AlexisTM/rtk_ros

GPS_RTK using NTRIP

ryanyej opened this issue · 3 comments

ryanyej commented

hello, after reading mavros GPS_RTK related work, i have more questions about /mavros/gps_rtk/send_rtcm topic
when using NTRIP to get rtcm, then copy rtcm data to /mavros/gps_rtk/send_rtcm topic.
I am not sure to using rtcm data directly received from NTRIP caster
or I need to process these rtcm data first ,then convert to /mavros/gps_rtk/send_rtcm?

AlexisTM commented

Hi @ryanyej
All the processing of this node is handled by GpsDrivers from PX4, to ensure it has the same output as QGroundControl (both QGC & PX4 uses this GpsDrivers library).

I guess you might need to use the following code to create the RTCM message buffer.

https://github.com/PX4/PX4-GPSDrivers/blob/master/src/rtcm.cpp

The message splitting to fit Mavlink2 protocol is done in mavros's side, which is reproduced from QGroundControl's implementation.

https://github.com/mavlink/mavros/blob/b0297e39947a4dd6f60213370c864b9139254b37/mavros_extras/src/plugins/gps_rtk.cpp#L77-L115

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AlexisTM commented

Also, I do not have access to a drone nor an Ublox RTK so I cannot help you more than that. 😞
Good luck!

ryanyej commented

It's OK.
Already helped me a lot.
Thx.

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