System and method for intercepting an exo-atmospheric target using passive ranging estimation

Abstract

A target intercept system for guiding an interceptor to a target using passive ranging includes an EO/IR sensor that provides target azimuth and elevation angles, target irradiance, target area and target length. A dual Kalman Filter architecture is implemented where, prior to a target image becoming resolved, i.e., prior to endgame, a first Kalman Filter provides guidance as a function of target azimuth and elevation angles and target irradiance measurements. After the target image becomes resolved, i.e., at endgame, a second Kalman Filter provides guidance as a function of target azimuth and elevation angles, target area and, optionally, target length, instead. The dual Kalman Filter approach improves the estimates of time-to-go by optimizing the on-board EO/IR sensor measurements at the optimal times.