Method for mitigating multipath effects in radio ranging systems

摘要

This invention involves a method for mitigating multipath effects in radio ranging systems which is based on searching for and finding a maximum likelihood estimate of range for a received signal in a signal ranging system. In determining the maximum likelihood estimate, the correlation process uses a high resolution step method in processing the received signal sample values to develop an estimation statistic. The estimation statistic using the correlations of the received signal is based on a new derived representative set of coefficients formed from a nonlinear combination of parameters of the received signal transformed into an invertible linear combination which allows solution of the maximization process of the estimation statistic. Additionally there is a method of constraining the relative amplitude of received secondary signals to obtain a refinement of the optimal solution of range. Also the method includes a process to reduce the magnitude of the processing required by the receiver by reducing the size of the overall sample of the signal that must be managed by the receiver. The method may be used in a signal environment where multiple secondary path signals are received by the signal ranging system.