Different reading from multiple rovers at same physical location


I am setting up a Sirius F9P base, with multiple F9P rovers. Rover are connected with a PX4 autopilot system, and the base are connect to a PC with ground control software. The RTCM is broadcast to each rovers through wireless network.

I notice that different PX4 system report different GPS height values (for example, one reads 200.0m, others could be 202.0m) while they are all physically on the ground. Also, each PX4’s height reading are jumping/floating a lot. (For the same drone, sometimes 200.0m, a few seconds later, it jumps to 201.5m). Can someone help me understanding the cause of this:

  1. Within a single rover, what is the typical the GPS height values (altitude) accuracy? Is 1 meter floating around normal?
  2. With multiple rovers, are the different reading across them a normal practice or this is a bug?


You are paying attention to the altitude. So how do the values for longitude and latitude change?
The accuracy of RTK FIX solution is about 2cm, Float is about 20-50cm, 3DGPS is about 1m to 2m. . (According to the XY axis).
The elevation accuracy (Z-axis) can have a larger difference than longitude and latitude.
With many Rovers, reading different values (at 1 meter) would be unusual if they were configured the same and operated in RTK FIX solution mode.
If the RTK mode is 3DGPS or Float, a difference of 1 to 0.5 meters is acceptable