Yesterday, as I was preparing to land in an area with many puddles I noticed a flat dry area several feet in front of car. As I was touching down my H suddenly lurched toward my car and ended up sideways against a front tire. The ST16 indicated I was in 5 prop mode and I should land immediately. Except for some light scuffs on the props no damage. I knew I gave no input that would have caused this and strongly suspect that my car interfered with the GPS signal causing this erratic result. My take away: starting or landing (or flying for that matter) stay away from any large metal objects.Yes, exactly and not only metal, also buldings, rockface and so on. It is called GPS multipath.
See here: Multipath - Navipedia
I lost some props due to this and crashed my Blade 350QX in the past. We all have to learn the hard way...
br HE
And my sincerest appreciation and gratitude for q500log2kml . The only problem I have with it is that I suspect it's smarter than I am. Thanks Helmut!