Trimble Catalyst advanced configuration

Follow Avatar Kelly, Marcus
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You can customise the Trimble Catalyst DA2 to use an external NTRIP correction service or to ensure that the GNSS data used in your output files matches your desired reference frame or

NOTE: You must have a valid Trimble subscription or use On Demand hours for these settings to become active during your surveys.


GNSS configuration

To navigate to this screen:

  1. In Trimble Mobile Manager, tap and select GNSS configuration 



GNSS correction source

From this setting you can modify the DA2 correction source.

There are 2 options:  

  1. Auto (Trimble Correction Hub)

This is the Default settings and is the one you must choose if you are using a Trimble subscription or On Demand hours.


  1. Custom local (local NTRIP correction service)

This is setting to use to enter the details of an external NTRIP service.

NOTE: The accuracy achieved is based on the accuracy provided by the correction service selected but it will be not better than your subscription level (1cm, 10cm, 30cm or 60cm) or on demand hours (1cm) you are using.


  1. Select your corrections service Protocol (either NTRIP or Direct).
    This setting should be left to NTRIP. 

  2. Enter the URL and Port number for the server you obtain corrections from. 
    Trimble Mobile Manager uses the URL and port number you have entered to connect to the server and obtain a mount point table.

  3. When the mount point list is available, select the base station to use from the list.

  4. Select the GNSS source reference frame used by your correction source. Trimble Mobile Manager allows you to choose from a list of known source reference frames. If you do not know the correct reference frame, contact your correction service provider. If you are still unsure, select Auto, and Trimble Mobile Manager chooses the best available reference frame based on your current geographic location.

NOTE: If you are near a county, state or country boundary, selecting the correct reference frame for your system of record will reduce the chance of Trimble Mobile Manager selecting the incorrect reference frame.

  1. Trimble Mobile Manager will use the default reference epoch if you have specified a custom GNSS source reference frame for your local correction source. For most users, the default value will be correct for your region. If you are working in a tectonically active region, you may wish to specify a custom epoch. To set a custom reference frame epoch, tap the Customize epoch switch to enable it and then enter the date of the epoch in the Epoch field using the format YYYY.DD, where DD is a decimal representation of the time of year between 00 and 99. The Customize epoch switch is not available when Auto is selected in the GNSS source reference frame field.

  2. If required, set your corrections service account user name and password.

See the Trimble Manager Mobile Manager Help Portal article, from which this section is based:  Configure real-time corrections


GNSS Output Reference Frame




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. In the GNSS output tile, tap Detection mode and select an option from the list. Select:
    • Auto selection
      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.

      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.
  1. If you set the Detection mode field to Select from list, tap the Frame field and select the 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.

  2. 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


See the Trimble Manager Mobile Manager Help Portal article, from which this section is based:  Configure GNSS output