Relative Position Estimation Using Airport Image from a Camera of Missile-borne
In vision aided terminal inertial navigation system, the camera always attaches rigidly, or straps down, to the body of missile. Because the pitch angle of the missile usually is not constant and varies with time, the optical axis of the camera is not vertical. Then the rectangular border of the runway stripe in horizontal land plane is projected as trapezoid in the image plane. The weak perspective camera model does not destroy the parallel structure of the runway. Using the parallel structure of the runway, weak perspective image of the runway can be achieved from the perspective image of the missile-borne camera. When the length of the runway is known, based on the error position of the feature points of the runway in perspective image and weak perspective image, an algorithm estimating the relative position of missile to the runway is presented in this paper. Theoretical deduction and the results of simulation experiments demonstrate that the method proposed is feasible and performs well.