IMUFilter

Orientation calculation using an inertial measurement unit filter.

blockType: IMUFilter

Path in the library:

/Navigation/Multisensor Positioning/Navigation filters/IMUFilter

Description

Block IMUFilter Combines accelerometer and gyroscope sensor data to estimate device orientation.

Ports

Input

# Accel — accelerometer readings in the coordinate system of the sensor housing, m/s²
the matrix

Details

Accelerometer readings in the coordinate system of the sensor housing in m/s², given as a real matrix of the size on , where — the number of samples, and the three columns of the matrix represent measurements respectively.

Data types	`Float32`, `Float64`
Complex numbers support	No

# Gyro — gyroscope readings in the coordinate system of the sensor housing, rad/s
the matrix

Details

The gyroscope readings in the coordinate system of the sensor housing in rad/s, set as a real matrix of the size on , where — the number of samples, and the three columns of the matrix represent measurements respectively.

Data types	`Float32`, `Float64`
Complex numbers support	No

Output

# Orientation — orientation of the sensor housing coordinate system relative to the navigation coordinate system
the matrix | array

Details

The orientation of the sensor housing coordinate system relative to the navigation coordinate system, returned as a real matrix on or as an array of rotation matrices on on . Each row of the matrix on It contains four quaternion elements.

Number of input samples and the parameter value Decimation factor determine the size of the output data .

The output format depends on the parameter value Orientation format.

Data types	`Float32`, `Float64`
Complex numbers support	No

# Angular Velocity — angular velocity in the coordinate system of the sensor housing, rad/s
the matrix

Details

The angular velocity, taking into account the displacement of the gyroscope in the coordinate system of the sensor housing in rad/s, returned as a real matrix of the size on .

Number of input samples and the parameter value Decimation factor determine the size of the output data .

Data types	`Float32`, `Float64`
Complex numbers support	No

Parameters

Filter Settings

# Reference frame — navigation coordinate system
NED | ENU

Details

The navigation coordinate system, set as NED (north-east-down) or ENU (east-north-up).

Values	`NED` \| `ENU`
Default value	`NED`
Program usage name	`DispRefFrame`
Tunable	No
Evaluatable	No

# Orientation format — orientation output format
quaternion | Rotation matrix

Details

Output data format Orientation:

quaternion — the Orientation output port outputs a real matrix on . Each row of the matrix contains four quaternion elements.
Rotation matrix — the Orientation output port outputs an array of rotation matrices on on .

Number of input samples and the parameter Decimation factor determine the size of the output data .

Values	`quaternion` \| `Rotation matrix`
Default value	`quaternion`
Program usage name	`OrientationFormat`
Tunable	No
Evaluatable	No

# Decimation factor — decimation coefficient
Real number

Details

The decimation coefficient by which the data transfer rate from the input sensor is reduced, set as a positive integer.

The number of rows in the Accel and Gyro input data matrices must be a multiple of the decimation factor.

Default value	`1`
Program usage name	`DecimationFactor`
Tunable	No
Evaluatable	Yes

# Initial process noise — the initial noise of the process
Matrix of real numbers

Details

The initial noise level of the process, set as a real matrix of size on .

Default value	`[0.000006092348396 0 0 0 0 0 0 0 0; 0 0.000006092348396 0 0 0 0 0 0 0; 0 0 0.000006092348396 0 0 0 0 0 0; 0 0 0 0.000076154354947 0 0 0 0 0; 0 0 0 0 0.000076154354947 0 0 0 0; 0 0 0 0 0 0.000076154354947 0 0 0; 0 0 0 0 0 0 0.009623610000000 0 0; 0 0 0 0 0 0 0 0.009623610000000 0; 0 0 0 0 0 0 0 0 0.009623610000000]`
Program usage name	`InitialProcessNoise`
Tunable	No
Evaluatable	Yes

Measurement Noise

# Accelerometer noise ((m/s²)²) — noise dispersion of the accelerometer signal, (m/s²)²
Real number

Details

The noise dispersion of the accelerometer signal in (m/s²)², given as a positive real scalar.

Default value	`0.0001924722`
Program usage name	`AccelerometerNoise`
Tunable	Yes
Evaluatable	Yes

# Gyroscope noise ((rad/s)²) — noise dispersion of the gyroscope signal, (rad/s)²
Real number

Details

The noise dispersion of the gyroscope signal in (rad/s) ², given as a positive real scalar.

Default value	`9.1385e-05`
Program usage name	`GyroscopeNoise`
Tunable	Yes
Evaluatable	Yes

# Gyroscope drift noise ((rad/s)²) — gyroscope displacement drift variance, (rad/s)²
Real number

Details

The variance of the gyroscope displacement drift in (rad/s)², given as a positive real scalar.

Default value	`3.0462e-13`
Program usage name	`GyroscopeDriftNoise`
Tunable	Yes
Evaluatable	Yes

Environmental Noise

# Linear acceleration noise ((m/s²)²) — noise dispersion of linear acceleration, (m/s²)²
Real number

Details

The noise variance of linear acceleration in (m/s²)², given as a positive real scalar. Linear acceleration is modeled as a white noise process filtered out by a low-pass filter.

Default value	`0.009623610000000001`
Program usage name	`LinearAccelerationNoise`
Tunable	Yes
Evaluatable	Yes

# Linear acceleration decay factor — attenuation coefficient for linear acceleration drift
Real number

Details

Attenuation coefficient for linear acceleration drift, given as a scalar in the range [0, 1). If the linear acceleration changes rapidly, set this parameter to a lower value. If the linear acceleration changes slowly, set this parameter to a higher value. Linear acceleration drift is modeled as a white noise process filtered out by a low-pass filter.

Default value	`0.5`
Program usage name	`LinearAccelerationDecayFactor`
Tunable	Yes
Evaluatable	Yes