The invention relates to the method for determining the direction of arrival of radio signals in the presence of aliasing, the method using an interferometric array (12) with four antennas (16) with identical diagrams, and sampling by two distinct sampling frequencies per antenna (16), the method also comprising, for all of the detected wanted signals: the determination of the interference situation for each antenna (16), for the antennas (16) other than the antenna (16) affected by the double interference, the phase of the wanted signal, and for any antenna (16) affected by the double interference, the estimate of the phase of the wanted signal.

Methods and systems for spatial filtering transmitters and receivers capable of simultaneous communication with one or more receivers and transmitters, respectively, the receivers capable of outputting source directions to humans or devices. The methods and systems use spherical wave field partial wave expansion (PWE) models for transmitted and received fields at antennas and for waves generated by contributing sources. The source PWE models have expansion coefficients expressed as functions of directional coordinates of the sources. For spatial filtering receivers a processor uses the output signals from at least one sensor outputting signals consistent with Nyquist criteria representative of the wave field and the source PWE model to determines directional coordinates of sources (wherein the number of floating point operations are reduced) and outputs the directional coordinates and communications to a reporter configured for reporting information to humans. For spatial filtering transmitters a processor uses known receiver directions and source partial wave expansions to generate signals for transducers producing a composite total wave field conveying communications to the specified receivers. The methods and communications reduce the processing required for transmitting and receiving spatially filtered communications.

Techniques and apparatuses are described that implement a smart-device-based radar system capable of performing angular estimation using machine learning. In particular, a radar system 102 includes an angle-estimation module 504 that employs machine learning to estimate an angular position of one or more objects (e.g., users). By analyzing an irregular shape of the radar system 102's spatial response across a wide field of view, the angle-estimation module 504 can resolve angular ambiguities that may be present based on the angle to the object or based on a design of the radar system 102 to correctly identify the angular position of the object. Using machine-learning techniques, the radar system 102 can achieve a high probability of detection and a low false-alarm rate for a variety of different antenna element spacings and frequencies.

An electromagnetic vector sensor (EMVS) system, having a plurality of EMVS devices consisting of a plurality of loop antenna elements spatially orthogonally integrated with and electrically isolated from a plurality of dipole antenna elements, mounted on a rotatably adjustable platform having a true north orientation, including active circuitry residing in antenna housings, and external executing software programs causing the active circuitry in cooperation with the EMVS device and receivers to determine angle of arrival and resolution of incoming wave vectors and polarization of incoming signals and to perform accurate high frequency geolocation signal processing; the programs which perform calibration and antenna element placement determination operations, also cause the system to collect data of known transmitted high frequency skywave signals, and estimate direction of arrival of unknown signals by detecting, resolving and measuring components of an electric field and a magnetic field at a single point.

Methods and systems for spatial filtering transmitters and receivers capable of simultaneous communication with one or more receivers and transmitters, respectively, the receivers capable of outputting source directions to humans or devices. The methods and systems use spherical wave field partial wave expansion (PWE) models for transmitted and received fields at antennas and for waves generated by contributing sources. The source PWE models have expansion coefficients expressed as functions of directional coordinates of the sources. For spatial filtering receivers a processor uses the output signals from at least one sensor outputting signals consistent with Nyquist criteria representative of the wave field and the source PWE model to determines directional coordinates of sources (wherein the number of floating point operations are reduced) and outputs the directional coordinates and communications to a reporter configured for reporting information to humans. For spatial filtering transmitters a processor uses known receiver directions and source partial wave expansions to generate signals for transducers producing a composite total wave field conveying communications to the specified receivers. The methods and communications reduce the processing required for transmitting and receiving spatially filtered communcations.

The invention relates to a method for determining by a direction finder (DF) the direction to a Target, which comprises (a) providing an antenna at the DF, and an array of antennas at the Target; (b) providing a compass at each of the DF and the Target, for determining the azimuth of the DF Heading and of the Target Heading, respectively, with respect to the North; (c) providing at the DF a look-up table which describes n antenna patterns, one per Transmission Mode that may be used respectively at the Target; (d) sequentially performing x Transmission Modes from the Target, each time using another pair of antennas, and during each of the Transmission Modes intentionally, and in a controlled manner attenuating a reception signal at the DF until a loss of communication, and recording the respective attenuation levels; (e) based on the x recorded attenuations levels and the look up table, determining by the DF the direction from the Target to the DF; and (f) receiving at the DF the azimuth of the Target, and based on (i) the determined direction from the Target to the DF (ii) azimuth of the Target; and (iii) azimuth of the DF; calculating by the DF the direction from the DF to the Target.

The present disclosure discloses a three-dimensional co-prime cubic array direction-of-arrival estimation method based on a cross-correlation tensor, mainly solving the problems of multi-dimensional signal structured information loss and Nyquist mismatch in existing methods and comprising the following implementing steps: constructing a three-dimensional co-prime cubic array; carrying out tensor modeling on a receiving signal of the three-dimensional co-prime cubic array; calculating six-dimensional second-order cross-correlation tensor statistics; deducing a three-dimensional virtual uniform cubic array equivalent signal tensor based on cross-correlation tensor dimension merging transformation; constructing a four-dimensional virtual domain signal tensor based on mirror image augmentation of the three-dimensional virtual uniform cubic array; constructing a signal and noise subspace in a Kronecker product form through virtual domain signal tensor decomposition; and acquiring a direction-of-arrival estimation result based on three-dimensional spatial spectrum search.

There is provided mechanisms for orientation determination of a wireless device with respect to a first coordinate system. A method is performed by a control unit. The method comprises obtaining first angular measurements of the wireless device at a first access node and second angular measurements of the first access node at the wireless device. The first access node is oriented in the first coordinate system. The wireless device is oriented in a second coordinate system. The method comprises determining, by aligning the second angular measurements with the first angular measurements, an amount of rotation of the second coordinate system with respect to the first coordinate system. The orientation of the wireless device with respect to the first coordinate system is defined by the amount of the rotation.

Mechanisms compressive sampling to detect direction of arrival (DoA) of a signal of interest (SoI), comprising: in each of a plurality of receiver paths, receiving the SoI and producing a received signal using an antenna; and using a modulator to: receive a modulator input signal (MIS) based on the received signal produced by the antenna in the path; modulate the MIS at multiple points in time (MPIT) based on different ones of a plurality of pseudo-random numbers; and produce a plurality of modulated output signals in response to the modulating of the MIS at the MPIT; summing across the receiver paths the one of the modulated output signals produced by each of the receiver paths for each of the MPIT, to produce a plurality of sum signals each corresponding to one of the MPIT; and performing a compressed sensing recovery algorithm to recover the DoA of the SoI.

A radio receiver is made much more immune to jamming signals. A vector EM sensor, in a 2-dimensional (3-axis sensor) or 3-dimensional (6-axis sensor) sensor configuration, is combined with a unique digital rotation to a preferred direction to create a new reference channel and, using an advanced frequency domain noise mitigation algorithm or other noise cancellation algorithm, can effectively reject jamming and other interference signals and improve the signal-to-noise ratio (20-40 dB) and the receiving performance of the receiver. The method can cancel both near-field and far-field interference and improve accuracy for various applications concerned with establishing the direction, or bearing, to a source. A communication receiver with the vector sensor and the cancellation algorithm has unique anti-jamming capabilities even for multiple jamming sources.