Position

Use this page to set receiver position-related settings.

Select Receiver Configuration / Position.

 

PDOP Mask – Use the PDOP mask to enter the value for PDOP above which the calculation of new RTK positions is suspended until the PDOP falls below the mask value again. A DGPS position is output when the PDOP for the RTK position exceeds the PDOP Mask.

NOTE – This applies only to the calculation of position solutions. It does not affect the logging or streaming of GNSS measurements.

RTK Mode – Set the RTK Mode to Synchronous or Low Latency.

  • Synchronous – The rover receiver must wait until the base station measurements are received before computing a baseline vector. Therefore, the latency of the synchronous position depends on the data link delay. A synchronous RTK solution yields the highest precision possible but is subject to latency. This mode is suitable for static and low-dynamic positioning.

  • Low Latency – Provides a slightly lower precision solution than Synchronous mode but with a constant low latency, typically less than 20 msec. This mode is ideal for high-dynamic positioning where latency is an issue.

RTCM 2 Type 31 Input GLONASS Datum – If receiving RTCM 2 corrections from a GLONASS source, you can select the datum (PZ90 or PZ90.02) that they are based on.

Autonomous/Differential Engine – By default, the Kalman filter is on and results in higher quality position solution for autonomous or DGPS solutions when compared with a Least Squares solution. The Kalman selection works substantially better than a Least Squares solution in a mobile vehicle when there are frequent satellite signal dropouts around bridges or high buildings, and gives improved performance around forested areas.

A Kalman solution uses the time history of the position and velocity it has created, whereas a Least Squares option does not use the time history. Trimble recommends using the Kalman filter for most operations. Select Least Squares for non linear movement such as on a suction cutter dredge. The Least Squares option is available for rare cases if you decide to trial it.

Receiver Motion (Dynamic model) – Set to operate as a static or kinematic receiver. This mode determines if the receiver is Static or Moving for base station applications and OmniSTAR initialization.

Horizontal Precision – The required horizontal precision that you set. This threshold determines when the horizontal quality indicator on the receiver display switches from flashing (precision threshold not met) to not flashing (precision threshold met). It also determines when an OmniSTAR solution has initialized.

Vertical Precision – The required vertical precision that you set. This threshold determines when the vertical quality indicator on the receiver display switches from flashing (precision threshold not met) to not flashing (precision threshold met).

 

DGNSS Age of corrections – Defines the maximum age of the corrections, in seconds, for each constellation. When this maximum age is exceeded, the corrections are not used in the position solution.

 

For Trimble RTX-capable receivers, running firmware version 6.20 and later, the following menu items are available:

ITRF Realization (2020)

Epoch – The default is Fixed.

  • Fixed to an epoch means that the position of a point surveyed at different dates is reported as if it was surveyed at the chosen fixed epoch. This uses a tectonic plate motion model to perform a time-dependent transformation, which results in the same position (within the expected measurement and transformation error) for that point, accounting for the movement in the chosen tectonic plate during the time between measurements.

  • If Current is selected, then the latitude, longitude, and height are determined in the ITRF2020 reference frame at the current date. The same point surveyed at a later date results in a different position; the magnitude of the difference depends on the amount of movement of the tectonic plate over the time between surveys.

Click OK to apply the changed settings to the receiver.