the theoretical noise of the first order ionosphere free combinations PC and LC and compare with the noise of first order and second order ionosphere free combinations LC2 and PC2 found in the previous exercise Consider the Galileo signals E1 E7 and E1 E7 E8 Which combinations are more suitable to navigate the PC LC or PC2 LC2 2 Using files gien327sw 090 and orb15591 sp3 make a plot to compare the code noise of the first order ionosphere free combination of Galileo signals E1 E7 and the first order and second order iono free combination of signals E1 E7 E8 3 The same questions using files 15dt1260 090 15dt1260 09n for the GPS signals L1 L2 L5 gA GE UPC oe up o Br Astro RR ge chnical University of Catalon
19. Bending in RO 1 Run the program RO per1 over the file RO obs and generate the combinations of measurements indicated in the previous table Note the results are provided for the occultation associate to PRN 02 and CODE 1241 that corresponds to LEO 4 and Antenna 1 This is hard code in the program but can be changed as well Execute the file RO obs must be available in the directory RO perl gt bending dat 2 Discuss next plots amp gA GE UPC J Sanz amp J M Juan 99 Research group of Astronomy amp Geomatics Technical University of Catalonia LWP2 Atmospheric Bending in RO P1 Plot DDdL1 DDdRho and DDdL2 DDdRho as a function of time and discuss the results found graph py f bending dat x 12 11 y4 1 DDdL1 DDdRho f bending dat x 13 11 y4 1 DDdL2 DDdRho xn 0 4 xx 4 COSMIC 4 Antenna 1 PRNO2 fF pparbp Q1 Justify the discrepancy DDdL2 DDdRho between the two plots Answer 1 6500 z diiad i The curves in the plot show phase excess rate due the effect of both 6500 ionosphere and troposphere e As the bending in the ionosphere is op DRE a frequency dependent effect the contribution is different for each 6300 06 05 0 15 36 25 30 35 4 0 signal L1 and L2 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 100 LWP2 Atmosph
20. C1 100s smoothing and divergence of ionosphere graph py f upc3 C1 s l1 C1 Raw mn f upc3 C1s100 s cl r 1 C1 SF smoothed NT M Ii AN Mtl xn 35000 xx 40000 yn 5 yx 5 I x1 time s yl meters t PRN 3 C1 100s smoothing and iono div 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 115 LWP3 lono Divergence on Smoothing 3 Using 2 frequency carriers It is possible to generate a combination with the same ionospheric delay the same sign as the code to avoid the code carrier divergence Ea 2 prvee L 2a L L p l1 B 6 R f eu 60 a Apply the Hatch filter to compute the DFree smoothed code gawk BEGIN Ts 100 if NR gt Ts n Ts else n NR C1f 11 L1f 14 2 1 55 14 16 C1fs C1f n n 1 n C1fs L1f Lip Lip L1f print 4 C1fs L1f 21 3 upc3 meas gt upc3 C1DFs100 PRNO3 C1 1005 smoothing and divergence of ionosphere Cl Raw b Plot results and compare with the row C1 code vred a s C1 DFree smoothed 100s graph py f upc3 C1 s 1 C1 Raw f upc3 C1s100 s cl r 1 C1 SF smoothed 100s f upc3 C1DFs100 s cl g 1 C1 DFree smooth 100s xn 35000 xx 40000 yn 5 yx 5 xl time s yl meters 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 116 LWP3 lono Divergence on
21. Catalonia Research group of A echnical Unive Example 1 gLAB processing In command line NEU positionin g error SPP Fu ll mo ode Execute in a single line gnuplot can also be used graph py f gLAB out x4 y18 s c 1 OUTPUT 1 North error f gLAB out x4 y19 s c 1 z OUTPUT 1 East error f gLAB out x4 y20 s c 1 OUTPUT 1 UP error yn 20 yx 50 xl time s yl error m t NEU positioning error SPP Full model graph py f gLAB out x4 y20 s c 1 OUTPUT 1 Full model f gLAB1 0ut x4 y20 s c 1 OUTPUT 1 No Iono cl yn 20 yx 50 x1 Time s yl Up error m t Vertical positioning error SPP graph py f gLAB1 out x19 y18 so c 1 OUTPUT 1 No Iono clr f gLAB out x19 y18 so c 1 OUTPUT 1 Full mod cl b x1 East error m yl North error m xn 20 xx 20 yn 20 yx 20 t Horizontal pos error SPP graph py f gLAB out x4 y25 s c 1 MODEL EET mE f gLAB out x4 y 10 9 s c 1 INPUT cl r xl time s yl meters yn 0 yx 40 t Ionospheric Combination Klobuchar STEC e All PRN Ple P2 P1 d hul 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia Example 1 gLAB processing In command line bloc 2ndorde
22. J Sanz amp J M Juan 142 HW2 Combinations of three frequency measur Answer to question A 1 Calculate the theoretical noise of the first order ionosphere free combinations PC and LC and compare with the noise of first order and second order ionosphere free combinations LC2 and PC2 Assuming uncorrelated and with the same o or o y Pi Pj ae PC O par 7 5 y l 7 y l dem y 7 fil f 2 y Li Lj y l LC y 1 Ore y l OL Thence for the Galileo signals C1 C7 and C1 C7 C8 it follows Open 72 9190 pc 106 800 Results show that the LC2 and PC2 are two orders of magnitude noisier than the 2 81 O 106 80 O renn OL AE original measurements Thus they are f f 154 118 1 703 not suitable to navigate gA GE UPC J Sanz amp J M Juan 143 rch pe upo or As tronomy amp Geomatics m chnical Un dius of Catalo HW2 Combinations of three frequency measur Answer to question A 2 Make a plot to compare the code noise of the first order ionosphere free combination of Galileo signals E1 E7 and the first order and second order ionosphere free combination of Galileo signals E1 E7 E8 1 Using the configuration file meas cfg READ the RINEX and generate the MEAS message EG MEAS YY Doy sec GAL PRN el Az N list C1B L1B C1C L1C C7Q L7Q C8Q L80 Execute 123 4 5 6 78 9 10 11 12 13 14 15 16 17 18 gLAB linux input cfg meas cfg input obs gien327sw 90
23. L2 in meters of L1 L2 delay where the impact parameter must be sorted from larger to lower value gt Only measurements with negative elevation must be given i e occultation The output data is n p n L1 L2 n Ne n where Ne is given in e m p Tangent point LEO elev O impact parameter Note the Impact parameters can be s to GPS computed from the LEO elevation elev and its distance to Earth s centre ri go by see figure P rng Cos elev e GE UPC J Sanz amp J M Juan 90 oe up o Br Astro RR ge chnical University of Catalon Geocenter LWP1 Electron Density Profile from RO Exercise The file RO obs contains the following fields see Ex 5 YY DoY HH HH CODE PRN elev r LEO AR LEO DEC LEO r GPS AR GPS DEC GPS L1 L2 L1 L2 arc deg km Deg Deg km Deg Deg cycles m 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 Using the file RO obs select the measurements with negative elevations for GPS satellite PRNO2 the LEO 4 and antenna 1 and generate the input file p n L1 L2 n for program abel perl Selecting CODE 1241 and PRN 2 and negative elevations ocult grep 1241 RO obs gawk if 5 02 amp amp 6 lt print 0 gt ro tmp Generating the input file gawk printf 49 5f 7 5f n 7 cos 6 3 14 180 15 ro tmp gt abl tmp Sort the file by impact parameter sort nr k 1 abl tmp gt abl dat 9 gAGE UPC Rese
24. LWP2 and HW1 plots for the GPS signals see R 1 Answer GNSS signals at different frequencies e g L1 L2 L5 have in general different APCs and they can produce an elevation dependent effect in the LI2 combination Indeed referring the geometric range to a common reference the Antenna Reference Point ARP and assuming only APC in the UP component it follows see figure Dr P pP ApP where Ap A sing Thence the APC correction to apply to LI2 combination APC LZ iS gi by SP TUNE gt or PIS 3 QA Sin bias k k APC correction term where the bias term Is due to the carrier ambiguities ARP FEE Note the satellite APC is not considered as the deviation angle anz M Juan 132 from the direction pointing to the Earth centre is less than 142 Ge HW1 APC effect on the LI2 combination Question 2 Knowing the L1 and L2 signals APCs estimate the L5 APC a The file 15dt 1260 090 has been collected by a TRIMBLE NETR8 receiver with TRM59800 00 antenna According the ANTEX file igs05 1525 atx the antenna phase centers of L1 and L2 are given by TRM59800 00 TYPE SERIAL NO G L START OF FREQUENCY 0 37 NORTH EAST UP GO2 START OF FREQUENCY 0 09 NORTH EAST UP Taking into account previous results estimate the APC of L5 signal Note Neglect the North East components against the UP component According previous table gt A 0 09002m A 0 11989m gA GE UPC
25. Large positioning errors mainly in vertical appear when neglecting ionospheric corrections 24 J Sanz amp J M Juan Example 1 2 frequency lonosphere free solution From previous configuration set following options gLAB Version 2 0 0 gLAB Version 2 0 0 Q esa gLAB 9 gAGEUPC ur m httpi www gagees Preferences About Preferences Positioning Analysis Modelling Options Measurements amp Satellite clock offset correction Positioning Analysis Troposhere Selection Estimate Troposphere Consider satellite movement during signal flight time Pseudorange M Consider Earth rotation during signal flight time Pseudorange Carrier phase Satellite mass center to antenna phase center correction Available Frequencies Le m Receiver antenna phase center correction D 1 S ad b l e i Receiver antenna reference point correction eee ik Relativistic clock correction orbit excentricity Iono correct Iono free PC Kinematic Q Ps Other options Coordinates le8 m M P1 Cl correction Flexible 2 le8 m Backward filtering p1 D2 TGDS Receiver Clock 9e10 m 9e10 m Wind up correction Carrier phase only Solid tides correction m Tropospheric correction UNB 3 Nominal Simple Mapping 7 a n d Parameters P1 P2 correction Relativistic path range correction Save Config Show Config SPP Template PPP Template Run gLAB Show Output Save Config S
26. Smoothing 4 Generate the ionosphere free combinations of code and carrier measurements to compute the lonosphere Free IFree smoothed code B rm B yL L 7 C P i I Free C y 1 Free C y 1 e gawk BEGIN g 77 60 2 pc g 13 15 g 1 lc g 14 16 g 1 print 3 4 pc 1c 3 5 upc3 meas gt upc3 PC Apply the Hatch filter to compute the IFree smoothed code gawk BEGIN g 77 60 2 pc g 13 15 g 1 lc g 14 16 g 1 if NR gt 100 n 100 else n NR ps 1 n pc n 1 n ps lc lcp lcp lc print 4 ps 1c 3 5 upc3 meas gt upc3 PCs100 e Plot results and compare with the unsmoothed PC graph py f upc3 PC s l IFree raw f upc3 PCs100 s cl black 1 Ifree 100s xn 35000 xx 40000 yn 5 yx 5 xl time s yl meters 8g Q J Sanz amp J M Juan 117 Research group of Astronomy amp Geomatics Technical University of Catalonia LWP3 lono Divergence on Smoothing 5 Repeat previous plots but using N 360 N 3600 and compare results Plot also the ionospheric delay from L1 L2 see more details in R 1 T 100s T 360s T 3600s PRNO3 C1 100s smoothing and Bvargencs of ionosphere PRNO3 C1 360s smoothing and divergence of ionosphere PRNO3 C1 3600s smoothing and divergence of ionosphere STEC PRNO3 shifted C1 C1 ClRaw Cl Raw 1 Raw 4 C1 s 1 SF smoothed 1005 C1 SF smoo
27. as an ideal gas Its effects vary with the temperature and atmospheric pressure in a reasonably predictable manner and it is responsible for about 90 of the delay e A wet component caused by the water vapor condensed in the form of clouds It depends on the weather conditions and varies faster than the hydrostatic component and in a totally random way For high accuracy positioning this component must be estimated together with the coordinates and other parameters in the navigation filter AGE UPC Lan Mining E AC ku p J Sanz amp J M Juan Technical Un Ha 43 OVERVIEW A Introduction A The gLAB tool suite Examples of GNSS processing using gLAB Laboratory session organization LABORATORY Session A Starting up your laptop A Basic Introductory lab exercises lono amp Posit SF storm TIDs Medium Laboratory Work Projects LWP1 to LWP4 A Advanced Homework amp g J Sanz amp J M Juan 44 Research group of Astronomy amp Geomatics Technical University of Catalonia n Laboratory session organization A The laboratory session is organized as an assisted activity where a set of exercises must be developed individually or in groups of two A As they are conceived as self learning work a detailed guide is provided in the slides pdf file to carry out the exercises A A notepad file with the command line instructions is also provided to help the sentence writing doing copy
28. e Al m of LW DA IS to bu Id d aar EEE and LE order DLE comb APC correction applied n z LI2 125 combination of carriers measurements at three different frequencies to remove the geometry and the first order ionosphere effects meters of L1 delay Once this combination is dr ni uim obtained its suitability to depict the second order ionospheric effects will be analyzed e c J Sanz amp J M Juan 120 Research group of Astronomy amp Geomatics Technical University of Catalonia The assessment will be based on actual GPS measurements at frequencies L1 L2 and L5 LWP4 Second order lonospheric Effect First order lonospheric delay As commented before about the 99 9 of the ionospheric N 40 7 delay depends on the inverse of squared frequency where STEC is the number of electrons per area unit STEC N ds along ray path STEC Slant Total Electron Content 4 Its effect on code and carrier is equal but with opposed sign I 1l carr code Second order lonospheric delay Previous expression comes from a simplification of the ionospheric delay derivation where the dependence of the refraction index with the magnetic field B is neglected If such dependence is taken into account higher order terms appears but they represent less than 0 1 of total effect l The second order ionospheric term is given by 2 Fa N B cos ds gt L2Zear TT code n g
29. generated from files http cosmic io cosmic ucar edu cdaac podObs 2006 253 004 01 01 rnx leoorb 2006 253 004 01 2009 2650 sp3 igs13920 sp3 9 gAGE UPC J Sanz amp QM Juan 66 Research group of Astronomy amp Geomatics Technical University of Catalonia More information can be retrieved from occultation measurements For instance e Electron Density Profile of the lonosphere LWP 1 e Phase excess rate which is related to the bending of ray LWP 2 meters of L1 L2 RO L1 L2 COSMIC 4 Antenna 1 PRNO2 4 2 4 3 4 4 4 5 time H 4 6 Given that session time is limited to 2h participants who feel comfortable using gLAB can skip part of the next basic exercises Ex3 Ex6 and jump to the Laboratory Work Projects LWP There if you prefer you can jump to slide 487 and choose one from the four LWPs amp g J Sanz amp J M Juan 68 Research group of Astronomy amp Geomatics Technical University of Catalonia no of Ex 3 Solar Flare October 28 2003 On October 28 2003 an intense solar eruption a Solar Flare was detected around 11h UT in an active region which had grown one of the largest sunspots ever seen by the SOlar Helioscopic Observatory SOHO It appeared as a bright spike in the SOHO ultraviolet images This sudden enhancement of the solar radiation in the X ray and extreme ultra violet band produced a sudden increase in the ionospheric e
30. input sp3 orb15591 sp3 gien meas 2 From gien327 09 meas file generate a file with the following content sec PC LC PC2 LC2 select the Galileo satellite PRN16 as well 1 2 3 gawk if 5 GAL amp amp 6 16 print 4 11 1 42 15 11 1241 42 12 16 6 96 11 12 78 32 15 16 72 35 17 518 gien meas gt gienPc2Lc2 dat Note The following expressions have been used to compute PC and LC Pi Pj 1 Li Lj 1 Pye R P B gt PCy F 1 42 P F LG 3 P y 1 y 1 7 1 y 1 e gA GE UPC Bac ku D J Sanz amp J M Juan 144 Research group of Astronomy amp Geomatics Technical University of Catalonia L Lj gt LC L 142 L L HW2 Combinations of three frequency measur 3 Plotting results graph py f gienPc2Lc2 dat x1 y3 l PC2 LC2 178 f gienPc2Lc2 dat x1 y2 1 PC LC 17 cl r yn 100 yx 100 xl time s yl meters lst order and 1st 2nd order ionosphere free combination noise ne As expected from the theoretical results ee the measurement noise and mutipath are i eee eee ee ee ee E ee strongly amplified in the PG2 combination Thence it makes no sense to remove the second order ionospheric effect which Is at the level of few centimetres using this noisier combination Note The theoretical noise values found are 70000 3000 80000 85000 Opcnn 2 8 lo O c21178 106 80 meters eo 198000 65000
31. list C1C L1C C1P L1P C2P L2P 1 2 3 4 5 6 7 8 9 10 11 xx xx 14 15 16 idretter gLAB linux input cfg gLAB configuration file gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan Example 2 lonospheric delay analysis 0000 2 Manipulate the file with the easy amp powerful awk or gawk programming language to compute the combinations of measurements P1 L1 P2 12 Id YY Doy sec GPS PRN el Az N list C1C L1C C1P L1P C2P L2P gt From coco meas file 4 5 3 4 5 6 7 8 9 10 11 xx xx 14 15 16 Compute different ionospheric combination of codes and carriers and generate the obs txt file containing the fields PRN sec P2 P1 P2 L2 5 09 P1 L1 3 09 L1 L2 Elev 10 gawk print 6 4 15 11 15 16 5 09 11 14 3 09 14 16 7 10 coco meas gt obs txt L1 L2 14 16 ner ml J Sanz amp J M Juan 36 gA GE UPC oe up o Br Astro RR ge chnical University of Catalon Example 2 lonospheric delay analysis 3 Plot results with graph py you can use the gnuplot as well PRN sec P2 P1 P2 L2 5 09 P1 L1 3 09 L1 L2 Elev 10 gt Fromiobs txt file 1 2 3 4 5 6 7 Show in the same plot the following iono delays for satellite PRNO1 P2 P1 P2 L2 5 09 P1 L1 3 09 L1 L2 Elev 10 lonospheric Refraction code and carrier phase Condition Fields to plot 2 x axis Select PRNO1 from 1 st
32. o 9 gAGE UPC 139 J Sanz amp J M Juan Research group of Astronomy amp Geomatics Technical University of Catalonia HW2 Combinations of three frequency measur Note The previous expressions correspond to A p LC2 First order and Second order lonosphere Free combination A I1 LII Geometry free and Second order lonosphere Free combination I2 LI Geometry free and First order lonosphere Free combination Hint Let y Ax the previous equations system where Y IL L L x p 11 12 Y andA is the associated matrix evaluated at the given frequencies Thence the coefficients of LC2 LI LP are given by A The sigmas are the square root of diagonal elements of matrix A A The same question for GPS codes C1 C2 C5 Show that C p Il 212 PC2 7 081C 26 130C 20 050C Om 33 70 C p yul 2544 12 I PII 12 368C 60 215C 47 847C 5 Op 11 90 C p y 11 2y7 12 PI2 3 144C 17 042C 13 899C Eo LL gAGE UP 140 J Sanz amp J M Juan Research group of Astronomy amp Geomatics Technical University of Catalonia HW2 Combinations of three frequency measur a The same question for Galileo carriers E1 E7 E8 and codes C1 C7 C8 Show that L p IL 12 LC2 6 694L 78 318L 72 354L Om 106 80 L p y y I2 gt LII 12 110L 182 385L 170 275L 0 249 80 L P Vell 1712 LI 6 146L 104 067L
33. varying ionosphere induces a bias in the single frequency smoothed code when it is averaged in the smoothing filter This effect is analysed as follows Let Where P includes all non dispersive terms geometric range clock offsets troposphere and represents the frequency dependent terms ionosphere and DCBs B Is the carrier ambiguity which is constant along continuous carrier phase arcs and account for code and carrier multipath and thermal noise thence Note the carrier noise 4 IS P L 21 B X 21 Code carrier divergence neglected against code noise substituting P L in Hatch filter equation see the previous slide 110 P k L k P L p k I By 21 B k p k 1 0 2 1 00 gt P p 1 bias 0v Au M bias where 0 is the noise term after where being the ambiguity term B a constant bias thence smoothing B B and cancels in the previous expression 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 111 LWP3 lono Divergence on Smoothing Raw assessment of the induced bias on P smoothed code by ionosphere Let assume a simple model where the STEG vary linearly with time L t 2I Irt where 7 is the Hatch filter smoothing time constant i e 7 N in previous eq Exercise Proof the previous statement Solution Letbe f t 1
34. x2 y4 1 94 EL f PI txt c 1 04 x2 y3 so 1 94 f PI txt c 1 04 x2 y3 so 1 4 xn xx 144 xn 70 xx 78 s IONO Halloween Storm 280ct 02Nov garl Lat 40 Lon 119 ALL P2 P1 PRNO4 ELEV e e PRNO4 P2 P1 meters of L1 L2 delay meters of L1 L2 delay 40 60 100 Hours from 2003 Oct 28th Oh GPS time Hours from 2003 Oct 28th Oh GPS time gAGE UP Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 80 Ex 6 Travelling lonospheric Disturb Travelling lonospheric Disturbances TIDs are understood as plasma density fluctuations that propagate through the ionosphere at an open range of velocities and frequencies The trend of such fluctuations can be seen from the geometry free combination of GPS carrier measurements L L L Some authors distinguish between Large Scale TIDs LSTIDs with a period greater than 1 hour and moving faster than 0 3 km s and Medium Scale TIDs MSTIDs with shorter periods from 10 minutes to 1 hour and moving slower 0 05 0 3 km s The LSTIDs seem to be related to geomagnetic disturbances i e aurora ionospheric storms etc The origin of MSTIDs seems to be more related to meteorological phenomena such as neutral winds eclipses or solar terminator that produces Atmospheric Gravity Waves AGW being manifested as TIDs at ionospheric heights due to the collision between ne
35. 0 30000 isum sio 60000 70000 80000 90000 200j l15 10 5 6 5 10 is 20 Ime S Fast error m 20 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 26 Example 1 lono effects on single freq Posit lonospheric delay The ionosphere extends from about 60 km over the Earth s surface until more than 2000 km with a sharp electron density maximum at around 350 km The ionospheric refraction depends among other things on the location local time and solar cycle 11 j years First order 99 9 ionospheric delay 1 depends ji 203 STEC AG on the inverse of squared frequency 7 where STEC is the number of electrons per area unit along ray path STEC Slant Total Electron Content STEC N ds so I Two frequency receivers can remove this error SOUrce up to 99 9 using ionosphere free combination f Pl f P2 PC of pseudo ranges PC or carriers LC T Single frequency users can remove about a 50 70 of the ionospheric delay using the Klobuchar model whose parameters are broadcast in the GPS navigation message e gA GE UP Bac kup J Sanz amp J M Juan 2 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 1 lono effects on single freq Posit Annex gLAB processing in command line 9 gAGE UPC stronomy amp Geomatics 0 J Sanz amp J M Juan rsity of
36. 000 15 input nav brdc1250 00n pe Example 1 NEU Position Error plot from gLAB out gLAB Version 2 0 0 fesa gEABs Ed NEU mu E SPP Full model rst mars N E plot template CO nfiguration 3 North error East error UP error Horizontal positioning error Zenith Tropospheric mm i inati FULL SPP model gAGE UF http www gage es lonospheric combinations DilutiBn Of PreWision Satellite skyplot Carrier phase ambiguities Measur Multipath Noise Mogel componen prefit residuals Postfit residuals Orbit and Clock comparison Global Grafbhic Parameters Title N error m positioning error X label time s Y label error m Clear v Autoffhatic Limits X min X max Y min Y max nd ide Din Configuratig z Source File gLAB out Examine Dotted Line v Condition OUTPUT v Fi 1 OUTPUT Blue v 209 10000 20000 30000 40000 50000 60000 70000 80000 90000 X Colmes sec Y Column DSTAN v 18 Label North error time s Equivalent command line sentence graph py f gLAB out x4 y18 s c 1 OUTPUT f gLAB out x4 y19 s c 1 OUTPUT f gLAB out x4 y20 s c 1 OUTPUT l North error l East error 1 UP error yn 20 yx 50 xl time s yl error m
37. 84 Research group of Astronomy amp Geomatics Technical University of Catalonia Ex 6 Travelling lonospheric Disturb Execute in a single line sodb PRN14 graph py f sodb dLi meas s f mhcb dLi meas s l mhcb PRN14 f monb dLi meas s l monb PRN14 xn 55500 xx 57000 yn 0 05 yx 0 07 x1 time s yl Detrended STEC meters of L1 L2 delay t MS Travelling Ionospheric Disturbance MSTID propagation T ureuay ional 4a ies SN MS Travelling lonospheric Disturbance MSTID propagation Area uU V r Gori San Francisco sodb PRN14 mhcb PRN14 monb PRN14 0 06 San Francisco Bay South San Francisco 0 04 a Buringame b san Mateo 0 02 nS D Redwood G 4 ap N East 1 7 PaloAlto gt DI Palo Alto A qe de SONE Miptas me 0 00 0 02 Detrended STEC meters of L1 L2 delay 0 04 55600 55800 56000 56200 56400 56600 56800 57000 3 A A SN time 5 ME Ne nt S EM m gus OVERVIEW A Introduction A The gLAB tool suite 4 Examples of GNSS processing using gLAB Laboratory session organization LABORATORY Session A Starting up your laptop A Basic Introductory lab exercises lono amp Posit SF storm TIDs gt Medium Laboratory Work Projects LWP1 to LWP4 A Advanced Homework amp g J Sanz amp J M Juan 86 Research group of Astronomy amp Geomatics Techn
38. C1 C1C Sample INPUT 2006 200 0 00 GPS 19 1 23119003 9020 23119002 6110 23119004 0750 23119002 7507 23119004 0925 gLAB linux messages 7 g gLAB Version 2 0 0 i Em glab gage Example 2 lonospheric delay analysis Example 2 Depict the ionospheric delays for the different satellites in view from station amc2 e This is a simple exercise aimed to illustrate how to use gLAB to easily analyze GNSS measurements and their combinations gLAB will used to read the RINEX measurements file and to generate a text with the measurements provided in a columnar format more suitable to make plots e From text file compute and plot the onospheric delay for a given satellite by using code and carrier P L 24 I ambiguityl measurements at f1 f2 P L 2 amp l ambiguity2 J Sanz amp J M Juan 32 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 2 lonospheric delay analysis m The target is to generate 14 this plot to depict the T 12 ionospheric delay from Q code amp carrier data o 10 E o 8 H P KA I K LEM L L L I Ambiguity O E 4 i Q P L 24 I ambiguityl SE ej P L 2 l ambiguity2 Q 0 v 1 5 2 1 546 1 4 vil 4 2 2 0 10000 20000 30000 40000 50000 60000 70000 80000 90000 Va fi fr 054 120 UT seconds 1997 January 9th 9 gAGE UPC Research gr
39. Catalon J Sanz amp J M Juan 152 HW2 Combinations of three frequency measur Answer to questions Question C 1 Measurement noise From previous results Opp 11 50 o 22 20 seen at the beginning of Q g Cin 143 00 On 44 40 this exercise Thence the measurement noise Is strongly amplified in these combinations as In the previous case gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 153 HW2 Combinations of three frequency measur Questions C 2 and C3 LI2 Plots Following a similar procedure as in previous cases see detailed instructions in the notepad Galileo E1 E7 E8 signals GPS L1 L2 L5 signals Carrier Geometry free and 1st order iono free comb I5dt126 LI2 125 Elev 10 Carrier Geometry free and 1st order iono free comb gien327 Elev 10 meters of L1 delay e meters of L1 delay j 30000 35000 40000 45000 80000 85000 time s 60000 65000 70000 75000 time 5 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 154 HW2 Combinations of three frequency measur Comment 1 In previous plot of GPS LI2 combination a clear pattern of about 2m appears See this plot generation in LWP2 Geometry free and first order iono free combination meus LI2 125 This pattern is an elevation dependent
40. EE mt T Developed by gAGE Research group of Astronomy amp GEomatics Technical University of Catalonia UPC Authorship statement The authorship of this material and the Intellectual Property Rights are owned by J Sanz Subirana and J M Juan Zornoza These slides can be obtained either from the server http www gage upc edu or jaume sanz upc edu Any partial reproduction should be previously authorized by the authors clearly referring to the slides used This authorship statement must be kept intact and unchanged at all times e gA GE UPC J Sanz amp J M Juan 2 Research group of Astronomy amp Geomatics Technical University of Catalonia OVERVIEW gt Introduction A The gLAB tool suite A Examples of GNSS Data Processing using gLAB Laboratory session organization LABORATORY Session A Starting up your laptop A Basic Introductory lab exercises lono amp Posit SF storm TIDs A Medium Laboratory Work Projects LWP1 to LWP4 A Advanced Homework Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 3 Introduction A This tutorial is devoted to analysing and assessing different issues associated with GNSS signal propagation effects in the atmosphere A The laboratory exercises will be developed with actual GPS measurements and processed with the ESA UPC GNSS Lab Tool suite gLAB which is an interactive software pac
41. F storm TIDs A Medium Laboratory Work Projects LWP1 to LWP4 A Advanced Homework e g J Sanz amp J M Juan s Research group of Astronomy amp Geomatics Technical University of Catalonia The gLAB Tool suite A The GNSS Lab Tool suite gLAB is an interactive multipurpose educational and professional package for GNSS Data Processing and Analysis A gLAB has been developed under uiis ESA AE m contract N P1081434 x Main features High Accuracy Positioning capability Fully configurable Easy to use e Access to internal computations 9 gAGE UPC Researc h group of Mii uos du Geomatics Technical University of Catalo J Sanz amp J M Juan 6 The g LAB Tool suite A Students Newcomers Easy to use Intuitive GUI e Explanations Tooltips over the different GUI options Guidelines Several error and warning messages Templates for pre configured processing Save Config SPP Template PPP Template Run gLAB A Professionals Experts Powerful tool with High Accuracy Positioning capability e Fast to configure and use Templates and carefully chosen defaults Can be executed in command line and included in batch processing File Edit View Terminal Help g4 workspace edunav gt gLAB linux input obs test madr2000 060 input sp3 test igsl3843 sp 3 input ant test igsO5 atx e gA GE UPC J Sanz amp J M Juan f Research group of Astro
42. FIT Messages v Print FILTER Messages model as was set in the EE default configuration Output Fil Examine Set output file as gLAB1 out SPP Template PPP Template Run gLAB 3 Equivalent command line sentence GLAB1 0ut Messages v Print INFO Messages Save Config gLAB linux input cfg gLAB pi NoIlono cfg 18 input obs ramo1250 000 input nav brdc1250 00n Example 1 NEU Position Error plot from gLAB1 out gLAB Version 2 0 0 esa g5 En NEU error ELLE No lono corr 4th May 2000 mi ma NEU plot template configuration ZEN fz North error n LAB1 t East error g K ou e UP error Horizontal positioning error Zenith Tropospheric mm lonospheric combinations L 3 No lono correction gAGE UPC http www gage es EE ee ne ee re ee DilutiBn Of PreWision Satellite skyplot Carrier phase ambiguities Measur Multipath Noise Mogel componen prefit residuals Postfit residuals Orbit and Clock comparison m 20L E Global Graphic Parameters o Title N positioning error X label time s Y label error m Clear D 10 i v Autoffhatic Limits X min X max Y min Y max odd plotis Configuratigg 0 Plot Nr 1 Plot Nr 2 Plot Nr 3 Plot Nr 4 Source File LAB out Examine Dotted Line vi ET EN UEM NS Se EN SME SG SE E
43. Francisco Bay BN Baywood Park e Palo Alto Palo Alto rgoreuay gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 83 Ex 6 Travelling lonospheric Disturb Exercise Execute In a single line a gLAB linux input cfg meas cfg input obs mhcb2910 010 gt mhcb meas gLAB linux input cfg meas cfg input obs monb2910 010 gt monb meas gLAB linux input cfg meas cfg input obs sodb2910 010 gt sodb meas b gawk gawk gawk c gawk gawk gawk Reading RINEX files Selecting satellite PRN16 if 6 14 print 0 mhcb meas gt mhcb 14 meas if 6 14 print 0j monb meas gt monb 14 meas if 6 14 print 0 sodb meas gt sodb 14 meas v Vv Detrending on the geometry free combination L1 L2 for i i lt 21 i t i t i 1 1 i 1 i 1 t 21 4 1 21 14 16 if NR gt 21 tt t t 10 t 20 if tt 0 print t 10 1 10 1 0 1 20 2 mhcb 14 meas gt mhcb dLi meas for 1 0 1 lt 21 i t i t i 1 1 i 1 i 1 t 21 4 1 21 14 16 if NR gt 21 tt t t 10 t 20 if tt 0 print t 10 1 10 1 0 1 20 2 monb 14 meas gt monb dLi meas for 1 0 1 lt 21 i t i t i 1 l1 i 1 i 1 t 21 4 1 21 14 16 if NR gt 21 tt t t 10 t 20 if tt 0 print t 10 1 10 1 0 1 20 2 sodb 14 meas gt sodb dLi meas 9 gAGE UPC J Sanz amp J M Juan
44. IMilDf alttetdrrer rn ds Se MMITLLL easy LI SU eb P I TLLA tee d BSD I Pees eol e I TELLE LEE ese T Vessiirttt E PPP MARI YJ LEE E E EOL e bee g ALL OP poe daba T eetteses i e ePRNO3 wt eee er fr TEN e B Su io RE Po lee e oe AN n S P H r DP Me eva MT ny i WAS usine d e p p A aan b P Pps e pt ur S ut ru D SG 2288 57 TON FET ANTE ROS EE 9 CX WS o6 E p Lips e n f st k al ee op oe I ERETEETT eT hd TY guesses Beg eoo o AP Js ete y Blue INPUT 1 INPUT Condition 0 5 0 0 South 0 0 1 0 0 5 0 5 South PRN Pi P2 P1 e Lab 10 9 y um Y Col EC x Column Satellite skyplot Plot oky plots at different latitudes e cc a o o je e PRN3 1 0 PPT ee TER ON OP a p g MD Mame RUN d c ee as All sat e ePRNO3 ste Oo den sa evo x kor rige pre aeosvecre d mes dm Re ME ahahaha at Lot bb ETER aut ee ef ET ee ae QE UMS Min M ttti enn S oe s P Lese ARM Ln Al ge n TE T ad ue et oo CA b ed esses SHTDIIHUBHEPL i 1 gee os occas C rd LT T d vi Ugeteee eee uf eene nej g NUS a ss Y eye YE vette a ov Fae pe ie
45. N Condition OUTPUT 5 Fi 1 OUTPUT Blue ue ims MR p l l i X Col CU REESE 0 10000 20000 30000 40000 50000 60000 70000 80000 90000 Rye SEC Y Column DSTAN v 18 Label North error time s Equivalent command line sentence graph py f gLAB1 out x4 y18 s c 1 OUTPUT 1 North error f gLAB1 0ut x4 y19 s c 1 OUTPUT 1 East error f gLAB1 out x4 y20 s c 1 OUTPUT 1 UP error yn 20 yx 50 x1 time s yl error m t NEU positioning error SPP No Iono Corr 9 gAGE UPC J Sanz amp J M Juan 19 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 1 VPE plot from gLAB out gLAB1 out gLAB Version 2 0 0 gLAB Version 2 0 0 Vertical positioning error SPP Full model 20 No lono corr 20 dil Cesa gJEAB Gesa fh i Ng Analysis NL NAN Pretence o Vel Positioning Analysis en Abou M Templates Positioning Analysis Up error m o Templates als NEU positioning error Horizontal positioning error Zenith Tropospher EWIE ME NEU positioning error Horizonte onospheric combinations Dilution Of Precision Satellite skyplot Carrier phase aml E Dilution Of Precision Sat 5 ur Multipath Noise Model components Prefit re
46. P1 P2 correction RINEX Nav File Print PREFIT Messages M P1 Cl correction Flexible v amp Print POSTFIT Messages Wind up correction Carrier phase only Print FILTER Messages Solid tides correction Print OUTPUT Messages Relativistic path range correction Save Config SPP Template PPP Template Run gLAB Show Output Save Config SPP Template PPP Template Run gLAB Wow Output Equivalent command line sentence gLAB linux input cfg gLAB p1 NoIono cfg input obs amc3030 030 input nav brdc3030 03n PENE samet 99 Ex 1 Processing with PC gLAB2 out 3 Reprocess the same files but with 2 frequency ionosphere free PC gLAB Version 2 0 0 Cesa Positioning Analysis Modelling Options amp Satellite clock offset correction P gL AB Q sAGEUF Preferences About M Consider satellite movement during signal flight time M Consider Earth rotation during signal flight time Satellite mass center to antenna phase center corre Receiver antenna phase center correction Disable lonospheric corrections and P1 7 P2 corrections Receiver antenna reference point correction lonospheric correction UNB 3 Nomige v Simple n orbit excentricity P1 P2 correction exible Wind up correction Carrier phase only Solid tides correction Relativistic path range correction Save Config SPP Template PPP Template Run gLAB Show Output Equivalent command line sentence gLAB linux
47. QYTUBTPAOFTAM 07 Ux rf Mari TINE I O u T O ZASLI O Pi or y QC O iV 0 INE ELE C e JJ i a T or YE f f A gt C AA KO FJ IDA 1 Fi ty of Catatonia UPU 153 uie 3 03 5 Applications Places LEE Computer bloc_2ndorder_w WordPad File Edit View Insert Format Help D ux amp d X Eel 1 a 3 4 5 6 7 69 10 11 i 13 14 15 16 17 168 H MEAS YY Doy sec GAL PRN el z N list C1B LIB C1C Lic CYO L7Q C8Q Lg glab s Home ii Plot results gt EE gawk if 5 GAL amp amp 6 16 print 4 11 1 42 15 111 12 1 42 12 1611 6 93 1 11 121 78 32 1 15 161472 35 Terminal graph py gien327PczLc2 dat x1 y3 1 PCz LC2 178 f gien327PcezLc2 dat x1 ye l PC LC 17 cl r yn i Generate MEAS file GNSS Formats f Note RINEX file UPC53620 080 does not provides P1 code H Nevertheless this is not a problem because gL B works in v f XE E EEC ETT gt Tica US M my For Help press F1 RUM To run a command as administrator user root use Sudo lt command gt See man sudo root for details glab gage fj j Y by 4 x NTT r s search group of Astronomy amp GEomatics T Y ara t nt Y 4 J y D E niversity of Catalonia UPC SN 9 gLAB Version 2 0 0 FI glab gage Era 54 OVERVIEW Introduction A The gLAB tool suite Examples of GNSS processing using gLAB La
48. REFIT Messages v Print POSTFIT Messages v Print FILTER Messages Y Print OUTPUT Messages Save Config Run gLAB gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia HEN The procedure explained here is applicable for all model terms iono tropo 1 In Modeling panel disable the model component to analyze in this example gLAB Version 2 0 0 gLAB esa Preferences About Positioning Analysis Modelling Options v Satellite clock offset correction vi Consider satellite movement during si vi Consider Earth rotation during sig Lo MN Disable lonospheric correction Satellite mass center to antenna pha Receiver antenna phase center correc Receiver antenna reference point corr lonospheric correction RINEX Nav File v orbit excentricity 3 Nominal v Simple Mapping v P1 P2 correction vi P1 C1 correction Flexible v Wind up correction Carrier phase only Solid tides correction Relativistic path range correction Save Config SPP Template PPP Template Run gLAB disable lonospheric correction Cesa Preferences About Positioning Analysis 2 Save as gLAB1 0 the associated output file Notice that the gLAB out 7 nT Mes Print MEAS Message file contains the processing 4 iieu Print EPOCHSAT Messages It t h t h r U L L v Print PREFIT Messages re S U S WI e v Print POST
49. S L1 L2 L5 O pri V20 2 m 2a O rij 526 O Cline J20 From previous results Ow 249 80 seen at the beginning of Cin 249 86 this exercise Thence the measurement noise Is strongly amplified in these combinations as In the previous case gAGE UPC ics et re eomatics ge chnical University of Catalon J Sanz amp J M Juan 149 HW2 Combinations of three frequency measur Question B 2 LI1 Pl1 Plots Following a similar procedure as in previous cases see detailed instructions in the notepad Galileo E1 E7 E8 signals Carrier Geometry free and 2nd order ionosphere free combination gien327 Code Geometry free and 2nd order ionosphere free combination gien 327 10 y g l LI2 178 PI1 178 ME E 200 KE i i PI 17 C arriers 5L HMM gt Iu a T z a z 0 5 0 ui qu 9 T Qi E E Se AN EET eee ea 40000 65000 70000 75000 80000 85000 60000 65000 70000 75000 80000 85000 im time 5 gAGE UP Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 150 HW2 Combinations of three frequency measur Question B 3 LI1 PI1 Plots Following a similar procedure as in previous cases see detailed instructions in the notepad GPS L1 L2 L5 signals Code Geometry free and 2nd order iono free comb 15dt126
50. amp paste A A set of questions is presented and the answers are also included in the slides A Teachers will attend individual or collective questions that could arise during exercise resolution J Sanz amp J M Juan 45 Research group of Astronomy amp Geomatics Technical University of Catalonia Laboratory session organization A The exercises are organized at three different levels of difficulty The student can choose the level of exercises to do although at least one introductory exercise is recommended to learn basic gLAB usage A 1 Basic Introductory exercises From 1 to 6 They consist of simple exercises to 1 Study the lonosphere effects on single frequency positioning 2 To depict the STEG on a Radio occulation 3 Solar Flare effect on TEC 4 5 TEC evolution during the Halloween Storm 6 To depict a TID propagaction Th f MN E f KN AEE i a 0000 75000 80000 85000 90000 950d BEN 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 46 COSMIC 4 Antenna 1 PRNO2 DDdL1 DDdRho DDdL2 DDdRho A minimum knowledge of UNIX e g awk would be desirable EE EE AM RN Laboratory session organization A 2 Medium Laboratory Work Projects LWP Four different LWP are proposed to choose from e LWP3 To study the code carrier ionosphere divergence
51. arch group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 91 LWP1 Electron Density Profile from RO 2 Run the program abel perl over the generated file abl dat to compute the electron density profile Ne p Sort the file by impact parameter cat abl dat abel perl gt Ne dat 600 Ne COSMIC 4 Antenna 1 PRNO2 3 The output file abl dat contains the fields n p n L1 L2 n Ne n Plot the electron density profile Ne as a function the impact parameter p and as a function of height above Earth s Plot1 As a function of p graph py f Ne dat x4 y2 x1 Ne e m3 yl p km Plot2 As a function of height 71007 m graph py f Ne dat x4 y 2 6370 x1 Ne e m3 yl h km heigh km 2 5 3 0 3 5 amp gA GE UPC J Sanz amp J M Juan 92 Research group of Astronomy amp Geomatics Technical University of Catalonia LWP1 Electron Density Profile from RO Questions 1 Taking into account the relationship between the electron density N and the critical frequency f e minimum frequency for a signal not being reflected R 1 f 8 98 N N ine m f in Hz Compute the minimum frequency of a signal to cross through the ionosphere Answer From previous plot the N of the maximum is 3 7E 11 e m Thence f 8 98v3 7 10 5 46MHz 2 Calculate the height where a signal with frequency f 4 MHz w
52. boratory session organization LABORATORY Session A Starting up your laptop gt Basic Introductory lab exercises lono amp Posit Solar Flair Halloween storm TIDs Medium Laboratory Work Projects LWP1 to LWP4 Advanced Homework amp g J Sanz amp J M Juan OD Research group of Astronomy amp Geomatics Technical University of Catalonia EX 1 Halloween storm October 2003 A severe ionospheric storm was experienced on October 29 31 2003 producing and increase of the electron density which led to large ionospheric refraction values on the GPS signals Such conditions were beyond the capability of the GPS Klobuchar model broadcast for single frequency users producing large errors in the SPS see details in R 3 Dual frequency users navigating with the ionospheric free combination of GPS signals were not affected by such ionospheric errors as the ionospheric refraction can be removed up to 99 9 using dual frequency signals amp g AGE UPC B k 56 Research group of Astronomy amp Geomatics a C u D J Sanz amp J M Juan Technical University of Catalonia Ex 1 Assessing lono effects on single freq pos Exercise Repeat the previous study of Example 1 to analyze the single frea solution but for the Halloween storm The following steps are recommended 1 Using files amc23020 030 brdc3030 03n compute with gLAB the following solutions 1 Solution with full SPS modeling Name outpu
53. ds STEC 1 1 Where c is the light speed B is the module of the earth magnetic field and o is the angle between B and the propagation direction Units are in the International System SI The value B 4 10 Tesla can be taken for magnetic field module at the pierce point of the satellite receiver ray with the ionospheric layer the lonospheric Pierce Point IPP assumed at about 400 km in height Note f 21575 420 10 Hz c 2 99792458 10 m s 1TECU 10 e Im 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 157 HW3 Theoretical exercises on 2 order iono Question 2 Assuming that the STEC can be estimated from smoothed code PI after removing the DCBs 1 with an accuracy better than 5 TECUs and assuming a negligible error in the magnetic field B value 2 show that the second order l2 effect can be calculated from the expression given in previous question 1 with an error less than 1 millimetre of delay in the L1 carrier Note 1 The DCBs can be obtained from the IONEX files available at the IGS site ftp cddis gsfc nasa gov gps products ionex 2 The subroutines International Geomagnetic Reference Field IGRF could be used as well to compute the magnetic field gA GE UPC oe up o Br Astro nomy amp Geomatics s chnical University of Catalonia J Sanz amp J M Juan 158 HW3 Theoretical exercises on 2 order iono
54. e Measurements modelling frr ul ll centimetre level accuracy centimetre Centimetre level accuracy level over 24h data is achieved PSP EEE eM aoe ce oS a in PPP static mode NEU sit ja 5 Ylabel error m Clear 1 1 1 1 1 Y Automatic Limits X min X max Y min Ymax mers nat torte 0 10000 20000 30000 40000 50000 Plot Nr I Plot Nr 2 Plot Nr 3 Plot Nr 4 Source File orAB out Examine Dotted Line w ti ie s Condition OUTPUT v NEU positioning error Static PPP North error East error UP error error m gLAB e seeure 0 60000 70000 80000 90000 v 12 OUTPUT Blue X Column 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 41 Example 3 Zenith Troposphere Delay estimation gLAB Version 2 0 0 Cesa http www gage es Preferences gater Em Zenith 19 ospheric Dela Ema gEABs00e re temere Dels LL About Positioning Analysis Templates NEU positioning error Horizontal positioning error Zenith Tropospheric Delay Carrier phase ambiguities lonospheric combinations Dilution Of Precision Satellite skyplo Measur Multipath Noise Model components Prefit r siduals Postfit residuals Orbit and Clock comparison Global Graphic Parameters Title Zenith Tropospheric Delay label time s gl Automatic Limi
55. ents a higher code carrier divergence error is induced by the ionosphere This is because the ionospheric refraction has opposite sign on code and carrier being its effect twice on the difference of code and carrier This double ionospheric refraction is propagated forward through the filter producing a bias The error induced by the code carrier divergence of the ionosphere on the single frequency smoothed codes Is assessed in this exercise for different filter lengths gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 109 LWP3 lono Divergence on Smoothing The noisy code P can be smoothed with the precise but ambiguous carrier L measurements his carrier smoothing can be done in real time applying the Hatch filter Pek P k Pk 1 Lao L k 1 n n where n k i k lt N and n Nif k2 N The algorithm is initialised with P FN The previous algorithm can be interpreted as real time alignment of carrier with code lonospheric combination meters Pek P k p 1 LO L k 1 n n 4 O 10000 20000 30000 40000 50000 60000 70000 80000 90000 UT seconds 1997 January Sth L k P L where 1 E Cid DE PU L k P Lun 2 P00 LK 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 110 LWP3 lono Divergence on Smoothing Time
56. eol dl the large drift at the bottom e dL1 dLc cancels common effects in both signals like troposphere and ionosphere But as there is no bending effect due to the ionosphere on Lc see 0 0 0 5 1 0 15 20 2 5 3 0 3 5 4 0 previous plot P2 thence the curves match for p 6420 km 6300 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 102 LWP2 Atmospheric Bending in RO mme P4 Plot dL2 dLc and DDdL2 DDdRho as a function of time Discuss results graph py f bending dat x10 y4 1 dL2 dLc f bending dat x 13 11 y4 l DDdL1 DDdRho x1 m L2 s yl p km xn 0 4 xx 4 y4 COSMIC 4 Antenna 1 PRNO2 6800 Q4 Justify the discrepancy between the two plots Answer 4 M RM MM TENE SEMINE MINE ME NM The same answer as in previous plot p km gus 0 0 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 m s 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 103 LWP2 Atmospheric Bending in RO P5 Plot dL1 dRho and dL1 dLc as a function of time Discuss results graph py f bending dat x 6 5 y4 1 dL1 dRho f bending dat x9 y4 l dL1 dLc x1 m L1 s yl p km t COSMIC 4 Antenna 1 PRN 2 COSMIC 4 Antenna 1 PRNO2 6800 Bibi ue dLi dRho fe
57. erent signals and amp is the elevation of ray a GE UPC NE D oe up o Br Astro RR ge chnical University of Catalon LWP4 Second order lonospheric Effect Question 2 Using the following values for the APCs 4 0 09 A 0 12 Ag 0 28 in meters see HW1 plot the previous expression and discuss results Now the combination to plot is LI2_corr 6 287 L 0 09 sin 34 084 L 0 12sin amp 27 797 L 4 0 28sin 1 Using previous file 15dt meas generate a file content gawk if 6 01 s sin 7 3 14 189 print 4 6 287 14 0 09 s 34 084 18 0 12 s 27 797 20 0 28 s 7 l5dt meas gt LI2corr dat 2 Plot results raph py f LI2corr dat x1 y 2 5133 s 1 LI2 125 f LI2 dat x1 y 3 10 1 Elev 10 s xn 29700 xx 49200 yn 7 yx 7 xl time s yl L1 meters gA GE UPC oe up o Br Astro nomy amp Geomatics s chnical University of Catalonia J Sanz amp J M Juan 128 LWP4 Second order lonospheric Effect Final questions 1 Discuss if the second order Geometry free and first order iono free comb APC correction applied ionospheric effect can be JE u21251 depicted from GPS data Elev 10 Hint 1 The expected 2 effect on a ground receiver is less than 2cm in L1 delay see HW3 2 The estimation noise of LI2 is Thence even in an ideal case without APC errors and no carrier multipath take for instance
58. eric Bending in RO mme CE EN P2 Plot DDdLc DDdRho as a function of time Discuss results graph py f bending dat x 14 11 y4 xn 0 1 xx 0 3 x1 m Lc s yl p km t DDdLc DDdRho COSMIC 4 Antenna 1 PRNO2 coo DDdLc DDdRho COSMIC 4 Antenna 1 PRNO2 Q2 Why there is no excess tg ray path for p 6420 km BTOD ecce eere UR Answerer 2 3 The ionospheric bending effect on Li pano see and L2 is proportional to the inverse x id of squared frequencies and cancels 6500 pee EE in the ionosphere free combination of 4 carriers Lc FE JE EE EE ecce There is only bending effect in Lc due to the troposphere which produces 6300 10 oos ooo oos olo oils 020 035 the path at the bottom of the figure 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 101 LWP2 Atmospheric Bending in RO P3 Plot dL1 dLc and DDdL1 DDdRho as a function of time Discuss results graph py f bending dat x9 y4 1 dL1 dLc f bending dat x 12 11 y4 l DDdL1 DDdRho x1 m L1 s yl p km xn 0 4 xx 4 y4 IN Q3 Justify the discrepancy COSMIC 4 Antenna 1 PRNO2 between the two plots dLl dLc DDdL1 DDdRho ANswer 3 3 DDdL1 DDdRho accounts for the 6800 6700 L4 isis contribution of ionosphere and E troposphere The troposphere produces amp
59. field File to plot f obs txt c e X2 y4 1 P2 L2 5 09 f obs txt c bn 01 x2 y5 1 P1 L1 3 09 f obs txt c 1 01 x2 y6 1 L1 L2 f obs txt c 1 01 x2 y7 1 Elev 10 yn 10 yx 15 x1 time s yl meters of L1 L2 delay versus 3 y axis of L1 L2 delay meters 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 3 Example 2 lonospheric delay analysis lonospheric Refraction code and carrier phase 15 P2 P1 P2 L2 5 09 P1 L1 3 09 L1 L2 Elev 10 10 P F HB I1 K L L I Ambiguity Zoom Lanlik Ads e ee zur carrier phase F L 20 I ambiguityl P2 P1 P2 L2 5 09 derer P L 2G I ambiguity2 L1 L2 E T Wo aut 929 4 1 KR t T e oe Ag LA owe 4 79 k T av n 8 te tap tee o ow bg ot p ae xf Kar ee T ag Tx AV dr Ri AA er Por e O on p ae PE DEE RIS fd gt i e meters of L1 L2 delay UL d 1 546 1 4 p Vai ya f f 54 120 meters of L1 L2 delay 12000 14000 16000 18000 20000 22000 24000 26000 28000 30000 time s 10 10000 20000 30000 40000 50000 60000 70000 80000 90000 time 5 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 38
60. fit residuals Postfit residuals Orbit and Clock comparison Ut Global Graphic Parameters Title lonospheric combinations X label time s Y label meters of L1 L2 delay m Clear 40 80000 90000 Automatic Limits X min X max Y min 0 Y max 10000 20000 30000 40000 50000 60000 70000 Individual Plot s Configuration time s Plot Nr 1 Plot Nr 2 Plot Nr 3 Plot Nr 4 lonospheric combinations Source File gi AB out Examine Circles v e e Klobuchar STEC e e All PRN PI P2 P1 Condition INPUT T 1 INPUT Blue v X Column sgc z 4 Y Column P2 P1 meters of L1 L2 delay m 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia 00 10000 20000 30000 40000 50000 60000 70000 80000 90000 time s Example 1 Summary Klobuchar model performance Vertical positioning error SPP gLAB1 0ut m N O Up error eLAB out S 10000 20000 30000 40000 50000 60000 70000 80000 90000 Time s Model lono corrections SPP AU gLAB out 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia Horizontal positioning error SPP e No n COIT gLAB1 out e 2 9 E o c g 0 x t o Z 5 gLAB out 20 15 10 5 0 5 10 15 20 lonospheric correction broadcast Klobuchar lonospheric delays are larger at noon due to the higher illumination
61. how Config SPP Template PPP Template Run gLAB Show Output gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia Equivalent command line sentence gLAB linux input cfg gLAB pc IFree cfg 25 input obs ramo1250 000 input nav brdc1250 00n Example 1 Single frequency vs Dual frequency gLAB Version 2 0 0 esa glLAB e e o o Preferences Positionin Analysis e NEU positioning error orizontal positioning error Zenith Tropospheric Delay ionospheric combinations Dilution Of Precision Satellite skyplot Carrier phase ambiguities Measur MullipalhvNorse 50 NEU pos one error SPP Full model 20 Horizontal positioning error SPP North error 1 freg SPS Z e with Klobuchar error m Model components arison Marth error rn Global Graphic Parameters Title NEU positioning error IM Automatic Limits X min Individual Plot s Configuration m A gLAB out Plot Nr 1 Source File gLAB out tted Lin 20 i i i i i i i i 207 15 10 5 5 10 15 30 Condition OUTPUT 1 QUTPUT Blue 0 10000 20000 30000 40000 50000 60000 70000 80000 9000 f time s East error m X Column SEC Y Column DSTAN Label North error en NEU positioning error 2 freq lono free m Horizontal positioning error 2 freq lono free North error 2 freq E ape Iono free EE error m North error m gLAB2 out 0 10000 2000
62. i graph py f gLAB out x4 y20 s c 1 OUTPUT 1 Full model f gLAB1 0ut x4 y20 s c 1 OUTPUT 1 No Iono cl yn 40 yx 90 xl Time s yl Up error m t Vertical positioning error SPP graph py f gLAB1 out x19 y18 so c 1 OUTPUT 1 No Iono clr f gLAB out x19 y18 so c 1 OUTPUT 1 Full mod cl b x1 East error m yl North error m xn 40 xx 40 yn 40 yx 40 t Horizontal pos error SPP P2 P1 shifted 4 m graph py f gLAB out x4 y S c 1 INPUT f gLAB out x4 y S C 1 MODEL cl r x1 time S yl meters yn 5 yx 80 t Ionospheric Combination Research group of Astronomy amp Geomatics Technical University of Catalonia Ex 1 Assessing lono effects on single freq pos Vertical positioning error SPP ETT EE C No lono corr gLABl out p 60 PNE 40 E 5 O 20 Q al 0 d 3 pert EE Redeem lb gLAB out 409 10000 20000 30000 40000 50000 60000 70000 80000 90000 lonospheric Combination PI P2 P1 shiifted 4m 70 AA Klobuchar STEC 60 L NE RN ON EE 50 f S 40 7 E 30 0 10000 20000 30000 40000 50000 60000 70000 80000 9000 time s Horizontal positioning error SPP e Nolono corr e Full model a u gLAB1 out North error m Fast error m
63. ical University of Catalonia no of 8 As it is know STEC and Ne are related by LEO STEC p N dl An equivalent expression assuming spherical symmetry STEC p 25 NPL where p stands for the impact parameter the closest point to the Earth centre along the optical ray path 88 LWP1 Electron Density Profile from RO from GPS to LEO Thence starting from the outer ray P 1 go for a given ray i where i 7 with impact parameter p Its STEC can be written in a discrete representation as j i l STEC p 2 N p L gt N p j l where p stands for the impact parameter the closest l o point to the Earth centre along the optical ray path where is the fraction of th ray within de listen kunde sd de As measurements we use L1 L2 carrier The previous equation defines a phases that are related with the STEC by triangular linear equations system that L L a STEC b can be solved recursively for the where the bias term bis eliminated making electron density Ne p differences to a reference in the arch data gA GE UP J Sanz amp 89 Juan 89 Research group of Astronomy amp Geomatics Technical University of Catalonia LWP1 Electron Density Profile from RO The program abel perl implements the previous algorithm to estimate the Ne p profile from GPS L1 L2 carrier measurements The input data is p n L1 L2 n with pin km and L7
64. ill be reflected according to the previous plot of N profile Answer i H N f 8 98 4 10 8 98 21 98 10 gt 150 km gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 93 D 94 No bending L p cdt B p p T al e Ap _ AL Acdt At At At A p Note LEO and GPS orbits are known at the level DD DD of few cm 5cm thus the Euclidean range can be At At calculated accurately and thus the range rate At 95 L p cdt B p p T a ll j 1 2 Lo p cdt B 3 p p T i AL sat AL Ap AG Ach pp AP ppi At At At At At O sat O Ap Ag Acdt gt DD Ap gt DD AL At At At At At A A occult AL j A em ER a DD DD At At At At A an A m AL A a E MEG gg fn sl At At At At DD GPS LEO GPSret LEO O GPS LEOrer GPSret LEOrer 96 LWP2 Atmospheric Bending in RO Another possibility to remove the clock term could be to subtract the LC combination from L1 or L2 The result will provide the discrepancy between L1 or L2 and LC excess ray path That is AD i AL B Acdt lec o At At At AP eat AP AL Ale j 1 2 gt Api Alo Acdtil At At At At rec At At At Notice that the Euclidian range rate is not needed to subt
65. ity can be computed and from these one can then derive atmospheric quantities such as Pressure Temperature and the partial pressure of water vapor and electron density among others GPS Signal VA GPS Satellite lo osphere Fic Schematic diagram illustrating radio occultation of GPS signals Figure courtesy of NSPO 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia Backup J Sanz amp J M Juan 107 LWP3 lono Divergence on Smoothing The target of LWP3 is to analyze the error induced by the divergence of the ionosphere between code and carrier into the Single Frequency SF carrier smoothed code time s The Divergence Free Dfree This effect will be analyzed analytically and tested with and the lonosphere Free single and double frequency IFree smoothed codes will be GPS measurements under compared with the SF one large ionospheric gradients Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 108 LWP3 lono Divergence on Smoothing The noisy code can be smoothed with the precise but ambiguous carrier measurements This carrier smoothing can be done in real time applying the Hatch filter The smoothing depends on the time smoothing constant or filter length The more the filter length is used the more smoothed the code is but with single frequency measurem
66. kage for GNSS data processing and analysis A All software tools including gLAB and associated files for the laboratory session are included in the USB stick delivered to those who attend the lecture A The laboratory session will consist of a set of exercises organized in three different levels of difficulty Basic Medium and Advanced A set of introductory examples range from a first glance assessment of the ionosphere effects on single frequency positioning and Zenith Tropospheric Delays estimate to showing different perturbation effects in the ionosphere Solar Flair Halloween storm TIDs Electron density profiles Ne retrieval bending effects analysis phase excess rate depicture as well as in depth analysis of the code carrier ionosphere divergence on single frequency smoothed codes and the second order ionospheric effects are analysed in detail in four Laboratory Work Projects Other topics are given as homework A The target is to provide the participants with a wide range of selected exercises to choose from according their interests and their level of knowledge of these topics gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 4 OVERVIEW A Introduction gt The gLAB tool suite A Examples of GNSS Data Processing using gLAB Laboratory session organization LABORATORY Session A Starting up your laptop A Basic Introductory lab exercises lono amp Posit S
67. lectron density on the daylight hemisphere see R 3 e g J Sanz amp J M Juan 69 Research group of Astronomy amp Geomatics Technical University of Catalonia Ex 3 Solar Flare October 28 2003 Exercise Analyze the effect of the Solar Flare on the Slant Total Electron Content STEG measurements of four permanent IGS receivers ankr asc1 kour and qaq1 vena a dedi range of longitude and latitude Data sets ankr3010 030 asc13010 030 kour3010 030 qaq13010 030 gA GE UPC J Sanz amp J M Juan 70 rch oh up o or Astronomy amp akk je chnical Un dius of Catalo Ex 3 Solar Flare October 28 2003 2 Id YY Doy sec GPS PRN el Az N list C1C L1C C1P L1P C2P L2P eene gLAB linux input cfg meas cfg input obs ankr3010 030 gt ankr3010 03 meas gLAB linux input cfg meas cfg input obs asc13010 030 gt asc13010 03 meas gLAB linux input cfg meas cfg input obs kour3010 030 gt kour3010 03 meas gLAB linux input cfg meas cfg input obs qaq13010 030 gt qaq13010 03 meas graph py f ankr3010 03 meas x4 y 14 16 1 ankr f asc13010 03 meas x4 y 14 16 1 asc1 f kour3010 03 meas x4 y 14 16 1 kour f qaq13010 03 meas x4 y 14 16 1 qaq1 x1 time s yl meters of L1 L2 xn 38500 xx 40500 yn 20 yx 20 t 28 Oct 2003 Solar flare 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia
68. levation added graph py f LI2 dat x1 y 2 5133 s 1 LI2 125 f LI2 dat x1 y 3 10 s 1 Elev 10 s xn 29700 xx 49200 yn 7 yx 7 x1 time s yl meters of L1 delay Geometry free and first order iono free combination s s s U2 125 with the x axis This bias is due to the carrier ambiguity see HW1 e GE UPC J Sanz amp J M Juan 126 oe up o Br Astro RR ge chnical University of Catalon LWP4 Second order lonospheric Effect mm Aa NI Answers to the previous discussion 1 What is the order of magnitude of the second order ionospheric effect 2 Is the pattern seen in the figure due to the 2nd order ionospheric effect or it is related to other phenomena The I2 effect on ground measurements is typically less than 2cm of L1 delay see HW3 or R 5 Thence the pattern must be related to another phenomena as explained as follows e In the derivation of previous combination LI2 the antenna phase center APC correction for the GPS signals has not been taken into account Indeed as L1 L2 and L5 have different APCs the geometric range for such signals is slightly different producing an elevation dependent error if it is not modelled e In HW1 it is shown that assuming only APC correction in the UP component the APC effect can be removed from LI2 as where 4 4 4 are the combination coefficients A A are the antenna phase centres for Jup the diff
69. lobal geodetic computations 2 mainly affects to the satellite clock estimates cm level and orbits few mm but the impact on receiver positions is smaller thanimm see R 5 and R 1 9 gAGE UPC J Sanz amp J M Juan 121 Research group of Astronomy amp Geomatics Technical University of Catalonia LWP4 Second order lonospheric Effect Second order lonospheric delay combination Question 1 Show that there is a unique linear combination of three carriers cancelling both geometry and first order ionospheric refraction a Apply results to GPS L1 L2 and L5 signals b Using file L5dt 1260 090 depict such combination of carriers Hint Let a L a L a L be a linear combination of three carrier measurements at frequencies fi f f The coefficients a a js s shall verify the conditions t ta 0 lt geometry free 9 M d Pa pa 0 lst oder iono free 3 ye lt 2nd order 10no a fia Bia 1 with p f f Note The first equation cancels all non frequency dependent effects geometric range clocks troposphere The second equation cancels all effects that depends of inverse squared frequency 15 order ionosphere and instrumental delays The last equation is to normalize the coefficients giving the combination in delay units at frequency 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M J
70. model oatellite positions oatellite clock error correction oatellite movement during signal flight time Earth rotation during signal flight time oatellite phase center correction Receiver phase center correction frequency dependent Relativistic clock correction Relativistic path range correction lonospheric correction Klobuchar Tropospheric correction Simple and Niell mappings Simple and UNB 3 nominals Differential Code Bias corrections Wind up correction Solid tides correction up to 2 9 degree J Sanz amp J M Juan 9 Filtering module e Able to chose different measurements to process 1 or more with different weights This design could be useful in future Galileo processing where processing with different measurements may be desired e Fixed or elevation dependent weights per observation e Troposphere estimation on off e Carrier Phase or Pseudo range positioning e otatic Kinematic positioning full Q Phi PO customization e Able to do a forward backward processing e Able to compute trajectories no need for a priori position 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia The gLAB Tool suite Back A Output module e Cartesian NEU coordinates e Configurable message output A Other functionalities e Computation of satellite coordinates and clocks from RINEX and SP3 files e Satellite co
71. n previous case with the Galileo C1 C7 and C8 signals it does not make sense to use the PC2 P oiyisiT 2sg Ru eene 6a49 combination to navigate Tx Note 50 The theoretical noise values found are 1095000 35000 40000 penn 2 9800 gt Opcapzs 33 100 time s 3 gAGE UPC Technical University of Catalonia HW2 Combinations of three frequency measur B Geometry free amp Second order lono Free combination analysis Questions analyse the suitability of the combinations Pl1 and LI1 obtained in the previous exercises to estimate the STEC 1 Calculate the theoretical noise of the geometry free combinations PIZP2 P1 and LI L1 L2 and compare with the noise PI1 and LI1 combinations found in the previous exercise Consider the Galileo signals E1 E7 and E1 E7 E8 Which combinations are more suitable to navigate the PI LI or PI1 LI1 2 Using files gien327sw 090 and orb15591 sp3 make a plot to compare the code noise of the geometry free combination of Galileo signals E1 E7 and the geometry free and first order ionosphere free combination of signals E1 E E8 3 The same questions using files 15dt1260 090 15dt1260 09n for the GPS signals L1 L2 L5 gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 148 HW2 Combinations of three frequency measur Answer to questions Question B 1 Measurement noise GAL E1 E7 E8 GP
72. nation corrected by the antenna phase center values A 0 09 A 0 12 A 0 28 in meters Now the combination to plot is LI2_corr 6 287 L 0 09 sin 34 084 L 0 12 sin 27 797 L 0 28sin 1 Using previous file 15dt meas generate a file content gawk if 6 01 s sin 7 3 14 180 print 4 6 287 1440 09 s 34 084 18 0 12 s 27 797 20 0 28 s 5133 7 15dt meas gt LI2c dat 2 Plot results graph py f LI2c dat x1 y2 s 1 LI2 125 f LI2c dat x1 y 3 10 s 1 Elev 19 xn 29700 xx 49200 yn 7 yx 7 x1 time s yl L1 meters gA GE UPC oe up o Br Astro nomy amp Geomatics s chnical University of Catalonia J Sanz amp J M Juan 136 HW1 APC effect on the LI2 combination Geometry free and first order iono free comb APC correction applied LI2 125 Elev 10 meters of L1 delay 30000 35000 40000 45000 time 5 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 137 HW2 Combinations of three frequency measur This HP2 is an extension of previous LWP2 and it is devoted to analysing the three different combinations of three frequency signals see R 1 1 The first and second order ionosphere free combination LC2 PC2 2 The geometry free and second order ionosphere free combination LIT PI 3 I he geometry free and first
73. nd not dependent terms x l TY M C L 2a L L am aa ya 0 p Id YY Doy sec GPS PRN el Az N list C1C L1C C1P L1P C2P L2P a Generate the meas file for PRN03 1 2 3 4 5 67 8 9 10 11 a2 13 14 15 16 gLAB linux input cfg meas cfg input obs UPC33510 080 gawk if 6 03 print 0 gt upc3 meas b Using previous expression compute the C1 multipath and code noise PRNOS C1 Raw unsmoothed measurement n gawk print 4 11 14 3 09 14 16 21 3 upc3 meas gt upc3 C1 results are Shifted by 21 3 to remove the carrier ambiguity c Plot the raw unsmoothed measurements for PRNO3 graph py f upc3 C1 s l C1 Raw xn 35000 xx 40000 yn 5 yx 5 xl time s yl meters t PRNO3 C1 Raw measurement noise and multipath 114 e gA GE UPC J Sanz amp J M Juan Research group of Astronomy amp Geomatics Technical University of Catalonia LWP3 lono Divergence on Smoothing ee AMEN 2 Apply the Hatch filter to smooth the code using a filter length of N 2100 sample as the measurements are at 7Hz this means 100 seconds smoothing Then as in the previous case depict the multipath and noise of the smoothed code a Smoothing code T 100sec gawk BEGIN Ts 100 if NR gt Ts n Ts elsetn NR C1s 11 n n 1 n C1s 14 L1ip L1p 14 print 4 C1s 14 3 09 14 16 21 3 upc3 meas gt upc3 C1s100 b Plotting results and compare with the row C1 PRNO3
74. nomy amp Geomatics Technical University of Catalonia The g LAB Tool suite n order to widen the tool availability gLAB Software has been designed to work in both Windows and Linux environments A The package contains e Windows binaries with an installable file e Linux tgz file e Source code to compile it in both Linux and Windows OS under an Apache 2 0 license Example data files e Software User Manual e HTML files describing the standard formats J Sanz amp J M Juan 8 Research group of Astronomy amp Geomatics Technical University of Catalonia no of The gLAB Tool suite A Modelling module A Read files capability RINEX observation v2 11 amp v3 00 RINEX navigation message SP3 precise satellite clocks and orbits files ANTEX Antenna information files Constellation status DCBs files GPS_Receiver_Type files SINEX position files Pre processing module 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia Carrier phase pre alignment Carrier phase pseudo range consistency check Cycle slip detection customizable parameters Melbourne W bbena Geometry free CP combination L1 C1 difference single frequency Pseudo range smoothing Decimation capability On demand satellite enable disable Elevation mask Frequency selection Discard eclipsed satellites Backu Fully configurable
75. oe up o Br Astro nomy amp Geomatics s chnical University of Catalonia J Sanz amp J M Juan 3 Ex 4 Halloween storm P2 P1 analysis mm O RS ZEE The measurement files garl3010 030 garl3020 030 garl3030 030 garl3040 030 garl3050 030 garl3060 030 were collected by the permanent receiver garl in Empire Nevada USA 40 42 deg 119 36 deg from October 28 to November 2 2003 Using these files plot the STEC for all satellites in view and discuss the range of such variations Analyse in particular the satellite PRN 04 and calculate the maximum rate of STEC variation in mm s of L1 delay Add the elevation of satellite PRN 04 in the plot The associated broadcast navigation les are brdc3010 03n brdc3020 03n brdc3030 03n brdc3040 03n brdc3050 03n brdc3060 03n amp g J Sanz amp J M Juan 14 Research group of Astronomy amp Geomatics Technical University of Catalonia Ex 4 Halloween storm P2 P1 analysis Exercise Depict the ionospheric delays for the different satellites in view from station amc2 This is a simple exercise aimed to illustrate how to use gLAB to easily analyze GNSS measurements and their combinations gLAB will used to read the RINEX measurements file and to generate a text with the measurements provided ina columnar format more suitable to make plots Using such text file the STEG pattern for the different satellites in view during the storm is depicted f
76. order ionosphere free combination LI2 P12 The target is to analyze the suitability or not of such combinations to provide LC2 PC2 A measurement free from 15 and 2 order ionospheric effects LI1 Pl1 A direct measurement of the 15 order ionosphere free from 2 order LI2 PI2 A direct measurement of the 2 order ionospheric effect The last case i e LI2 PI2 has been already studied in the previous LWP2 for the GPS signals L1 L2 L5 This study will be extended here to the Galileo signals gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 138 HW2 Combinations of three frequency measur Preliminar Combinations of three frequency signals derivation Let L L L the carrier measurements at frequencies f f f and 1 2 the first and second order ionospheric effects at the frequency including instrumental delay terms Show the following expressions where P is the geometrical range plus all other non dispersive terms and the carrier ambiguity L p 1l 12 2 3 2 with y 4f Li p y l ty 12 L P Yall y 12 Consider the GPS carriers L1 L2 L5 Show that LC2 7 08L 26 130L 20 050L 3 O 33 0 Note LII 212 368L 60 215L 47 8472 0 4 11 90 f 154f f 120f f 115f LI2 6 287 L 34 084L 27 797L 0 44 40 being LC2 o p LILe 11 LI2 12 The carriers L are assumed uncorrelated and with the same
77. ordinates comparison mode For instance RINEX navigation vs SP3 or SP3 vs SP3 along track cross track and radial orbit errors clock errors SISRE e Show input mode No processing only parsing RINEX observation files Current version allows full GPS data processing and partial handling of Galileo and GLONASS data Future updates may include full GNSS data processing J Sanz amp J M Juan 10 up GNSS learning material package Includes three different parts allowing participants to follow either a guided or a self learning GNSS course e GNSS Book Complete book with theory practical examples and with a Laboratory course on GNSS Data Processing amp Analysis R 1 e gLAB tool suite Source code and binary software files plus configuration files allowing processing GNSS data from standard formats The options are fully configurable through a GUI e gAGE GLUE Bootable USB stick with a full environment ready to use based on LINUX Ubuntu OS Research group of Astronomy amp Geomatics Technical University of Catalonia OVERVIEW A Introduction A The gLAB tool suite gt Examples of GNSS processing using gLAB Laboratory session organization LABORATORY Session A Starting up your laptop A Basic Introductory lab exercises lono amp Posit SF storm TIDs A Medium Laboratory Work Projects LWP1 to LWP4 A Advanced Homework amp g J Sanz
78. orrection Carrier phase only O Solid tides correction amp gA GE UPC J Sanz amp J M Juan 17 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 1 Model component analysis IONO gLAB Version 2 0 0 gLAB 6 mces M http www gage es Preferences About Cesa Positioning Analysis Default configuration for SPP v Consider satellite movement during signal flight time Consider Earth rotation during signal flight time Satellite mass center to antenna phase center correction Receiver antenna phase center correction Receiver antenna reference point correction vi Relativistic clock correction orbit excentricity vi lonospheric correction Klobuchar v Vi Tropospheric correction UNB 3 Nominal v Simple Mapping v v P1 P2 correction RINEX Nav File v v P1 Cl correction Flexible v Wind up correction Carrier phase only Solid tides correction Relativistic path range correction Save Config SPP Template PPP Template Run gLAB http www gage es Preferences About esa Positioning Analysis Output De Output Fild gLAB out Messages v Print INFO Messages Examine In the Default configuration the output file was gLAB out SPP Template PPP Template v Print CS Cycle Slip Messages vi Print INPUT Messages Print MEAS Message v Print MODEL Messages v Print EPOCHSAT Messages v Print P
79. ositioning error Horizontal positioning error enith Trop Cesa Dao Y r e ize a c Preferences About Horizontal positioning error SPP A priori receiver position E RINEX Observation File home gLAB ramo1250 000 Calculate Use RINEX Position cac x euro Carrie Si ANTEX Specify Use SINEX File 5 NOW Model compone Prefit residuals Orbit and Clock Source x Broadcast Precise 1 file Precise 2 files imr OT Y m Global Graphic Parameters RINEX Navigation File home gLAB brdc1250 00n Examine mE Z m Title NEU positioning error bel time s Re m Automatic Limits X min K max i i SINEX File SE PE to Ce VICMCHIVIERU Individual Plot s Configuration Show Broadcast same as navigation Broadcast specify Plot Nr 1 Plot Nr 4 NEU positioning error SPP Full model Source File M gi AB out North error Dotted Line v Auxiliary Files East error DEE P1 Cl Correction P1 P2 Correction EEE UP error Show Show OUTPUT v Blue X Columgf SEC v 4 error error m Save Config PP Template PP Template Run gLAB mow Output g LAB O u t ll gt aZ amp mm ee Oe 205 10000 20000 30000 40000 50000 60000 70000 80000 90000 time s Equivalent command line sentence gLAB_linux input cfg gLAB p1 Full cfg input obs ramo1250
80. oup of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 33 Example2 GPS measurements content Code measurement content Carrier measurement content P p 1 K e L p 01 B 6 P p 4 1 K 5 L p 0 1 B 65 P Refers to all non dispersive terms geometric range clocks tropo delay lonospheric delay i 40 3 F f7 10 STEC I is in m of L L delay see R 1 STEC N dl STEC is in TECUs 2300627 1a Du I TECU 10 e m 0 10m of LI L2 delay Interfrequency bias As the satellite clocks are referred to the ionosphere free combination of codes P the Ki cancels in such combination K K e Ko Note rGD K is broadcast in GPS nav Message Carrier ambiguities Db E AN b N is an integer number b is a real number fractional part of ambiguity gAGE UPC Backup Technical University of Catalon J Sanz amp J M Juan 34 Example 2 lonospheric delay analysis 1 Read RINEX file with gLAB and generate a measurements file in a columnar format the easiest to manipulate and plot content 3 Using the configuration file meas cfg READ the RINEX and generate the MEAS file meas cfg input obs coco0090 970 input nav gt coco meas meas RINEX RINEX Measurement Navigation file file OUTPUT measurement file in columnar format idretter YY Doy sec GPS PRN el Az N
81. p Posit SF storm TIDs A Medium Laboratory Work Projects LWP1 to LWP4 A Advanced Homework amp g J Sanz amp J M Juan 50 Research group of Astronomy amp Geomatics Technical University of Catalonia n Starting up your laptop 1 Plug the stick into an USB port and boot your laptop from the stick 2 Access the Boot Device Menu when starting up the laptop Note The way to do It depends on your computer Usually you should press ESC or F4 F10 F12 amp g J Sanz amp J M Juan 51 Research group of Astronomy amp Geomatics Technical University of Catalonia The US keyboard is set by default X You can change it on by clicking on the upper right corner ESA Summer School gLAB Manual e e ad un oO Q 31 OE E D 3 D D vi 52 43 Applications Places System EC Computer credits txt P glab s Home esa Positioning Analysis Input E H Preprocess H Modelling tt sn Hiter Terminal GNSS Formats C 4A Fo x N glab gage File Edit View Terminal Help To run a command as administrator user root use Sudo lt command gt See man sudo root for details glab gage Console fm 9 gLAB Version 2 0 0 glab gage Tue Jun 21 8 48AM Gi glab Ep M c Q un WY 4 7 Z2 a i EE gt Ree LL DITT f A
82. put File Examine Messages Print INFO Messages Print CS Cycle Slip Messages Print INPUT Messages Print MEAS Message By default the output Print MODEL Messages Print EPOCHSAT Messages file name is gLAB out Print PREFIT Messages amp Print POSTFIT Messages Print FILTER Messages Print OUTPUT Messages Save Config SPP Template PPP Template Run gLAB Show Output J Sanz amp J M Juan 58 Ex 1 lono Disabled gt gLAB1 out ee EE 2 Reprocess the same files with the iono corrections disabled gLAB Version 2 0 0 gLAB Version 2 0 0 G gAGE U http www gage es Cosa gLAB Preferences About Preferences About Positioning Analysis Modelling Options amp Satellite clock offset correction Positioning Analysis Output Desti Output File b gLAB1 out DB Examine M Consider satellite movement during signal flight time M Consider Earth rotation during signal flight time Messages amp Print INFO Messages Satellite mass center to antenna phase center corre tion Disable lonospheric arnom Print MEAS Message mn orbit exg ity m Change output file CO rrections Print MODEL Messages NB 3 Nominal v Simple Mapping v Print EPOCHSAT Messages n a me to g LA B 1 a O ut Receiver antenna phase center correction Receiver antenna reference point correction lonospheric correction
83. r w WordPad Help 15 View Insert Format File Edit Dc E amp d e 6 5 Applications Places 14 2 3 4 5 7 69 10 12 13 1 H MEAS YY Doy sec GAL PRM el z H ii Plot results Bas gawk if 5 GAL amp amp 6 16 graph py gien327PczLez dat Terminal Generate MEAS fils i Hows gL iB linux inputictg meas cfg input obs this is not a problem GNSS Formats Note Nevertheless lll 6906 glab gag eee vm oul fo Help press F1 To run a command as administrator user root use Sudo lt command gt See man sudo root for details Console to execute GAG 93 command line sentences glab gage glab gage fj Sm 9 gLAB Version 2 0 0 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia 15 11 list C1B LIB cic Lic C a Lio Cap Lao x1 y3 l CUp5os hospive 17 18 print 4 11 1 42 15 11 12 1 42 12 16 1 6 93 11 12 78 32 15 16 472 35 x1 72 PC LC 17 esl r syn f gisen3z 7PczLez dat l5dt126 09 mes GES gt grep Sdtl260 09n pre dec 5dt1260 090 input nawv RINES file UPC5S3620 0680 does not provides Fl code because gL B works in search group of Astronomy amp GEomatics niversily of Catalonia UPC with the command Ine sentence Is provided to facilitate the sentence writing just J Sanz amp J M Juan 30 gLAB Ve
84. ract as in the previous case because it is cancelled when taking the difference between L1 or L2 and Lc Other delays can also be cancelled In the following exercises we will plot the previous combinations and discuss the different contribution of the ionosphere and troposphere to the phase excess rate 9 gAGE UPC J Sanz amp J M Juan 97 Research group of Astronomy amp Geomatics Technical University of Catalonia LWP2 Atmospheric Bending in RO Exercise The program RO per1 uses the RO obs as input data and computes the following combinations of RO measurements 1 2 3 4 5 6 7 38 9 10 11 12 13 14 sec CODE PRN p dRho dL1 dL2 dLc d L1 Lc d L2 Lc DDdRho DDdL1 DDdL2 DDLC The output file where e Rho is the Euclidean Distance between GPS and LEO e d means differences in time e DD means Double Differences between GPS and LEOSs satellites Note the GPS PRN13 and LEO 1252 are used as reference satellites the rays between these satellites are not in occultation The results are computed for the RO between GPS PRNO2 and LEO 1241 the same occultation as in previous cases units m s The aim of this exercise is to analyse the phase excess rate in the different combinations due to the bending of the ray 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 98 LWP2 Atmospheric
85. rbances Affecting GPS Measurements Spatial and Temporal Analysis Journal of Geophysical Research Space Physics Vol 111 A07 511 2006 doi 10 1029 2005JA01 1471 R 5 Hernandez Pajares M J M Juan J Sanz Second order ionospheric term in GPS Implementation and impact on geodetic estimates Journal of Geophysical Research Solid Earth Vol 112 pp 1 16 2007 doi 10 1029 2006JB004707 R 6 Hern ndez Pajares M J M Juan J Sanz Improving the Abel inversion by adding ground data LEO to radio occultations in the ionospheric sounding Geophysical Research Letters Vol 27 16 pp 2743 2746 2000 R 7 Hajj GA Kursinsky ER Romans LJ Bertier WI Leroy SS A technical description of ri sounding by GPS occultation JASTP Vo 1 64 pp 451 469 2002 gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 161 Acknowledgements A The ESA UPC GNSS Lab Tool suite g_LAB has been developed under the ESA Education Office contract N P1081434 The other data files used in this study were acquired as part of NASA s Earth Science Data Systems and archived and distributed by the Crustal Dynamics Data Information System CDDIS To the NSPO UCAR Agency for the FORMOSAT 3 COSMIC data To Adri Rovira Garcia for his contribution to the editing of this material and gLAB updating and integrating this learning material into the GLUE gA GE UPC oe up o Br As
86. rier phase amt Dilution Of Pre Model components Prefit residuals Postfit residu Global Graphic Parameters Title Horizontal positioning err X label East error m Y label No Global Graphic Parameters Title Horizontal positioning err Abel East error m Le Y label esta rror m Automatic Limits X min 20 X max Clear 20 Plot Nr 3 Individual Plot s Configuration Q Plot Nr 1 OC Plot Nr 3 Plot Nr 4 Examine 1 OUTPUT Bue v Label Full Model v 1 OUTPUT m 3 gLAB1 cut OUTPUT E v DSTAE Y Column DSTAN gLAB out Plot amp gA GE UPC J Sanz amp J M Juan 21 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 1 Klobuchar iono corr plot gLAB out esa Preferences gLAB Version 2 0 0 P T Positioning Analysis Templates NEU positioning error Dilution Of Precision Satellite skyplot Horizontal positioning error http www gage es gAGEUPC a P Model lono corrections SPP gLAB About Zenith Tropospheric Delay lonospheric combinations Carrier phase ambiguities Measur Multipath Noise Prefit residuals
87. rom the geometry free combination of codes P2 P7 Note P F K J Sanz amp J M Juan 19 Research group of Astronomy amp Geomatics Technical University of Catalonia Ex 4 Halloween storm P2 P1 analysis The next commands read a RINEX file and generate a text file in columnar format that allows to easily plot the measurements and their combinations 1 Using the configuration file meas cfg READ the RINEX and generate the MEAS message with data format Id YY Doy sec GPS PRN el Az N list C1C L1C C1P L1P C2P L2P 123 4 5 67 8 9 10 11 xx 13 14 15 16 Execute gLAB linux input cfg meas cfg input obs amc23030 030 input nav brdc3030 03n gt amc23030 03 meas 2 From meas txt file Compute the ionospheric combination of codes PIZP2 P1 Generate the file Pl txt with the following content PRN hour PI elevation gawk print 6 4 3600 15 13 7 amc23030 03 meas gt PI txt 3 From PI txt file Plot the PI P2 P1 for time interval 15 to 24 hours Show in the same graph 1 ALL satellites 2 PRN 13 28 and 29 and 3 The elevation of each satellite 13 28 and 29 graph py f PI txt x2 y3 l ALL f PI txt c 1 28 x2 y3 so 1 28 P2 P1 f PI txt c 1 28 x2 y4 1 29 ELEV f PI txt c 1 29 x2 y3 so 1 29 P2 P1 f PI txt c 1 29 x2 y4 1 13 ELEV E f PI txt c 1 13 x2 y3 so 1 13 P2 P1 f PI txt c 1 13 x2 y4 1 13 ELEV xn 15 x
88. rsion 2 0 0 Ba J x esa CLAD INPUT messages Pr input data message It is shown after an epoch is read and decimated It contains the measurements for each satellite for this Positioning Analysis epoch Field 1 INPUT FF Field 3 Doy Jutput Destination Field 4 Seconds of day Output File gLAB out Field 5 GNSS System GPS GAL GLO or GEO Field 6 PRN satellite identifier A Field 7 Arc length number of undecimated epochs after the last cycle slip For GPS Field 8 C1 C1C Field 9 P1 C1P Field 10 P2 C2P Field 11 L1 L1P prealigned in meters ET Field 12 L2 L2P prealigned in meters 200 STET For Galileo GAL essages i p gt e Field 8 C1A File Edit View 7 FREE MER Field 9 C18 To run a command as administrator user root use sudo lt command gt Print POSTFIT Messages Field 10 C1C See man sudo root for details Print FILTER Messages ua DE EI 5 e Field 12 C8Q glab gage Jj v Print OUTPUT Messages Field 13 L1A prealigned in meters Field 14 L1B prealigned in meters Field 15 L1C prealigned in meters Save Config Field 16 L7Q prealigned in meters Run gLAB Show Output Field 17 L8Q prealigned in meters For GLONASS GLO Field 8 C1 C1C Field 9 C2 C2C Field 10 L1 L1P prealigned in meters Field 11 L2 L2P prealigned in meters For GEO Field 8
89. s FO ur i L r Iw um Fa ft Bre This is a simple exercise where the STEC variation along a radio occultation will be depicted using GPS L1 L2 measurements from a receiver on board a LEO of COSMIC constellation In the LWP1 Electron Density Profiles will be retrieved from this data using an algorithm equivalent to the Abel Transform aaaea 64 Battery Filter Telar Battery Charge Regulater Array S band Transmiter amp Receiver Tri Bamd Bearom TRA TIF Elec conics Tiny lomaspkeric Phete mater CTIF GOA Artenna SE band Antenna GOX Arena i 7 THE Ante una MIT upper POMbaitemi 65 Torque red Fuel Tank Flight Computer upper ACE middle GPS Receiver be tiom Ex 2 STEG in a Radio Occultation RO Exercise The file RO obs contains the following fields YY DoY HH HH CODE PRN elev r LEO AR LEO DEC LEO r GPS AR GPS DEC GPS L1 L2 L1 L2 arc deg km Deg Deg km Deg Deg cycles m 6 4 8 9 10 11 12 13 14 15 16 Plot the L1 L2 measurement in function of time to depict the variation of STEC along the occultation Select for instance PRN 02 and CODE 1241 that corresponds to LEO 4 and Antenna 1 Selecting CODE 1241 and PRN 02 grep 1241 RO obs gawk if 5 02 print 3 15 gt ro dat Ploting L1 L2 P graph py f ro dat xl time H E yl meters of L1 L2 t RO L1 L2 COSMIC 4 Antenna 1 This file has been
90. siduals Postfit residu gt Model components Prefit residuals Global Graphic Parameters m Title Vertical positioning error X label time s Y label jeri Global Graphic Parameters Title Vertical positioning error X label time 5 C Automatic Limits X min Individual Plot s Configuration O Automatic Limits x min X max amp Plot Nr 1 Plot Nr 2 Plot Nr 3 Individual Plot s Configuration G ril eO Plot Nr 1 D Plot Nr 4 C m EE Examine Dotted Line v s mn DSTAU v 20 3 OUTPUT ha Bue Bue vj nae Isc via Isc via 4 Full Model gLAB1 out 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 20 Example 1 HPE plot gLAB out gLAB1 out gLAB Version 2 0 0 g LAB E Ve rsion 2 0 0 Horizontal positioning error SPP No lono corr Full model gt esa gt esa Preferences Templates Positioning Analysis VE ee VE ee ee NEU positioning error Horizontal positioning error Zenith Tropospher Templates y lonospheric combinations X m l n Y m i n Y max m Medgur Multipath Noise Model components Prefit reg uals Postfit residuals orbit and Check comparison xs pe NEU positioning Dilution Of Precision Satellite skyplot Car
91. t Seteepeeseedeesot opremo d Upson renter OR Se prs 8 a P TL amp gr Ta 198 Vut ee b erre tamt r E e LONE 1 p Be aes Pt s Sesion 1 Ex5c4 Sky plot kour 2009 11 02 dE Pr I HN es ee frriljtjt 1 0 reo dedu Sa ovate es South 39 J Sanz amp J M Juan 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia Example 3 Zenith Troposphere Delay estimation PPP Template Static positioning with dual freq code amp carrier ionosphere free combination PC LC post processed precise orbits amp clocks 1 Select the PPP Template 2 Upload data files Measurement roap1810 090o mr ANTEX igs05 1525 atx 2 ME mn Orbits amp clocks igs15382 sp3 parle ome ABgs 1558203 SINEX igs09P1538 snx lonosphere Source if activated serer 3 RUN Q LAB Show SP3 File home gLAB igs15382 sp3 Auxiliary Files P1 Cl Correction P1 P2 Correction O Show Default output file gLAB out gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 40 Example 3 Zenith Troposphere Delay estimation Plotting Results Coordinates are taken as 0 20 constants in nav filter e Dual frequency Code and Carrier measurements e Precise orbits and clocks
92. t NEU positioning error SPP Full model 9 gAGE UPC J Sanz amp J M Juan 16 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 1 gLAB Modeling panel fa gLAB Version 2 0 0 i Ja The different model terms can g LAB O sAGEUPC be analyzed with gLAB Gesa L5 Ee Using the previous data file eens oi the impact of neglecting the ionospheric correction IS evaluated in the Range and Position domains gAGE UPC Modelling Options Satellite clock offset correction Consider satellite movement during signal flight time The modeling options set in this his is a baseline example of this analysis procedure The panel are applied same scheme must be by default to the applied for all model terms SPP solution troposphere relativistic correction full analysis er ee of the different model mmm Sep Template PPP Template Bug components can be found in R 2 Consider Earth rotation during signal flight time O Satellite mass center to antenna phase center correction O Receiver antenna phase center correction Receiver antenna reference point correction Relativistic clock correction orbit excentricity lonospheric correction Klobuchar Tropospheric correction UNB 3 Nominal v Simple Mapping P1 P2 correction RINEX Nav File v P1 Cl correction Flexible v O Wind up c
93. t file as gLAB out 2 Solution with the ionospheric corrections disabled gt gLAB1 out 3 Solution with the 2 freq lonosphere free code PC gt gLAB2 out 2 Plot results Note The gLAB GUI or the command line sentences can also be used A notepad with the command line sentence is provided to facilitate the sentence writing just copy and paste from notepad to the working terminal 9 gAGE UPC Researc h en or ee Geomatics Technical Un ity of Catalo J Sanz amp J M Juan SY Ex 1 Full processing gt gLAB out 1 Compute SPP using files amc23020 030 brdc3030 03n gLAB Version 2 0 0 B 6 sacews gLAB Preferences About A priori receiver position Calculate Use RINEX Position Specify Use SINEX File RINEX Observation File p mc23030 030 Examine Show ANTEX Orbit and Clock Source x Broadcast Precise 1 file Precise 2 files Inr RINEX Navigation File brdc3030 03n Y m Z m lonosphere Source if activated SINEX File Show Broadcast same as navigation Broadcast specify Auxiliary Files P1 Cl Correction P1 P2 Correction Show Show Save Config Run gLAB SPP Template fPPP Template Equivalent command line sentence gLAB linux input cfg gLAB p1 Full cfg input obs amc3030 030 input nav brdc3030 03n http www gage es gLAB Version 2 0 0 Preferences About Positioning Analysis Output Des Out
94. thed 360 1 Cl DFree smoothed 1005 ce DFree smoothed 360 Y bl THU he i ls vn d Mi Vine cA Z C1 SF smoothed 3600 Cl DFree smoothed 3600 MAPA MAL m IA n j i Y I VI i KN SSS SSS SSS fia caia Md IT IT m L L seann Sean SSAA Sennn sanan Annnn 15 __lonosphere Free ns uui 15 lonosphere Free combination smoothing 360 secon ds m TN uuu UNT nin 27000 38000 Note that the y range in bottom row plots is 3 times larger than in s Free smth 360s top plots he 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 118 LWP3 lono Divergence on Smoothing Repeat the previous exercise using the RINEX file amc23030 030 1Hz collected for the station amc2 during the Halloween storm Take N 700 I e filter smoothing time constant 72100 sec PRN13 C1 100s Bae LA and divergence of icles subs 120 STEC PRN13 shifted x Cl Raw 1 546 Ul L2 C1 SF smoothed 100 C1 DFree smoothed 60 meters of L1 delay 40 60000 65000 70000 75000 60000 65000 l 70000 75000 i time s time 5 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 119 LWP4 Second order lonospheric Effect Th
95. tro RR ge chnical University of Catalon J Sanz amp J M Juan 162
96. ts X ny Y label troposphere m Clear The e troposphere is M ya Xmax min Ymax estimated as a Random Individual Plot s Confj luration Plot Nr 3 Pot Nr 4 Walk rocess in the Kalman Source File home jaume edunav LECTURES TUTORIAL2 TUT2 roap igs trp Examine Lines Condition Green X Column Y Column C Label IGS 1e 1 T 0 10000 20000 30000 40000 50000 60000 70000 80000 90000 time 5 Plot ftp cddis gsfc nasa gov pub gps products troposphere new 2009 181 r0ap1810 092pd 92 The ZTD in this file is given in mm of delay Thus it is converted to m to compare with gLAB results grep ROAP roap1810 09zpd gawk FV print 3 gawk print 1 2 1000 gt roap igs trp 9 gAGE UPC J Sanz amp J M Juan 42 Research group of Astronomy amp Geomatics Technical University of Catalonia Example 3 Zenith Troposphere Delay estimation Tropospheric delay The troposphere is the atmospheric layer situated between the Earth s surface and an altitude of about 50 km The effect of the troposphere on GNSS signals appears as an extra delay in the measurement of the signal travelling from satellite to receiver The tropospheric delay does not depend on frequency and affects both the pseudo range code and carrier phases in the same way It can be modeled by e A hydrostatic component composed of dry gases mainly nitrogen and oxygen in hydrostatic equilibrium This component can be treated
97. uan LWP4 Second order lonospheric Effect mm TRE Answer to question 1a Show that there is a unique linear combination of three carriers cancelling both the geometry and the first order ionospheric refraction Apply results to the L1 L2 and L5 signals Applying previous equations system to GPS signals f 7 154 f gt f 2120 gt f 2115 fo a a ta 0 with a 6 287 a p2a p2a 0 6 154 1200 gt a 34 084 a pha Bra 1 P5 154 115 a 21 197 Thence the combination is LI 6 287 L 34 084L 27 797 L in delay units at f frequency On the other hand assuming the carriers L uncorrelated and with the same 07 the noise associated to this combination is given by o I Note As 12 aar the combination of codes is given by PD 3 144C 17 042C 13 899C 0 22 20 9 gAGE UPC 123 J Sanz amp J M Juan Research group of Astronomy amp Geomatics Technical University of Catalonia LWP4 Second order lonospheric Effect Answer to question 1b Make a plot to depict the geometry free and first order ionosphere free combination of GPS carrier phase measurements L1 L2 L5 Use files 15dt1260 090 15dt1260 09n and satellite PRNO1 1 Using the configuration file meas cfg READ the RINEX and generate the MEAS file with content MEAS YY Doy sec GPS PRN el Az N list C1C L1C C1P L1P C2C L2C C2P L2P C5X L5X 123 4 5 6 78 9 10
98. utral and ionised molecules gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 81 Ex 6 Travelling lonospheric Disturb In R4 2006 a simple method to detect MS TIDs is proposed It consists of detrending the geometry free combination of GPS carrier measurements from the diurnal variation and elevation angle dependences applying the following equation OL t L t L t 7 L t 1 2 where a value of 300sec is suitable to keep enough variation of LI i e STEG Using the previous equation the detrending is done simply by subtracting from each value an average value of the previous and posterior measurements i e the curvature of the LI temporal dependency It must be pointed out that that this detrending procedure can be used in real time with a single receiver so It is suitable for identifying these ionospheric perturbations in navigation applications gA GE UPC oe up o Br Astro RR ge chnical University of Catalon J Sanz amp J M Juan 82 Ex 6 Travelling lonospheric Disturb An example of MSTID propagation can be depicted as follows using the measurements of three stations SODB MHCB and MONB which are separated by a few tens of kilometres The target is to reproduce the figure 10 of the above mentioned paper R4 2006 R4 2006 Hern ndez Pajares M Juan M Sanz J 2006 Francisco Daly Citys San av South San
99. x 25 yn 0 yx 85 xl time s yl meters of L1 L2 delay 76 recnnicai Universit y OT Lataionia Ex 4 Halloween storm P2 P1 analysis IONO Halloween storm 2003 10 30 amc gol EEE Less VT PM de e ALL 3 28 P2 P1 ae eder EN VEN T 29 ELEV 29 P2 P1 ENGE bee eee EIL LL Lo n 29 ELEV 13 P2 P1 er an DEB EU c e e un e meters of L1 L2 delay 3 PURI ne he ine gt N October 16 18 20 22 OF 24 time s 9 gAGE UPC Research group of Astronomy amp Geomatics Technical University of Catalonia J Sanz amp J M Juan 1 Ex 5 Halloween storm evolution mme X NE Exercise Analyze the ionospheric delays for 6 consecutive days including the Halloween storm e his is a simple exercise aimed to illustrate the ionospheric delays variation during the Halloween storm A period of 6 consecutive days from October 28 to November 2 2003 are analyzed using measurements collected in the garl station in North America The STEG variations are depicted from the geometry free combination of codes P2 P1 Note P B I K B g J Sanz amp J M Juan 18 Research group of Astronomy amp Geomatics Technical University of Catalonia Ex 5 Halloween storm evolution Id YY Doy sec GPS PRN el Az N list C1C L1C C1P L1P C2P L2P 123 4 5 6 7 8 9 10 11 xx 13 14 15 16 1 Read RINEX file

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