Joint estimation of PN code delay and multipath using the extended Kalman filter

Abstracr-The problem of delay estimation in the presence of multipath is considered. It is shown that the extended Kalman filter (EKF) can be used to obtain joint estimates of time-of-arrival and multipath coefficients for deterministic signals when the channel can be modeled by a tapped-delay line. Simulation results are presented for the EKF joint estimator used for synchronization in a direct-sequence (DS) spreadspectrum system operating over a freqnency-selective fading channel. A simplised model of the EKF joint estimator is considered for analysis purposes. The evolution in time of the tracking error probability density function and the nonlinear tracking error variance is examined through numerical solution of the Chapman-Kolmogorov equation. Finally, the nonlinear tracking error variance is compared to both the linearized error variance estimate directly provided by the EKF and the Cramer-Rao lower bound.