Debiased converted position and doppler measurements tracking in direction cosine coordinates

This paper proposes a debiased converted measurement filter with Doppler measurement to deal with the problem of high nonlinearities in state space model measurement equation in direction cosines coordinates of phased array radar. Considering the relationship between the range measurement error and Doppler measurement error, a pseudo measurement is constructed by the product of range and Doppler measurements to reduce the high nonlinearities of the Doppler measurement. Then, via taking the second-order Taylor series expansion to the direction cosines variable, consistent estimations of mean and covariance of the converted measurement error are derived. Finally, the problem of pseudo measurement nonlinearities is coped with by sequentially processing the position measurement and pseudo measurement. The simulation results prove that the filtering performance is improved indeed by introducing the Doppler measurement. Moreover, compared with the common extend Kalman filter and unscented Kalman filter, the proposed debiased converted measurement filter shows better tracking performance indirection cosine coordinates.