# Satellite information

To view information about the satellites currently being tracked by the receiver, tap the satellite icon in the status bar.

In the Satellites screen, you can select the following options:

- To stop the receiver tracking a satellite, tap the satellite to display the satellite information and then tap Disable.

- To change the elevation mask and the PDOP mask for the current survey, tap Options. See Rover options.
- To enable SBAS outside of a survey, tap Options and then select Enable SBAS.
- In a real‑time survey, tap Base to see which satellites are being tracked by the base receiver. No values appear in the Az and Elev columns, as this information is not included in the correction message broadcast by the base.

- In a postprocessed survey, the L1 softkey appears in the Satellites dialog. Tap L1 to display a list of cycles tracked on the L1 frequency for each satellite.

  The value in the CntL1 column is the number of cycles on the L1 frequency that have been tracked continuously for that satellite. The value in the TotL1 column is the total number of cycles that have been tracked for that satellite since the start of the survey.

- With a dual‑frequency receiver, the L2 softkey appears in the Satellites dialog. Tap L2 to display a list of cycles tracked on the L2 frequency for each satellite.

  The SNR softkey appears. Tap SNR to return to the original screen and view information about the signal‑to‑noise ratio for each satellite.

Satellite identification

A satellite is identified by the space vehicle (SV) number.

- GPS satellite numbers are prefixed with a "G".
- GLONASS satellite numbers are prefixed with an "R".
- Galileo satellite numbers are prefixed with an "E".
- QZSS satellite numbers are prefixed with a "J".
- BeiDou satellite numbers are prefixed with a "C".
- OmniSTAR satellites are identified as "OS".
- RTX satellites are identified as "RTX".

Skyplot

To view a graphical representation of the position of satellites, tap Plot.

- Tap Sun to see the plot oriented towards the sun.
- Tap North to see the plot oriented towards north.
- The outside circle represents the horizon or 0° elevation.
- The inner, solid green, circle represents the elevation mask setting.
- The SV numbers on the diagram are placed in the position of that particular satellite.
- Satellites that are tracked but not used in the position solution appear in blue.

- The zenith (90° elevation) is the center of the circle.

  An unhealthy satellite is shown in red.

If a satellite is not being tracked and you expect that it should be:

- Check that there are no obstructions – look at the azimuth and elevation of the SV in the skyplot.
- Tap the SV number and make sure the satellite is not disabled.
- Make sure there are no transmitting antennas nearby. If there are, reposition the GNSS antenna.

Satellite list

To view the list of satellites, tap List.

- In the list of satellites, each horizontal line of data relates to one satellite.
- Azimuth ( Az ) and elevation ( Elev ) define a satellite's position in the sky.
- The arrow displayed next to the elevation indicates whether the elevation is increasing or decreasing.
- The signal‑to‑noise ratios (SNR) indicate the strength of the respective satellite signals. The greater the number, the better the signal.
- If a signal is not being tracked, then a dashed line (‑‑‑‑‑) appears in the appropriate column.
- The check mark on the left of the screen indicates whether that satellite is in the current solution, as shown in the following table.

Situation | A check mark indicates the satellite
--- | ---
No survey is running | Is being used in the current position solution
RTK survey is running | Is common to the base and rover receivers
Postprocessed survey is running | Is one for which one or more epochs of data have been collected

To see more information about a particular satellite, tap the appropriate line.

To use independent subsets of satellites tracked in RTK surveys

Some regulatory authorities require "independent" measurements of points in RTK surveys. This can include making repeated occupations at different times of day to ensure a change in satellite constellation. The SV subset function divides all tracked satellites into two subsets with an even spread throughout the sky, and can be used to measure and then remeasure the point using independent occupations without having to return at another time.

Trimble recommends only using SV subsets when tracking the most available satellites and constellations at your location. This helps ensure each subset has enough satellites to ensure good DOP for each independent occupation.

In the Satellites screen:

- To switch SV tracking to the first subset, tap the SV set A softkey.
- To switch SV tracking to the second subset, tap the SV set B softkey.
- To re-enable all SVs tap the All softkey.

When starting or ending a survey, all satellite tracking for the constellations selected in the survey style are re-enabled.

Use of the SV subset function takes full control over enabling and disabling SVs and overrides any custom enabling or disabling of satellites.

The SV subset functions can also be selected from the Method field in the RTK Initialization screen.

Tracking independent subsets of satellites is not available with the Trimble DA2 receiver.

To change which satellites are being tracked

To enable or disable the tracking of entire constellations such as all GLONASS or all BeiDou satellites, use the check boxes in the GNSS Signal Tracking group box. Ensure you have enough SVs enabled for RTK to operate optimally, as disabling entire constellations can compromise GNSS receiver performance.

- If you disable a satellite, it remains disabled until you enable it again. Even when the receiver is switched off, it stores that a satellite is disabled.

- Individually disabled satellites are not affected by changes to the check boxes in the GNSS Signal Tracking group. If an SV is already disabled it remains disabled when the constellation it belongs to is disabled or enabled.

To enable or disable tracking of SBAS satellites

When you start a survey configured to use SBAS with Trimble Access, the appropriate satellites are enabled in the receiver so that they can be tracked. To use a different SBAS satellite

1. Start the survey with the SBAS enabled style.
2. Tap the satellite icon in the status bar.
3. Tap the SV number of the satellite.
4. Tap Enable or Disable.

The SBAS satellites remain enabled or disabled until the next time that you start a new survey.