Adaptive multipath delay estimation

Two algorithms are proposed for the continuous tracking of multipath delay. The first is an efficient method for adaptively tracking the secondary peak in the autocorrelation function caused by multipath. In principle, it is equivalent to the correlation method commonly used in practice. The second is an adaptive inverse filter which can exactly remove the multipath transfer function. The methods use an adaptive delay line interpolated by a first-order filter. The interpolation coefficient is explicitly estimated using the recursive Gauss-Newton (RGN) algorithm often used for recursive system identification.