An Extended Kalman Filter for Use in a Shared Aperture Medium Range Tracker.

摘要

An extended Kalman filter algorithm, using outputs from a forward looking infrared (FLIR) sensor as measurements, is used to track a point source target in an open loop tracking problem. The filter estimates the translational position changes of the target in the FLIR field of view due to two effects: actual target motion, and apparent motion caused by atmospheric turbulence. Sixteen cases are examined to determine the performance of the filter as a function of signal-to-noise ratio, Gaussian beam, size, the ratio of RMS target motion to RMS atmospheric jetter, target correlation times, and mismatches between the true shape and the shape assumed by the filter. The performance of the extended Kalman filter is compared to the performance of an existing correlation tracker under identical initial conditions. A one sigma tracking error of .2 and .8 picture elements is obtained with signal-to-noise ratios of 20 and 1 respectively. No degradation in performance is observed when the beam size is decreased or when the target correlation time is increased over a limited range, when filter parameters are adjusted to reflect this knowledge. Sensitivity analysis shows that the filter is robust to minor changes in target intensity size. (Author)