Use RTK in mission planning and localisation

Hi everyone,

I have bought a Drotek Serius RTK module, which utilizes M8P ublox module for precision positioning. My goal is to use it to be able to autonomously fly my drone with greater precision, but so far I have been getting mixed results.

I have waited for a while to get a 0.5 m survey-in accuracy, but then still it can be seen that the drone drifts position in the X Y plane, though it is completely stationary on the ground (this drift is clearly larger than 0.5m, more in the range of +5 m). This drift would not seem necessary to me, as the drone and base station know eachothers whereabouts up to a few cm accurate, and the base station location is fixed in a radius of 0.5m. Is that correct?

My question: is the RTK only used for after processing, or can it also be used in mission mode? I thought this was the case, but because of my results I get a feeling it isn’t. Is there any hack that does enable it to be used in mission mode?

To clearify my findings, I have attached the log files from an experiment that I did in which I placed the drone outside in the middle of a spot which has a clear view of the sky. In the experiment I armed the drone, but didn’t take off the entire “flight”, thus keeping it completely stationary (for 10 minutes). The logs can be seen here:

As can be seen in the second plot, the GPS signal wanders off quite a bit (approx. 3m in the X direction, and 3 m in the Y direction). Compared to earlier results I good this is actually quite good (+5 m wandering off), although still way to much for my application.

Does anyone know if it is possible to set mission coordinates relatively to the base station position?

Thank you,


First, check satellites arrangement.

HDOP should be around 0.4 for RTK fixed.

Here are shown two RTK GPS’s close together. The differences in coordinates is the physical distance between them, both NS and EW, when having RTK fixed.