Patent ID: 9651677
Date: 2017-05-16
CPC Classifications: G01S

Claim:
1. A method of estimating a position of a rover antenna using a computer processor, the method comprising: receiving GNSS data derived from multi-frequency signals received at the rover antenna over a plurality of epochs; receiving correction data for the GNSS data from a network of reference stations over the plurality of epochs; at each of the plurality of epochs, estimating values defining a rover antenna position and a set of multi-frequency ambiguities using the GNSS data and the correction data; modeling variation in ionospheric bias per satellite using an ionospheric filter; estimating a set of ionospheric carrier-phase ambiguities; upon determining that the set of ionospheric carrier-phase ambiguities have converged, caching the set of ionospheric carrier-phase ambiguities; detecting an interruption of signal received at the rover antenna; determining reacquisition of signals received at the rover antenna; predicting an ionospheric bias per satellite over an interruption interval; for each satellite, combining a cached ionospheric carrier-phase ambiguity with the predicted ionospheric bias to obtain a post-interruption ionospheric ambiguity estimate; and estimating a position of the rover antenna subsequent to the reacquisition using the post-interruption ionospheric ambiguity estimates.