This patch makes the reporting of an absolute position solution less abbiguaous and ensures that relative position is always true if absolute position is true
Because synthetic position measurements at 0,0 are fused during position hold mode, a position timeout cannot be used as the only means of detecting position solution status.
Required to prevent acquisition of GPS mid flight causing unwanted change in position and velocity
A distinction has been mad between the arm and disarm transition and the decision to use position hold mode (formerly static mode)
When regaining GPS after a timeout, an offset is applied when fusing GPS velocity so that GPS velocity and position data as fused by the EKF is kinematically consistent.
This velocity offset is also accounted for when fusing air data so that wind estimates are not corrupted when the GPS position offset is being pulle back to zero.
The intended behaviour is that the EKF position will be pulled back to the GPS position at a rate of 5m/s for planes and 1 m/s for copters. This avoids large deviations in trajectory when GPS is regained.
When on the ground it is likely the flow sensor will be returning data that does not meet the minimum quality requirements selected.
The previous check was for the presence of valid data. This has been loosened to look for the presence of data.
When the vehicle becomes airborne, the quality of flow data normally improves as the image comes into focus.
This message is a bitmasked integer that will be used by control software to determine what data is available from the EKF and decide what control modes are available.
Duplicate static mode message removed. Static mode is now contained in the bitmasked solution status message
1) Un-used public methods to report height and position drifting have been removed
2) A time-out has been added to the airspeed innovation consistency check so that if we are relying on airspeed to constrain velocity drift, a filter divergence or other fault that causes the airspeed to be continually rejected will trigger a change in health status.
3) A timeout of velocity, position or height measurements does not cause a filter fault to be reported. Timeouts can be due to sensor errors and do not necessarily indicate that the filter has failed.
4) Time-outs of various measurements are used to present a consolidated bitmask which inidicates which parts of the solution can be used, eg attitude, height, velocity, relative position, absolute position, etc.
This class didn't add any functionality beyond what the NotifyDevice class
already provided so in keeping with our desire to keep things simple we
can remove this class
priseborough
Randy Mackay
Andrew Tridgell
Brandon Basso
The Gitter Badger