Abstract: A system and associated methods for mutual-aiding and mutual-calibrating positioning and navigation that fuse self-contained and referenced displacement measurements to provide position, velocity, and attitude estimates. In one embodiment the system includes a dead-reckoning device, a radio signal receiver, and a computational device that performs integration with mutual aiding and mutual calibration, leading to a position, velocity, and attitude solution. In another embodiment the system further includes auxiliary sensors. In one embodiment the method that performs fusion of dead-reckoning and radio signal measurements includes dead-reckoning mechanization, estimation of radio signal parameters including signal strength, code phase, and carrier phase, coarse initialization of navigation states with code phase and signal strength measurements, refinement of navigation estimation using temporal carrier phase differences, and estimation of dead-reckoning and radio measurement error terms.

Abstract: A receiver for continuous carrier phase tracking of low carrier-to-noise ratio (“CNR”) signals from a plurality of radio navigation satellites while the receiver is mobile. The receiver may have: a radio frequency (RF) front-end that provides satellite data corresponding to signals received from the plurality of radio navigation satellites; an inertial measurement unit (IMU) that provides inertial data; and a processor circuit in circuit communication with the RF front end and the IMU, the processor circuit being capable of using satellite data from the RF front-end and inertial data from the IMU to perform continuous carrier phase tracking of low CNR radio navigation satellite signals having a CNR of about 20 dB-Hz, while the receiver is mobile. The receiver may be a GPS receiver for continuous carrier phase tracking of low-CNR GPS signals.

Abstract: A method and apparatus for constructive use of a multipath signal in GPS signal processing is provided. In one embodiment, the method includes: a) receiving a GPS signal at a mobile object from a satellite vehicle, b) determining a distance characteristic relating a reflecting object to the mobile object, c) determining at least one inertial characteristic associated with the mobile object, d) predicting at least one multipath signal characteristic associated with reflection of the GPS signal by the reflecting object toward the mobile object, and e) determining the GPS signal received in a) includes a multipath signal associated with reflection of the GPS signal by the reflecting object toward the mobile object. In one embodiment, the apparatus includes: a GPS receiver, a storage device, an inertial measurement device, and a controller. In another embodiment, the apparatus also includes a distance measurement device.

Abstract: A receiver for continuous carrier phase tracking of low carrier-to-noise ratio (“CNR”) signals from a plurality of radio navigation satellites while the receiver is mobile. The receiver may have: a radio frequency (RF) front-end that provides satellite data corresponding to signals received from the plurality of radio navigation satellites; an inertial measurement unit (IMU) that provides inertial data; and a processor circuit in circuit communication with the RF front end and the IMU, the processor circuit being capable of using satellite data from the RF front-end and inertial data from the IMU to perform continuous carrier phase tracking of low CNR radio navigation satellite signals having a CNR of about 20 dB-Hz, while the receiver is mobile. The receiver may be a GPS receiver for continuous carrier phase tracking of low-CNR GPS signals.