Patent ID: 6331835
Filing Date: 2001-12-18
Classification: G01C,G01S

Abstract:
A system for determining a multidimensional navigation state for a navigation platform based on radio navigation data transmitted by external terminals comprising:a radio navigation data receiver for receiving and amplifying said radio navigation data embedded in noise;an extended-range bank of correlators for extracting said radio navigation data from said noise over an extended range of delay error, said correlators processing said radio navigation data and said noise to generate correlator output functions indicative of degree of correlation for each correlator in the extended-range bank between said radio navigation data and a known internal replica signal;an estimator for estimating the radio navigation data signal power and noise power from the correlator output functions; anda measurement update unit including a nonlinear filter, said measurement update unit for updating the navigation state based on a calculation of the conditional moments of the navigation state using a set of correlator moments, the calculation being based on the estimated radio navigation data signal power and noise power and the correlator output functions;wherein said correlator moments are calculated with said nonlinear filter and represent statistical expectations of nonlinear functions of the line-of-sight position errors.