• Turn the unit on (green button, lower left) and wait a few seconds well it recognizes itself. Once operational, in the lower right it will say "Connecting to GPS." Hit escape to get access to the Main Menu.
• Select File Manager (down arrow, then ENTER), and Delete File(s) (Highlight, then ENTER). Delete any files left on the system so you have room for your work. Go back to Main Menu (ESC key or MENU button) LAB RULE: ANY DATA LEFT ON ANY RECORDER CAN BE SAFELY DELETED BY THE NEXT USER – in other words, download your data as soon as you return to the lab. If the instrument says "this file not yet downloaded" you might want to reconsider...
• Selecting the Configuration Option leads to several sets of nested sub-menus:

  1. GPS Rover Options – when you are using the instrument to collect data, you are using the rover mode.

  • Logging Options, is the first sub-menu; generally set the parameters like this for acquisition of data. Hit ENTER when you are done to return to the sub-menu.

   

Point Feature – 10 s	Dynamics Code – LAND
Line/Area – 10 s	Audible Click – NO
Not in Feature – none	Log DOP – YES
Velocity – none	Log PPRT – YES
Confirm end feature– NO	Log QA/QC – YES
Carrier Mode – OFF, or ON to get sub-meter post-processed results	Allow GPS Update – WARN
Minimum Time – 10 for sub-meter	Warning Distance - Any

• Position Filters – is the next sub-menu.
  

  Position Mode – set at Manual 3D; Over Determined 3D is better but it requires one more satellite than the manual 3D model and Trimble will just quit collecting data if you lose the extra satellite. If you need really high precision data, use Over Determined 3D and pre-plan your survey using Quick Plan to make sure you will have sufficient visible satellites.

  Elevation Mask – set this at 15^o ; it should be set ~ 5^o higher than any base station you might use for differential corrections.

  SNR Mask = 6.0 works reasonably well.

  PDOP Mask = 8.0; you have to watch the satellite constellation carefully and/or pre-plan your surveys well to always get data with PDOP < 6.0. You can usually get by with PDOP set to 8.0 and still get reasonable differential corrections if you need to. If you need better, preplan.

  PDOP Switch = 8.0. This is only meaningful if you use the 2D/3D collection option which is generally useless unless you already know your elevation. It can be ignored for most any reasonable purposes.

  Apply Real-Time – turn this to AUTO if you want real-time corrections from a third source satellite sending a correction signal (a subscription service) or a fixed Coast Guard beacon. There will soon be a free correction signal sent out of Polson. AUTO allows the correction signal but still collects data when there is no signal. If you select YES, the system will simply not record any data (great feature huh?) when it doesn't see a correction signal. During tests of this in January 2001, our Racal-Landstar fee-based signal failed most of the time.

  RTK Mode, set to ON.

  ENTER to return up a menu-level to Rover Options.

• Antenna Options
  

  Height - I like to set this to 0.0 and then always record the distance of the antenna above the ground in my notes. Alternatively you could set this for every file depending on the height, or you could use a tripod that always places the antenna at the same height. This is a common source of error when comparing the results from multiple surveys or when trying to merge surveys done by different people.

  Measure – set to vertical to indicate you are going to measure to the antenna’s center. Alternatively, set to "uncorrected" and measure to the base of the antenna mount.

  Confirm – set to NEVER. Setting this to another value often leads to a weird and confusing series of sub-menus and steps when recording data. The simplest approach is to know your antenna setting (see above) and never ask Trimble to confirm it.

  Type - You should never have to change this from Integrated GPS/Beacon/Satellite GPS

  ENTER to return up a menu-level to Rover Options.

• Initial Position you should never have to change this unless you transport the instrument 100’s of miles; even then it will take care of itself if you forget to change it.
  
• 2D Altitude tells you where you last were…
  

  ESC takes you back to the configuration menu

2. GPS Base Station Options

Ignore this sub-menu if you are using the Pro XRS as a rover to collect data at different places. If you want to use either Bobolink or Avocet as a base station so you can differentially correct against it, make sure you use a lower elevation mask than for the rover.

3. Communications Options – Leave these alone; don’t change them without asking.

4. Coordinate System

• I tend to use latitude and longitude but you could select state plane (or UTM) for easier referencing to topographic maps. In any case, the software lets you export data in any coordinate system you want. Hit enter at your system of choice.
• Datum – use WGS 84. This will make data comparison and processing consistent with national standards
• Altitude units – meters
• Altitude Reference – use MSL, height above geoid for gravity work. You could save them as HAE and later correct them to MSL (Mean Sea Level which gives height above the geoid) using a fairly accurate geoid model from the National Geodetic Survey. MSL works fine for class assignments.

5. Map Display Options is not pertinent to collecting data at gravity stations.

6. Navigation Options is not pertinent to collecting data at gravity stations.

7. Units and Display – Use the MKS system.

• North Reference use true north as the reference (this is for bearings, etc.).

8. Time and Date – this just lets you set those formats, they should be OK.

9. Leave the following four sub-menu items alone: Quickmarks, Constant Offset, External Sensors, Hardware.