A Multiple IMM Estimation Approach with Unbiased Mixing for Thrusting Projectiles

We present a procedure to estimate the state of thrusting/ballistic endoatmospheric projectiles for the end purpose of impact point prediction. The short observation time and the estimation ambiguity between drag and thrust in the dynamic model motivate the development of a multiple interacting multiple model (MIMM) estimator with various drag coefficient initializations. A simple unbiased IMM mixing procedure (useful for quite general applications) is presented for state estimators with unequal dimensions and applied for the thrusting and ballistic modes in the case considered. Results with real data are given.