By using the line ofsight (LOS) measurements from space based infraredsensors, freeflightphasetrajectoryestimationproblem of ballisticmissileis studied.
In contrast to space-based weapons like Brilliant Pebbles which, thanks to their ability to attack ballistic missiles early in flighttrajectory and, thereby, to destroy multiple warheads with a single interceptor, have the potential to be more cost-effective than offensive forces stand-alone, ground-based defenses can only attack incoming warheads after they have been dispersed from the launching missile and in their final stage of flight.