Currently, throw mode checks for a valid navigation status as part of detecting a throw, and won’t detect a throw without it. But it seems (from reading the code) that it will let you arm without it.
bool ModeThrow::throw_detected()
{
// Check that we have a valid navigation solution
nav_filter_status filt_status = inertial_nav.get_filter_status();
if (!filt_status.flags.attitude || !filt_status.flags.horiz_pos_abs || !filt_status.flags.vert_pos) {
return false;
}
My use case is dropping a quad from another vehicle, and I want to be sure that it has a valid solution before I drop it so that it has the best chance possible of recovery. I’ve previously modified the code to perform the above check before arming, and only arm if it passes. That way I can determine that it’s ready to go based only on whether it’s armed or not. (as a side note, I’m not sure if there’s any other way to check nav filter status? There’s a MAVLink message that seems like it would (ESTIMATOR_STATUS), but it doesn’t look like it’s been implemented?)
I can submit this change as a pull request, and probably will, but thought I’d check here first in case anyone had any good reason why it shouldn’t change? The current check could remain in the code to prevent thrown quads trying to recover when they don’t know where they are (in my case, I tended to remove it, figuring that I’d rather the vehicle at least attempt to recover itself than not try). But does anyone have a reason why they’d need to arm without a valid navigation solution?