Novatel Inc.

Janet Brown Neumann

Thomas John Ford

Waldemar Kunysz

Ian Williamson

Marcia Bates

Robert S Harvey

A receiver that uses a single processor to control a GPS sub-system and an inertial (&ldquo;INS&rdquo;) sub-system and, through software integration, shares GPS and INS position and covariance information between the sub-systems. The receiver time tags the INS measurement data using a counter that is slaved to GPS time, and the receiver then uses separate INS and GPS filters to produce GPS and INS position information that is synchronized in time. The GPS/INS receiver utilizes GPS position and associated covariance information in the updating of an INS Kalman filter, which provides updated system error information that is used in propagating inertial position, velocity and attitude. Whenever the receiver is stationary after initial movement, the INS sub-system performs &ldquo;zero-velocity updates,&rdquo; to more accurately compensate in the Kalman filter for component measurement biases and measurement noise. Further, if the receiver loses GPS satellite signals, the receiver utilizes the inertial position, velocity and covariance information provided by the Kalman filter in the GPS filters, to speed up GPS satellite signal re-acquisition and associated ambiguity resolution operations.

Inertial GPS navigation system

A calibration procedure for reducing frequency-dependent bias effects in a fixed satellite-based ground-positioning receiver is disclosed, the receiver having the capability to receive both GPS and GLONASS satellite signals. The calibration procedure removes satellite dynamics by utilizing the respective satellite ephemeris data, estimates the change in receiver clock offset by means of GPS measurements, and acquires a set of two or more GLONASS pseudorange measurements while cycling a local oscillator in the receiver through a predetermined sequence of different frequencies.

Method for reducing inter-frequency bias effects in a receiver

A GPS receiver embodying the invention includes a first channel that preferentially processes line-of-sight signals and a second channel that preferentially processes multipath signals. It then compares the results to determine if the multipath has degraded the results of the processing of the line-of-sight signals.

Growing community of inventors

Calgary, Canada

Janet Brown Neumann