452results about "Multi-channel direction-finding systems using radio waves" patented technology

In the context of array sensors such as radar, sonar, and communications receiver arrays, the present invention exploits the geometry phase components of radiated wavefronts associated with the signals of interest in order to reduce the bandwidth requirements for DOA and beamforming processing. Additionally, geometry phase is exploited in order to effectively increase the resolution of an array without changing the size of its physical footprint or the number of array elements. Other embodiments of the invention include the use of virtual array elements for increase in effective array size.

A method for processing received radio signals that are subject to unwanted change during propagation through the atmosphere, from a transmitter to a receiver array. The multiple signals are received as cochannel signals at the antenna array, and are processed to eliminate the effects of modification of the signals during propagation, wherein the processing step includes cumulant-based signal recovery without regard for the geometrical properties of the antenna array. In the invention as disclosed, two different information signals having two different polarization states are transmitted, and at least one of the transmitted signals is subjected to an unwanted change of its polarization state. The received signals are processed to separate and recover the two information signals without regard to their polarization states.

In the context of array sensors such as radar, sonar, and communications receiver arrays, the present invention exploits the geometry phase components of radiated wavefronts associated with the signals of interest in order to reduce the bandwidth requirements for DOA and beamforming processing. Additionally, geometry phase is exploited in order to effectively increase the resolution of an array without changing the size of its physical footprint. Other embodiments of the invention include the use of virtual array elements for increase in effective array size.

A system and method for an arrayed sensor to resolve ambiguity in received signals, improve direction of arrival accuracy and estimate a location of one or more targets in an environment including signal interference.

A method of processing a signal includes taking a signal recorded by a plurality of signal recorders, applying at least one super-resolution technique to the signal to produce an oscillator peak representation of the signal comprising a plurality of frequency components for a plurality of oscillator peaks, computing at least one Cross Channel Complex Spectral Phase Evolution (XCSPE) attribute for the signal to produce a measure of a spatial evolution of the plurality of oscillator peaks between the signal, identifying a known predicted XCSPE curve (PXC) trace corresponding to the frequency components and at least one XCSPE attribute of the plurality of oscillator peaks and utilizing the identified PXC trace to determine a spatial attribute corresponding to an origin of the signal.

In a conventional automotive radar, a return occurs in a phase difference characteristic necessary for a super-resolution method, resulting in an increase of a detection error, or an extremely narrowed azimuth detection range. A transmitting array antenna, and receiving array antennas are composed of antenna elements respectively, and aligned in a horizontal direction. The weighting of receiving sensitivities of the antenna elements of the receiving array antenna 1 is A1, A2, A3, and A4, which are monotonically decreased from an inner side toward an outer side as represented by A1≧A2≧A3≧A4. On the other hand, the receiving array antenna 3 is symmetrical with the receiving array antenna with respect to the receiving array antenna 1.

A method and apparatus for a base station including an antenna array calculates a direction of a weight vector of a transmission beam to maximize in-phase component power for a common channel signal in a transmission channel signal for transmission to a mobile station and to minimize a sum of quadrature-phase power component and interference power for other mobile stations inside and outside a cell due to a transmission channel signal for the mobile station.

An on-board multibeam radar apparatus includes a plurality of beam elements that constitute an antenna transmitting a transmission wave and receiving an incoming wave being reflected and arriving from a target in response to the transmission wave, a control unit configured to select a beam element used for transmission and reception out of the plurality of beam elements so as to change a field of view, and a processing unit configured to apply a Fourier transformation to beam element data which are data of a received wave received through the beam element used for transmission and reception selected by the control unit based on the number of elements and the element interval of a desired virtual array antenna so as to create virtual array data, and to perform a predetermined process based on the created virtual array data.

Apparatus and a method utilizing correlation interferometer direction finding for determining the azimuth and elevation to an aircraft at long range and flying at low altitudes above water with a transmitting radar while resolving multipath signals. The signals from the radar are received both directly and reflected from the surface of the water using horizontally polarized and vertically polarized antenna arrays, are digitized and are stored in separate covariant matrices. Eigenvalues for the eigenvectors of the matrices processed on signal samples recorded on horizontally polarized X arrays are compared to the eigenvalues for the eigenvectors of the covariance matrices processed on signal samples recorded on vertically polarized X arrays. Incident field polarization is associated with the antenna array measurements that yield the strongest eigenvalue. The eigenvector and eigenvalues for the strongest signal are selected and used for subsequent signal processing. An initial global search assuming mirror sea-state reflection conditions using the signal eigenvector having the strongest eigenvalue is performed to yield an approximate elevation α and azimuth β to the aircraft. The approximate values are then used as the starting point for a subsequent conjugate gradient search to determine accurate elevation α and azimuth β to the aircraft.

An electronic scanning type radar device mounted on a moving body includes: a transmission unit transmitting a transmission wave; a reception unit comprising a plurality of antennas receiving a reflection wave of the transmission wave from a target; a beat signal generation unit generating a beat signal from the transmission wave and the reflection wave; a frequency resolution processing unit frequency computing a complex number data; a target detection unit detecting an existence of the target; a correlation matrix computation unit computing a correlation matrix from each of a complex number data of a detected beat frequency; a target consolidation processing unit linking the target in a present detection cycle and a past detection cycle; a correlation matrix filtering unit generating an averaged correlation matrix by weighted averaging a correlation matrix of a target in the present detection cycle and a correlation matrix of a related target in the past detection cycle; and a direction detection unit computing an arrival direction of the reflection wave based on the averaged correlation matrix.

A device for detecting an azimuth has a transmission array antenna having plural transmission antenna elements arrayed along an array axis and a receiving array antenna having plural receiving antenna elements arrayed along the array axis. A reception signal is acquired for each of channels by transmitting and receiving a search wave through each of the channels. The channels are arbitrary combinations of each of the transmission antenna elements and each of the receiving antenna elements. A first spatial frequency analysis is performed along the array axis of either ones of the transmission antenna elements and the receiving antenna elements using the reception signal. A second spatial frequency analysis is then performed along the array axis of the other ones of the antenna elements using results of the first spatial frequency analysis. An azimuth of a target is determined based on analysis results from the second spatial frequency analysis.

Direction findings by radio comprises arraigning an array of antennas, to receive signals from emitters, selecting individual antenna signals using a first multipole switch and determining, antenna signal strengths. Individual antenna signals are also selected by mutipole switch, which routes a selected signal to a third multipole switch. The third switch switches a phase shifter into and out of an antenna signal path. An adder is employed to add an antenna signal in a first signal path extending via the first multipole switch to a different antenna signal in a second signal path extending via the second and third switches. This determines combined signal strengths between pairs of antenna signals, one of which either has or has not been relatively phase shifted depending on the third switch position. Covariance matrix elements are determined from signal strengths enabling emitter bearings to be derived.

A FMCW-type radar device generates snapshot data from a beat signal that represents a received condition of the radar device every modulation period. Auto-correlation matrices generated by the snapshot data every modulation period are averaged every set of plural periods. The radar device calculates the target azimuth of a target object such as a preceding vehicle based on the averaged auto-correlation matrix based on MUSIC (MUltiple SIgnal Classification) method. This averaging is performed by weighting average based on an amount of mixed noise (or an interference amount) contained in the snapshot data in each modulation period. A weighting coefficient to be applied to the auto-correlation matrix in each modulation period is set to a value corresponding to the amount of mixed noise, namely, the interference amount of this modulation period. The weighting coefficient becomes large when the interference amount is small, and on the other hand, becomes small when it is large.

A beam-forming apparatus and method for improving system performance using a spatial interpolation and at least one Angle of Arrival (AoA) in a system based on regular spatial sampling is provided. The AoA is estimated using a carrier-to-interference ratio. Beam-forming angles are distributed and steered in a predefined scheme such that an identical process is applied in all directions. According to this steering, a linear system model is computed based on regular spatial sampling using regular spatial separation at beam angles. Beam-forming performance is improved by compensating for a difference between adaptive and sector-type arrays. Only the steps of computing a spatial interpolation and determining an angle range for beam-forming using at least one AoA are added. The precision of estimating an AoA and the precision of beam-forming increase without an additional antenna. Because the system is simpler than that of an adaptive beam-forming system, significant gain is obtained.