Linear Least-Squares Determination of Doppler Time Derivative for NAVSPASUR-Like Signals

A method is derived for optimum estimation of doppler, doppler time derivative, and other parameters for doppler-type radar returns, using linear least-squares estimation procedures. It is used on radar returns from the Naval Space Surveillance System to obtain improvement of at least one order of magnitude in doppler measurement from previous practice; doppler derivative has been measured for the first time. The accurate measurement of doppler derivative (typically ±0.2 Hz2) has enabled a resolution of the inherent geometric degeneracy in the coplanar NAVSPASUR system, to provide a significant improvement in single-pass orbit determination accuracy.