robotdisplacement.m

it is a matlab file foe develop SLAM localization this is a toolbox for develop develop realtime e

%ROBOTDISPLACEMENT Predict global map after a robot displacement.
%   G = ROBOTDISPLACEMENT(G,XR,CR,FXR) updates the global map G given
%   the predicted 3x1 robot pose XR, its predicted 3x3 covariance 
%   matrix CR and the 3x3 process model Jacobian linearized around
%   the prediction, FXR.
%
%   The predicted map is returned, with the updated first row and 
%   column of the map covariance matrix.
%
%   See also SLAM.

% v.1.0, Kai Arras, Nov. 2003, CAS-KTH


function G = robotdisplacement(G,xr,Cr,Fxr);

% Predict map
n = length(get(G,'x'));
C = get(G,'c');
for i = 2:n,
  C(1,i).C = Fxr*C(1,i).C;
  C(i,1).C = C(1,i).C';
end;
G = set(G,'c',C);             % set map state covariance first...

% Check on positive definiteness
[x,C] = getstate(G);
if det(C) < 0,
  disp('--> robotdisplacement: cov negative definite!');
end;