User Guide for the GER1500
Contents
1. It is always easier to resolve problems before you collect spectra rather than trying to make sense of spectra collected using incorrect methods 6 General notes on the Panasonic Toughbook PC m Always charge the internal battery from the mains overnight before use Always connect a 12V battery to the computer using the car adapter and 12V converter as the computer s internal batteries are not sufficient for a full day in the field Take care if using the pen as it takes a while to get used to the way that it operates Watch out when using it within Windows Explorer as it is very easy to move files around that are critical to the operating system which may cause major problems with the computer DO NOT INSTALL ANY EXTRA DEVICES ONTO THE PC This has been known to confuse the serial port settings and prevent communication with the spectrometer In case of a major technical difficulty with the Panasonic you should always phone FSF to ask advice 7 SUMMARY of key points to remember in field 1 r9 CO NOY UE 10 Always connect 12V battery to computer using the car adapter and 12V converter as the computer s internal batteries are not sufficient for a day in the field Only work when solar conditions are optimal 2 3 hours either side of Solar noon and when it is sunny and clear Be extra careful about working in sub optimal conditions Warm up the instrument prior to use 15 mins is ideal Take a reference scan of Sp2. spectravista com The serial number should appear below the version number of the software e g 2038 as demonstrated above If this is not the case you will need to edit the program s initialisation file ger ini Before doing this you should contact FSF for instructions At your training session FSF staff will make sure that the ger ini file is set to the correct configuration so there should be no need to change this Assuming that the software has launched correctly click the OK button on the prompt box and then proceed to select the FILE menu and then New Choose the folder in which to save your data i e the folder you just created in Windows Explorer and give a root name for your spectra click OK Click on the drop down menu called CONTROL and choose the option labelled Read Memory The computer will now communicate with the spectrometer and determine the number of scans in the on board memory of the GER1500 A box will appear which states the number of scans held on the memory and the starting filename as specified in step 5 If you are completely happy that you collected all of your scans with the correct Ref Tar attribute set on the spectrometer head just prior to data collection then proceed with the download and press OK Your data will now be written to a GER sig file The target scans will be written to a file with the immediately previous reference scan and given an incrementally increasing filename and a s
3. stand alone use it is recommended that you use Both as this will enable you to position the spectrometer head accurately using the laser pointer before collecting a scan 3 7 Finally press the MENU key again This will take you to the last menu option called OPTIC This refers to the format you wish to save your data in Here we require an option known as Unity Function which means that we wish to save the data as raw Digital Numbers DN This setting corresponds to optic number 5 in the GER software Therefore press the EDIT key followed by the up or down arrow keys to set the optic to option 5 3 8 The spectrometer is now set up ready for data collection 3 9 Note that on the top line of the LCD display you will see a TAR or REF display followed by a number This number represents the voltage in the spectrometer power supply If this drops below 6V you are in a critical battery status situation Turn the spectrometer off and replace the power supply with a fully charged one NOTE that switching the spectrometer off will not cause your scans to be lost from the memory 4 Data collection To collect a scan with the GER1500 head you must position the head over the target of interest The head can be stabilised on a tripod or hand held Use the arrow keys on the front of the spectrometer panel to switch between the REF and TAR modes Use REF mode for Spectralon reference measurements and
4. 3 Sampling Strategies FSF cannot recommend particular sampling strategies as the ideal sampling will vary from project to project and is under the responsibility of the PI However we can recommend that for each point measured a number of spectra be collected i e a number of Ref Tar pairs These can then be averaged to provide a certainty measure of the spectral variability over a fixed point in space It is up to the PI to determine the most appropriate method for sampling the surfaces of interest with respect to spatial coverage 4 4 Mounting The spectroradiometer should be mounted securely during field deployment and this can be performed using a tripod arrangement Try to mount the radiometer so that it is viewing from nadir The levelling device on the radiometer head will allow you to do this You can also hand hold the radiometer with the carrying handle but this is not likely to be so stable 4 5 Field Of View It is VERY important to accurately define the Instantaneous field of view IFOV of the sensor before going into the field You need to make sure that the size of the area you wish to measure is LARGE relative to the IFOV of the sensor The FOV is approximately circular and is 3 degrees A spreadsheet is provided to help you You should work out the range of heights you intend to use for the radiometer mounting and then work out the diameter of the area to be measured The reason that this is important is that if you measure an a
5. Field Spectroscopy e amp Facility NATURAL ENVIRONMENT RESEARCH COUNCIL User Guide for the GER1500 Stand Alone Mode Version 3 0 2005 by Fran Fogwill PC version Panasonic Toughbook Ownership NERC FSF Original created by Karen Anderson EPFS Southampton 2002 This User Guide provides reminders of the key processes involved in the setting up and use of the GER1500 spectrometer in stand alone mode This mode is where the on board memory of the spectrometer is used to save scans which are then downloaded later using the computer It is recommended that this mode only be used if it is not possible to use the computer controlled mode single or dual beam 1 Power Ensure all batteries 12V and 6V smartpack cells are fully charged before departing into field Ideally we recommend that you take a Voltmeter with you to check the charge of the 12V batteries which should bear a charge of 13V when fully charged 2 Spectrometer Warmup It is recommended that you warm up the GER1500 prior to use for spectral measurement collection Ideally we recommend at least 15 minutes This means that you should attach the 12V battery 6V smartpack cell and switch the spectrometer on so that the red light appears at least 15 minutes before use This will minimise errors caused by warming of the spectrometer array inside 3 Setup 3 1 Connect a power supply to the spectrometer Use a power converter insert or 6V smartpack bat
6. TAR mode for measurements of your target surface i e rocks soil leaves It is essential that you remember to change the mode of measurement between REF and TAR accordingly each time as mistakes are difficult to rectify afterwards When you are positioned over the surface that you wish to measure press the red trigger button on the front of the spectrometer If you set the trigger function TRG to both then pressing the red button will result in the laser pointer being activated Use this to position the radiometer over your desired surface for measurement Once you release the trigger the laser pointer will switch off and the spectrometer shutter will open You will hear two clicks of the shutter Between these two clicks the radiometer must remain in a static position over the surface to be measured After the second click it is safe to move the radiometer In the field you should always collect one reference scan of spectralon for every target scan of your field spectra The reference scan and target scan should be as close together in time as possible This is essential in order to minimise the effects of the changing atmosphere on the resultant spectra Therefore your data should resemble RTRTRTRTRIRTRIRTRIRTRTRTRTRTRT etc And not RTTTT RTTTT RTTTT RTITT RTTTIT etc 4 1 Spectralon Panel care Handle the spectralon panel carefully do not touch the surface Mount the spectralon on a tripod using the panel m
7. aging A conversion table for converting the averaging settings is provided below Computer averaging setting Actual number of scans averaged 1 1 O COIN Ov OT AWIN Ww N 3 5 Press the MENU key again You will now be on a menu called INTSP This sets the integration speed for the spectrometer head which is comparable to the shutter speed on a camera The darker the surface the longer integration speed should be used We recommend that you leave this set to AUTOMATIC This will enable the spectrometer to adjust the integration speed according to the surface being measured without you having to adjust it every time yourself If an A is displayed on the LCD screen then it is set to automatic Ignore the number displayed next to the A this is the integration speed used at the last scan and is not relevant at this stage If an A is not displayed you will need to set this To do so press the EDIT key followed by the MENU key This should cause the A to be displayed on the screen When this happens press the EDIT key again to set this parameter 3 6 Press the MENU key again You will now see a menu called TRG This sets the functioning for the red trigger button on the front of the spectrometer head You can set this to Laser Scan or Both This is set using the EDIT key followed by the up or down arrow keys followed by EDIT to set the trigger function For
8. ectralon for every target measurement Keep accurate log sheets Accurately determine the size of the IFOV at a given height before going into field Make sure that the IFOV is completely filled with the target of interest Collect more than 1 spectrum over each target to get an idea of the spectral variability of each surface Process and examine a few spectra each evening to check that they are correct and of good quality Lack of power is actually one of the most common problems so MOST IMPORTANTLY CHARGE YOUR BATTERIES EVERY NIGHT FSF staff have experienced most technicalities with this system and will normally be able to offer advice over the telephone So remember if you are not sure about anything ring FSF Tel 44 131 6505926
9. ig extension e g grass_000 sig grass_001 sig grass_002 sig etc If you know that at some point during data collection you saved a scan with the incorrect Ref Tar attribute i e a Ref scan was saved as Tar then you should check the box labelled EDIT SCAN TYPES before proceeding to download The computer will now download each scan at a time one by one and ask you to check the Ref Tar attribute Where necessary you can prompt the software to change it from Ref to Tar or vice versa This process is very lengthy if you have collected a lot of scans TIP IF THE SETUP BOX DOES NOT APPEAR SOON AFTER SELECTING Control Read Memory THEN THERE IS LIKELY TO BE A CONNECTION PROBLEM AN ERROR MESSAGE WILL APPEAR SAYING COULD NOT OPEN PORT CHECK THE SERIAL CABLE CONNECTION AND CHECK THAT THE RADIOMETER IS SWITCHED ON YOU WILL ALSO NEED TO CHECK THAT COM1 IS SELECTED AS THE COMPUTER PORT IN THE Setup WINDOW 5 2 Processing If you are out in the field for more than 1 day it is recommended that you process a couple of spectra of each measurement sequence in the evening FSF Post Processing templates can be downloaded from http fsf nerc ac uk resources post processing At least if you spot problems which might indicate a problem in data collection you will have a chance to rectify these on succeeding days If you don t understand something please contact FSF to discuss the problem so that mistakes can be rectified quickly and easily
10. ounting clamp If insects or dirt land on the surface gently blow them away preferably using an air duster do not squash crush swipe as this will impair the surface of the panel Pay particular attention when transfering the panel or putting it back into its case as the surface will dent very easily if it comes into contact with hard surfaces or corners If the panel becomes dirty please contact FSF for instructions on how to clean it 4 2 Weather conditions It is recommended that you only collect field spectral measurements when the weather is fine and stable Even hazy conditions can cause significant changes in irradiance which will have an impact on spectra collected using the GER1500 system If it is necessary to sample in sub optimal conditions you must pay extra attention to the method described above keeping R and T measurements as close together in time as possible If there are clouds passing overhead wait for a large enough clear spell before collecting measurements Do not be surprised if your data are of sub optimal quality if collected under changeable conditions Ideally you should work when the sun is highest in the sky to minimise the effects of shadowing and solar zenith changes Ideally 2 hours either side of Solar noon are perfect Solar noon 1pm BST You should not conduct fieldwork with the GER1500 in wet conditions as the electronic equipment is very sensitive to damp and should not be exposed to wet conditions 4
11. rea which is infringed by an area of contrasting reflectance it can lead to confusing spectra which are very difficult to analyse and correct after the event 4 6 Log Sheets It is immensely important to keep accurate log sheets when in the field Document any changes in solar irradiance and also make a note of every filename and the corresponding surface 5 Downloading data from the on board memory to the PC At the end of the day s data collection you will need to download the scans from the on board memory of the spectrometer and save them to file on the PC provided 5 1 PANS ao 10 11 12 13 14 To Download Connect the spectrometer to a power supply and switch on Take a serial cable and connect this to the spectrometers COM2 port Attach the other end of the serial cable to COM1 on the Panasonic Toughbook PC Power up the Panasonic ensuring that it is connected to an external power supply Mains 12V Open Windows Explorer Create a directory for yourself in the My Computer C drive FSF Users folder Launch the GER1500 exe software Check that the opening prompt box which appears on launch of the software displays the correct serial numbers for your spectrometer configuration As an example a pop up box will appear which will display the following x Ger1500 32 Bit Graphing Application Version 2 0 1 Instrument Serial Number 2038 QV Cc Spectra Vista Corporation De V Yu www
12. tery If using the power converter connect a 12V gel cell using the white cables provided Switch the spectrometer on using the Power switch 3 2 Use the menu button on the spectrometer s front panel to navigate through the various options There are five options repeatedly pressing the menu button will take you through all five options 3 3 The first menu you come to will be called MEM This needs to be reset to a value of 1 before each day s data collection Do this by pressing the EDIT key followed by the downwards pointing arrow key to the right hand side of the menu key When you have reset the memory to 1 press EDIT again to toggle out of edit mode BEWARE that resetting this to 1 will wipe all previous data from the on board memory so only do this if you have already downloaded your data from the previous day 3 4 Press the MENU key again The second menu that you will come to is called AVG and sets the spectrum averaging for each scan Increasing the averaging improves the signal noise ratio of your spectra but be aware that more averaging means longer scan times Remember that the averaging is actually 2 where x is the averaging setting selected So a setting of 5 here is actually averaging 16 and 6 is actually averaging 32 scans It is recommended that you use an averaging of 5 or 6 under field conditions Change the setting by pressing EDIT followed by the up or down arrow key followed by EDIT to set the desired aver
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