when you have a moving baseline pair of ublox GPS modules and the
rover GPS does not have full fixed RTK lock on the base GPS then we
should not use it as our primary GPS as it's position and velocity can
be badly affected by the attempts of the GPS to gain a fixed lock.
This was observed in a flight with two F9P GPS, where the GPS velocity
data from the rover GPS went way off when it lost full RTK lock. It's
status stayed at 4, so it was selected as the primary GPS
this fixes the status reported for a UAVCAN GPS when the cable is
unplugged. It should be "NO GPS", but was instead reporting "NO
FIX". The user had no way to distinguish between not finding a CAN GPS
at all and it not getting satellites
thanks to CUAV for reporting
This does not yet:
- validate the receiver configuration
- manage timing out stale GPS heading info
- relPosNormalized usage isn't clear, which may defeat the STRICT_LENGTH_CHECK
the Drotek F9 GPS ships with TMODE enabled, which means we don't get a
3D fix.
This also adds the VALGET/VALSET msgs we will need for automatic
moving baseline config
when we have corrupt input due to loss of bytes on a UART we can end
up with a u-blox packet with zero payload bytes. When that happens we
need to bypass payload reading as otherwise we will end up keeping
reading bytes until the driver resets at 4 seconds, causing a GPS
outage.
This was causing GPS outages every few hours in copters running 3.6.7,
and was also reproduced in SITL using SIM_GPS_BYTELOSS.
The NMEA GPHDT sentence can be used to determine the vehicles bearing
instead of a compass even when the vehicle is stationary. This type
of GPS is normally very expensive and does the bearing using some sort
of phase ambituity algorithm.
This improves log analysis of bad GPS health messages when you have a
report of bad GPS health but lost the MAVLink message, or didn't have
access to the autopilot log with the information for some reason.
If the event pin floats, this can lead to UART congestion, causing the
EKF to reject the GPS data, and the vehicle will drift around the sky in
a most disturbing manner
