Critical GPS update rate issue

@LorenzMeier @dagar

I think there may be a big issue with trying to use RTK in a plane. With a plane mapping at 15 m/s and a gps update rate of 5hz this would give us a 3m max accuracy on our image geotags. Things get better with the zubax with update rates at 15hz which would give us 1m accuracy (Assuming PX4 supports 15hz refresh rates on zubax) This leads me to my following questions:

  1. Does PX4 interpolate GPS positions to get higher accuracy than whats stated above?
  2. Does PX4 support 15hz refresh rates on zubax GPS?
  3. Is there another way to impliment the use of RTK effectively that PX4 team is working on to get 10 cm or below accuracy?

(Yes I realize though GPS’s I was just referring to are not RTK but the issue is the same)

Yes PX4 has an estimate of your position between those 5Hz GPS updates and it’s faster than 15Hz. If you’re familiar with flightplot ( take a look at a GPS vs GPOS in your flight logs.

Inexpensive RTK GPS with the u-blox m8p should be available soon.

@dagar Thats awesome you have a solution for the GPS update rate am I safe to assume that when we geotag images that the geotag recorded is from the estimation formula px4 uses? If not, we would have a serious mapping problem.

Check the geotagging script you use. If it’s using GPOS instead of GPS you should be good. If you plot both GPS and GPOS with each point marked you’ll see the difference.