ALGORITHMS FOR REDUCING RADAR OBSERVATIONS OF A HYPERBOLIC NEAR-EARTHFLYBY

This paper presents uniform, c-function-based algorithms for defining and refining the position and velocity estimates of a space object on a near-Earth flyby path, using radar observations comprised of azimuth , elevation, range, and range-rate measurements. The propagation model uses closed-form, f and g functional representations based upon Karl Stumpffs c-functions. The initial path determination algorithm is an e xtension of Gauss's method valid for all path eccentricities. The diff erential correction employs the uniform state transition matrix of Wil liam H. Goodyear. Tracking data from the Galileo Earth-flyby of Decemb er 8, 1990 were used to validate the algorithms. The techniques presen ted were developed to assist U.S. Space Command in reducing radar data from subsequent gravity-assist flybys by man-made space objects.