Trimble R8 Fast-Static Surveys

Introduction

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WERC uses the Trimble R8 survey gps to measure the elevations of our benchmarks across the state. This document will outline the procedure and glaze over some better practice type issues. With proper use, benchmarks can be gps-surveyed to better than 1cm accuracy in the vertical direction.

Things to do before you go into the field

1. Check the satellite coverage (optional)
2. Charge R8's Lithium Ion battery
3. Charge Trimble TSCe handheld computer
4. Charge the 12 volt battery

Things you will need in the field

1. Survey Tripod
2. Tribrach to hold Trimble R8 GPS in position on the survey tripod
3. Trimble R8 GPS
4. Trimble 12V Battery cable with alligator clips on one end and LEMO connector on the other.
5. Trimble Communication cable (LEMO connectors on both ends)
6. Trimble TSCe handheld computer
7. Extra R8 GPS Li-ion battery
8. 12 Volt Battery
9. Tape measure
10. Voltmeter
11. Fieldbook

Suggested helicopter traveling package

• 12 volt battery in the back storage with the 12 volt alligator-LEMO cable
• R8 mounted to the hockey puck & tribrach sitting on the seat between the two backseat passengers.
• Survey Tripod secured outside to one of the baskets
• Trimble TSCe handheld computer, LEMO-LEMO cable, and extra R8 battery in the yellow nylon case placed in your backpack or some other safe place.

Things to do in the field, your first visit to the benchmark

First up, physical setup

1. Locate the benchmark (often easier said than done...) but you'll probably have available to you sketches and pictures of the site showing where the bench marks and other significant markers are. If the snow is too drifted to find the benchmark you're looking for hopefully you can either find another surveyed location or pound something new in with the aim of doing a follow up optical survey after snowmelt.
2. Extend the tripod legs until the tripod platform is even with face. Do the initial level by eyeball. Put the tribrach on and check to see that the gps is centered over the benchmark. If it isn't, use your foot as a guide and look through the aiming site until the tripod is roughly centered over the benchmark. The lines on tribrach leveling are roughly at midpoint. Before doing final leveling, reset to midpoint.
   Leveling the tribrach
3. Next, sight through the optical plummet to be sure you have the unit nicely centered over the benchmark. The optical deal has a focusing ring so if things are fuzzy... Also watch out for parralax. There's a ring for that, too.
   Looking through the eye plummet at the benchmark
4. Before putting the GPS onto the tribrach, replace the Li-ion battery. You'll only use this battery while configuring the unit but it doesn't hurt to start with a fresh one every new survey.
5. Attach the R8 gps to the tribrach.
6. With the GPS now in place over the benchmark, with the help of a second person make six distance measurements with the measuring tape (record in your field book the distance in units of centimeters):
   1. There is a blue bumper around the R8. Measure from the middle of this blue bumper to the top-center point on the bench mark. The angle your tape measure makes (not being vertical) is by design so make an invisible straight line from the benchmark to the blue bumper and that is what you will measure. Repeat this between all three legs.
   2. Next, measure once again from the top-center of the benchmark but this time to the bottom of the R8. You'll need to do some bobbing and weaving with an eye towards the sliver of light between the hockey puck the R8 is mounted to and the rounded bottom of the R8. This definitely feels more art that science. Anyway, in the bobbing and weaving process you'll see a point in the bob when there is the most daylight showing between the two objects. Your eye is about even with the bottom at that point so record the number on the tape measure for this point. Once again, repeat this for the other two spaces between the legs, working your way around the tripod.
   3. It goes without saying that these numbers should go into your logbook. Optional but desirable is to log both the name of the distance measurer and the person holding the tape to the fieldbook and if you're badly cross eyed, gently decline the job of measuring and just hold the tape.

Next, computery stuff:

1. Power on the TSCe handheld
2. Connect the TSCe to the R8 using the LEMO-LEMO connector and delete any files on the R8
   1. A brief aside: The 18 hour limit on logged data is a function of the amount of flash memory in the R8. With a different model more than 18 hours of position data could be logged. But, you go to war with the army you have rather than the army you wish you had. So, each time a survey is performed the first digital operation to be performed is to clear the memory off the R8 so you can log 18 more hours of position data. To do this;
   2. If it isn't already running, start the program Survey Controller. You'll see the icon on the home screen (similar in some ways to a typical Windows OS desktop).
   3. Wait for the instrument to appear on the right hand icon area. You should see two sets of battery information when the handheld is communicating with the R8 gps.
   4. After the handheld has found the gps again click on instrument
   5. Click on receiver files...
   6. Click on import from receiver
   7. Select any files on the gps and delete them using the 'delete' button along the lower edge of this screen. These files are being deleted off the gps, not the handheld.
   8. Click esc to leave this screen once the memory is empty.
3. You're now ready to set up a fast static survey. Be sure configuration file gage10 is loaded.
   1. If Gage10 isn't the active job:
   2. Single click files in upper left corner
   3. Click open job from context menu
   4. Select GAGE10 as the job. Click it once and then click select in lower right corner.
4. When ready click survey icon --> fast static... --> start base receiver, a new window will appear
   1. Punch in the station name
   2. Set antenna height to zero
   3. Start the survey
5. Disconnect the TSCe from the R8 gps.
   1. This time, just pull the LEMO cable out of the TSCe.
6. Wait a moment, then reconnect the cable
7. Wait longer till the gps has been communicated with (the double battery icons) and click on the instrument icon.
8. Look at the receiver files and see the file on the instrument that is currently being logged to, make a note in your logbook.
   1. I believe there should be one file present and every time you navigate to the receiver files window the file size of this .dat should increase.
9. Pull the LEMO cable free of the R8
10. Plug in the external power LEMO end of the LEMO/alligator clip cable
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11. Leave the site and return the next day to retrieve.

Things to do on your follow up visit to the site the next day

1. Repeat the bumper measurements & the measurements to the bottom of the R8 gps. Seems silly but this will let you know if you made a mistake the previous day or if the unit shifted while you were away (record this in your fieldbook of course).
2. If the LED is still doing a slow blink rather than being a solid LED, no blinking,
   1. Connect the TSCe
   2. Start Survey Controller (if it isn't already running).
   3. Click from within Survey Controller: Survey -> End Survey
3. Download the data; to download the data:
   1. Disconnect the LEMO/alligator cable
   2. Reconnect the LEMO/LEMO cable and the TSCe
   3. Wait for the instrument to appear on the right hand icon area. You should see two sets of battery information when the handheld is communicating with the gps.
   4. Click Instrument
   5. Click Receiver files...
   6. Click import from receiver
   7. Click on the file e.g. 13531560 and click import.
   8. It will take a really long time to import. It's a good idea to keep the handheld warm for the battery so stick it inside your jacket and check on it occasionally.
4. Once it has downloaded, verify you have the file by exiting the Survey Controller program on the TSCe and once at the home screen double click My Computer
   1. Navigate to /disk/trimble data/. You should see the file here for example 13531560 the modified date should be when you downloaded the data. The size should be a bit over 42MB if you let it log until the memory was full.
5. After verifying the presence of the file, exit the file explorer and start the Survey Controller again.
   1. After the handheld has found the gps again click on instrument
   2. Click on receiver files...
   3. Click on import from receiver
   4. Select any files on the gps and delete them using the delete button along the lower edge of this screen. These files are being deleted off the gps, not the handheld.
   5. click esc to leave this screen once the memory is empty.

Things that will suggest to you that the system is working as advertised:

1. Overview of the Trimble R8 LED codes
   1. Fast Blink = R8 isn't doing anything
   2. Slow flash = R8 is logging position
   3. Solid LED = R8 has filled it's memory (you'll see this on your return visit)

So, you won't want to leave until the R8 is giving you the slow blink.

Things to watch out for and other generalities

• Watch out for hitting the power button on the Trimble handheld. This may be urban legend, I can't remember but am passing it on as it appears in my notes... If you use the power button on the TSCe to turn off the handheld while connected by LEMO-LEMO cable to the R8 it will turn the GPS off, too.. Obviously not desirable when starting a survey.
• Middle LED icon on the front of the R8 is for radio (doing a different type of gps surveying) and can be ignored.
• Hold power for just a few seconds to turn gps and TSCe off. 15 s equals factory reset. Hold the power on the TSCe down until it makes a sound (kind of a squeaky 'cl-lick' noise). A message will appear on the screen telling you that you can release the power button. If you do not release the power button it will do a hard reset (wipe all the memory clean).

Things for recording in your Fieldbook

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1. The name of the benchmark being surveyed
2. The serial number of the R8
3. The start time of the survey
4. File name of the data file being recorded on the R8 for this survey
5. The distance from the blue bumper to the monument between all three legs.
6. The distance from the bottom of the R8 to the monument between all three legs.
7. A sketch of the area, monument relative to other features (river would be good, maybe a station if you're nearby one)

Back at camp

Charging

• Charge the Li-ion battery you brought back
• Attach the super dongle to the TSCea and plug in an AC adapter to the AC adapter plugin.

Computer to TSCe interaction

1. Install Microsoft ActiveSync on your laptop.
2. Use USB connector and comically large TSCe adapter to connect the handheld to your computer.
3. After active sync is connected unit may buzz...
4. Don't set up a partnerahip, leave as guest.
5. Then navigate from your computer to the TSCe: My Computer --> Trimble data
   1. Data files are 4digits of serial number (1353) + time