Configure GNSS output

The GNSS output settings enable consistent coordinate output while using different correction sources, or to use coordinates in a different reference frame from your correction source frame. This means you can output the GNSS data in a reference frame to match your source data or system of record.

To apply a transformation from the source (corrections) reference frame to your desired output reference frame.

  1. Tap and select Configuration.
  2. In the Output tile tap on the drop-down and select:
    • Auto

      The receiver automatically transforms coordinates from the source reference frame to the optimal reference frame for your geographic location.

      This is the default setting, and is the best choice if you are unsure of which reference frame to use.

    • Select from list

      Select a target reference frame datum from a list of available datums. A list of common known reference frames are provided, including a number of global reference frames such as WGS84 [current], commonly used on services such as Google Maps.

      If the local correction source frame you are using is not listed, select Same as source (Transformation off) to forward any positions as received in terms of your local correction source reference frame.

    • Same as source (Transformation off)

      This setting should be selected if you are using:

      • a Custom local correction source.

      • an iOS device with a third-party app that uses the iOS Location Service because GNSS output transformation parameters have no impact on positions from iOS Location Services positions. See Location sharing with other apps.

      When using this setting, reference frame transformations are completely disabled, and the output position is left in the same frame as the configured correction source.

  3. If you set the Output field to Select from list, tap the GNSS output field and select the required reference frame.

    If Trimble Mobile Manager is configured to use custom local corrections, select the reference frame used by the NTRIP caster. In contrast to global correction streams like SBAS or Trimble RTX, the reference frame of a local correction stream cannot always be auto‑populated with 100% accuracy.

  4. To use a local grid file instead of the default EGM96 global geoid, tap the Geoid field and select a grid file from the list.

    Trimble Mobile Manager downloads the selected grid file and outputs altitude values as ellipsoid HAE (Height Above Ellipsoid) and orthometric MSL (Mean Sea Level) values. Both altitude values are output in location extras.

    If the grid file you want to use is not in the list, you can transfer your own grid file to the \GeoData folder on the device. The next time you open Trimble Mobile Manager, select the new grid file, which will appear at the bottom of the Geoid list.

Setting an output reference frame also sets the output EPSG code, which can be queried and used as position meta-data for other Trimble Catalyst enabled applications using Trimble Mobile Manager. The EPSG code is undefined for a position collected using the Same as source (Transformation off) method. For more information on EPSG codes and their use, refer to the official website