Name

CL_dsp_covCoord — Change coordinates of covariance matrix

Calling Sequence

   [means2,cov2]=CL_dsp_covCoord(means,cov1,coord[,mu])
   
   

Description

  • Given a covariance matrix in a type of coordinates (1), this function converts the covariance matrix into another type of coordinates (2). Allowed conversions are some of those available in topic SL_coordinates of CelestLab ('cir2car','car2cirEqua','car2kep', 'cirequa2kep' and reciprocal conversions).
  • Last update : 06/12/2007

Parameters

means1:

vector of mean values of variables type 1 (6xN)

cov1:

covariance matrix of variables type 1 (6x6xN)

coord:

string defining conversion of coordinates. It is the name of the function defining the conversion without the prefix 'co_'

mu :

(optionnal) geocentric gravitational constant [m^3/s^2] (default value is %CL_mu)

means2:

vector of mean values of variables type 2 (6xN)

cov2:

covariance matrix of variables type2 (6x6xN)

Authors

CNES - DCT/SB

See also

CL_cor2cov, CL_stat

Examples

//change correlation matrix from cartesian to adapted circular parameters
bulletin = [-1877901 -3909428 -5026025 7428.157 -1541.857 -1576.532]'; //position and velocity
cor = [1 -0.467016 -0.447601 0.960396 0.987145 0.995826;...
0 1 -0.088751 -0.359696 -0.412472 -0.540655;...
0 0 1 -0.248472 -0.582834 -0.431908;...
0 0 0 1 0.915197 0.943178;...
0 0 0 0 1 0.980679;...
0 0 0 0 0 1]; //upper triangle of correlation matrix
cor = cor+cor'-eye(cor);  //complete correlation matrix (symmetric)
sd = [15939.68154 2912.099353 3079.494708 6.81910416 9.50017639 12.14624495]'; //standard deviations
cov_car = CL_cor2cov(cor,sd); //covariance matrix in cartesian parameters
[bulletin_cir,cov_cir] = CL_dsp_covCoord(bulletin,cov_car,'car2cir');
[cor_cir,sd_cir] = CL_cov2cor(cov_cir);