Target motion analysis based on RF power and Doppler measurements

This paper investigates target motion analysis (TMA) based on noisy measurements of power and Doppler from a radio frequency (RF) emitter. The research is motivated by the fact that Doppler measurements for RF signals are much easier to obtain and power measurements are always available. More importantly power and Doppler measurements complement each other in terms of the Fisher information content. However both these measurements are highly nonlinear functions of the TMA parameters, specified uniquely by its initial position and velocity. In addition direct use of these measurements in TMA introduces the nuisance parameters leading to poor numerical conditioning because of the very high source frequency, and very small power proportional constant for RF signals. Hence ratios of the neighboring measurements are used to eliminate the nuisance parameters and provide normalization of the measurement equations. An iterative least-squares (LS) algorithm is developed, and is shown to be effective through a numerical example.