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How to record in OS GB not LatLong

  • 1.  How to record in OS GB not LatLong

    Posted 04-18-2020 02:09

    Recording in OSGB

     

    My catalyst only seems to output in Lat Long. I really need to output in OSGB. I've setup OSGB in Mobile Manager but UAV Ground Station which I use to record the Ground Control Points is still reporting in Lat Long.

     

    How can I record my GCP's in OSGB?

     

    Thanks

    Chris



  • 2.  Re: How to record in OS GB not LatLong
    Best Answer

    Posted 04-20-2020 05:54

    Hi Chris

     

    I'm assuming you are using the UAV Ground Control App with Catalyst for this solution?

     

    There's a similar (now slightly outdated) thread based on what the latest Trimble Mobile Manager (TMM) app can do here

    Trimble Mobile Manager supports 'local'/global geodetic datums and now geoids, but does not include transformations to local systems like the UK's OSTN15 for example nor does it include OSGB36

    • For a list of supported Geodetic datums take a look at the post here

     

    Step 1 - Configuring Trimble Mobile Manager

    The OSGB36 Datum is based on ETRS89

    So you'll need to set* the GNSS Output in TMM to ETRF2000(R05) (which is a specific realisation of ETRS89)

    1. Open TMM and go to the menus screen below
    2. GNSS Configuration > GNSS Output > Select from list > ETRF2000(R05)

     

     

    Note

    * If you are using the Timble Correction Hub as your GNSS Source you can leave the GNSS Output to Auto or Same As Source and it will do the same job.

    TMM is able to calculate which datum to use based on your location, in this case ETRF2000(R05) for the United Kingdom - for more information on this take a look at the TMM help here

    If you are using a local NTRIP and NOT the Trimble Corrections Hub then you will need to specific the GNSS Source Reference frame to compensate for any localised Datum shifts

     

    You will also note the Geoid option - this is a newly supported addition to the TMM app, unfortunately the UAV GCP app does not support geoidal heights at this point so all heights will be in HAE.

     

     

    Step 2 - UAV Ground Control App

    Once this is configured you can close and forget about TMM and use the UAV Ground Control App as you have been.

    All positions will be given in lat/lon HAE so there is nothing we can do here BUT you can use the Ordnance Survey tools to convert the decimal degree/HAE values straight into OSGB36 - OSTN15 Easting and Northings.

    1. Export the GCP's from the app
    2. Use the Ordnance Survey tools below to convert the Lat/Lon/HAE coordinates into local OSGB36 OSTN15 Easting/Northing and orthometric heights
      • The Ordnance Survey Online Transformation tool 
      • Or download the Grid Inquest software version of this online tool which allows you to load in text files for batch transformations. This would be quicker if you want to transform all the height values in one go then update your GIS database/ report using whatever tools are available

     

    To simplify this workflow Trimble do offer other Catalyst enabled applications that can record control points in local UK OSTN15

    • Penmap Android already supports local coordinate systems 'in app' (including OSTN15/OSGM15)
    • Terraflex will begin to support local coordinate systems later this year

     

    If you have any further questions you can also reach out to your local Trimble reseller Korec who have technical support teams with local knowledge of both Catalyst and the UK coordinate system setup