A CARTESIAN COORDINATE CONVERSION ALGORITHM FOR RADAR TRACKING WITH RANGE RATE MEASUREMENT

Using the target location and the target range rare as radar observati on data, a tracking filter based on the extended Kalman filter is disc ussed. For this tracking filter, the Cartesian coordinate will be used , with the north as one axis, the one with the object position vector as one axis, or the one with the target velocity vector as one axis. H owever, it has not been reported if the computed variables (estimate v alues of the motion parameters of the object, such as location and vel ocity, and the error covariance matrix as the evaluation value of the estimation error) in a tracking filter using a specific Cartesian coor dinate can be converted to the parameters in the tracking filter using another Cartesian coordinate. Because it remains to discover whether conversion is possible, research still continues to find a Cartesian c oordinate that has good tracking performance. It is proven here, using a mathematical induction method in regard to the sampling time, that no matter which Cartesian coordinate is used in the forementioned trac king filter, its computational parameters can be converted to those of the tracking filter using an arbitrary Cartesian coordinate. As a res ult, comparison and evaluation of the tracking filter performance are unnecessary when different Cartesian coordinates are used. In addition , the equations are derived for conversion of the target motion parame ters, covariance matrix, and gain matrix between these tracking filter s.