QTS Transformation to Angular Acceleration Vector Time Series

This function projects a quaternion time series into the space of angular acceleration vectors.

Usage

qts2aavts(x, spar = 0)

Arguments

x

An object of class qts.

spar

smoothing parameter, typically (but not necessarily) in \((0,1]\). When spar is specified, the coefficient \(\lambda\) of the integral of the squared second derivative in the fit (penalized log likelihood) criterion is a monotone function of spar, see the details below. Alternatively lambda may be specified instead of the scale free spar=\(s\).

Value

A time series stored as a tibble::tibble with columns time, x, y and z containing the angular acceleration vector at each time point.

Examples

qts2aavts(vespa64$igp[[1]])
#> # A tibble: 101 × 4
#>     time         x         y          z
#>    <int>     <dbl>     <dbl>      <dbl>
#>  1     0  0.00234   0.00106   0.000561 
#>  2     1 -0.00128  -0.00256  -0.000736 
#>  3     2  0.000199 -0.00104  -0.000725 
#>  4     3  0.00168   0.000476 -0.000713 
#>  5     4  0.00156   0.000278 -0.000373 
#>  6     5  0.00159   0.000252 -0.000467 
#>  7     6  0.00162   0.000225 -0.000560 
#>  8     7  0.00100  -0.000258 -0.000572 
#>  9     8  0.000387 -0.000741 -0.000583 
#> 10     9 -0.000597 -0.000377 -0.0000683
#> # ℹ 91 more rows