Abstract: A system for enhancing the performance of a wireless communication device (WCD) while executing a direction of arrival (DoA) estimation. The performance may be improved through device management, and may include the collection of information from one or more sensors installed within the WCD. The sensor information may initially be used to determine an appropriate configuration for the device. Further, the sensor information may also be used to affect the behavior of the device while performing the DoA estimation.

Abstract: A method for calibrating an antenna and signal processing system enabling angle of arrival (AOA) determination for a frequency hopping signal, in which a calibration coefficient is determined in response to one or more calibration signals injected into the system at one or more of the frequencies in the hopping sequence and proximate in time to reception of the communication signal. The calibration coefficients are reflective of a frequency and time dependent parameter of a path between the antenna and wireless location sensor. The AOA is determined as a function of the calibration coefficient and the radio frequency energy of the received communication signal. Several embodiment of the method are illustrated.

Abstract: A radio wave direction-of-arrival estimation apparatus and method that can estimate, at high speed and with good accuracy, the direction of arrival of a plurality of incoming waves having high correlation.

Abstract: Apparatus and method are disclosed for estimating direction of an arrival wave, such as radio or acoustic waves. A correlation matrix of an arrival wave is computed, and matrices for obtaining eigenvalues and eigenvectors are produced. Column norms of the matrix, which is subject to a Householder transformation, are computed. Whether a maximum value of the column norms is the same as or lower than a predetermined threshold is judged. A Householder transformation of the matrix is performed only if the maximum value of the column norms is determined to be greater than or equal to the threshold, and not when the maximum value of the column norms is less than the threshold. The eigenvectors and the eigenvalues of the correlation matrix are obtained by further implementing the Householder transformation. The number of arrival waves is judged from the number of times the Householder transformation is performed.

Abstract: A method for calibrating an antenna and signal processing system enabling angle of arrival (AOA) determination for a frequency hopping signal, in which a calibration coefficient is determined in response to one or more calibration signals injected into the system at one or more of the frequencies in the hopping sequence and proximate in time to reception of the communication signal. The calibration coefficients are reflective of a frequency and time dependent parameter of a path between the antenna and wireless location sensor. The AOA is determined as a function of the calibration coefficient and the radio frequency energy of the received communication signal. Several embodiment of the method are illustrated.

Abstract: An adaptive antenna radio communication device comprises a divided band direction estimating unit (4) for estimating the direction by calculating the cross correlations between a pilot signal and sub-carrier signals of the respective divided bands received by an array antenna (1) and calculating a spatial profile from correlation matrices determined by combining the correlation values between antenna elements of the different sub-carriers according to the output of the cross correlation calculation; a divided band array weight creating unit (5) for creating a weight of a receive array having a directional beam in the direction of estimation for each divided band; and a sub-carrier directivity creating unit (6) for creating a directivity by multiplication-combining the created receive array weight with the corresponding sub-carrier signal.

Abstract: The disclosed embodiments relate to a system and method for providing user specific beams in a fixed beam network. In one embodiment, there is provided a mobile transceiver comprising a first device configured to receive phase reference signal data from a base station, the phase reference signal data being indicative of a first phase reference signal and a second phase reference signal that may be used by the mobile transceiver during a communication session, and a second device configured to determine whether the second phase reference signal is likely to provide improved reception between the base station and the mobile transceiver with respect to the first phase reference signal, wherein the second device is configured to transmit data to the base station, the data being indicative of whether the first phase reference signal or the second phase reference signal is likely to provide improved reception between the base station and the mobile transceiver.

Abstract: A single transmit multi-receiver modulation radar modulates radar return signals received through an associated receive-signal path with one of a plurality of differing modulation waveforms having low-cross correlation products. Each receive-signal path may be associated with a different receive direction. The differently modulated return signals from each receive-signal path may be combined and correlations may be performed on the combined and differently modulated radar return signals using the modulation waveforms to locate a target. In some embodiments, the trajectory of the target may be extrapolated and the target's source location may be determined.

Abstract: A receiver having an array antenna estimates arrival directions of multiple paths that arrive with an angular spread. Consequently, arrival direction estimation accuracy can be ensured without increasing throughput even if the power every path is low by estimating an average arrival direction of an entire set of multiple paths having the angular spread from a result of one angular spectrum by multiple correlation operation units that perform mutual correlation operations with pilot signals for baseband signals received by the array antenna, a path detection unit that detects multiple arrival path receiving timings by generating a delay profile based on output of each of the correlation operation units, a path correlation value synthesis unit that synthesizes a correlation operation value calculated in the multiple correlation operation units and an arrival direction estimation unit that collectively estimates multiple path arrival directions using output of the path correlation value synthesis unit.

Abstract: Estimating an angle-of-arrival of a signal includes receiving a signal sent from an emitter. The signal is received at a singly polarized antenna system associated with an antenna response model. An autocorrelation matrix having noise-related eigenvectors is generated in response to the signal. Polarization ratios are determined from projections of a noise-related eigenvector onto the antenna response model. A minimum polarization ratio variance is established for the polarization ratios. A polarization vector corresponding to the minimum polarization ratio variance is identified. An angle-of-arrival of the signal is estimated in accordance with the identified polarization vector.

Abstract: A receiver (1) of a position-finding system comprises a calculation unit (6, 7, 8) for calculation of a statistical value (?) on the basis of a received signal, and a detector unit (9) for comparison of the statistical value (?) with a threshold value (?) and for determining whether the received signal is a synchronized location signal, an estimation unit (10) for estimation of the Rice factor (K) of the radio link via which the received signal has been transmitted, and a determination unit for calculation of the threshold value (?) on the basis of the Rice factor (K).

Abstract: A receiver includes a processor and an RF bridge. The RF bridge is coupled to the processor to receive a reference signal from the processor. The RF bridge includes first and second frequency converters coupled to respective first and second antennas. The RF bridge also includes a third frequency converter coupled to outputs of the first and second frequency converters. In an alternative receiver the processor is coupled to receive an information signal from the RF bridge. The processor includes a digital frequency source to generate the reference signal based on a signal from a clock source and circuitry to detect a frequency difference from the information signal based on the signal from the clock source. In a variant, the circuitry to detect includes a first Fourier transformer having a first center frequency and a second Fourier transformer having a second center frequency different than the first center frequency.

Abstract: A system includes a first antenna that is located on one side of a motor vehicle and a second antenna that is located on another side of the motor vehicle. The system includes a controller, a switch and a receiver. In response to a heading of the motor vehicle, the controller selectively couples the receiver to one of the first antenna and the second antenna.

Abstract: An apparatus for estimating direction of arrival of signal is provided that has excellent performance in terms of angular resolution and the number of signals that can be identified. In an array sensor comprising a plurality of sensor elements, the two outermost sensor elements are alternately selected by a switch for use as a transmitting sensor, and the other sensor elements are selected in time division fashion as receiving sensors. With this arrangement, the effective aperture is increased to about twice the physical aperture, to improve angular resolution in a direction-of-arrival estimator.

Abstract: Techniques for determining the angles of arrival of multiple simultaneous cochannel sources using only a single RF receiver sampling and downconversion channel is disclosed. This is accomplished by sequentially forming several known mixtures of multiple antenna signals in the RF domain prior to downconversion and digitization. Angle of arrival information is then recovered through the application of higher order statistics and subspace fitting techniques. The same principles can be applied to other P-element receiver arrays (e.g., acoustical receiver array).

Abstract: An adaptive antenna base station apparatus comprises an array antenna including N (N being a natural number) antenna elements; N reception sections for respectively performing orthogonal detection of high-frequency signals, respectively received by the antenna elements, after frequency conversion; N×M despreading sections for performing despreading operations, corresponding to delay times of M (M being a natural number) path components included in output signals of the reception sections; M correlation computing sections for performing correlations among the antenna elements for each path; a correlation combining section for combining output signals of the correlation computing sections; and a DOA estimating section for estimating a direction of arrival (DOA) by using an output of the correlation combining section. This can ensure collective estimation of DOAs of M path components, thereby reducing the amount of computation of estimating the DOAs for plural paths and the cost for the apparatus.

Abstract: L overlapping forward subarrays with {overscore (q)}(?q) antenna elements are formed with, where q is the number of desired signals, a cyclic correlation matrix is formed from the cyclic correlations between the received signals of L forward subarrays and a received signal of the first predetermined antenna element, the cyclic correlated matrix is divided into two upper and lower submatrices, an orthogonal projection operator in the noise subspace is calculated by performing a linear operation on these two upper and lower cyclic correlation matrices, then by calculating a spatial spectrum or a polynomial by using the estimated orthogonal projection operator, the directions are estimated from of the position of q highest peaks of the spatial spectrum or the phases of q roots of the polynomial closest to the unit circle in z-plane.

Abstract: A Direction Finding DF Method and System Using Transmission Signature Differentiation is disclosed. Also disclosed is system that is able identify which signal is coming from which transmiitter. Futhermore, the syatem can take each respective transmitter's Line-of-Bearing (LOB) data and process them separately. The system is further capable of being fully automated in order to reduce to processing time and eliminate the necessity of human intervention. In an alternative embodiment of the present invention the system can feasibly be remotely controlled by a network such that the information can be collected from other from similar systems. In this way, a far more efficient DF System can be achieved in which multiple transmitters' positions can be determined one quickly from a centralized command facility.

Abstract: The disclosed embodiments relate to a system and method for providing user specific beams in a fixed beam network, the fixed beam network comprising a plurality of fixed beams, each of the plurality of fixed beams being defined by a plurality of fixed beam correlation coefficients. The system may comprise a device that computes reception correlation data for a received signal, and a beamformer that is adapted to determine transmission weighting coefficients to be applied to a return signal based on the difference between the reception correlation data and the fixed beam weighting coefficients associated with at least one of the plurality of fixed beams.

Abstract: A method and apparatus is disclosed for determining the range between two planes, ownship (10) and target (12). Model data (66) estimating the velocity and position of target (12) is compared to actual flight path data of the target (12) passively received by ownship (10). The model data (66) and actual data is compared, and an error measurement is calculated. The model data is also subject to position and velocity constraints (78 and 82) which penalize unrealistic estimates. The error measurement and penalties are used to create a perturbation model (90) which is added to the model data to generate new model data. When the model data (66) conforms closely to the actual data, a range is computed from the model data (66).

Abstract: A DOA estimation unit is provided with at least one of two DOA estimation techniques to determine the DOA of signals wireless transmitted. A first technique includes determination of the DOA based at least in part on a relationship between a received signal vector and a number of signal directional vectors. The second technique includes determination of the DOAs of the L multipaths of a signal by searching in a direction range centered on a determined DOA of the signal.

Abstract: A global position system radio receiver achieved through use of an electronic warfare receiver, and particularly one of the electronic warfare receiver output frequency channels, as a front-end signal processor for the global position system receiver. Electronic warfare receiver channel selection for such usage is described and the attenuating effect of electronic warfare receiver channel center frequency and global position system signal frequency differences are considered. A favorable comparison of present invention and conventional global position system receiver-generated results in processing a global position system signal are included along with control of a sampling frequency characteristic within the electronic warfare receiver in order to align global position system signal frequency and electronic warfare receiver channel location to an electable better degree.

Abstract: An electronic warfare apparatus for determining the location of for example a ground based source of electromagnetic radiation from a platform such as an aircraft. Location is determined using angle of arrival based vector determinations provided by signal differences detected in the ground based signals arriving at platform antennas. Elimination of angle of arrival errors arising from imprecise knowledge of platform electronic warfare antenna characteristics is a focal point of the invention and is accomplished through precision use of global position system information received via the same electronic warfare antennas. Accurate determination of electronic warfare antenna characteristics prior to consideration of the large distance multiplication factors imposed by aircraft to distant signal source geometry enables accurate distant signal source location using the invention.

Abstract: A passive navigation system for an airborne platform includes an on-board computer having a database that contains preprogrammed information regarding pre-existing ground-based signal emitters (e.g. cell-phone, television and radio broadcast transmitters). For each emitter, the database includes the geolocation of the emitter and identifying signal characteristic(s) of each emitter's signal such as frequency, bandwidth and strength. An antenna array and digital receiver cooperate with the computer on the platform to passively receive signals from the emitters and determine a direction of arrival (DOA) for selected signals. The computer also extracts identifying signal characteristic(s) from selected received signals and matches them against the database information to ascertain the geolocation of the emitter that corresponds to the received signal. The platform location is then calculated from the DOA(s) and emitter geolocations using a triangulation-type algorithm.

Abstract: A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring all angle sweep for arrival angle estimation of MUSIC method or the like.

Abstract: An in-vehicle device data communicates with data processing resources, including global network based data processing resources for the purpose of programming and receiving data from an in-vehicle device where the data communicated can include sampling intervals, global position system (GPS) data, or scientific instrumentation data related to certain weather, environmental, traffic, or road conditions. Scientific instrumentation data gathering can be effectuated proximate to a vehicle, wherein the vehicle has an in-vehicle device and the in-vehicle device has a scientific instrumentation interface. In this regard, scientific instrumentation data can be obtained while the vehicle is stationary or in motion. Scientific instrumentation data gathered at the data processing resource or gathered by the in-vehicle device can be utilized to effectuate a wide variety of data dissemination.

Abstract: Methods and systems are provide for precision direction finding capabilities for a sensing system, the method comprising providing a sensing system that utilizes an amplitude direction finding scheme, receiving a received signal in at least two receivers of the energy wave sensing system, the received signal generated by a first object, comparing the received signal at each receiver in a processor of the sensing system utilizing an amplitude direction finding technique to produce amplitude direction finding technique data, the amplitude direction finding technique data indicative of course direction of the first object, processing the received signal further to determine angle of arrival data based on an interferometric technique to produce interferometric technique data, the interferometric data indicative of a more precise direction of the first object than provided by the amplitude direction finding technique and determining the direction finding data of the first object based on a residual phase error of

Abstract: A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring an angle sweep for arrival angle estimation of MUSIC method or the like.

Abstract: A method and device are provided for determining distributed signal sources of a base station that includes a pair of circular array antennas that maintain a predetermined distance from each other. The method and device may estimate primary central vertical angles of the distributed signal sources received by each sensor according to TLS-ESPRIT, for example. The method and device may further convert a 2-dimensional cost function into a first 1-dimensional cost function by using the estimated primary central vertical angles of the distributed signal sources. Central horizontal angles may be estimated by making the first 1-dimensional cost function have a maximum. The 2-dimensional cost function may be converted into a second 1-dimensional cost function by using the estimated central horizontal angles of the distributed signal sources. The central vertical angles may be estimated by making the second 1-dimensional function have a maximum.

Abstract: Emitter target range and heading are estimated from bearing measurements enhancing bearings-only estimator convergence to a target track, and permitting optimization of an observer position relative to the target at the end of the total bearing measurement period. One or more estimates of the target range, speed and heading made from bearing measurements before an observer maneuver are used to determine the most appropriate observer maneuver giving complete bearings-only target-motion-analysis observability. A set of parameters characterizing a set of potential emitter signal sources is generated based on measured emitter characteristics. A most probable set of emitter platforms is identified and the emitter operating mode and corresponding platform set are associated with a kinematic regime set. A specific speed or discrete set of speeds best adapted to a set of all possible platform missions, emitter speed as a continuous function of emitter range, and emitter range are all determined.

Abstract: Provided is a Doppler based automated direction finding system that detects radio frequency (RF) leaks in a cable television plant. During a ride-out, the system detects leaks and stores leak data, such as amplitude, location, and bearing. The stored data is uploaded to a computer that performs a leak analysis. The leak analysis isolates the leaks using Doppler-based bearing information and separates cable leaks from other RF sources, such as power sources and noise. Erroneous information that results from RF reflections (multi path) may be eliminated while processing the data using triangulation. After the leak analysis, the computer generates work orders and maps, makes the data available to users, and may also compile information and file reports based on the data.

Abstract: A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring all angle sweep for arrival angle estimation of MUSIC method or the like.

Abstract: A method of determining an azimuth and elevation of a radiation emission source using a single-axis direction finding system is provided. The method includes receiving a plurality of radiation signals at the single-axis direction finding system. The plurality of radiation signals are emitted from the radiation source, each of the plurality of radiation signals being received at one of a plurality of attitudes of the single-axis direction finding system. The method also includes measuring an angle of arrival of each of the plurality of radiation signals with respect to the single-axis direction finding system. Additionally, the method includes calculating an azimuth angle of each of the plurality of radiation signals with respect to the single-axis direction finding system using the respective measured angle of arrival. Further, the method includes calculating a respective vector corresponding to each of the azimuth angles at different elevation angles within a predetermined range.

Abstract: A Direction Finding Method and System Using Transmission Signature Differentiation is disclosed. Also disclosed is a system that is able to identify which signal is coming from which transmitter. Furthermore, the can take each respective transmitter's LOB data and process them separately. The system is further capable of being fully automated in order to reduce the processing time and eliminate the necessity of human intervention. In an alternative embodiment of the present invention the system can feasibly be remotely controlled a network such that the information can be collected from other from similar systems. In this way, a far more efficient DF System can be achieved in which multiple transmitters' positions can be determined more quickly from a centralized command facility.

Abstract: The direction-of arrival estimation by means of a subspace-based algorithm such as MUSIC or ESPRIT is formed by using reduced-bandwidth signals as compared with communication signal waves. The narrower-bandwidth signals is obtained by each mobile telephone transmitting a modulated version of a lower-transmission rate test signal as well as a communication signal wave or by band-pass filtering the received communication signal waves in a base station. A direction-of-arrival estimation is formed by using a reduced number of signals for the direction-of arrival estimation. The number of direction-of-arrival estimating signals is reduced by discarding a part of the received signals, by multiplexing the received signals by the sub-array and forming a direction-of arrival estimation for each sub-array, or by using an additional array antenna having a reduced number of elements.

Abstract: A method and computer program product are disclosed for locating signal jammers in a digital beamforming receiver having an antenna with a plurality of associated antenna orientations. An associated antenna gain value is calculated for a first of a sequence of the plurality of antenna orientations at each of a series of sample points. The antenna gain values from the first antenna orientation are evaluated for null spaces to obtain a set of candidate null locations. Associated antenna gain values are calculated and evaluated for subsequent antenna orientations only at the set of candidate null locations. Candidate null locations are eliminated from the set after any evaluation in which they are not found to be null spaces.

Abstract: A system is provided for assisting in the detection and tracking of narrowband signals arriving at an antenna array operating over a wide detection bandwidth and in a crowded RF environment. Since the nature of the detection mission is constrained to be a general search, the system does not attempt to detect signals of interest via matched filtering mechanisms (i.e. training sets), but exploits general properties such as power, frequency, time and angle of arrival. For the purposes of providing sufficient Frequency/Time resolution as well as to avoid array overloading in the detection process, the digitized wideband streaming data is frequency channelized using a sufficiently high revisit rate for the signal set of interest, constrained by the required feature detection accuracy or environment adaption rates. Within each frequency subchannel, efficient array signal subspace tracking techniques are used to separate and track spatially separated cochannel signals.

Abstract: A receiver (9) for receiving a plurality of different signals at the same time, said receiver (9) comprising means for identifying at least one strongest signal of said plurality of different signals and means for attenuating said at least one strongest signal with respect to the other of said plurality of signals wherein the said attenuating means comprises hybrid means (140 and 160).

Abstract: A calibration method, which allows calibration with high precision and which can perform calibration normally even when a specific radio receiving portion has a problem, and an array antenna receiving apparatus using the method. The array antenna receiving apparatus multiplexes calibration signals having predetermined symbol patterns from a multiplexing circuit (103) to signals received by array antennas (101) and inputs the results to radio receiving portions (104). The calibration signals having passed through the radio receiving portions are extracted by a calibration signal extracting portion (110), and an SIR detecting portion (111) determines one of the radio receiving portions having the best receiving quality as a reference branch based on the calibration signals.

Abstract: An interference protection system includes a receiving section for receiving an electromagnetic signal, a detector for detecting a jamming signal, and a control system for orienting a changeable null direction of an antenna system to reduce interference in a receiver from the jamming signal.

Abstract: A system and method are provided that includes at least a pair of spaced antennas having overlapping fields of view. The system further includes at least a pair of receivers respectively coupled to the pair of antennas. Each of the receivers includes a spectral separator having a plurality of output signals. Each of the output signals represents a signal value at one of a plurality of predetermined frequencies. A plurality of analog to digital converters are coupled to a corresponding one of the spectral separators for respectively providing a digital representation of each of the output signals. A digital processor coupled to an output of each of the plurality of analog to digital converters calculates an angle of arrival of the transmitted signal in at least one dimension from the digital representations.

Abstract: A system and method for detecting and tracking a target object, including the calculation of the target object's altitude, is disclosed. During the processing of signals received by a receiver, the system selectively calculates the altitude of the target object from signals modified by an interference effect pattern formed by the signals broadcast by a transmitter, or from the calculation of geometric shapes associated with three or more transmitters and determining the intersection point of those shapes.

Abstract: In a method of co-operative radio direction-finding in transmission in a system of radio direction-finding for a radiocommunications system comprising one or more transmission sources or transmitters, the transmitted signal comprises a reference sequence formed by a sequence of symbols {Sk}, the receiver comprising at least one array of several sensors coupled to a radio direction-finder. The method comprises the following steps: a) determining the reference signal or signals di(t) associated with a transmitter m from the reference symbols {Sk} and from the modulation defined by the format of the signals; b) defining the instant of arrival tk of one or more reference signals; c) from the signal x(t) received at the sensors, the instants of arrival tk and the reference signal or signals di(t) derived from the step a), determining the value or values of incidence of the signals for a given transmitter. The method can be applied to GSM or UMTS signals.

Abstract: A method for determining a location of an emitter in a monitored area includes the step of providing an array representative of the monitored area, the array including a plurality of elements. Next, at least one first curve and at least one second curve is provided in the array. The first and second curves are representative of possible locations of the emitter in the monitored area. Then, possible emitter locations are identified at intersections of the first and second curves. The intersections are identified by determining locations in the array where an element having an assigned attribute corresponding to a first curve has a predetermined number of adjacent elements having an assigned attribute corresponding to a second curve.

Abstract: A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring an angle sweep for arrival angle estimation of MUSIC method or the like.

Abstract: A/D conversion section 103 converts the signal received by array antenna 101 and frequency-converted to a digital signal by frequency conversion section 102. Correlation detection section 105 uses the chip rate as a cycle frequency and calculates a cyclic correlation matrix of spread spectrum signals stored in data storage section 104. Cycle frequency detection section 106 detects the cycle frequency of an interference signal output from A/D conversion section 103. Correlation detection section 107 uses the detection result of cycle frequency detection section 106 as a cycle frequency and calculates a cyclic correlation matrix of the signal, which becomes an interference signal, using the signal output from A/D conversion section 103.

Abstract: For interferometric and/or tomographic remote sensing by means of synthetic aperture radar (SAR) one to N receiver satellites and/or transmitter satellites and/or transceiver satellites with a horizontal across-track shift the same or differing in amplitude form a configuration of satellites orbiting at the same altitude and same velocity. Furthermore, a horizontal along-track separation, constant irrespective of the orbital position, is adjustable between the individual receiver satellites. In this arrangement one or more receiver satellites orbiting at the same altitude and with the same velocity are provided with a horizontal across-track shift varying over the orbit such that the maximum of the horizontal across-track shift occurs over a different orbital position for each satellite, the maxima of the horizontal across-track shifts are positioned so that the baselines are optimized for across-track interferometry.

Abstract: A method and apparatus for tracking a target. A signal from the target is received using a directional antenna and is digitized to provide a time series of samples. The samples are transformed, preferably by a wavelet transform. A signature of the target is identified in some of the transformed samples and a direction to the target is determined from others of the transformed samples. Target identification and target direction determination are iterated, with the identification being based on the most recently determined direction, and with the direction determination being based on the most recent identification, until a termination criterion is satisfied. Using wavelet transforms gives the antenna an effective beamwidth twenty percent narrower than the antenna aperture.

Abstract: A method for processing radar return data to determine a physical angle, in aircraft body coordinates to a target, is disclosed. The radar return data includes a phase difference between radar return data received at an ambiguous radar channel and a left radar channel, a phase difference between radar return data received at a right radar channel and an ambiguous radar channel, and a phase difference between radar return data received at a right radar channel and a left radar channel. The method includes adjusting a phase bias for the three phase differences, resolving phase ambiguities between the three phase differences to provide a signal, and filtering the signal to provide a physical angle to the target in aircraft body coordinates.

Abstract: A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring an angle sweep for arrival angle estimation of MUSIC method or the like.