Abstract: A method for upgrading GNSS equipment to improve position, velocity and time (PVT) accuracy, increase PVT robustness in weak-signal or jammed environments and protect against counterfeit GNSS signals (spoofing). A GNSS Assimilator couples to an RF input of existing GNSS equipment, e.g., a GPS receiver, and extracts navigation and timing information from available RF signals, including non-GNSS signals, or direct baseband aiding, e.g., from an inertial navigation system, frequency reference, or GNSS user. The Assimilator fuses the diverse navigation and timing information to embed a PVT solution in synthesized GNSS signals provided to a GNSS receiver RF input. The code and carrier phases of the synthesized GNSS signals are aligned with those of actual GNSS signals to appear the same at the target receiver input. The Assimilator protects against spoofing by continuously scanning incoming GNSS signals for signs of spoofing, and mitigating spoofing effects in the synthesized GNSS signals.

Abstract: A navigation system provides a significant level of protection against all forms of interference or jamming to GPS in a cost-effective way. The system employs a network of ground reference stations and Low Earth Orbiting (LEO) satellites in conjunction with GPS. A common-view ranging geometry to a GPS satellite is established that links a reference station and a user. A second common-view geometry to a LEO satellite between the same reference station and user pair is also established. The ground stations synthesize real-time aiding signals by making carrier phase measurements of GPS the LEO satellite signals. This aiding information is transmitted via the LEO satellites to the user receiver at high power to penetrate ambient jamming. The user receiver locks onto the carrier phase of the LEO satellite, demodulates the aiding information, then applies the carrier phase measurements and the aiding information to enable extended coherent measurements of the GPS signals.

Abstract: A navigation system provides a significant level of protection against all forms of interference or jamming to GPS in a cost-effective way. The system employs a network of ground reference stations and Low Earth Orbiting (LEO) satellites in conjunction with GPS. A common-view ranging geometry to a GPS satellite is established that links a reference station and a user. A second common-view geometry to a LEO satellite between the same reference station and user pair is also established. The ground stations synthesize real-time aiding signals by making carrier phase measurements of GPS the LEO satellite signals. This aiding information is transmitted via the LEO satellites to the user receiver at high power to penetrate ambient jamming. The user receiver locks onto the carrier phase of the LEO satellite, demodulates the aiding information, then applies the carrier phase measurements and the aiding information to enable extended coherent measurements of the GPS signals.

Abstract: A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

Abstract: A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.

Abstract: A real-time software receiver that executes on a general purpose processor. The software receiver includes data acquisition and correlator modules that perform, in place of hardware correlation, baseband mixing and PRN code correlation using bit-wise parallelism.