A Two-Stage Mass-to-drag Ratio Estimation Algorithm for Reentry Vehicles

Ballistic target tracking and identification is a key task for missile defense systems. A vital problem in ballistic target identification is how to estimate the target mass-to-drag ratio fast and accurately. The reentry phase of a ballistic missile is the last stage of its flight, and the reentry trajectory is significantly affected by the atmospheric drag. Based on the constraints of space flight dynamics, this paper proposes a two-stage algorithm to estimate the mass-to-drag ratio. This algorithm first estimates the position and velocity of the target in the free flight stage by using the least-squares method, and then estimates the mass-to-drag ratio of the target by using the radial range measurements from the reentry stage. Several trajectories of a ballistic target under different mass-to-drag ratios are simulated, and the proposed algorithm is verified using these simulated trajectories.