Hi Pere,
There are two options to use local coordinates for the filter "GPS" updates. You can either use the correct object function on insfilterMARG, or use the default reference location of [0 0 0].
filt = insfilterMARG;
stateIdx = stateinfo(filt);
gpsPos = [1 2 3]; % GPS position measurement in local coordinates (m)
Rpos = 1; % Covariance of GPS position (m^2)
correct(filt, stateIdx.Position, gpsPos, Rpos)
OR
lla0 = [0 0 0];
filt = insfilterMARG;
filt.ReferenceLocation = lla0;
gpsPos = [1 2 3]; % GPS position measurement in local coordinates (m)
Rpos = 1; % Covariance of GPS position (m^2)
gpsLLA = ned2lla(gpsPos, lla0, "ellipsoid");
fusegps(filt, gpsPos, Rpos);
Thanks,
Ryan
