Thomas, what sort of GPS accuracy were you seeing? Were you using the standard GPS?
Did you perform some sort of local calibration on-site just before the competition?
@mroberts,
I was using a uBlox LEA-6 GPS and a HMC5883L compass. There is no local calibration for the GPS (in this case the open sky and minimal masking above the competition site provided a max number of sats of around 12) and the compass declination is automatic for the lat and lon.
The ArduRover2 firmware that I was using was pre L1 code and our heading accuracy was well under a meter.
Since the 2013 AVC, we have updated the ArduRover2 firmware to include L1 code enhancements. The L1 enhancements were adopted from the aircraft L1 code. There have been corrections to the heading calculation code that has significantly improved the accuracy of the heading knowledge and recently there have been changes to the GPS configuration that has significantly reduced the GPS latency factor. This has resulted in very accurate straight line and turn navigation as well as very good performance in chicane types of navigation.
Regards,
TCIII ArduRover2 Developer
Interesting. I’m seeing a couple of metres difference in position from day to day, and even after rebooting. If I sit the rover on the same physical point and tag a waypoint then reset, the indicated location may move by a couple of metres.
GPS Drift is a common occurrence even with a solid lock and several satellites,
It has to do with a lot of factors and is not easy (or cheap) to compensate for, a few meters difference is normal and you can sit your GPS somewhere with a good lock hooked up to Mission Planner and watch it drift around quite a lot.
Intrinsic limitation to GPS at this point and not yet economically practical to solve.
Some small improvement might result from combining GPS and Glonass but we haven’t done that yet.
Best Regards,
Gary