RTK GPS Survey

2016 Setup instructions for RTK (for a brand new to you location)

Information for your fieldbook

• Base GPS height above the ground control point (specify to blue bumper typically)
• Rover GPS height
• Date / Time
• Ground Control Point you are at
• If logging raw data for OPUS, record the file name
  • Start & End Times
• If creating a new point might sketch a map in your fieldbook etc

General Notes

• In this document, 'turn off TSC3' means press the teal power button in the lower left hand corner for about 1-2 seconds. There are escalating levels of 'turn off' that you can do such as shutting down the Trimble Program on the TSC3 / completely powering down the TSC3 through the windows menu or by depressing the power button for 5-10 seconds. Those are all over kill. It is plenty just to do this much.
• If you approach the Trimble Documentation, you'll see there are a number of settings you can set / things you can do.
  • For this particular TSC3, those things are already taken care of. So, when you enter the Measure menu and choose an activity, in effect you are fast forwarding through all of the options and parameters that you could set to just the configuration that you need to perform the activity you are after... if that doesn't make sense we can talk about this is informally or in a short course.

Strategy

• If you are revisiting the same place over and over, you can reuse the original job for the most part.
• If you are just visiting once, but want to lock in position info, perform the RTK survey first, relative to Here.
  • Then, once the survey is complete, turn off the base receiver.
  • Turn it back on and this time set it up to log position (at 15 seconds interval).
  • Continue your occupation for another 30 - 45 minutes.
  • Power off the base receiver again
  • turn it back on to make sure the file saved properly
  • Depart and later send the raw file to OPUS & continue on with the usual work flow outlined below.

Base Setup

1. Set Tripod up over Rebar / control point.
2. Mount the Tribarach to the tripod
3. Screw the base GPS into a 6" range pole extension, and mount to the hockey puck on the tribarach
4. screw the antenna on to the base gps
5. connect the base station battery to the gps
6. Measure from the Middle of the blue rubber bumper on the base gps to the ground control point.

New Site Coordinate Database Setup

1. Turn on the TSC3. From the Trimble Software select General Survey
2. Next, Select Jobs; New Job
3. This will bring up a new window. The coordinate system will need to be selected.
   1. Side note: If you want to use like the 2012B GEOID it is easiest to set that up using the Trimble Business Center on the toughbook, import this job as noted lower in this page. I think that might be generally the best practice: Set up the job before visiting the survey site actually. Anyway, if you aren't doing it that way...
4. Select the Coordinate System
5. Select it from the Library:
   1. System: UTM
   2. Zone: 3 = Nome; 4 = Barrow; 6 = Prudhoe... check your handheld GPS if you're not sure what zone you're in.
   3. Datum: NAD1983 Alaska
6. Project Height: 100
7. Now the job is setup.

Base Station GPS Setup

1. Connect Base GPS to power
   1. sometimes you will use an internal battery but more often an external battery w/ a cable running to what is called the LEMO port on the GPS.
2. Turn on Base GPS
3. With the Base GPS both turned on:
   1. Click on the Measure Button
   2. Click rtk int radio...
   3. Click Start Base Receiver
   4. For a site you've never visited before, once you start the base receiver it will prompt you for a point name.
      1. Select Key In
      2. Select Here
      3. Name the point
      4. Enter Antenna Height, a quantity you measured earlier in the setup process
      5. Measured to: Center of bumper
   5. Click Start
   6. For a site you have already set up a job for, it can be easier to select the point from a list of points. Enter the antenna height same as noted above and click start.
   7. For a site you have already set up a job for... but don't remember the name of your control point although you have the GPS set up over it...
      1. once your TSC3 is communicating with the base you can switch to map view. Once you are in map view zoom in on your current location to see the point you are standing near. Then, go through the steps of setting up the base receiver and choose this point from the list.
   8. Once the base gps is running in RTK Internal mode, turn off the TSC3

Set up the Rover GPS

1. Mount the Rover GPS to the Range Pole
2. Connect the rover battery and antenna
3. I call the two range-pole set up with flat bottom 97.5 inches to the bottom of the antenna mount
4. If you are using an adjustable range pole, you should measure first.
5. If you are mounting the rover to a backpack you should measure before running through the TSC3 setup.
6. Step away from the base GPS system to talk with the rover...
7. Turn on the rover GPS
8. Turn on the TSC3
9. The active job should still be the one you set up earlier. Again from the main Trimble software, click Measure then Measure Points
   1. The handheld will try to establish a link to the rover GPS.
   2. You will be prompted for the base gps you wish to connect to. Index 27 is ours.
   3. If you are too close for some reason the TSC3 may / will try to communicate with the base GPS treating it as the rover rather than the rover GPS you want to communicate with. The clue is subtle. Basically, when you start the rover talking to the rover it will quickly identify a base with ID I believe 27. When you the TSC3 communicates with the base rather than the rover when you are trying to communicate with the rover you may several things:
      1. the rover GPS spends a lot of time searching for the base
      2. the communications link between TSC3 and rover gps is spotty and you may receive a communications error.
      3. If any of these things happen. Shutdown all of your instruments, return to the base and set it up as outlined in the section above.
10. Now you're nearly ready to survey. First though the Rover GPS parameters will need to be entered.
11. Set the Antenna Height to what you measured / what you know given the range pole configuration.
12. Measured to: Center of Bumper
13. Click the Options button at the bottom of the screen
14. Change the number of measurements from 20 to 5
15. You're now ready to survey.

• Once you start surveying, there are a handful of error messages you may see.
  • Excess Movement - If you receive that message, cancel your measurement and pause for a few seconds. The Rover has a bad lock on the satellites and if you pause it will reset itself. This can happen if the GPS is under a lot of movement before starting the measurement or, if the antenna plane is off-horizontal when it receives the RTK correction from the base.
  • Waiting for base - I'm hazy if that is the proper name or not but it's close. If you receive this message the rover is unable to receive RTK corrections from the base. This can happen as you walk further away or if you have a bit of topography in between the base and the rover. If you have topography, sometimes if you hoist the range pole high over your head the GPS will receive a correction. If that happens you will see something to that effect on your TSC3 icons on the right side of the screen. As soon as you have a valid correction, smash the pole to the ground and start your measurement.

Back in town reviewing collected survey data

• Connect the TSC3 to your computer
• Navigate with Windows Explorer to the folder on the TSC3 with the job.
  • Copy the job and paste it somewhere in your main file system, like c:\users\me\documents\current.job etc
  • Start Trimble Business center
  • Create a new project
  • With the TBC window not maximized but in the background, navigate in windows explorer to:
    • c:\users\me\documents\
    • Drag and drop current.job into the TBC 'Plan View' window.

At conclusion of a ground control point survey

• Power off the Base Receiver
• Turn back on the base GPS receiver
• Connect the TSC3 to the base GPS using bluetooth
  • sometimes it is easiest to do a quick:
    • open job if there is none active (select any old job)
    • click Measure
    • click 'Start Base Receiver'
    • once you see that the TSC3 has connected with the base GPS, cancel out of this setup mode.
  • Click Instrument
  • Click Import from Receiver
  • Download the position file for instance, 31752570.T02 (look for one with extension *.T02 which corresponds to the start time of the logging.
  • It may take a few minutes but the file will slowly transfer to your TSC3.
  • Once transferred, you can shutdown the base GPS & the TSC3

Send raw GCP position data to OPUS

• Connect TSC3 to your computer
• Navigate with Windows Explorer to the folder on the TSC3 with the data
  • Possibly: /Trimble Data/jcherry/
• copy the *.T02 file to your computer
• Turn off the TSC3.
• Start the windows program 'Convert to RINEX'
  • Download here if you don't have it already installed: http://www.trimble.com/support_trl.aspx?Nav=Collection-40773&pt=Trimble%20RINEX
• Navigate through the main menu: File -> Open -> Select the *.T02 file just copied to your computer.
• You'll see Scanning 31752370.T02... If you have an extended occupation you may think the program has frozen but it's just rather inefficiently reading in the file.
• You'll know the scanning is finished when you see Complete! and some file settings info appears.
• Revisit the File menu: File -> Convert Files
• The collection or RINEX converted files will appear in the same folder as where the *.T02 is copied to.
• Navigate to the main OPUS page and configure their input options:
  • http://www.ngs.noaa.gov/OPUS/
• The data file you will up load has extension "*.16o" (it also should be the largest file in the directory since it contains the detailed satellite information for every time step logged in an ascii format.
  • you could also compress the file (using gzip most commonly) before uploading. I find the Chrome browser to be better for the large file uploads, it seems to be more tolerant of time outs in the upload process.
• You will need to select the GNSS Antenna, too. A quick look at the *.16o file in a text editor may show the antenna type.
• Add the antenna height, recorded in your fieldbook.
• Enter your email address.
• Click Options
  • Change the default output format to standard + XML (Draft)
• Finally, upload the file.
  • You should receive an email shortly after submitting.

Add OPUS computed position information to a TBC project

• When emailed the resulting position information, save the xml file to your computer
• The file will probably have file name that is a series of numbers.
  • rename this file to match with the ground control point in the TBC project.
  • Open the xml file in a text editor.
  • Change line 10 to reflect the name from your TBC: <RINEX_FILE>cl-bm01.16o</RINEX_FILE>
• Now, from TBC, import this xml file. The GCP should now be located at the location on earth that OPUS computed.

Useful Links

• http://geoline.com/wp-content/uploads/2014/01/TechTalk_TBC_Workflow_OPUS_.xml-files.pdf
• http://www.ngs.noaa.gov/surveys/forms/obslog-OPUS.pdf

Less useful older information

2013 April Update

Trimble 2009 Geoid http://www.trimble.com/support_trl.asp?pt=&Nav=Collection-66364

Stake outs

So, how to get this all going for doing stakeouts:

1. Start Trimble Business Center
2. Set the Projection information for the project
3. File Menu -> Import -> CSV
4. Select All of the points (CTRL-A)
5. File Menu -> Export
6. Select 'Trimble Field Software exporter (jobXML)
7. Click Export Button and save
8. Copy the resulting file onto the TSC3
9. From the TSC3 Start a General Survey
10. Click on Job
11. Click on Import / Export
12. Click on Import Fixed Format Files
13. File Format: Trimble Job XML
14. Navigate to & import the file.
15. Now, back at the General Survey Menu
16. Click on Job
17. Click on Open Job
18. Navigate to and select the recently imported job.
19. Now , back at the General Survey Menu
20. Click on Stakeout
21. Click on the communication path