An angle-only tracking filter for a maneuvering target
David V. Stallard · Guidance, Navigation and Control Conference · 1990
A nine-state extended Kalman filter for tracking a maneuvering target with angle measurements only, by an interceptor missile executing a low-frequency spiral maneuver with moderate acceleration, is described. The filter coordinate system is that of the seeker at the last measurement. The state variables are: the two boresight errors; the two line-of-sight angular rates; 1 /range; (range-rate)/range; and the three components (along the three principal axes of the seeker) of target absolute acceleration divided by range. The choice of axis system, state variables, missile dither maneuver and accuracy of measurements are important. In a simulation with noise, the estimated variables were reasonably accurate near intercept and led to a low miss distance. Improvements in analysis and design are possible.