TRU (Topcon Receiver Utility) : Basic Applications

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Checking Receiver Information

  • The user should check the following on the Receiver Information screen:
    • GNSS Firmware version is up to date with the latest revision on Topcon TotalCare.
    • If collecting GNSS raw data files, the device storage size (whether the receiver raw data storage is internal or external) can be read successfully..
    • If the receiver uses 1x or 2x internal batteries, the voltage can successfully be read from all receiver batteries.


Checking GNSS Satellite Status

  • Connect the GNSS receiver to TRU and select the Status icon in Receiver Managing mode.  
  • On the Position tab, the following information is displayed:
    • Current UTC Time of the receiver.
    • Current WGS84 Position of the Antenna Phase Center of the GNSS receiver.
    • Current PDOP (Position Dilution of Precision).
    • Current HRMS/VRMS (Positional Accuracy).
    • RTK Base Distance (if available).
  • The Position tab also displays the number of GNSS satellites being tracked as well as those used in the position solution by the GNSS receiver:
    • GPS is displayed in green 
    • GLONASS is displayed in orange
    • Galileo is displayed in cyan
    • BeiDou is displayed in magenta
    • SBAS in purple
    • QZSS in blue
  • The “wings” on each satellite icon indicates the satellite is being used in the position solution. Those without “wings” are only being tracked


  • Generally, under open sky conditions, the user should check the following on the Position tab:
  • The receiver obtains a standalone GNSS position.
  • The receiver is tracking and using an adequate number of satellites versus all available satellites for a given time and location.
    • Checking all satellites which can be tracked for a given time/location can be done through Topcon’s Mission Planning tool (on TotalCare)
    • Ideally the number of tracked vs. used satellites is the same, however this is not always the case.
      • Depends on satellite elevations, local multipath, obstructions, etc. 



  • On the SV List tab of the Status screen, detailed information about each satellite is displayed:
    • The individual satellite identifiers for each satellite in each constellation being tracked.
    • The current elevation for each satellite and whether the satellite is ascending or descending in the sky.
    • SNR (Signal to Noise) Ratio (in dB*Hz) for each satellite for the following frequencies:
      • L1 C/A channel
      • L1 P channel
      • L2 P channel
      • L2C channel
      • L5 channel
  • Tracking time (in minutes) since last loss of lock in C/A channel (TC).


Checking GNSS Satellite Status

  • On the Sky Plot tab of the Status screen, the general location of all satellites for all constellations currently being tracked by the receiver is displayed.


  • The sky plot gives the user a general indication of how well the satellites are spread throughout the sky for the current location.
    • The center of the sky plot indicates satellites that are directly overhead (90 degree elevation)
    • The furthest extent of the sky plot indicate satellites that are near the horizon (0 degree elevation)
    • The red line indicates the receiver’s elevation mask used for positioning (by default this is set to 5 degrees). Tracking elevation mask is 0 degrees. 
  • Generally, under open sky conditions, the user should check the following on the Sky Plot tab:
    • All the satellites being used in the position solution aren’t all tightly grouped, in a line, or on the horizon.  Ensure that they are spread out throughout the sky.
    • Having all the satellites used in the position solution grouped together, in a line or on the horizon can degrade the accuracy (high HRMS/VRMS) and precision (high PDOP) of the measurements collected by the receiver.


Resetting the Receiver

  • Connect the receiver to TRU and select the Tools icon in Receiver Managing mode. 
  • The Tools screen allows the user to perform the following functions, including:
    • Reset the Receiver (power cycle)
    • Factory Reset (clear NVRAM)
      • Clears current almanac and ephemeris data
      • Resets all receiver parameters to default
    • Reset Parameters
      • Doesn’t clear NVRAM
      • Resets all receiver parameters to default
    • Reset the RTK engine
    • Power off the receiver or place into sleep mode