Installing RTK GPS On ModalAI Sentinel Drone

Hello All,

I am planning to remove the default M8N GPS onboard my ModalAI Sentinel drone and replace it with the HolyBro H-RTK F9P GNSS Series (Helical).
Sentinel drone is powered by the VOXL2 board which runs PX4 Autopilot.

What should my steps be?
Should I unplug the M8N and plug in the H-RTK F9P, or will I have to tweak some params/settings to make it work?

Please help.


With the caveat that I don’t have one and know little about it, it should be more or less “plug-n-play” - as per Holybro H-RTK F9P GNSS | PX4 User Guide (main) the connectors are the same. PX4 should auto detect this type.
There is normally no special configuration other than survey-in as per RTK GPS | PX4 User Guide (main)

But the fact is that this is not a generic PX4 question any more. You should probably ask on the VOXL forums.

The default configuration does detect the GPS positioning but I am having 2 issues here:

  1. Even after the Servey-in completes on the RTK Base station, by GPS On board does not receive any RTK corrections (No LED indications)
  2. The Heading/YAW estimates are erroneous.

You don’t get yaw by default from RTK/GPS - it comes from a compass. Unless you have a GPS from yaw setup (usually 2 F9Ps on vehicle) - do you?

Are there incoming Messages (common) · MAVLink Developer Guide messages on the vehicle - i.e. I know you don’t think the data is getting to the GPS, but is it getting to the flight stack?

@JulianOes Any thoughts on how to debug this, or ideas on who else to ask? I thought it was plug-n-play if you had a QGC/Vehicle connection.