Here4 periodic gps loss

Here GPS
1

We have on two separate occations experienced a special type of GPS dropouts with one of our Here4 units. We get 1 logged sample of fix type 6 and seemingly valid data, and then fix type 0 and no populated fields. This repeats around every 10 seconds.

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The unit is connected to a CubeOrange flight controller running PX4 1.13. It receives RTK corrections from a NTRIP service as RTCMData Dronecan messages. It operates as a moving baseline rover.

GPS version: HW: 0019000 SW: EXT CORE 1.00 (49f616)
Firmware: v1.13.3

This is our current GPS config:
gps_cfg.zip (902 Bytes)

PX4 Log where the error occurs:
https://review.px4.io/plot_app?log=c687b668-e2a1-4233-b4b9-b70181aee3fe

Has anyone experienced a similar error, or have a hypothesis of what is wrong here? Currently this is a grounding issue for our test platform.

2

Do you see the problem with v1.14 as well? And are you sure nothing else is also publishing GPS? E.g. a second GPS or some other sensor?

3

I had a recent issue with GPS dropout midway through flight. It’s probably not related as your setup with RTK/NTRIP is adding some complications and you use PX4 whereas I use Ardupilot. But in my case I lost GPS data for many seconds and then it seemed like it came back. The whole time, the mag data was still working fine though. I’m not sure if that helps at all.

Does your problem go away if you stop using RTK?