I working on EKF and try to add a bias(1 degree or 1 arcsec) to the measurements. I have two measurements(angles) and finding the position(3) and velocity(3) so total state(6) so I want to extend the filter and for bias estimation (7th and 8th state). The idea is that add bias value to measurements and estimate this values. For example, one of the measurement(190 degree) and the second one(5 degree). If I add 1-degree bias to my measurements new values are 191 and 6 degrees, respectively. My simulation result is, starting from 1 degree and going through zero If I am estimating the bias but I am expecting the result that will start about zero and approximately goes 1 degree.
Where am I wrong? Can you share your ideas or provide some documents for this idea?