Pixhawk reporting RTK float in secondary GPS (non-RTK) instead of primary GPS (Here+ Rover)


I’m using the Here+ system in my hexacopter, but sometimes it seemed like it wouldn’t change the status to RTK float or fixed. However, by looking at the logs and then checking the telemetry during flight, it seems like my secondary GPS is getting an RTK solution instead of the primary. This doesn’t happen always, so it’s a bit difficult to reproduce the issue.

Some details of my setup:

  • Pixhawk 1 (from mRobotics)
  • Here+ RTK
  • Primary GPS is Here+ Rover
  • Secondary GPS is the original 3DR GPS (I believe it’s a ublox LEA-6H)

How could I indicate the Pixhawk the corrections are meant to be for the primary GPS? I’m using the secondary GPS as a backup in case the primary disconnects or somehow stops working, since I know it’s not going to autoswitch in a normal scenario (Here+ always gets over 12 satellites, while the other one is always under 10). Attached are my log files (0000005.BIN shows correct behavior: RTK Fix in primary GPS, 0000006.BIN shows strange behavior: RTK float in secondary GPS).

Thanks for your help,


Has anyone else experienced this issue? Or am I the only one flying with RTK and a backup GPS as secondary?

Today I tried setting the parameter GPS_INJECT_TO. By default it is set to 127,which means to send the corrections to all GPS,so I changed it to 0,which is supossed to send only to the first GPS. However,it still sends the correction to my secondary GPS,as evidenced by the gps status being RTK float (4).

Is there anything else I need to change?

Hola Javier,

Then, you are not using Here+ RTK set? In this case GPS base (which is RTK solution) is primary GPS and Rover( the one on the drone) is secondary. It makes me difficult to understand how it is possible to have float or fix if you don’t have in RTK base GPS


What I mean by primary and secondary are the GPS modules used in the drone (rover). I also have a GPS Base which is sending the RTK corrections. This would be my setup:


  • Here+ Base RTK


  • Here+ Rover RTK (primary GPS)
  • 3DR GPS (secondary GPS, meant to be a backup)