# DCM2Q: Convert from Direction Cosine Matrix to rotation Quaternions In RSpincalc: Conversion Between Attitude Representations of DCM, Euler Angles, Quaternions, and Euler Vectors

## Description

`DCM2Q` converts from Direction Cosine Matrix (DCM) to Quaternions (Q).

## Usage

 `1` ```DCM2Q(DCM, tol = 10 * .Machine\$double.eps, ichk = FALSE, ignoreAllChk = FALSE) ```

## Arguments

 `DCM` Direction Cosine Matrix (DCM) is a rotation matrix 3x3 (N=1) or an array 3x3xN `tol` Tolerance from deviations from unity for the determinant of rotation matrices or the the vector length for unitary vectors. `ichk` Logical, FALSE=disables near-singularity warnings. `ignoreAllChk` Logical, TRUE=disables all warnings and error checks (use with caution!).

## Value

Quaternion (Q) vector [q1, q2, q3, q4].

Jose Gama

## References

by John Fuller, 14 Jul 2008 SpinCalc, Function to Convert between DCM, Euler angles, Quaternions, and Euler vectors. http://www.mathworks.com/matlabcentral/fileexchange/20696-function-to-convert-between-dcm–euler-angles–quaternions–and-euler-vectors

Paolo de Leva, 01 May 2013 SpinConv, Conversion from a rotation representation type to another. http://www.mathworks.com/matlabcentral/fileexchange/41562-spinconv

`Q2DCM`

## Examples

 ```1 2 3``` ```DCM <- matrix(c(-0.3573404, -0.1515663, 0.9215940, 0.6460385, 0.6724915, 0.3610947, -0.6744939, 0.7244189, -0.1423907),3,3,byrow=TRUE) DCM2Q(DCM) ```

### Example output

```           [,1]      [,2]      [,3]      [,4]
[1,] -0.5414703 0.1677489 0.7369231 0.3682588
```

RSpincalc documentation built on May 2, 2019, 10:59 a.m.