Magellan Systems Japan, Inc.

Thales Navigation, Inc.

Mitac International Corporation

Sergey Lyusin

Nobuhiro Kishimoto

Todd V Townsend

Authentication mechanism is provided to open service signals in Global Navigation Satellite Systems (GNSS), by inverting a plurality of bits in a pseudorandom noise code in a GNSS signal having a predetermined period of a binary bit sequence of N bits. A position of each inverted bit in the binary bit sequence is specified by a serial number generated for each period using a cryptographic pseudorandom number generator, where at least one of the position of the inverted bit and a number of the inverted bits in the period varies period by period. A decryption key is provided to a GNSS receiver, which correlates, using a corresponding cryptographic pseudorandom number generator, the received GNSS signal, and accumulates an amplitude thereof at the inverted bit, thereby determining if the received signal is counterfeit based on the ratio of the inverted bit amplitude with respect to the signal amplitude.

Method and system for providing authentication to GNSS open service signals and interoperable secure positioning

A GNSS receiver receives GNSS signals from satellites of a plurality of Global Navigation Satellite Systems, and a front end section thereof outputs corresponding navigation signals. A plurality of baseband processing channels receive and process the navigation signals so as to output navigation measurements which are divided and grouped into a plurality of sets. Each of a plurality of first application processing blocks receives a respective set of the navigation measurements and calculates a navigation solution. A general application processing block receives and compares the navigation solutions from the plurality of first application processing blocks, determines if there is a faulty navigation solution which is inconsistent or substantially different from other navigation solutions, discards the faulty navigation solution, produces a common navigation solution based on the remaining or non-faulty navigation solutions, and suspends, for a predetermined time period, use of the navigation measurements corresponding to the faulty navigation solution.

Highly reliable navigation receiver

A GNSS spoofing signal detection/elimination includes tracking acquired candidate GNSS signals for each target GNSS signal, identifying the acquired candidate GNSS signals as authentic, unauthenticated, or counterfeit, removing the counterfeit GNSS signal(s) from tracking, generating a first list of the authentic GNSS signals and a second list of unauthenticated candidate GNSS signals, creating a plurality of sets of GNSS signals by selecting at least four GNSS signals from among the first list and the second list, such that each set includes all of the authentic GNSS signals, if any, and at least one unauthenticated candidate GNSS signal such that each set includes only one candidate signal per target GNSS signal, calculating PVT solutions and post-fit residuals for each set, thereby obtaining a plurality of estimated solutions, estimating authenticity of unauthenticated GNSS signals by analyzing the plurality of estimated solutions.

Detection and elimination of GNSS spoofing signals with PVT solution estimation

A GNSS spoofing signal detection and elimination includes acquiring and tracking a plurality of GNSS signals, authenticating the acquired signals based on available authentication information to determine if the acquired signals are authentic, unverified, or counterfeit, creating a first list of the authentic signals and a second list of unverified signals, by removing the counterfeit signal(s), creating a plurality of sets of the signals by selecting at least four GNSS signals such that each set includes all of the authentic signals and at least one unverified signal, calculating PVT solutions and post-fit residuals for each set, estimating authenticity of unverified signals by analyzing the PVT solutions and post-fit residuals, estimating authenticity and accuracy of PVT solutions based on the estimation, and outputting a list of all of the acquired GNSS signals with the respective authenticity, and a list of all possible PVT solutions with the respective authenticity and accuracy.

Embodiments of the present invention relate to a method and apparatus for reducing interference in a positioning system. According to one or more embodiments of the present invention, the receiver in a conventional positioning system is configured to communicate with a terrestrial broadcast station. The terrestrial broadcast station transmits assistance signals to the receiver and may be another receiver. The assistance signals enable the receiver to locate very weak signals being transmitted from the satellites in the positioning system. In one embodiment, the assistance signals include Doppler frequencies for the satellites. In another embodiment, the assistance signals include Ephemeris data. In another embodiment, the assistance signals include almanac data. In other embodiments of the present invention, the assistance signal includes navigation bits demodulated from the carrier phase inversion signal of the satellite, time synchronization signals, and pseudo range differential corrections. A conventional correlation path is used to provide ghost satellite cancellation. When a signal is detected in the conventional path, it is inverted and subtracted from the assisted correlation path.

Growing community of inventors

Moscow, Russia

Sergey Lyusin