- sensor_baro.msg use SI (pressure in Pascals)
- update all barometer drivers to publish directly and remove PX4Barometer helper
- introduce baro cal (offset) mainly as a mechanism to adjust
relative priority
- commander: add simple baro cal that sets baro offsets to align with
GPS altitude (if available)
- create new sensors_status.msg to generalize sensor reporting
- remove all remaining IOCTLs for accel and gyro and handle all calibration entirely in sensors module with parameters
- sensor_accel and sensor_gyro are now always raw sensor data
- calibration procedures no longer need to first clear existing values before starting
- temperature calibration (TC) remove all scale (SCL) parameters
- gyro and baro scale are completely unused
- regular accel calibration scale can be used (CAL_ACC*_xSCALE) instead of TC scale
This avoids the need for recalibration, and also cleans up other driver
ID's (merge separate accel/gyro).
The SPI address was previously set to a board-specific (arbitrary) value,
and is now set to 0. This will allow extending for multiple sensors of the
same type on the same bus.
