Abstract: A phase interpolation circuit with a high linearity includes a first parallel circuit constituted by M phase interpolation units, and a second parallel circuit constituted by N phase interpolation units. An input terminal of the first parallel circuit is connected to a first clock input terminal and grounded via a first capacitor. An input terminal of the second parallel circuit is connected to a second clock input terminal and grounded via a second capacitor. An output terminal of the first parallel circuit and an output terminal of the second parallel circuit are connected to a clock output terminal and grounded via a zeroth capacitor. A circuit parameter of each phase interpolation unit corresponds to a target output weight respectively. The target output weight of each phase interpolation unit is determined by iteration to minimize a phase difference between all output clock signals of the phase interpolation circuit.

Abstract: Methods and apparatus for reducing and/or canceling signal interference between receiver and transmitter components of a wireless communications device are described. The methods and apparatus are well-suited for use in a wide range of devices including user equipment devices such as cell phones as well as in network equipment such as base stations. Opto-mechanical devices are used in some embodiments as part of an apparatus which performs interference cancelation on RF (Radio Frequency) signals.

Abstract: Methods and apparatus for reducing and/or canceling signal interference between receiver and transmitter components of a wireless communications device are described. The methods and apparatus are well suited for use in a wide range of devices including user equipment devices such as cell phones as well as in network equipment such a base stations. Opto-mechanical devices are used in some embodiments as part of an apparatus which performs interference cancelation on RF (Radio Frequency) signals.

Abstract: Methods and apparatus for reducing and/or canceling signal interference between receiver and transmitter components of a wireless communications device are described. The methods and apparatus are well suited for use in a wide range of devices including user equipment devices such as cell phones as well as in network equipment such a base stations. Opto-mechanical devices are used in some embodiments as part of an apparatus which performs interference cancellation on RF (Radio Frequency) signals.

Abstract: A mobile terminal, operational both to receive and transmit, may comprise a mobile antenna and an antenna controller that may be configured to control the mobile antenna at least for keeping it pointed towards the satellite, e.g. as the mobile terminal and/or the satellite move. Disclosed is a method that may be used by the antenna controller for optimizing the pointing of the mobile antenna, the method may be based on assessing both the reception quality and the transmission quality. This method may be used for overcoming degradation, mainly to transmission quality, that may result from squints between an optimal reception direction and an optimal transmission direction associated with the mobile antenna.

Abstract: Methods and apparatus for reducing and/or canceling signal interference between receiver and transmitter components of a wireless communications device are described. The methods and apparatus are well suited for use in a wide range of devices including user equipment devices such as cell phones as well as in network equipment such a base stations. Opto-mechanical devices are used in some embodiments as part of an apparatus which performs interference cancelation on RF (Radio Frequency) signals.

Abstract: Methods and apparatus for reducing and/or canceling signal interference between receiver and transmitter components of a wireless communications device are described. The methods and apparatus are well suited for use in a wide range of devices including user equipment devices such as cell phones as well as in network equipment such a base stations. Opto-mechanical devices are used in some embodiments as part of an apparatus which performs interference cancelation on RF (Radio Frequency) signals.

Abstract: At least two input signals, each characterizing a radio signal having a radio frequency (RF), are received. The input signals are converted into at least three output signals. The output signals have a unique combination of corresponding magnitudes for each RF phase difference between the input signals. A set of magnitudes corresponding to the output signals is measured using a mobile measuring device. An RF phase angle value is determined based the measured set of magnitudes. The RF phase angle value is converted into an angle value indicative of the direction of arrival of the radio signal.

Abstract: The present disclosure relates to an active antenna array for a mobile communications network. The active antenna comprises a base band unit coupled to a base station, a plurality of transceiver units and at least one link. The plurality of transceiver units is terminated by at least one antenna element. The at least one link couples individual ones of the plurality of transceiver units to the base band unit 10. The at least one link is a digital link and is adapted to relay an individual transmit signal concurrently and in synchronisation with a transmit clock signal. The present disclosure further teaches a method for relaying radio signals in a mobile communications network. The present disclosure further relates to a computer program enabling a computer to manufacture the active antenna array of the present disclosure and to execute the method of relaying radio signal in a mobile communications system.

Abstract: The present disclosure teaches an active antenna array for a mobile communications network. The active antenna array comprises a base band unit, a plurality of transceiver units terminated by at least one antenna element; and at least one link. The link couples the individual ones of the plurality of transceiver units to the base band unit. The link is a digital link and is adapted to relay a payload signal at a selectable payload rate. The digital link is further adapted to relay a timing signal at a fixed timing rate, when the timing signal is embedded in the payload at a selectable payload rate. The present disclosure further teaches a method for relaying radio signals and a computer program for manufacturing the active antenna array and for executing the method.

Abstract: A feed network for an antenna subarray includes a first feed arrangement having an sum output, a second feed arrangement having an delta output, a fixed attenuator having a first port and a second port, the first port connected to the delta output of the second feed arrangement, a first power divider/combiner having a first and second port and a third port; the first port connected to the second port of the fixed attenuator, a variable phase shifter having a first port and a second port, the first port connected to the second port of the power divider/combiner, a variable attenuator having a first port and a second port, the first port connected to the second port of the variable phase shifter, a second power divider/combiner having a first and second port and a third port; the first port connected to the second port of the fixed attenuator, a first circulator having a first port, a second port and a third port, the first port connected to the sum output of the first feed arrangement, and a third power divide

Abstract: Provided are an active radio frequency identification (RFID) system for port logistics and a communication method in the RFID system in which the forms of commands and response messages in the current standard are not changed in order to maintain compatibility with the current standard and to support multi-hop communication and some fields that are not generally used are used so as to enable communication between a tag in a shadow area and a reader by multi-hop communication using other surrounding tags.

Abstract: An antenna array (10) for the transmission of signals (20) is disclosed. The antenna array (10) comprises: a plurality of transmission paths (30-1, 30-2, 30-K) for transmitting a plurality of wanted signals (25) and at least one calibration signal generator (40-1, 40-2, 40-K) for the generation of at least one calibration signal (45). A plurality of calibration signal mixers (50-1, 50-2, 50-K) mixes the at least one calibration signal (45) with the plurality of wanted signals (25) to produce a plurality of transmission signals (20). A path sum signal device (60) sum the plurality of transmission signals (20) to produce a summed transmission signal (65); and an interference estimator (90) accepts the at least one calibration signal (45) and generates an estimated interference signal (92).

Abstract: A sparsely populated array of antenna elements on a plane is provided such that the angle of arrival (AoA) measurement for a radiofrequency signal received by the array has high resolution and is non-ambiguous within a 360-degree azimuthal field of view. The array comprises a two-dimensional antenna array developed using fuzzy genetic logic based on specified criteria. In response to one specified set of criteria, the array comprises having a first large element formation combined with a second smaller element formation. The first large element formation supports high DF accuracy while the second smaller cluster facilitates ambiguity resolution.

Abstract: A method is provided for constructing a histogram to represent the root-mean-squared phase differences for a signal received at pairs of elements in an array. A pair-wise element phase difference (“PEP”) between a signal received at an angle of arrival ?1 and a signal received at an angle of arrival ?2 are determined. The difference ?? between the differential phase measurements at ?1 and ?2 is computed. The process is repeated for all unique pairs of angles (?1, ?2) from 0 to 359 degrees and the results are summed over all PEPs to calculate the root mean squared phase difference ?{square root over (??2(?1,?2))} between two different angles of arrival ?1 and ?2. A two-dimensional histogram is created by pairing the measurements ?{square root over (??2)} and ??, where ??=?2??1.

Abstract: A wide-angle null-fill antenna with no null in the depression angle range, an omni antenna using the same, and radio communication equipment. A null-fill antenna comprises a first antenna array including antenna elements arranged with a prescribed point as the center, and a second antenna array having amplitude characteristics substantially equal to those of the antenna elements forming the first antenna array. The first antenna array is excited so that the excitation amplitude distribution is to have symmetry with respect to the prescribed point, while the excitation phase distribution is to have point symmetry with respect to the prescribed point. The phase center of the first antenna array is substantially coincident with that of the second antenna array.

Abstract: A method and a corresponding device determines the speed of a moving entity carrying at least two antennas for receiving a transmission signal the antennas being displaced at a predetermined distance. In order to provide a more simple and accurate method which can be used with different transmission signals the method includes the steps of: receiving a transmission signal by the antennas, determining signal characteristics from the transmission signal as received by the determining a time offset between the reception of the transmission signal at the antennas by comparing the signal characteristics determined for the antennas, and determining the speed of the moving entity from the determined time offset, the distance of the antennas and the direction of movement of the moving entity relative to the arrangement of the antennas.

Abstract: A beam-forming antenna for transmission and/or reception of an electromagnetic signal having a given wavelength in a surrounding medium includes a transmission line electromagnetically coupled to an array of individually controllable antenna elements, each of which is oscillated by the signal with a controllable amplitude. The antenna elements are arranged in a linear array and are spaced from each other by a distance that does not exceed one-third the signal's wavelength in the surrounding medium. The oscillation amplitude of each of the individual antenna elements is controlled by an amplitude controlling devices such as a switch, a gain-controlled amplifier, or a gain-controlled attenuator. The amplitude controlling devices, in turn, are controlled by a computer that receives as its input the desired beamshape, and that is programmed to operate the amplitude controlling devices in accordance with a set of stored amplitude values derived empirically for a set of desired beamshapes.

Abstract: A method and system is disclosed for enhancing reception of wireless communication signals. A beam pattern including at least one set of beams is generated. Where the beam pattern includes at least two sets of beams, the beam sets may be offset with respect to each other and alternated to enhance reception. Beams may be selected for data processing based on a signal-to-noise ratio (SNR) and may be maximal-ratio combined where signals from a single WTRU are detected within more than one beam and are used for data processing.

Abstract: A cosite interference rejection system allows cancellation of large interfering signals with an optical cancellation subsystem. The rejection system includes an interference subsystem coupled to a transmit system, where the interference subsystem weights a sampled transmit signal based on a feedback signal such that the weighted signal is out of phase with the sampled transmit signal. The optical cancellation subsystem is coupled to the interference subsystem and a receive antenna. The optical cancellation subsystem converts an optical signal into a desired receive signal based on an interfering coupled signal and the weighted signal. The weighted signal is therefore used to drive the optical cancellation subsystem. The rejection system further includes a feedback loop for providing the feedback signal to the interference subsystem based on the desired receive signal.

Abstract: 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.

Abstract: A monopulse precision landing or other land-based radar system uses an array antenna and a beamformer to produce sum, azimuth difference and elevation difference beams relative to the array. The rows and columns of the array are skewed relative to the horizontal for tending to reduce the effects of multipath propagation on altitude estimates. A coordinate converter converts target information from the skewed antenna coordinates to ordinary vertical and horizontal coordinates.

Abstract: Improved punch-through performance is provided for applications such as sum and difference mode processing for IFF and other applications. With an array including a row of elements, difference sidelobe levels are increased relative to sum sidelobe levels by independently controlling relative signal levels of difference mode signals provided from signals received by central elements of the array. By processing signals from central elements independently from processing of signals from outer elements of the array, difference mode signals derived from the central elements may be employed at higher signal levels in order to raise difference mode sidelobe levels to improve punch-through performance. Antenna systems and methods are described.

Abstract: Embodiments of the present invention relate to a method and apparatus for reducing interference in a positioning system. According to one or more embodiments of the present invention, the receiver in a conventional positioning system is configured to communicate with a terrestrial broadcast station. The terrestrial broadcast station transmits assistance signals to the receiver and may be another receiver. The assistance signals enable the receiver to locate very weak signals being transmitted from the satellites in the positioning system. In one embodiment, the assistance signals include Doppler frequencies for the satellites. In another embodiment, the assistance signals include Ephemeris data. In another embodiment, the assistance signals include almanac data. In other embodiments of the present invention, the assistance signal includes navigation bits demodulated from the carrier phase inversion signal of the satellite, time synchronization signals, and pseudo range differential corrections.

Abstract: A method for measuring range and bearing of an object. At least a portion of a first signal is transmitted from a sensor. The transmitted signal is reflected from an object and received by the sensor. At least a portion of the first signal is applied a first mixer and a second mixer. The received signal is applied to the first mixer and the second mixer. A second signal is generated from the first mixer, and a third signal is generated from the second mixer when the portion of the first signal that was transmitted overlaps the reflected signal at least partially. Bearing angle, degree on or off boresight and object range may be determined from the second and third signals, or a combination thereof. Also disclosed is a sensor for object range and bearing measurement.

Abstract: Embodiments of the present invention relate to a method and apparatus for reducing interference in a positioning system. According to one or more embodiments of the present invention, the receiver in a conventional positioning system is configured to communicate with a terrestrial broadcast station. The terrestrial broadcast station transmits assistance signals to the receiver and may be another receiver. The assistance signals enable the receiver to locate very weak signals being transmitted from the satellites in the positioning system. In one embodiment, the assistance signals include Doppler frequencies for the satellites. In another embodiment, the assistance signals include Ephemeris data. In another embodiment, the assistance signals include almanac data. In other embodiments of the present invention, the assistance signal includes navigation bits demodulated from the carrier phase inversion signal of the satellite, time synchronization signals, and pseudo range differential corrections.

Abstract: An interference canceller capable of reducing interference between users by generating appropriate replicas. This canceller carries out a hard decision on a signal after FEC decoding and carries out error detection on the resulting signal, and, when an error is detected, generates a replica with a smaller weighting factor assigned to an erroneous signal or generates a replica using a provisionally detected value prior to FEC decoding (hard decision value or soft decision value). Or when the error detection result in the previous stage is OK, the canceller generates a replica using the hard decision value in the previous stage.

Abstract: A system for instrumenting time sampled predicting interference suppression, particularly in a side-lobe canceller system. Main and auxiliary channel signals are supplied to a canceller loop where correlating weights are sampled just prior to a radar pulse transmission on command of a radar pretrigger pulse. A sampling circuit stores both current and past weights and combines the current weight with the integral of the difference between the current and past weight to form predicting weights over each pulse repetition period. The predicting weights are used to form a translating signal for operating on the auxiliary channel interference signal so that it will cancel the interference in the main channel. By sampling just prior to radar pulse transmission and forming the predicting weights, cross modulation of clutter and antenna scan error can be reduced in order that a side-lobe canceller may be used compatibly with Moving Target Indicators.

Abstract: A method and apparatus for training a receiver on a source are provided. The receiver is an antenna and the source is a broadcast satellite. A first signal sensor receives at least one signal from the source. The first signal sensor may be a first low noise block (LNB) downconverter of the antenna. At least one secondary signal sensor measures a strength of the received signal. The secondary signal sensor comprises four LNB downconverters, wherein each of the four LNB downconverters are located on each of four sides of the first signal sensor. The measured strength of the received signal is used to provide guidance information for training the receiver on the source. When the broadcast satellite moves relative to the antenna, the secondary LNB downconverters detect a variance in the measured strength of the at least one signal and provide guidance information based on the detected variance, thereby reducing the training time for the antenna.

Abstract: A signal processing apparatus for minimizing interference and for reducing effects of noise by controlling beam patterns of a telecommunication system having an array antenna, comprising: a means for computing a residue vector, by using a signal vector provided from said array antenna at each snapshot, a final array output signal of said telecommunication system at the last previous snapshot and a value of a gain vector of the present snapshot, and for outputting said residue vector; a means for synthesizing a scalar value, which is needed to generate a search direction vector, from said residue vector; a means for producing said search direction vector, by using said residue vector and said scalar value; a means for producing an adaptive gain, by using said signal vector, said search direction vector, said final array output signal of said telecommunication system at the last previous snapshot and the value of said gain vector of the present snapshot; and a means for updating said gain vector, by using said

Abstract: The disclosed method uses the ancillary antennas of a radar, and consists in determining the positions of the phase centers of these ancillary antennas, compensating for the difference in optical path between the reflection lobe of the processed channel and that of the ancillary channel, and generating a synthetic channel by an SLO type processing in performing a coherent subtraction between the processed channel and the ancillary channels used, on the desensitized zone of the doppler distance/frequency ambiguous domain of each of the processed channels.

Abstract: This invention relates to automatic direction finding methods and systems for an electromagnetic or acoustic signal source by utilizing the concept of adaptive nulling of a narrow or wideband signal received by one sensor from the same signal received by the other, along with appropriate adjustments, in a two-sensors-interferometer. Plurality of sensors can be used to measure two orthogonal angles of arrival of a signal. Inventive methods and devices permit singling out a particular signal of interest among others by allowing a frequency tuning and selective amplification of the particular signal of interest without destroying the differential phase or time delay between the signals received by the sensors that determine the angle measurement. A high degree of signal cancellation during the adaptive nulling process permits a correspondingly high degree of accuracy and resolution for the angle measurement and also permits a relatively short baseline for the interferometer.

Abstract: The invention pertains to the sensing and elimination of jamming signals transmitted by jammers towards radar antennas. According to the invention, we associate with a main space surveillance radar antenna an auxiliary antenna that is outfitted with a modulating filter which enables the sensing of jammers, and the elimination of jamming effects by opposing, to the secondary lobes of the main antenna corresponding to the jamming directions, corresponding secondary lobes which are appropriately amplified by the auxiliary antenna. The invention applies to anti-jamming of radar antennas with mechanical or electronic sweeps.

Abstract: A distance measuring system for measuring a distance between two objects has a transmitter assembly mounted on one of the two objects, for transmitting a plurality of electromagnetic waves having respective wavelengths different from each other at respective levels toward the other of the two objects, a receiver assembly mounted on the other object, for receiving the electromagnetic waves transmitted from the transmitting means, and a distance detector for detecting a ratio of levels at which at least one set of electromagnetic waves of the electromagnetic waves is received by the receiving means, as corresponding to a distance between the two objects, and determining the distance between the two objects from the ratio.

Abstract: An adaptive nulling communication system for nulling undesired signals from communication signals in multiple separate and distinct coverage areas is disclosed. The adaptive nulling communication system includes a phased array antenna having multiple receiving elements to form a single aperture for receiving multiple signals. A first set of beam forming networks coupled to the phased array antenna forms the multiple separate and distinct coverage areas. A distribution network coupled to the first set of beam forming networks distributes the signals received from these coverage areas. A nulling processor having a second beam forming network coupled to the distribution network weights and adjusts the second beam forming network in response to the undesired signals to null these undesired signals from the communication signals.

Abstract: The invention relates to apparatus for reducing the masking effect in the doppler frequency domain of wind sheared clutter upon the radar returns of moving targets. The invention consists in forming two beams from the elements of a radar antenna array by means of adjustable complex weights which are then summed. One of the two beams is then delayed by a predetermined amount and added algebraically to the other beam to form a composite beam containing a narrow trough-like depression in beam angle/doppler frequency space. Means are then provided for adjusting the weights to bring coincidence between the depression and the clutter to cause attenuation of the clutter with a minimum reduction in the usable doppler frequency domain.

Abstract: A radar interference circuit which rejects both continuous noise and shorulse interference signals. A plurality of omni-directional antennas are placed around the main directional radar antenna and connected in differing sets to a plurality of canceller means to each of which the main antenna signal is also connected. The canceller means for each set of three Omnis and the main antenna cancels out the white-noise interference received by that group of antennas. The outputs of the plurality of canceller means are then taken in different sets of two each, subtracted and compared to a threshold signal. If one or more comparator outputs are above the threshold, signifying that the antenna pulse signal is being received through the sidelobes of the antenna patterns, the outputs of these comparators will be a one signal and the OR gate, to which the comparator outputs are fed, will provide an output to blank the radar.

Abstract: A method and apparatus are provided for filtering noise from a plurality of input signals in a sensor system. One first main input signal and several first auxiliary input signals are obtained and interior weights corresponding to the first main and auxiliary signals are determined. Thereafter, equivalent linear weights corresponding to the interior weights are determined and the equivalent linear weights are applied to second main and auxiliary input signals to filter the second main and auxiliary signals and produce one final output signal. Alternatively, the first input signals can be a subset of the second input signals such that a large set of input signals can be filtered by calculating weighting factors from a subset thereof.

Abstract: Improved radar system performance in a jamming environment is achieved by detecting the AM difference frequency produced by the beating of the desired radar signal with the jamming signal and applying same to one input of a balanced modulator while simultaneously applying the received signal (containing both the desired radar signal and the jamming signal) to the other input of the balanced modulator whereby the output from the balanced modulator contains the desired signal but not the jamming signal.

Abstract: An interference suppression system for cancelling undesired signals recei through the mainlobe of an antenna as well as its sidelobes. The interference suppression system has a main channel input having high gain for receiving desired signals and undesired signals and forming a main channel waveform, and an auxiliary channel input having low gain for receiving desired signals and undesired signals and forming an auxiliary channel waveform. A control circuit senses the relative undesired signal power in the two channels and responds by switching the waveforms in the two channels between two inputs of an interference-reducing circuit according to whether sidelobe or mainlobe interference is present in the main channel.

Abstract: A system for cancelling jammer signals entering the mainlobe of a monopulse adar and providing target locations with respect to the jammer position comprising for a sequential lobing embodiment: measuring the angular position of the jammer in the radar's mainlobe via the use of monopulse sum and difference signals, pointing the radar antenna so that the jammer is positioned within the 3 dB points of the mainlobe of the monopulse antenna, converting the sum and difference echo signals received with the antenna in this position from the next radar transmission into a second set sum and difference signals, applying this second set of sum and second set of difference signals to the inputs of an adaptive canceller to cancel the jamming signal therein and storing these signals in time sequential order, changing the orientation of the radar antenna by a small arbitrary elevation angle, converting the sum and difference echo signals received with the antenna in this new position from a third radar transmission into a

Abstract: A digital, open-loop, sidelobe canceller system includes an arrangement of uxiliary-channel preprocessing cancellers and a series of main-channel cancellers in which specific cancellers average a different number of samples for cancelling both barrage (continuous) jamming and false-target-repeater jamming, which enter the sidelobes of a radar antenna. The preprocessing cancellers and each of the main-channel cancellers, except the last succeeding main-channel canceller, use long-time averaging (averaging over a large number, n, of samples of the main and auxiliary signals, where n>>2) for removing barrage jamming from the main signal. The last succeeding main-channel canceller uses short-time averaging (averaging over approximately 2-4 samples) for removing false-target-repeater jamming from the main signal.

Abstract: A system for instrumenting time sampled interference suppression, particuly in a side-lobe canceller system. Interference signals are sampled just before a radar transmits on command of a sample gate or radar pulse, with main and auxiliary channel signals being delayed by the time between two successive samples. The two samples are then combined to allow interpolation such that weighting functions can be formed to adjust the delayed auxiliary signal so that interference in the delayed main channel signal can be suppressed at all times. By sampling just prior to radar transmission and interpolating between samples, cross modulation of clutter, and antenna scan error can be reduced in order that a side-lobe canceller system may be used compatibly with Moving Target Indicators (MTI).

Abstract: The elimination of jamming signals from received radar signals is conventionally accomplished by side lobe cancellation techniques. Large interfering signals caused either by clutter or other sources, however, can cause intolerable degradation of coherent side lobe cancellation (CSLC) systems. In the present invention an inhibit signal is used to open the input to the coherent side lobe cancellation error sensing circuits thus preventing large signals from entering the coherent side lobe cancellation loop. Large signals entering coherent side lobe cancellation loops give rise to erroneous transients in the output. The invention effects storage of previously sensed error signals so as to continue jammer cancellation until new data become available to update the error signals. The inhibit signal is generated by a combination of coherent side lobe cancellation sensing circuits and logic control circuits that determine when an inhibit signal should be generated.

Abstract: An interference signal suppression system and method that suppresses coherent jamming signals. The system comprises first and second receiving antennas that are physically separated from each other to generate non-coherent received signals of interest. The antennas are positioned to receive communication signals that are jammed with coherent energy. The separation distance is typically 40 to 50 wavelengths of the non-coherent scattered wave radio frequency signals. Phase and amplitude adjustment circuitry is provided that alters the phase and amplitude of the received signals such that the coherent received signals are balanced and out-of-phase. These signal are then summed in a summing circuit and the output of this circuit generates signals wherein the coherent signals are nulled and the non-coherent signals are detectable. The signal suppression system and method is independent of the direction of arrival of the coherent signals, which overcomes limitations of conventional techniques.

Abstract: An improved signal processing system and technique for preprocessing auxiry data signals by sequential decorrelation, particularly for use in systems employing adaptive cancaller loops. Each of a plurality of signal channels sample the environment of a plurality of signal sources and provide inputs to a configuration of adaptive canceller loops. The loops are connected such that an adaptive loop decorrelates the signal from two signal channels to form a preprocessed signal, and each of the remaining adaptive loops are sequentially connected such that each auxiliary channel signal is decorrelated from the preprocessed signal of the previous adaptive loop until all signal channels have been utilized. In a side-lobe canceller system each of the preprocessed outputs is used to form an auxiliary sample input to a main channel canceller loop to cancel interference in the receiving system.

Abstract: An adaptive interference canceller for use in a dual polarized radar system for receiving cross-polar and like-polar signals and generating an output signal corresponding to the received cross-polar signal with a like-polar interfering component cancelled therefrom. A modified adaptive filter is provided with a self-adjusting impulse response conforming to a least means square adjustment cancelling the influence of the like-polar signal, which is generally much stronger on the cross-point signal. The resulting output has a high target-to-clutter ratio and therefor a high probability of detection.

Abstract: Interference signal cancelling is provided by a multiplexed interference celling system that utilizes a primary high gain antenna and an auxiliary antenna pair including a low gain notch antenna in conjunction with a low gain omnidirectional antenna. The output of the two low gain auxiliary antennas are subtracted from each other to provide an output that is substantially free of all input signals except for the interfering signal received in the narrow notch of the notch antenna. This signal is then subtracted from the composite output signal of the primary antenna. One of these auxiliary antenna pairs is employed for each separate jamming signal source to be cancelled, thus enabling each jamming signal to be orthogonally isolated, whereupon its magnitude and phase is then adjusted to be equal to and 180.degree. out of phase with the same component contained in the composite signal from the primary antenna.

Abstract: This invention relates to a mainlobe jamming cancellation system which can e used to allow a radar to detect targets even when relative motion exists between the jammer and the radar platform. In particular, this invention relates to a mainlobe canceller that utilizes a main antenna and one or more widely spaced auxiliary antennas in conjunction with one or more phase locked loops (PLL), to automatically align the jamming signals received by the several antennas. The alignment is necessary to realize a high degree of jammer cancellation.

Abstract: A radar ECCM system for degrading the effect that a standoff noise jammer has on a radar receiving site that is tracking an incoming aerial target. The system effectively removes from the mainlobe of the beam emanating from the site the component of random noise contained in the jamming signal.