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Numerous satellites , poor accuracy

  • 1.  Numerous satellites , poor accuracy

    Posted 10-04-2022 15:59
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    We are using both the DA1 and DA2 antenna on Android Devices, with on demand hours to the highest accuracy service. On numerous occassion and across the Australian continent we have issues where we have a large number of satellites ( see image) ad represented in a blue circle. The accuracy is quite poor and varies in this instance greater than 0.25m, with a supposed 0.01m accuracy service. Yes, it depends on location on the number of satellites and location, however in these locations we have got down to 0.1m accuracy ( horizontally) quickly. It also pops up a message relating to the RTX/ViaIP message. ( I did not capture this). Any info would be great, even any work arounds tricks etc.

    TAP Admin Maxam

  • 2.  RE: Numerous satellites , poor accuracy

    Posted 10-05-2022 01:47

    thanks for sharing this information and picture from the device.
    I assume that you are using Trimble Corrections hub as an correction service.
    The blue colored satellite number indicates that you get a RTX solution.
    Typically an RTX solution takes longer to get to a fixed position, even if the antenna tracks 21 satellites.

    Please check the position status: Tab&hold on the GNSS button --> GNSS Position

    Please get in touch with your local Trimble dealer.
    He should be able to tell you what accuracy you can expect at your location and how long it typically takes to get it. 
    He can also check if there should be a VRS service available in your region.


    Thomas Schucker

  • 3.  RE: Numerous satellites , poor accuracy

    Posted 10-05-2022 08:02
    Edited by Tom Harrison 10-05-2022 10:02
    Hi @TAP Admin Maxam

    To add to Thomas's comments - the DA2 is able to achieve much better accuracy with RTX than the DA1 thanks to its updated GNSS engine and Propoint technology (take a look at the Catalyst Hardware section here)
    • The DA2 is therefore capable of achieving 2cm horizontal and 5cm vertical RMS with RTX (datasheet here) over L-band OR IP 
    • To achieve 1cm level with the DA1 you need to either be inside a VRSNow network OR connected to a local NTRIP. That is the only way to achieve this type of accuracy with the DA1
    • Using RTX only with the DA1 I would expect the you to achieve 20-30cm's in good conditions after 5-15mins
    So from the information you have provided I would say the DA1 units are performing to spec with RTX If they are hitting 0.25m and If you test a DA2 in this same location you will achieve much better results

    Reach out to your local Trimble reseller for more details on the differences between the DA1 and DA2 and what you should expect in your location

    Tom Harrison