Heading or Bearing

I also noticed that sometimes they don't send the speeds, and never heading 8)

id=61171705&lat=xx.1921871&lon=yy.9033072&timestamp=1785438639&accuracy=19.44499969482422&altitude=146.50001525878906&batt=64&charge=false
id=61171705&lat=xx.1921449&lon=yy.9032632&timestamp=1785438678&accuracy=20.856000900268555&altitude=146.3000030517578&batt=64&charge=false
id=61171705&lat=xx.19214074&lon=yy.90311832&timestamp=1785438780&accuracy=12.252382278442383&altitude=168.241455078125&speed=0.0&batt=63&charge=false