Patent ID: 7551126

Claim:
An apparatus for determining a global navigation satellite system (GNSS)-based position from GNSS signal samples recorded in an event data file medium, comprising: a data file reader for reading an event data file medium, said event data file medium having GNSS signal samples corresponding to GNSS signals received at said event from GNSS satellites and an approximate time tag corresponding to a time said GNSS signals were received, said approximate time tag differing from GNSS clock time by a receiver time error; a correlation machine for correlating said GNSS signal samples from said event data file medium with local GNSS replicas for measuring code phase offsets corresponding to said GNSS satellites with respect to a local replica clocking offset; and a GNSS locator including an event time calibrator constructed to use one or more prior or later receiver time errors corresponding to one or more of prior or later events, respectively, for calibrating said approximate time tag; and a GNSS matrix resolver for using said measured code phase offsets, said calibrated time tag and velocities estimated for said GNSS satellites for a resolution of said local replica clocking offset, said receiver time error and a GNSS-based position of said event.