This patch reduces the level of 5Hz and 10Hz 'pulsing' heard in motors due to GPS and altimeter fusion which cause a small 5Hz and 10Hz ripple on the output under some conditions. Attitude, velocity and position state corrections from GPS, altimeter and magnetometer measurements are applied incrementally in the interval from receiving the measurement to the predicted time of receipt of the next measurement. Averaging of attitude state corrections is not performed during periods of rapid rotation.
Time stamps are now explicitly initialised to the current IMU time to avoid unwanted activation of timeout logic on filter start and the various calls to the hal.scheduler->millis() object have been consolidated.
Unused variables have been removed
If the inertial solution velocity or position needs to be reset to the GPS, the stored state history for the corresponding states should also be reset.
Otherwise the next GPS measurement will be compared to an invalid previous state and will be rejected.
The position state should be reset to a GPS position corrected for velocity and measurement latency. This will make a noticeable difference for high speed flight vehicles, eg 11m at 50m/s
Re-initialisation of the magnetic field states and yaw angle is now only performed a maximum of two times after start-up.
Once when coming out of static modefor the first time (first arm event)
Again (for copter only) when the altitude gain above the arming altitude exceeds 1.5m
this prevents magnetic interference present at arming (eg arming on a metal roof)from corrupting the magnetic field states enough to cause bad heading errors and toilet bowling on copter
Add support for /dev/spidev<bus>.<cs> in-kernel SPI CS handling, and convert
existing SPI devices over.
* Add a new member _subdev to the LinuxSPIDeviceDriver class, and initialiser
in LinuxSPIDevice constructor. Use subdev 0 for GPIO-managed CS
* Extend the _cs_pin to signed 16 bits and define SPI_CS_KERNEL (-1) for
kernel-managed CS
* Move to per-device file descriptors (required for in-kernel CS)
* Extend spidev filenames to include bus and subdevice numbers, possibly
longer than 1 digit each
* Allow support for platforms enumerating /dev/spidevNNN from non-zero bases
* Convert existing users over to the new API
Signed-off-by: John Williams <john@whelanwilliams.net>
