Missile aim identification

This work deals with the following question: using passive (line-of-sight angle) observations of a missile from an aircraft, how can one infer that the missile is or is not aimed at the aircraft. The observations are assumed to be made only on the initial portion (about 1/4) of the missile's trajectory. The approach is to model the trajectory of the missile with a number of kinematic and guidance parameters, estimate them and use statistical tools to infer whether the missile is guided toward the aircraft. A mathematical model is constructed for a missile under pure proportional navigation with a changing velocity (direction change and speed change), to intercept a nonmaneuvering aircraft. A maximum likelihood estimator is presented for estimating the missile's motion parameters and a goodness-of-fit test is formulated to test if the aircraft is the aim or not. Using measurement data from a realistic missile aimed at an aircraft shows that the proposed method can solve this problem successfully. The estimation/decision algorithm presented here can also be used for an aircraft to decide whether appropriate countermeasures are necessary.