dtIMUactual has been spit into a separate dtDelAng and dtDelVel and dtDelVel1 and dtDelVel2 delta time in recognition of the amount of timing jitter and different update rates for the IMU's
Vibration in the 400Hz delta angles could cause the angular rate condition check for in-flight magnetic field alignment to fail.
The symptons were failure to start magnetic field learning as expected when EK2_MAG_CAL=3 was set.
The calculation of a delta rotation between consecutive magnetometer samples has been introduced instead of the most recent IMU delta angle as this is less affected by noise and give an upper bound on the angular error.
the check has been moved into the magnetometer fusion control function so that any reset will be performed using fresh magnetometer data
Fixes a potential error where changes to timing and arrival rate of magnetometer and baro data could block the fusion of synthetic position and velocity measurements, allowing unrestrained tilt errors during operation without GPS or optical flow.
Fusion of synthetic position or velocity measurements is now timed to coincide with fusion of barometer observations.
If a new barometer observation has not arrived after 200 msec then the synthetic position or velocity is fused anyway so that fusion of synthetic position or velocity observations cannot occur any slower than 5 Hz
This method checks for consistency between accelerometer readings and switches to the unit with the lowest vibration of the difference exceeds 0.3g
The threshold of 1.7 m/s/s corresponds to a maximum tilt error of 10 deg assuming one IMU is good, one is bad and the EKF is using the bad IMU.
This commit changes the way libraries headers are included in source files:
- If the header is in the same directory the source belongs to, so the
notation '#include ""' is used with the path relative to the directory
containing the source.
- If the header is outside the directory containing the source, then we use
the notation '#include <>' with the path relative to libraries folder.
Some of the advantages of such approach:
- Only one search path for libraries headers.
- OSs like Windows may have a better lookup time.
This prevents bad inertial or GPS data combined with the post takeoff heading alignment check used by plane from resulting in earth field states that have an incorrect declination
Prolonged yaw rotations with gyro scale factor errors can cause yaw errors and gyro bias estimation errors to build up to a point where EKF health checks fail.
This patch introduces the following protections:
1) The assumed yaw gyro error is scaled using a filtered yaw rate and an assumed 3% scale factor error (MPU6000 data sheet)
2) When the filtered yaw rate magnitude is greater than 1 rad/sec, the Z gyro bias process noise is zeroed and the state variance set to zero to inhibit modification of the bias state
3) When the filtered yaw rate magnitude is greater than 1 rad/sec, the magnetometer quaternion corrections are scaled by a factor of four to maintain tighter alignment with the compass
The interface definition has been modified so that it returns true for a position obtained usin geither the normal inertial navigation calculation, or a raw GPS measurement.
This enables this function to be used to set a home position before flight.
If a calculated position is not available, the function will return a value based on raw GPS or last calculation if available, but the status will be set to false to indicate that it cannot be used for control.
Andrew Tridgell
Paul Riseborough
Randy Mackay
Jonathan Challinger
Gustavo Jose de Sousa
Paul Riseborough