Reach RX NMEA Output Altitude Precision

Reach RX Hardware integration
1

I’m trying to use Reach RX to Configure Mock Locations on my Android Tablet. I’ve setup “GPS Connector” app and also “Bluetooth GNS” app, and got the NMEA stream coming in. The altitude field of the $GNGGA Lines are only giving precision to 1DP, or 10cm (example 18.8,M). In the Emlid Flow app I’m Using RTK and getting a fix and the UI is reporting heights with 3DP (example 18.782m). Is this a limitation of the NMEA from Reach RX or is there something I can do to get that extra altitude precision into the NMEA sentence?

Side Note: I tried ‘Lefebure NTRIP Client’ on 2 devices and had no success getting Mount point/Data Stream List or to connect via Bluetooth, it may now be obsolete?

4

Hi @reubenDN,

Welcome back to the community!

I just checked, and the streamed position from Reach uses three decimal places of precision. Could it be a setting within the NTRIP client?

I can’t test Lefebure at the moment, but one of our users successfully used it last week without any issues. Just to clarify—does the mount point load in another NTRIP client app but not in Lefebure?

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Thanks, Yes I’m able to load the Mount point Lis in ‘Bluetooth GNS’ app. Here is an example output $GNGGA,025240.80,4333.54511,S,17241.06740,E,4,12,0.54,6.8,M,8.4,M,0.8,0078*4D

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There is something else I’d like to know about NMEA outputs. Some but not all of these 3rd party apps allow for NTRIP Corrections. If I have NTRIP Corrections being applied in Emlid Flow (shown above in the GGA sentence as value [4: RTK Fixed], Can I just assume I don’t need the NTRIP Corrections? I’m confused by this because the Emlid guidance on using Lefebure includes entering NTRIP details. Getting Reach coordinates on Android devices via Bluetooth | Reach RX Does this article assume that The Emlid reach App is not in use?

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I’ve also read some other threads and will try the GNSS Master app.

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Which 3rd party software you want to integrate it with?

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I want to set mock locations so they can be used with web browser for using https://www.datanest.earth/ (Progressive Web App)

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Emlid Flow is also an NTRIP client, but the mock location feature won’t work when you use it as such.

I checked Bluetooth GNSS and I couldn’t find the option to change the precision. GNSS Master might be worth checking if Lefebure isn’t working for you.

$GNGGA,025240.80,4333.54511,S,17241.06740,E,4,12,0.54,6.8,M,8.4,M,0.8,0078*4D

Could it be that the elevation on this specific point is actually just 6.800, thus the value? When you move to a different location, does the elevation change?

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Thanks for having a look. The height values in my test only jumped 10cm 6.7, 6.8 etc.

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Oh, I see. I’ll test it and report back here. On a side note, what elevation is showing in the web app? Does it also have the same precision?

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You can verify the output elevation and horizontal cords by occupation of a passive control mark. Just make sure you’re using the same projection and vertical datum i.e., Geoid18, that the passive control is in if you’re using an RTN.

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@reubenDN,

I tested Lefebure today, and it could load the Mount Points. It might be worth uninstalling and then installing the app. Also, please check that the NTRIP credentials are correct.

I also tested the Bluetooth GNSS app. The altitude in the GGA message has three decimal precision.

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I can’t find any settings in the app changing the precision, so I suggest contacting their support about this.

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Thanks, I updated the firmware to V1.8 and it solved the issue. Lefebure is also now working for me.

1 Like
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Oh, I see. What version was installed on your device previously?

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Version 1.0