Other

Sirf Technology Holdings, Inc.

Sigtem Technology, Inc.

Chun Yang

Hansheng Wang

Di Qiu

Andrey Soloviev

A system and associated methods for coordinate-free measurement-domain navigation and guidance utilizing a plurality of radio signals of opportunity, without knowing the coordinates of transmitters of said radio signals in a reference system that steers a user from an initial location to a destination without calculating coordinates in said reference system. In one embodiment, radio signal parameters comprise received signal strength indications, differential times of arrival, and sector angles from a user to at least a pair of radio sources and a combination thereof that are used for coarse navigation and guidance toward the vicinity of said destination. In another embodiment, radio signal parameters comprise temporal characteristics of radio signals, propagation channel impulse responses, radio signal power spectra, propagation channel transfer functions, and a combination thereof that are used for vernier navigation and guidance within the vicinity of said destination.

Coordinate-free measurement-domain navigation and guidance using location-dependent radio signal measurements

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. In another embodiment the method also includes identification and estimation of non-line-of-sight multipath signals for mitigation and removal.

Method and apparatus for fusing referenced and self-contained displacement measurements for positioning and navigation

A cooperative position location device (CPLD) that integrates a broadcast digital transmission (BDT) receiver, a data link transceiver, and a displacement sensor; a computer program product tangibly stored in computer-readable media; and associated methods for receiving and processing special codes embedded in BDT signals from a plurality of transmitters to produce time of arrival (TOA) measurements thereof; for sending and receiving special messages between cooperative position location devices (CPLDs) to produce time difference of arrival (TDOA) of common events of BDT at and time of flight (TOF) measurements between the CPLDs; and for integrating differential and relative ranges between CPLDs to a plurality of BDT transmitters and displacement measurements to yield a joint position solution of the CPLDs.

Cooperative position location via wireless data link using broadcast digital transmissions

A Global Navigation Satellite System (GNSS) receiver and associated method capable of acquiring weak GNSS signals from a plurality of GNSS satellites produces a GNSS signal's code time, carrier frequency, and data bit transition parameters for subsequent signal tracking and position fixing. The GNSS receiver includes a baseband signal processor with special functionalities for acquiring weak signals. In a preferred embodiment, the time and frequency uncertainty space is reduced using available information and then special techniques are used to rapidly search the remaining uncertainty space. Successive reversal of short-length correlations within a data bit interval (a block) enables data bit transition detection and data bit sign correction prior to coherent integration. Fast Fourier Transform (FFT) is applied as a bank of bandpass filters to coherently accumulate blocks of short-length correlations over extended coherent integration intervals to boost the signal power while averaging noise out despite unknown data bit transitions.

Method and device for acquiring weak global navigation satellite system (GNSS) signals

A Global Navigation Satellite System (GNSS) receiver and associated method for the reception and processing of GNSS signals. The GNSS receiver includes an antenna and an analog front-end to intercept the incoming radio-frequency signal and to convert it to an appropriate intermediate frequency for digital sampling. A baseband signal processor is organized into functionally identical channels, each dynamically assigned to a different satellite visible. The baseband signal processor processes the signal samples to generate the satellite signal channel impulse response for a number of Doppler frequency shifts. This results in a two-dimensional delay-Doppler map of satellite signal responses from which the baseband signal processor extracts the code time and carrier phase and frequency parameters as well as navigation data for timing, positioning, and environment mapping in the data processor.

Global navigation satellite system (GNSS) receivers based on satellite signal channel impulse response

A broadcast digital transmission (BDT) receiver, computer-readable media, and associated method for receiving and processing of BDT signals from a plurality of transmitters. A BDT receiver includes an antenna to intercept broadcast radio signals and an analog front-end to down-convert it to a suitable frequency for digitization. A baseband signal processor acquires and tracks designated codes in BDT signals using a generalized correlator to produce time of arrival measurements thereof. A data processor, coupled to the baseband signal processor and with input from an auxiliary sensor and a digital database, first calibrates time offsets of said transmitters relative to the BDT receiver's time base and then operates on offset-adjusted time of arrival measurements to produce a position solution.

Self-calibrating position location using periodic codes in broadcast digital transmissions

A GPS receiver that determines its own attitude under jamming conditions is created by augmenting it with an array antenna and a novel signal processing system. The augmented signal processing system comprises a cascaded parallel architecture inserted between the array antenna and the GPS receiver. A blind adaptive nulling processor is cascaded ahead of the GPS receiver so that the GPS receiver can operate on the jamming-suppressed signals in a normal manner. A monopulse angular measurement unit in series with an attitude determination unit interacts in parallel with the blind adaptive nulling processor and the GPS receiver. Constrained beamforming adaptive monopulse is used to simultaneously place nulls in both the sum and difference beams toward jammers while maintaining the monopulse ratio for accurate angular measurement. In this way, the GPS receiver is capable of providing rotational information in addition to regular time and translation information.

Method and device for obtaining attitude under interference by a GSP receiver equipped with an array antenna

A GPS receiver and associated method that embodies high-dynamic, fast acquisition, and interference-suppressing capabilities for the reception and processing of GPS signals from a plurality of GPS satellites to produce GPS signal time and frequency parameters and navigation fixes. The GPS receiver includes an antenna and an analog front-end to intercept the incoming radio-frequency signal, band-limiting amplify the signal, and to convert it to an appropriate intermediate frequency so that it may be converted to digital form. One or more high-speed digital signal processors (DSP) constitute an all digital software baseband processor that process the sampled and quantified signals to form a two-dimensional delay-Doppler map of correlation power and to extract the signal time and frequency parameters and navigation data. The baseband processor is organized into functionally identical channels, each dynamically assigned to a different satellite visible. The baseband processor performs the incoming signal time-tagging, transformation, replica generation, interference-suppressing, delay-Doppler mapping and frequency uncertainty planning. The baseband processor also performs integration for larger processing gain, parameter extraction, and operational management. A relatively slow-speed microprocessor, coupled to the baseband processor, integrates the signal time and frequency parameters and navigation data from a plurality of GPS satellites to produce a navigation solution by a Kalman filter or a least-squares estimator.

Method and device for rapidly extracting time and frequency parameters from high dynamic direct sequence spread spectrum radio signals under interference

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Harleysville, PA, United States of America

Chun Yang