Constant gain tracker with variable frame time

A three-parameter constant-gain recursive filter is augmented by a residual-dependent frame time algorithm that automatically increases sampling rates when a target maneuvers. Computer simulations show that tracking performance is essentially independent of the particular target trajectory. It is found that radial distance errors remain effectively constant over different trajectories. It is the number of observations dictated by the adaptive frame time algorithm that is trajectory-dependent. The filter equations along with the frame time adjustment algorithm are first described, and a comparison made with a similar procedure. Examples given use the nonlinear observations generated by a passive sensor system