Rockwell Collins, Inc.

Bae Systems Information and Electronic Systems Integration Inc.

United States of America As Represented by the Secretary of the Air Force

Michael H Stockmaster

Matthew J Mueller

Ryan D Downey

Christopher J Hogstrom

Ying Cho J Lai

Brian J Herting

James B Y Tsui

Charles E McDowell

Thomas V DeWulf

Donald A Stratton

Jeffrey B Bishop

Thomas V Dewulf

Scott R Ernst

Ying Cho Lai

Aaron P Shaffer

Charles E Mc Dowell

Dennis M Akos

Techniques are provided for jammer detection. A methodology implementing the techniques according to an embodiment includes steering a beam in a specified direction to generate a power measurement, the specified direction selected from a plurality of directions, such that the method comprises scanning through the plurality of directions. The method also includes adaptively steering a null in the specified direction and measuring a gain of the received signal in the null direction. The method further includes calculating a difference between the power measurement and the measured gain and generating a difference-based detection that the received signal is associated with a jammer at the specified direction. The difference-based detection is based on a comparison of the power difference to a power difference threshold value. The power difference threshold value is based on a desired probability of false alarm and probability of detection, and/or desired angular resolution.

Difference-based jammer detection system

Techniques are provided for jammer detection. A methodology implementing the techniques according to an embodiment includes estimating an angle of arrival of a jamming signal, the jamming signal included in a received signal, and generating a direction finding (DF) confidence indicator associated with the estimated angle of arrival. The method also includes extracting the jamming signal from the received signal. The method further includes correlating the extracted jamming signal with previously extracted jamming signals to generate a correlation score and using the correlation score as a uniqueness assessment of the extracted jamming signal. The method further includes identifying characteristics of the extracted jamming signal and generating a characterization confidence indicator. The method further includes demoting the extracted jamming signal to non-jammer status based on one or more of the DF confidence indicator, the uniqueness assessment, and the characterization confidence indicator.

Jammer detection system

Techniques are provided for automatic gain control processing to reduce adverse effects associated with clipped samples resulting from conversion of analog signals to digital signals. A methodology according to an embodiment includes identifying a clipped sample of the digital signal, for example by comparison of the digitized sample values to a threshold value associated with a full scale value of the converter. The method also includes applying a window function to portions of the digital signal. The window function is configured to attenuate samples of the digital signal within a region centered on the identified clipped sample. A Hilbert finite impulse response (FIR) filter may be applied to the digital signal prior to applying the window function. Parameters of the window function are selected based on frequency response characteristics of the FIR filter and on signal to noise ratio requirements of an application that receives the windowed digital signal.

Automatic gain control system for processing of clipped signal samples

An antenna system may include an antenna array configured to receive one or more signals. In embodiments, the antenna system further includes one or more signal processors configured to: determine a beamforming weight vector (W) for the antenna array; determine a first seeding weight vector (W) for the antenna array, wherein the first seeding weight vector (W) comprises a first nulling weight vector (W) or a second beamforming weight vector (W); determine a first nullforming adjustment factor (&#x3b7;) for the antenna array; calculate a first nullforming weight vector (W) based on at least the beamforming weight vector (W), the first seeding weight vector (W) and the first nullforming adjustment factor (&#x3b7;); and form a first antenna pattern based on the first nullforming weight vector (W) to generate a first antenna electronics (AE) output signal, wherein the first antenna pattern generates a first set of one or more nulls.

System and method for nullforming with anti-jam antenna electronics

A receiver for null steering in a navigation or positioning system includes a controlled reception pattern antenna (CRPA) comprising elements, a switch array coupled to the elements of the CRPA, and a receiver circuit. The receiver circuit is configured to receive an incoming radio frequency (RF) satellite signal from the switch array. The receiver circuit is configured to control the switch array to receive digitized samples, wherein each sample is in a respective time interval for each element of the CRPA elements. The receiver circuit is configured to apply a weight value to each sample and sum the samples to provide a null steering beam.

Systems for and methods of nullsteering in a receiver

Embodiments of the inventive concepts disclosed herein are directed to systems and methods for signal processing. An antenna array can receive signal information. A signal processing device can perform a time-domain-to-transform-domain transform with N transform domain bins, on the signal information. The signal processing device can determine N covariance matrices each corresponding to a respective one of the N transform domain bins. The signal processing device can group covariance matrices from the N covariance matrices into groups of M covariance matrices. Each group can correspond to a respective group of M adjacent bins from the N bins. The signal processing device can produce a combined spatial covariance matrix for each group of M covariance matrices, by performing a weighted combination of covariance matrices within the respective group of M covariance matrices. The signal processing device can calculate spatial weights from each of the spatial covariance matrices, for anti-jamming processing.

Scalable space frequency adaptive processing (SFAP)

Efficient transform-based quantization methods and quantization processors implementing such efficient transform-based quantization methods are disclosed. A transform-based quantization method may include: receiving an input signal transformed in a transform domain; producing a low-resolution signal by reducing a resolution of the input signal according to a reduction ratio; inversely transforming the low-resolution signal to produce an inversely transformed low-resolution signal; and quantizing the inversely transformed low-resolution signal to produce a quantized output.

Efficient transform-based quantization processing

Wavelet transformation based anti-jam processing methods and systems are disclosed. An anti-jam processing method may include: generating a wavelet transformation for a unit of a received signal; weighting each element in the wavelet transformation to generate a weighted wavelet transformation; evaluating jammer suppression performances of a plurality of time and frequency resolution levels defined for an inverse wavelet transformation; selecting a particular time and frequency resolution level among the plurality of time and frequency resolution levels; and applying the inverse wavelet transformation to the weighted wavelet transformation, wherein the inverse wavelet transformation is applied based on the particular time and frequency resolution level selected.

Wavelet transformation based anti-jam processing techniques

An integrated surrogate positioning system and method is disclosed for converting a received positioning signal to a desired output based on existing infrastructure of a host receiver. The system and method comprises a signal processing system for receiving and downconverting to digital, radio frequency positioning signals from a variety of constellations. A radio frequency signal generator receives the positioning solution and determines output positioning signal parameters based on the requirements of the host receiver. The signal generator produces an output baseband positioning signal based on the received positioning solution and the output positioning signal parameters and transmits the positioning signal to the host receive through existing infrastructure.

Surrogate navigation receiver for transferring capabilities to a host navigation receiver and related method

An anti-jam receiver for coordinating with a frequency hop jammer includes a receiver assembly for receiving a spread spectrum signal, and a processor for removing an undesired signal from the spread spectrum signal. The processor utilizes an anti-jam algorithm in the frequency domain. The processor has an update interval during which frequencies that have been identified with undesired signals are removed from the spread spectrum signal. The frequency hop jammer has a hop interval during which a jamming signal is transmitted at a constant frequency. By coordinating the update interval of the processor with the hop interval of the frequency hop jammer, the frequency hop jammer appears to be a continuous wave jammer to the anti-jam receiver, while appearing to be a broadband jammer to other anti-jam systems that are not coordinated with the hop interval of the frequency hop jammer.

Coordinated frequency hop jamming and GPS anti-jam receiver

A method and apparatus for receiving geolocation signals wherein the geolocation signals are received by receiving a plurality of perspectives of a geolocation signal and a jamming signal; generating a plurality of wavelet transformations corresponding to the plurality of perspectives; determining a covariance between corresponding elements in the plurality of wavelet transformations; weighting each element in each wavelet transformation by weights derived from the determined covariance; generating a nulled wavelet transformation by summing together corresponding weighted elements from each of the plurality of wavelet transformations; and generating a time-domain rendition of the geolocation signal according to the nulled wavelet transformation through use of the inverse wavelet transform.

Method and apparatus for receiving a geo-location signal

A positioning system receiver is disclosed. The positioning system receiver includes an antenna for receiving radio frequency (RF) signals. The positioning system receiver also includes a radio frequency front end system configured to convert the received RF signals into intermediate frequency signals. The positioning system receiver further includes a digital processing and correlation system, receiving the intermediate frequency signals and including a plurality of taps on the autocorrelation function main lobe and a plurality of taps on at least one of the autocorrelation function side lobes. The digital processing and correlation system uses the signals received from the taps in a dot product detector algorithm to improve the signal-to-noise ratio of the receiver system.

Multiple lobe dot product detector for M-code GPS receivers

Delays associated with anti-jamming systems utilized in GPS systems can be determined to reduce pseudo range errors. The pseudo range errors are corrected so that proper ionospheric corrections can be made. An extrapolation method can be utilized to improve ionospheric corrections.

Accommodation of anti-jamming delays in GNSS receivers

The present invention is a method and apparatus for providing anti-jam protection for GPS receivers. The anti-jam system of the present invention may require less space and less power than conventional anti-jam systems. The anti-jam circuitry of the present invention may provide anti-jam protection while reducing the number of high-power usage components and integrating the components into an overall reduced form factor. Complex signal processing may be avoided whereby hardware manipulations are handled by hardware components rather than a digital signal processor.

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Cedar Rapids, IA, United States of America

Michael H Stockmaster