Terrain elevation matching with observations of radar by using active point-mass filter

In this paper an active point-mass filter is applied to match the radar observations with terrain reference map utilized in aircraft navigation. In the proposed matching method, based on an recursive Bayesian estimation approach, the point-mass filter is modified in order to become robust against the suddenly errors of radar system and Inertial Navigation System (INS) as well as to avoid instability of the estimation process when the aircraft passes from very smooth regions. The point-mass filter considers a network of points around the estimation point and assigns separated probabilities to them. The probabilities show uncertainties of the aircraft location. The probabilities are similar initially; however, they converge to true values gradually through a recursive estimation based on Bayesian approach. The simulation results demonstrate the robustness and efficiency of the proposed approach in terrain navigation systems and put it in the category of developing and operational systems.