Adaptive time delay and Doppler shift estimation for narrowband signals

A computationally inexpensive algorithm suitable for fast, high-resolution estimation of time delays and Doppler shifts (which are necessary for targe t ranging and tracking) between narrowband signals is presented. The algori thm uses a modulated Lagrange interpolation filter and an LMS-type algorith m. The problem of delay and Doppler estimation is reduced to a linear regre ssion problem. Convergence and performance analysis of the method is studie d both analytically and through simulation. It is demonstrated that the met hod provides more (or as) efficient estimates than modulated sine interpola tion or the corresponding unmodulated algorithms for a variety of condition s.