SparkFun RTK Facet L-Band Drifting While Stationary

GPS/GNSS Development Boards
1

I have been working with the Sparkfun RTK Facet L-Band GPS and it has been great getting fixed coordinates while dynamically moving. The problem I am having right now is that when the GPS is sitting on a table, I can see the reported position drifting significantly (3ft+) over 7-10 seconds. The GPS is in fixed mode and it also has 20 satellites in view.

Two things I have tried are:

  • setting an atmospheric mask so that it ignores satellites up to 20 degrees above the horizon

  • setting a static hold minimum speed which works to hold the position but when actually moving, it creates a new issue of inaccurate position reporting

Are there any other settings that I can tweak in order to have the L-Band GPS stop drifting.

2

Does your GIS software have a place to input the ARP & antenna height offsets? Check out https://docs.sparkfun.com/SparkFun_RTK_ … _software/ and see if that helps

3

tldr; Move outside with a clear view of the sky.

The problem I am having right now is that when the GPS is sitting on a table, I can see the reported position drifting significantly (3ft+) over 7-10 seconds. The GPS is in fixed mode and it also has 20 satellites in view.

Are you indoors? If yes, you’ll have considerable degradation in your position information. 3+ feet (1m) is considered good for an occluded view.

Are you getting a Fix or an RTK Fix? The difference can be seen in your data collector software or on the display: https://docs.sparkfun.com/SparkFun_RTK_ … er-rtk-fix

While 20 satellites sounds good, you should see 30 or more. 20 tells me you may have an obstructed view of the sky. An RTK fix (0.01 to 0.1m accuracy) requires a clear view of the sky, whereas a regular fix can be obtained near windows or in dense foliage but the accuracy will only be 0.3 to 1m.

Are you getting L-Band corrections? You can see on the display a triple point satellite dish indicating good L-Band reception and decryption: https://docs.sparkfun.com/SparkFun_RTK_ … ys/#l-band

setting an atmospheric mask so that it ignores satellites up to 20 degrees above the horizon

This is fine, but what version of firmware are you using? We have only implemented Min SV Elevation in the latest RC: https://github.com/sparkfun/SparkFun_RT … issues/395

setting a static hold minimum speed which works to hold the position but when actually moving, it creates a new issue of inaccurate position reporting

I do not believe this setting is available in the RTK Firmware. What setting are you accessing in the ZED-F9P and how are you setting it?