# residual

Residuals and residual covariances from direct state measurements for insfilterMARG

Since R2020a

## Description

example

[res, resCov]= residual(FUSE,idx,measurement,measurementCovariance) computes the residual, res, and the residual covariance, resCov, based on the direct state measurement and measurement covariance. The measurement maps directly to the states specified by indices, idx.

## Examples

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Create an insfilterMARG object and display its state.

filter = insfilterMARG;
disp(filter.State')
1.0000         0         0         0         0         0         0         0         0         0         0         0         0         0         0         0   27.5550   -2.4169  -16.0849         0         0         0

Specify a measurement of altitude and vertical velocity.

idx = [5 6 7];
measure = [10 20 30];
measureCov = 1e-2*diag([5 5 5]);

Obtain the residual for the measurement.

[res,rescov] = residual(filter,idx,measure,measureCov)
res = 1×3

10    20    30

rescov = 3×3

0.0500         0         0
0    0.0500         0
0         0    0.0500

## Input Arguments

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insfilterMARG, specified as an object.

State vector index of measurement, specified as an N-element vector of increasing integers in the range [1, 22].

The state values represent:

StateUnitsIndex
Orientation (quaternion parts) 1:4
Position (NED)m5:7
Velocity (NED)m/s8:10
Delta Velocity Bias (XYZ)m/s14:16
Geomagnetic Field Vector (NED)µT17:19
Magnetometer Bias (XYZ)µT20:22

Direct measurement of state, specified as a N-element vector. N is the number of elements of the index argument, idx.

Covariance of measurement, specified as an N-by-N matrix. N is the number of elements of the index argument, idx.

## Output Arguments

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Measurement residual, returned as a 1-by-N vector of real values.

Residual covariance, returned as a N-by-N matrix of real values.

## Version History

Introduced in R2020a