Abstract: A method of adapting weather radar thresholds is disclosed. The method comprises generating a location from a location sensor, retrieving information representative of a weather type from a database, based on the location, and adjusting, automatically, the threshold for a radar display based on the information.

Abstract: A method for reducing the interference between a source transmitting pulses and equipments having nominal bandwidths which are outside the nominal bandwidth of the transmitted pulses, but which respond to sideband energy of the pulses. Phase perturbations are applied to the edges of the pulses produced by the source, to thereby tend to null the sideband energy lying in the nominal bandwidth of the equipments occupying the adjacent nominal bandwidths.

Abstract: A vehicle-installed radar sensor system includes a transmission section, a reception section, and a shield member. The transmission section is disposed in a closed space formed between a permeable member provided in a vehicle and a vehicle body, and transmits a radar wave to outside of the vehicle through the permeable member. The reception section is disposed in the closed space at a distance from the transmission section, and receives a reflected wave by a target through the permeable member. The shield member is disposed in at least one of the transmission section and the reception section, and suppresses at least one of occurrence of a reflected wave by the permeable member and reception of the reflected wave by the permeable member.

Abstract: The dual synthetic aperture array system processes returns from the receiving arrays. The two identical receiving arrays employing displaced phase center antenna techniques subtract the corresponding spectrally processed data to cancel clutter. It is further processed that a moving target is detected and its velocity, angular position and range is measured, in or out of the presence of clutter. There are many techniques presented in the disclosure. These techniques are basically independent but are related based on common set of fundamental set of mathematical equations, understanding of radar principles and the implementations involved. These many techniques may be employed singly and/or in combination depending on the application and accuracy required.

Abstract: A target is detected under a forest canopy or other elevated clutter where the target is obscured by the elevated clutter. Radar returns reflected from the target on the surface, combined with those from the elevated clutter are digitized. Motion compensation is performed for the radar returns with respect to the target to obtain a focused first synthetic aperture image of the target. Next, the radar returns are motion compensated with respect to the elevated clutter at various heights above the surface to obtain images of the elevated clutter. The elevated clutter within the images at the various heights above the surface is identified and coherently subtracted from the original synthetic aperture images.

Abstract: A radar system and method use a radar FMCW chirp having variable chirp characteristics.

Abstract: Reducing antenna boresight error includes receiving radar pulses reflected from the ground, where pulses are emitted from the antenna of a radar system, reflected by the ground, and received by the antenna. The return pulses carry information about the ground. Measurement indices are established from radar and platform parameters, and a clutter spectrum is generated from the return pulse information. The amplitude of the clutter spectrum is measured at each of the measurement indices. Whether there is an amplitude imbalance is established in accordance with the measured amplitudes. An error estimate describing an antenna boresight error is determined if there is an amplitude imbalance.

Abstract: A radar transmits electromagnetic energy in pulse repetition intervals and receives reflections from objects in range gates including Doppler filters. The radar approves desirable ambiguous echoes and suppresses ambiguous echoes of no interest or that interfere with the radar's display. The radar frequency varies according to a staggered or wobbling pattern. The ambiguous echoes produce one pulse in the range gates within a predetermined number of periods. The Doppler filter works with an impulse function response that includes a small number of samples. The Doppler filter, during the predetermined number of periods, gives rise to independent samples from reflectors within the radar's unambiguous range. When the independent samples exceed the small number of samples, the radar approves the ambiguous echo. Otherwise, it is suppressed. In this way, ambiguous echoes are prevented from interfering with the reception or display of echoes. The suppression of asynchronous interferences can be made easier.

Abstract: To achieve a purpose of the present invention, a pulse wave radar device related to the present invention modulates a first transmitting pulse and a second transmitting pulse which are separated from each other by a predetermined lapse of time and transmits a transmitting pulse wave and, if a lapse of time from transmission of the transmitting pulse wave corresponding to the first transmitting pulse to outputting of a pulse by the receiving circuit is equal to a lapse of time from transmission of the transmitting pulse wave corresponding to the second transmitting pulse to outputting of a pulse by the receiving circuit, decides that the pulses are a receiving pulse reflected from a target.

Abstract: Systems and methods of tracking a beam-aspect target are provided. In embodiments, a target is tracked with a Kalman filter while detections are received. After a detection is missed, the Kalman filter may be concurrently propagated with a blind-zone particle filter until a probability that the target is in a blind zone exceeds a threshold. When the probability exceeds the threshold, the Kalman filter may refrain from further propagating. After a gated detection is received, the blind-zone particle filter and an unrestricted-zone particle filter may be concurrently propagated while a probability that the target is in an unrestricted zone exceeds a threshold. The system may return to tracking with the Kalman filter when a covariance of the unrestricted-zone particle filter falls below a predetermined covariance.

Abstract: A bistatic radar system having a transmitter that generates unique signals at spatially independent transmitter degrees of freedom and a receiver that filters the signal at each receiver degree of freedom into a group of signals identical in number to the number of transmitter degrees of freedom. The receiver formats the filtered signals into a 2-dimensional array of elements. The receiver rotates the array so that the new axes are aligned with the Doppler gradient. The data is then re-sampled and projected to linearize the clutter signal. The receiver may be integrated with a broad class of adaptive and non-adaptive clutter mitigation approaches such as electronic clutter tuning and projected bistatic space-time adaptive processing, or STAP.

Abstract: A method according to an aspect of the invention is for filtering coherent multipulse radar, sonar or lidar returns. The method comprises the steps of separating the returns into mutually orthogonal I & Q components, performing wavelet processing on the I and Q components to generate an I & Q wavelet filter output. The I & Q wavelet filter outputs are data compressed to remove clutter portions. Data compression may be removal of large-amplitude or earliest wavelet responses. An inverse wavelet filtering function is performed on the compressed wavelet filter outputs, to thereby generate edited coherent I & Q components. Doppler filtering, is performed on the edited coherent I and Q components to thereby generate frequency-domain target data in which the minimum discernible target velocity is improved.

Abstract: Disclosed is a radar apparatus equipped with a function for detecting an FM-AM conversion noise peak. When the direction of radiation is swept, any peak whose level remains substantially unchanged is judged to be a peak due to FM-AM conversion noise. Further, when FM modulation is stopped, any peak appearing in a region not lower than 50 kHz is judged to be a noise peak.

Abstract: Nonlinear target detection for the detection of extremely weak signals when buried in very high levels of noise is performed with improvement of the quality of the signals received in the data by the amplification of the signal to noise (S/N) ratio. The S/N ratio increases dramatically after the originally measured signal is passed through a nonlinear stochastic resonance filter.

Abstract: Analysis of electromagnetic (or acoustic) multipath propagation inventively confines the assessment of multipath propagation to a “surface interactive region” (“SIR”), intermediate the target and transmitter and/or the target and receiver. The down range time of the propagation, translatable to range distance, is related to error associated with such restriction. A SIR scope is selected commensurately with acceptable error. Jointly disclosed (practicable therewith or thereapart) is inventive focus upon the transmitter-to-target propagation (transmitted propagation reaching target via both direct pathway and forward scattered pathway) and the target-to-receiver propagation (re-transmitted propagation reaching receiver via both direct pathway and forward scattered pathway). Transmitter-to-target propagation is calculated using conventional multipath modeling technique.

Abstract: A pulse wave radar device transmits at a constant period a transmitting signal in which identification data for identifying of pulse wave radar devices is added to a distance-measuring signal so that any other pulse wave radar device can identify a receiving wave reflected by a target owing to a transmitting wave that itself has transmitted.

Abstract: SAR images are improved by a method for acquiring a synthetic aperture image from a sequence of periodic pulse returns where the sequence of periodic pulse returns is interspersed with interrupts, i.e. missing pulses. The interrupts mark the start and end of one or more segments, where the segments contain the periodic pulse returns form the SAR image. The method comprises the steps of: converting said pulse returns into a digital stream; performing an azimuth deskew on said digital stream to obtain a deskewed digital stream; forming a forward-backward data matrix from the deskewed digital stream for one or more segments; forming an average segment covariance from the forward-backward data matrix; computing a model order for the average segment covariance; computing one or more linear prediction coefficients using data contained in the forward backward data matrix, and model order; using the linear prediction coefficients to compute missing pulse returns belonging within the interrupts.

Abstract: Target detection in the presence of non stationary clutter is improved by a radar receiver on a moving platform for detecting a target using a plurality of short coherent arrays and a plurality of long coherent arrays synthesized from the short coherent arrays overlapping the target. The target is obscured by slow scale clutter and fast scale clutter in the vicinity of the target.

Abstract: In an FM-CW radar system, a frequency modulating wave output from said modulating signal generator has a frequency variation skew with respect to a time axis (modulation skew), and the radar system includes a means for varying the modulation skew by controlling the modulation frequency amplitude or modulation period of the modulating signal. The radar system further includes a means for discriminating a signal component varying in response to the variation of the modulation skew, thereby discriminating a signal related to a target object from other signals. In the case of an FM-CW radar system that performs transmission and/or reception by time division ON-OFF control, the radar system includes a means for discriminating a signal which, when the frequency used to perform the ON-OFF control is varied, varies in response to the variation of the frequency, thereby discriminating a signal related to a target object from other signals.

Abstract: The invention concerns a passive radar receiver with an array of antennas for a OFDM received signal comprising frames of symbols each emitted on coded orthogonal carriers. After formatting received signals into digital symbols, dummy signals from dummy OFDM emitters at different distances from and in different directions relative to the receiver are generated and added to the signals picked up by the antennas. The modified received signals are filtered by means of inverse covariance matrices in order to eliminate at least unwanted zero Doppler effect signals and to provide an isotropic reception diagram without blind sector of direct path being generated and by detecting mobile targets along the direct path.

Abstract: A method, an arrangement and a radar level gauging system for preventing interference, which radar level gauging system comprises at least two radar level gauges arranged to measure a filling level of a product kept in a container. Microwave pulses are transmitted towards the surface of said product and microwave pulses reflected by said surface are received by said at least two radar level gauges. Information is provided with said microwave pulses and said information is used for controlling the measurement pulses of said at least two radar level gauges.

Abstract: A signal separating system 1 comprises a frequency conversion element 3, a dynamic filter component 4 with associated coherent stop slot and non-coherent passband, optionally a signal wave enhancer 7 with bypass, and a frequency reconversion element 8. In operation of the system, mixed incoming signals 12 (CW or pulse signals) having known interference and unknown emission components can be effectively separated, permitting a virtually instantaneous separation of the known interference from the unknown emissions and permitting an unobscured monitoring and/or characterization of the extracted unknown emissions 21, if desired. The arrangement bears definite advantage over known arrangements and retains utility for various frequency/agile or multiple or non-agile unknown signal applications.

Abstract: The direct path of a radio signal from the transmitter to the receiver is frequently interfered with by reflections of the transmitted signal from stationary and moving objects. These reflections are known as multipath noise. The multipath canceler of this invention takes as input the direct path signal plus multipath noise. The canceler, after canceling the multipath noise, outputs a purified version of the direct path signal nearly devoid of multipath noise. The output of the canceler is fed back to a bank of delayers and frequency shifters. The outputs of this bank of delayers and frequency shifters are multiplied by a set of adjustable coefficients. These coefficients are adjusted to form very accurate replicas of the multipath reflections caused by each reflector. Which replicas are subtracted from the input which is the original direct path signal plus the multipath noise.

Abstract: Radar Pulse detection and radar signal length detection are used to detect and provide information for identifying radar signals. Pulse detection estimates a radar pulse size when it is too short for meaningful measurement. Pulse detection identifies a radar by identification of an in-band pulse without a communication or data packet encoded therein, or a communication error is detected with the in-band pulse. Signal length detection counts the length of a received signal after the received signal exceeds a radar threshold. The count identifies the received signal length upon drop of the power. The signal is identified as a radar when the power drops before a PHY error occurs, or when the power drop occurs after a PHY error and a delay time equivalent to the shortest radar signal. A radar signal is also identified upon a timeout wait for a power drop after a PHY error.

Abstract: A method of reducing depolarization of a wireless signal passing through an antenna radome. An angle of incidence of the signal relative to the radome is determined. From the determined angle of incidence, at least one offset to signal depolarization attributable to the radome is determined. The offset is applied to the signal to reduce depolarization of the signal. When the foregoing method is implemented, effects of radome depolarization in transmit and/or receive modes can be substantially reduced or eliminated.

Abstract: A method of removing returns from rain in Doppler radar systems (and corresponding apparatus and computer software) comprising receiving a Doppler radar return signal, transforming the signal into a range versus frequency map, for a plurality of range cells, performing a fit over frequency, for the plurality of range cells, calculating a total energy, for the plurality of range cells, comparing the calculated total energy to a threshold value, and replacing the return signal for a range cell with another signal if for the plurality of range cells the comparing step is positive.

Abstract: A method and system for adaptively reducing, in a displacement signal having a value indicative of a measured angular displacement between an antenna boresight and an apparent line of sight to a target, a noise signal having a value indicative of an angular error induced by a shift in the target radar centroid so as to provide an output signal having a value indicative of an estimate of a true angular displacement signal between the antenna boresight and a true line of sight to the target.

Abstract: A radar suppresses a dc component so as to improve the precision in processing a signal that belongs to a low-frequency band. The radar comprises a mixer that mixes a transmitted signal and a received signal, and an A/D converter that analog-to-digital converts an output signal of the mixer. The radar further includes: a removing unit that removes a dc voltage component by subtracting a predetermined removal voltage value from output data of the A/D converter; and an analyzing unit that Fourier-transforms data, which has the dc voltage component removed therefrom by the removing unit, so as to analyze the data.

Abstract: The invention concerns a passive radar receiver for a received orthogonal frequency division multiplex-type signal consisting of symbol frames each emitted on coded orthogonal carriers. After formatting the received signals into digital symbols (S1 S1), a filtering circuit (2) eliminates by subtraction or using a covariance matrix, in the symbol signal at least unwanted signals with null Doppler effect so as to apply a filtered signal (X?) including essentially signals backscattered by mobile targets to a Doppler-distance correlator (4).

Abstract: A synthetic aperture radar (SAR) compensates for ionospheric distortions based upon measurement of the group delay, particularly when operating in the VHF/UHF band. The SAR is based upon a multi-input multi-output (MIMO) technique for estimating the effective ionospheric conditions, which is referred to as the group delay approach. The group delay approach is divided into a 1-dimensional (range) approach and a 2-dimensional (range and cross-range) approach. The group delay measures the effective or observed TEC, which is used to reduce the ionospheric distortion.

Abstract: A synthetic aperture radar (SAR) for a moveable platform includes an antenna, a radar transmitter and radar receiver cooperating with the antenna. A radar processor is connected to the radar transmitter and radar receiver to account for the Faraday rotation introduced by propagation through the ionosphere by estimating an individual ionospheric distortion for each received echo pulse based upon a measured Faraday rotation, and reducing the ionospheric distortion for each received echo pulse based upon the estimated individual ionospheric distortion associated therewith for providing a compensated echo pulse.

Abstract: The present invention includes an application of a dynamic logic algorithm to detect slow moving targets. Show moving targets are going to be moving in the range from 0-5 mph. This could encompass troop movements and vehicles or convoys under rough terrain.

Abstract: One preferred embodiment of the present invention provides a system and method for suppressing motion artifacts introduced by movement of a radar detection system. Briefly described, in architecture, one embodiment of the system, among others, can be implemented as follows. The system includes a Doppler radar module configured to transmit a microwave signal directed towards an object and receive the reflected microwave signals from the object and a living subject positioned behind the object. Also, the system includes a reference module configured to transmit a reference signal towards the object and receive the reflected reference signal from the object. By comparing the two reflected signals from the Doppler radar module and the reference device, a signal processor suppresses motion artifacts generated by movement of the Doppler radar module to identify the presence of the living subject behind the object. Other systems and methods are also provided.

Abstract: A vehicle radar system extracts peak frequencies fbu and fbd of respective beat signals B1 to B9 representing the frequency difference between a transmission signal fs and a plurality of received signals fr1 to fr9. The phase difference of respective beat signals B1 to B9 at the peak frequencies fbu and fbd is converted into a frequency signal. In the case of reflection from a close range road surface or raindrops, the phase difference of each beat signal is irregular. The peak frequency intensity of a converted frequency signal is small. This system compares the peak frequency intensity of the converted frequency signal with predetermined criterion intensity. Then, the system identifies an objective with a close range road surface or raindrops when the peak frequency intensity of the converted frequency signal is not larger than the predetermined criterion intensity.

Abstract: A method for calculating a center frequency and a bandwidth for a radar doppler filter is herein described. The center frequency and bandwidth are calculated to provide radar performance over varying terrain and aircraft altitude, pitch, and roll. The method includes receiving an antenna mounting angle, a slant range, and velocity vectors in body coordinates, calculating a range swath doppler velocity, a track and phase swath bandwidth, and a phase swath doppler velocity. The method continues by calculating a range swath center frequency based on the range swath doppler velocity, calculating a phase swath center frequency based on the phase swath doppler velocity, and calculating a level and verify swath bandwidth based upon the track and phase swath bandwidth.

Abstract: A radar signal processing unit comprises a Fourier transform section 1 for executing Fourier transform of the received signal to a frequency signal, a frequency domain power calculation section 2 for calculating a power spectrum of electric power for each frequency from the frequency signal, an abnormal echo removal section 3 for determining the abnormal echo based on the power value of the power spectrum and outputting only the power spectrum not corresponding to the abnormal echo, an incoherent processing section 4 for performing incoherent integration of only the power spectrum not corresponding to the abnormal echo and averaging, and a signal detection section 5 for calculating the physical quantity of the atmosphere from the incoherent-integrated power spectrum.

Abstract: To provide a radar system mounted on a vehicle that reliably detects the reception of the interference wave with high-performance and inexpensively. There is provided a radar system mounted on a vehicle for detecting a target object, including a transmitter for transmitting an electromagnetic wave, a receiver for receiving the electromagnetic wave reflected by the target object, a signal processor for measuring a distance between a vehicle of his/her own and the target object and a relative velocity on the basis of the transmitting electromagnetic wave and the receiving electromagnetic wave, and an interference detector for suspending a transmit operation of the transmitter under a control of the signal processor to detect an interference signal from another external device.

Abstract: This application discloses a method for distinguishing targets from clutter, comprising the steps inputting data, calculating data statistics from said data and using said data statistics to select target specific feature information to distinguish specific targets from background clutter, generating said target specific feature information from said data statistics, extracting said target specific feature information from said data, using said target specific feature information to distinguish specific targets from background clutter, and outputting target and background clutter information. Classification systems, including hardware and software embodiments, are also disclosed.

Abstract: Radar Pulse detection and radar signal length detection are used to detect and provide information for identifying radar signals. Pulse detection estimates a radar pulse size when it is too short for meaningful measurement. Pulse detection identifies a radar by identification of an in-band pulse without a communication or data packet encoded therein, or a communication error is detected with the in-band pulse. Signal length detection counts the length of a received signal after the received signal exceeds a radar threshold. The count identifies the received signal length upon drop of the power. The signal is identified as a radar when the power drops before a PHY error occurs, or when the power drop occurs after a PHY error and a delay time equivalent to the shortest radar signal. A radar signal is also identified upon a timeout wait for a power drop after a PHY error.

Abstract: In a pulse-radar method, in particular for motor vehicles, different time slots of a time frame are predefined. During one time slot, a radar sensor emits at least one radar pulse and receives the echo signal(s). During the remaining time slots the radar sensor monitors whether interference signals occur. On the basis of the interference signals occurring per time slot, a decision is made whether the radar sensor should continue its transmitting and receiving operation in the predefined time slot or should switch to one of the remaining time slots of the time frame. The method is suited for the concurrent operation of a plurality of radar sensors, without this causing interference.

Abstract: The present invention relates to a method and an arrangement suitable for embedded signal processing, comprising a number of computational units (100), each computational unit comprising a number of processing elements (20) capable of working independently and transmitting data simultaneously. Said computational units are arranged in clusters, work independently, and transmit data simultaneously, and that said processing elements (20) are globally and regularly inter-connected optically in a hypercube topology and transformed into a planar waveguide.

Abstract: An asynchronous pulse detector including a data estimator which estimates the return signal based on the corrected return signal, a detector for detecting an asynchronous pulse in the return signal, and a selector for selectively outputting the estimated return signal in place of the return signal as the corrected return signal in the event the detector detects an asynchronous pulse in the return signal.

Abstract: A synthetic aperture radar (SAR) system includes a transmitter capable of transmitting a pair of signals that each have a predetermined frequency in the optical band of the electromagnetic spectrum. The predetermined frequency can be selected, for example, to provide a level of resistance to at least one of movement of the target, target vibration and optical path length variations, and can further be selected based upon a predefined range and azimuth resolution. The SAR system also includes a receiver capable of receiving at least a portion of the pair of signals that has been reflected off of a target. In this regard, the receiver is capable of processing the reflected portion of the pair of signals based upon a difference frequency between the transmitted pair of signals.

Abstract: An embedded multi-functional preprocessing input data buffer comprises a clutter lock loop circuit, a multiplier, a mode selective multiplexer, a dual-port memory, an input multiplexer, self-testing circuit, decode circuit and an output multiplexer. The clutter lock loop and multiplication circuit selectively executes a coefficient multiplication or a clutter lock loop operation for the received data according to a working mode of the radar system. After receiving the data, the mode selective multiplexer may selectively output data processed by the clutter lock loop and multiplication circuit. The dual-port memory is coupled to the mode selective multiplexer for receiving and temporarily registering the data processed. The output multiplexer selectively outputs the data temporarily stored in the dual-port memory via a number of the output channels according to the working mode of the radar system.

Abstract: Signals-of-interest are identified by distinguishing such signals from signals constituting environmental or internal receiver noise. A received signal is rapidly sampled in order to set a dynamic, system threshold. Signals above the threshold constitute signals-of-interest.

Abstract: This invention relates to a system and method for suppressing external interference in radar data provided by a plurality of sensors from a main sensor array, the data being pre-processed. The noise suppression system includes a first processing module and a second processing module. The first processing module receives the radar data and produces matched radar data while the second processing module receives the radar data and produces mis-matched radar data. The system further includes a beamformer that is in communication with the first processing module and an adaptive beamformer that is in communication with the second processing module and the beamformer. The beamformer receives the matched radar data and produces beamformed matched radar data.

Abstract: A radar device and a method of suppressing interference in a radar device in which signals are transmitted with a carrier frequency, and the signals are transmitted as pulsed signals with a pulse repetition frequency, the pulse repetition frequency or the carrier frequency being varied during operation of the radar device.

Abstract: A radar system that utilizes predetermined, pseudorandom, or random waveforms that may be substantially matched to the impulse response of the radar and any surrounding clutter such that the signal-to-clutter ratio may be optimized and/or such that specific targets may be identified and/or classified.

Abstract: A method of compensating for atmospheric effects to detect the actual location of low elevation objects using near horizon radar to detect an object which utilizes a preexisting satellite structured to send a signal indicating the position and velocity of said satellite, wherein the location of the satellite is known. The method includes a step of providing a radar site, a first receiver structured to receive a signal from the satellite indicating an apparent location of the satellite, and a second receiver, located at a distance from the radar site, structured to receive the satellite signal and which indicates the observed location of the satellite. The first receiver is utilized to receive a signal from the satellite when the satellite is at a low elevation. This signal indicates the apparent location and velocity of the satellite.

Abstract: The present invention relates to a system for using signals scattered by targets to determine position and velocity for each of the targets and comprises a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points. Each pair of transmitter and receiver, monostatic or bistatic, is named a measuring facility. The ranges of the transmitters are chosen so that a target at an arbitrary point within the position space can be measured via scattering in the target by at least four measuring facilities. For each measuring facility, target detection occurs with constant false alarm rate in the form of probabilities over resolution cells with regards to range and Doppler velocity and conceivable targets are placed in a 2-dimensional linear space belonging to the measuring facility.