[Postcard/LG290P] RTK Fix lost during kinetic testing

[nseidle]

Reported here.

This seems to be a new behavior for the LG290P (ie, we've tested driving with the LG290P plenty, and the RTK Fix was solid, but that was a few Quectel firmware versions ago). We need to test LG290P firmware v2.1 (the latest as of writing) to try to replicate. Assuming we see a similar issue, then we need to test lower versions. If we can pin an issue to a given firmware version, then we can let Quectel know.

[nseidle]

User reports using helical. We should test with both helical and 'ufo' antennas.

[PaulZC]

Update: Quectel added PQTMCFGNAVMODE in firmware v2.01. It defaults to Mower mode...!

Library updates in progress:

sparkfun/SparkFun_LG290P_GNSS_Arduino_Library#25

I suggest we make RTK Everywhere default to Mode 0 (Normal mode, "Basic mode applied to most scenarios, for example, driving scenario")

[PaulZC]

Humm... There's more to this than meets the eye...

I have added support for CFGNAVMODE and can now set firmware 2.01 and 2.02 into "Dynamic" mode (5).

2.02 Dynamic mode, 2.01 Dynamic mode, 1.06 and 1.05 all appear equally badly behaved.

I strapped a Postcard to a SparkFun L1/L2/L5 UFO antenna, configured it for NTRIP Client with corrections coming from RTK2go via WiFi, took it outside, waited for RTK Fix, then moved the antenna+Postcard quickly from left to right about half a metre each way, then held it still.

In all four cases, I see RTK go from Fix to Float, then return to Fix after a couple of seconds. Purely by eye, 2.02 Dynamic appears to behave no better than 1.06 or 1.05.

I will keep investigating...

[PaulZC]

CFGNAVMODE added in #1094 , but, as per above, purely by eye, Dynamic mode doesn't appear to provide better performance...

[PaulZC]

Could it be this?

[PaulZC]

Nope... I added support for CFGRTKRL. No changes - with very relax or very strict. Default is medium.

[nseidle]

While this feature has been added, the problem remains. The LG290P, as of its firmware v2.1, works well for gathering static points but seems to lose RTK Fix in mildly kinetic environments. If you are doing a project that requires fast location rates, we recommend using a product with a different GNSS engine (ZED-X20P, mosaic-X5, UM980, ZED-F9P).