Abstract: A new approach to radar imaging is described herein, in which radar pulses are transmitted with an uneven sampling scheme and subsequently processed with novel algorithms to produce images of equivalent resolution and quality as standard images produced using standard synthetic aperture radar (SAR) waveforms and processing techniques. The radar data collected with these waveforms can be used to create many other useful products such as moving target indication (MTI) and high resolution terrain information (HRTI). The waveform and the correction algorithms described herein allow the algorithms of these other radar products to take advantage of the quality Doppler resolution.

Abstract: Methods and systems consistent with the present invention allow identification of a true signal contained in a signal containing the true signal and noise. In general, digital signal information representing a signal of interest plus noise is utilized by the present invention. The first N samples of digital signal information are stored with the Nth sample being stored in manner which renders it accessible for additional operations. A specially selected set of weights are applied to the buffered N samples and, additionally, phase rotation is applied to the Nth sample. The phase rotated Nth sample and weighted samples are combined using a first equation, described in more detail below. The resulting signal, which exhibits an increased Signal-to-Noise ratio (SNR) and may be more effectively utilized in subsequent MTI processing by virtue of the operations performed on the previous N samples as described herein, is then available for further processing using conventional techniques.

Abstract: A real-time radar surveillance system comprises at least one land-based non-coherent radar sensor apparatus adapted for detecting maneuvering targets and targets of small or low radar cross-section. The radar sensor apparatus includes a marine radar device, a digitizer connected to the marine radar device for receiving therefrom samples of radar video echo signals, and computer programmed to implement a software-configurable radar processor generating target data including detection data and track data, the computer being connectable to a computer network including a database. The processor is figured to transmit at least a portion of the target data over the network to the database, the database being accessible via the network by at least one user application that receives target data from the database, the user application providing a user interface for at least one user of the system.

Abstract: A detector system has a first detector configured to detect a first high-frequency signal having amplitude-modulated (“AM”) noise to produce a first detected signal having at least a first detected AM noise signal component and a demodulated signal component and a second detector configured to detect a second high-frequency signal having the AM noise to produce a second detected signal having at least a second detected AM noise signal component. An algebraic combining network combines the first detected signal and the second detected signal to cancel the first detected AM noise signal component with the second detected AM noise signal component to produce an output signal including the demodulated signal component.

Abstract: A time sequence of raw radar data for a region of space is subdivided into a plurality of processing frames. The processing frames are subdivided into a plurality of processing cells and iteratively processed by selecting a single processing cell for processing, transforming the radar data of the processing cell to form transformed radar data in either the time domain or the Fourier domain. The transformed data is converted to a Power Spectrum Density Matrix in the case of the Fourier domain and a Time Space Correlation Matrix in the case of the time domain. This is smoothed and thresholded and then the clutter for the processing cell is estimated. Estimated local non-speckle clutter is estimated and removed from the transformed radar data, with the cleaned transformed radar data converted back to the time domain if required.

Abstract: A method of down-converting couples a first high-frequency signal to a first detector and to a second detector. An antenna receives a signal and the received signal is provided to at least the first detector. The high-frequency signal is detected to produce a first detected signal including a first detected high-frequency signal and a demodulated signal. The high-frequency signal is concurrently detected to produce a second detected high-frequency signal. The second detected signal is subtracted from the first detected signal so as to cancel amplitude-modulated noise on a detected signal output.

Abstract: A method for discrimination of a target from clutter, comprising: providing phase-range data associated with a return pulse of a radar device and second phase-range data associated with a subsequent return pulse; comparing the phase-range data and the second phase-range data to obtain a difference; differentiating the differences with respect to range; and discriminating the target from the clutter by identifying coordinates from the differentiated differences satisfying velocity thresholds associated with the clutter. In one embodiment, the subsequent return pulse is drawn after skipping one or more pulses after the return pulse. In another embodiment, the subsequent return pulse is drawn successive to the return pulse. In other aspects, the invention can be a detection system and/or computer-readable medium adapted implement the method.

Abstract: The present invention is a method and apparatus that provides detection, characterization, and intuitive dissemination of targets. This disclosure combines improvements to ultra-wideband (UWB) sensing and machine target characterization with a means to convey data in a format that is quickly and readily understood by practitioners of the technology. The invention is well suited for Situational Awareness (SA) support in areas that are occluded by rain, fog, dust, darkness, distance, foliage, building walls, and any material that can be penetrated by ultra-wideband RF signals. Sense Through The Wall (STTW) performance parameters including target range, stand-off distance, and probability of detection are improved herein by combining a dynamically positioned sliding windowing function with orthogonal feature vectors that include but are not limited to time amplitude decay, spectral composition, and propagation time position in the return signal data.

Abstract: A system for performing radar cross section measurements of a target may include a radar system and an antenna associated with the radar system to transmit signals and to receive reflected signals from the target and a clutter source. An EM tagging device is locatable proximate to the clutter source to spectrally tag the clutter source by causing changes in an electromagnetic signal reflected by the clutter source when a predetermined radar signal transmitted by the radar system is incident on the target, the clutter source and the EM tagging device. A module may identify a spectrally tagged component of reflected signals received by the radar system from the target, the clutter source and the EM tagging device.

Abstract: According to one embodiment, a dual polarization radar apparatus includes a received power calculation unit configured to calculate a horizontal polarization received power and a vertical polarization received power, the horizontal polarization received power indicating a power value of a horizontal polarization received signal reflected from an observation target, the vertical polarization received power indicating a power value of a vertical polarization received signal reflected from the observation target, a power ratio calculation unit configured to calculate a power ratio between the horizontal polarization received power and the vertical polarization received power, and an interference judgment unit configured to judge that an interference signal is mixed to the horizontal polarization received signal or the vertical polarization received signal when the power ratio is greater than a predetermined threshold value.

Abstract: A radar device is mounted on a vehicle, for detecting an object, and includes: a transmitting unit for transmitting an electromagnetic wave as a transmitter signal; a receiving unit for receiving a reflected signal that is reflected from the object as a receiver signal; a signal processing unit for measuring a distance and a relative velocity between the vehicle and the object on the basis of a beat signal that is obtained by the transmitter signal and the receiver signal; and an interference detecting unit for detecting the interference signal from another radar device or a communication device on the basis of a signal intensity of the frequency range that is not used for measuring the distance to the object and the relative velocity of the object.

Abstract: The invention relates to a method, an apparatus and a computer program product for correcting the weather data of radial speed, spectral width and/or differential reflectivity which have been acquired from radar echo data recorded by a ground-based, radar-based remote-sensing appliance (1) for measuring atmospheric conditions and including evaluable weather echoes and interfering ground echoes, corrected weather data being obtained by calculating out the interfering ground echoes from the acquired weather data by using a previously stored clutter map with an intensity distribution of radar echo data which include the ground echoes substantially without weather echoes.

Abstract: In one aspect, a system to generate radar signatures for multiple objects in real-time includes a first module including at least one processor to perform a shooting and bouncing (SBR) technique to solve for physical optics and multi-bounce characteristics of the objects. The at least one processor includes a central processing unit to perform dynamic ray tracing and a graphics processing unit (GPU) to perform far field calculations. The GPU includes a hit point database to store entries associated with rays that intersect an object.

Abstract: A method of for processing signals in a radar system is shown comprising an antenna system having at least two antenna elements, a beam forming arrangement (ABF_RX, ABF_TX) for selectively steering the directivity of the antenna system in a given selected direction, the directivity of the antenna system having a main lobe in the selected direction and a back lobe (BL) in another direction and of a lower magnitude than the main lobe. By utilizing various scale and subtract processing both noise levels and ghost signals can be considerably reduced. A SAR radar apparatus has moreover been shown.

Abstract: A collision sense and avoidance system and method and an aircraft, such as an Unmanned Air Vehicle (UAV) and/or Remotely Piloted Vehicle (RPV), including the collision sense and avoidance system. The collision sense and avoidance system includes an image interrogator identifies potential collision threats to the aircraft and provides maneuvers to avoid any identified threat. Motion sensors (e.g., imaging and/or infrared sensors) provide image frames of the surroundings to a clutter suppression and target detection unit that detects local targets moving in the frames. A Line Of Sight (LOS), multi-target tracking unit, tracks detected local targets and maintains a track history in LOS coordinates for each detected local target. A threat assessment unit determines whether any tracked local target poses a collision threat. An avoidance maneuver unit provides flight control and guidance with a maneuver to avoid any identified said collision threat.

Abstract: A method for determining a physical property of a structural member in a dynamic multi-path clutter environment is given. The method comprises transmitting an RF interrogation signal to a wireless sensor operable to receive the RF interrogation signal, produce a reference signal and a measurement signal, and transmit the reference signal and the measurement signal in the dynamic multi-path clutter environment. The reference signal is delayed by a first time delay and the measurement signal is delayed by a second time delay that is a function of the physical property to be determined. The first and second time delays are associated by a known relationship defined by the wireless sensor. The method further comprises receiving the transmitted reference signal and the transmitted measurement signal and comparing the transmitted reference signal and the transmitted measurement signal in the time domain. Finally, the method comprises using this comparison to determine the physical property of the structural member.

Abstract: A method and system for SNR enhancement in pulse-Doppler coherent target detection for applications in the fields of radar and ultrasound. In accordance with the method of the invention, complex signals are obtained for each of two or more sub-intervals of the time-on-target interval, allowing simultaneous range and Doppler measurements. A coherent integration is the performed on the signals to generate complex-valued folded matrices. The folded matrices are unfolded and target detection is then performed in a process involving one or more of the unfolded matrices. A pulse-Doppler coherent system is also provided configured for target detection by the method of the invention.

Abstract: The disclosure provides a radar device, which includes a determination module for extracting received data within a predetermined distance range out of a series of received data for which received signals are sampled, and determining whether the distance range is a distance range where rain-and-snow clutters or white noises are dominant, using the extracted received data.

Abstract: The code generation apparatus includes: a clock generator which generates a clock signal of a first frequency; a timing controller which generates a timing signal of a second frequency lower than the first frequency; a code table storage in which a plurality of code sequences serving as a source for a pseudo-noise code is stored; an address controller which selects, according to the timing signal, a code sequence to be read, from among a plurality of code sequences; a partial code sequence extractor which extracts, as a partial code sequence, a code of a predetermined length, from the code sequence to be read; and a parallel-series convertor which outputs the partial code sequence one bit at a time, according to the clock signal.

Abstract: Clutter filtering of broadband radar signals is performed by obtaining a measure of the impedance of an echo target. A distance resolution is selected and then a power spectrum is calculated for the necessary transmitting signal. Further a target area profile ?(?) is estimated by utilising a correlation between the radiated signal and the received signal in form of a convolution. The target impedance is then calculated, and thereafter, the target can be filtered out using the achieved impedance characterising the echo of the target.

Abstract: Ground clutter is effectively separated from true signals echoed by a cable in the flight path of an aircraft, by encoding a transmitted pulse wave in a radar system with at least one transmit (TX) coding sequence, so that received signals echoed by the cable on which the pulse is incident and associated ground clutter are orthogonal or separable from one another. The TX coding sequence is altered into two receive (RX) coding sequences one of which corresponds to the cable and the other to the ground clutter. The two RX coding sequences are then correlated with the received signals, thereby separating the true signals echoed by the cable from the associated ground clutter.

Abstract: A receiver that selectively samples a received signal in order to suppress an interference component of the signal while recovering a desired component. The selective sampling may be accomplished by low cost, low complex analog or digital circuitry. The receiver includes a first input that receives a first signal, including a desired signal component and an interference signal component and a second input that receives a second signal including the interference component only. The first and second signals are then provided to the sampling circuitry. First, the phase of the interference component of the both the first and second signals is aligned. Next, the points in a wave cycle that the second signal is at a power minimum are detected. Finally, first signal is sampled close to the point when the second signal is at the power minimum to recover the desired signal component and suppress the interference component.

Abstract: A radar warning receiver is implemented in low cost integrated circuit form utilizing only one analog component, namely a limiting amplifier. By taking the output of the limiting amplifier and utilizing monobit sampling of the output it has been found that one can provide an integrated circuit single chip radar warning receiver using delay correlation to extract frequency, amplitude and modulation type from signals at or below the noise level.

Abstract: A method for detecting radar signal comprises the steps of: receiving a signal by a receiver, wherein the strength of the received signal is controlled within a range; sampling the received signal so as to obtain a plurality of sampling values; dividing the sampling values into a plurality of segments; summing up the absolute values of the sampling values in each segment; and determining that the received signal includes radar signals if at least one summation is greater than a threshold.

Abstract: A system includes an Interferometric radar that transmits a first detection signal over a first spatial region and a second detection signal over a second spatial region. The second region has a first sub-region in common with the first region. The system further includes a processing device that assigns a first occupancy value to a first cell in an evidence grid. The first cell represents the first sub-region, and the first occupancy value characterizes whether an object has been detected by the first detection signal as being present in the first sub-region. The processing device calculates, based on the first and second detection signals, the probability that the first occupancy value accurately characterizes the presence of the object in the first sub-region, and generates a data representation of the first sub-region based on the probability calculation.

Abstract: A specific emitter identification (SEI) method and apparatus is capable of identifying and tracking objects within a geographical area of interest wherein the system and method has not been preprogrammed to look for particular signals. The system and method receives all of the emitted electromagnetic signals emitted from area of interest. The system and method next performs high order statistical analysis on the received signals and determines which signals emanate from possible targets of interest and which likely emanate from background clutter/noise by comparing the relative degrees of Gaussianness of the signals (for example using entropy measurements). The least Gaussian signals are deemed to likely be signals from potential targets of interest while those which are more Gaussian are deemed to be likely from background clutter or noise.

Abstract: Clutter filtering of broadband radar signals is performed by obtaining a measure of the impedance of an echo target. A distance resolution is selected and then a power spectrum is calculated for the necessary transmitting signal. Further a target area profile ?(?) is estimated by utilising a correlation between the radiated signal and the received signal in form of a convolution. The target impedance is then calculated, and thereafter, the target can be filtered out using the achieved impedance characterising the echo of the target.

Abstract: A method of detecting weather on an aircraft uses a weather radar system. The method includes determining a location of a reflective radar target, accessing a database having stored information relating to ground clutter of a reflective radar target, retrieving weather radar information associated with the location, and automatically adjusting the weather radar return threshold in response to the information. The method can adjust a threshold for a weather radar display, adjust a weather radar signal gain, adjust a tilt angle of the weather radar, or adjust a ground clutter suppression threshold. The method can be implemented by hardware and/or software.

Abstract: Methods and apparatus to provide Log-Amp-detected radar sea clutter voltage modeled by a polynomial, such as a cubic polynomial, and using that model as a basis for sea clutter reduction filtering. In an exemplary embodiment, a navigational radar includes an STC filter design based on the cubic sea clutter modeling.

Abstract: Ground clutter is effectively separated from true signals echoed by a cable in the flight path of an aircraft, by encoding a transmitted pulse wave in a radar system with at least one transmit (TX) coding sequence, so that received signals echoed by the cable on which the pulse is incident and associated ground clutter are orthogonal or separable from one another. The TX coding sequence is altered into two receive (RX) coding sequences one of which corresponds to the cable and the other to the ground clutter. The two RX coding sequences are then correlated with the received signals, thereby separating the true signals echoed by the cable from the associated ground clutter.

Abstract: A system for performing radar cross section measurements of a target may include a radar system and an antenna associated with the radar system to transmit signals and to receive reflected signals from the target and a clutter source. An EM tagging device is locatable proximate to the clutter source to spectrally tag the clutter source by causing changes in an electromagnetic signal reflected by the clutter source when a predetermined radar signal transmitted by the radar system is incident on the target, the clutter source and the EM tagging device. A module may identify a spectrally tagged component of reflected signals received by the radar system from the target, the clutter source and the EM tagging device.

Abstract: A method and apparatus for a simplified approach for determining the output of a total covariance signal processor. A single set of offline calculations is performed and then used to estimate the output of the total covariance signal processor. A simplified approach for performing matrix inversion may also be used in determining the output of the total covariance processor.

Abstract: A system and method for filtering clutter is contemplated that in one aspect performs clutter-filtering on complex-voltages. In one aspect, spectral coefficients identified from a series of spectral coefficients as having been affected by clutter are replaced by a refilling procedure to maintain the statistical properties of the spectral coefficients that are unaffected by clutter. Dual-polarization radar variables that have phase dependence can be subsequently generated from the modified spectral data.

Abstract: An acquisition channel (20) includes a UWB sampler block (21) coupled to an analog integration block (22) further coupled to a digital integration block (24) via an analog/digital converter (23). For each range cell the UWB sampler block (21) repeatedly samples the received signal by tuning the sampling instants to the range cells to be acquired. The acquisition channel (20) is further coupled to a processor (26) and a database (25).

Abstract: In a FM-CW or CW radar apparatus, when interference components are contained in channel signals obtained as beat signals from array antenna elements of respective channels, and the interference components result from directly receiving transmitted CW radar waves from an external source, phase shifting is applied to each of the channel signals to shift respective phases of the interference components of the respective channels to a condition corresponding to reception of interference waves from a predetermined direction. The interference components are then eliminated, and reverse phase shifting is applied to restore remaining components of the channel signals to their original phase condition.

Abstract: Systems and methods are presented for associating time slices of a received signal with previously encountered time slices. A parameter determination component determines at least one parameter for each received time slice. A content addressable memory stores a plurality of parameter values associated with the previously encountered time slices. The content addressable memory is searchable such that the determined at least one parameter for each received time slice can be compared to the stored plurality of parameter values to provide a memory output. An emitter matching component associates a given received time slice with one of a plurality of emitters according to the memory output.

Abstract: The present invention relates to a method of eliminating ground echoes for a meteorological radar. The ground echoes being received from a predetermined area by a radar, the radar illuminating, for a predetermined number R of transmission recurrences, the area over a number P of distance cells, the method includes a step for calculating a spatial statistical parameter of the cluttered echoes received by the radar in response to the recurrences over an analysis path for distance cells, and a step to compare the spatial variation level of the spatial statistical parameter along the analysis path, the echoes being considered to be ground echoes when the level of said variation is greater than a predetermined threshold.

Abstract: A method for the detection of moving objects by SAR images envisages the steps of: generating a pulse-repetition frequency signal starting from a radar signal; and generating a sequence of SAR images starting from the pulse-repetition frequency signal. In particular, SAR images with low azimuth resolution are generated by of coherent integration of the pulse-repetition frequency signal for a sub-aperture time shorter than an aperture time. In addition, the method envisages generating difference images through point-to-point difference between subsequent low azimuth resolution SAR images, and recognizing patterns associated to moving objects in the difference images.

Abstract: A radar sensor system and method for vehicles. An example radar system includes a processor, a plurality of transceivers having antenna(e). The antenna of the transceivers are located at various points around the vehicle. The transceivers include receive and transmit electronics that are in signal communication with the corresponding antenna. The transmit electronics output radar signals via the antenna. The transmit electronics include a voltage controlled oscillator (VCO), a dielectric resonator oscillator (DRO), a phase locked loop (PLL) component and a direct digital synthesizer (DDS). The receive electronics receive from the antenna any radar reflections corresponding to the outputted radar signals and send signals associated with the radar reflections to the processor. The processor generates output signals based on the signals received from the plurality of transceivers.

Abstract: A signal processing system for use in pulse-Doppler radar, arranged to receive frequency domain signals for each of a plurality of Doppler bins for each range cell, comprising a data processor arranged successively to threshold each Doppler bin signal under test relative to a local average of signals formed over plural Doppler bins and/or plural ranges adjacent to the Doppler bin under test, using a variable thresholding factor, and using the thresholding result as an indication of the presence of an object of interest; the data processor using a pulse-Doppler constant false alarm rate control process to set and reset the variable thresholding factor using closed loop feedback by counting the indications of presence and incrementing or decrementing the variable thresholding factor for each thresholding result by comparing the frequency of these counts with a predetermined probability of false alarms; whereby the constant false alarm rate thresholding is a function of the range and the Doppler frequency of the

Abstract: A method and system for generating images from projection data; a preferred embodiment comprising inputting projection data from at least one receiving element; generating a first aperture or array of data points containing positional and signal data; arbitrarily and/or randomly removing data points from the first array to form a series of subarrays comprising different sets of data points; generating preliminary images from the subarrays; comparing the corresponding image pixels from two preliminary images to determine for each pixel location the lesser or equal pixel values; forming a merged image from the lesser or equal pixel values; and repeating the comparison of corresponding image pixels of another preliminary image to the merged image to determine the lesser or equal pixel values until a merged image of the desired quality is obtained. A preferred embodiment of the system may comprise at least one processor, comparator and/or image generator.

Abstract: There is disclosed a method for filtering a signal y, the signal y being the reflection of a signal s emitted by a radar, the signal s having been reflected by a target. The method comprises a step of receiving the signal y and a step of estimating a filter w to be applied to the signal y, the filter w being compensated for an unwanted and beforehand unknown distorsion d in the emitted signal s.

Abstract: According to a particular embodiment, a method for evaluating different antenna designs includes receiving different sets of antenna patterns representative of the different antenna designs from a corresponding number of data sources. The different sets of antenna patterns are applied to a characterizer component for generating a sidelobe banking (SLB) characteristic map for each set of antenna patterns received. A SLB effectiveness chart is generated from the SLB characteristic map. A best antenna weighting set is selected based on which auxiliary antenna pattern exhibits the best performance. The best of antenna weighting factors are used for designating the antenna design having superior SLB performance characteristics.

Abstract: A method for detecting an occurrence of interference between a return of a radar wave which has been transmitted by a radar and has an oscillating amplitude in time and a radio wave transmitted by some other radar, Includes steps of: detecting extremal points of an incident radio wave in which the radio wave transmitted by the other radar is superposed on the return of the radar wave, extracting, sequentially in time, an emerging pattern of the extremal points of the incident radio wave within each of periods of time to obtain a series of emerging patterns of the extremal points, detecting a period during which the emerging pattern of the extremal points is irregular among the series of the emerging patterns of the extremal points, and determining that the interference occurs during the detected period of time.

Abstract: A method for clutter filtering staggered pulse repetition time data signals is provided. The method comprises the steps of receiving a plurality of staggered pulse repetition time data signals. The data signals may comprise one or more desired signals and one or more clutter signals. The method further comprises separating the staggered pulse repetition time data signals into a first separated data sequence and a second separated data sequence. The first and second separated data sequences comprise equally spaced data samples. The method also comprises the step of filtering the one or more clutter signals from the first and second separated data sequences.

Abstract: Embodiments of the invention process a radar image arising from a radar antenna, by reading the reflectivity information associated with each pixel forming the radar image, processing the reflectivity information, pixel by pixel, with the aid of a first procedure. The method further includes a second processing of the radar image using a second procedure that includes extracting objects from the radar image, then calculating the extent and the position of each object, with the aid of an angular aperture between two signals. For each part of the radar image processed by the first procedure, corresponding to an extracted object, pixel within the result of the first procedure are replaced by corresponding pixels of the radar image processed by the second procedure, if the reflectivity value associated with the second pixel is greater than the reflectivity value of the first pixel, the parts of the radar image corresponding to zones situated at a distance greater than a given threshold from the radar antenna.

Abstract: A method of operating synthetic aperture radar in a low PRF mode, comprising generating a stream of radar pulses, imposing onto said stream a predetermined modulation of the Pulse Repetition Frequency (PRF), directing said stream to a target area, and processing received pulses, comprising separating the received pulses as a sequence of sets, and superposing received radar pulses of said sets, whereby to enhance the central received lobe and to attenuate side lobes.

Abstract: In one embodiment, a radar is provided that is configured to construct an image of a target within or adjacent to a substrate according to scan points associated with a surface of the substrate while the radar is scanned in a first direction.

Abstract: A wireless network device includes a correlation module, an automatic gain control module, and a control module. The correlation module correlates a predetermined portion of a radio frequency (RF) signal and generates a correlation signal based thereon. The automatic gain control (AGC) module generates a gain control signal based on said RF signal. The control module selectively determines whether said RF signal is a radar signal based on said correlation signal and said gain control signal.

Abstract: Embodiments of the present invention provide a Gaussian adaptive filter for ground clutter filtering and signal parameter estimation for weather radars in the time domain. In some embodiments, the filtering can be applied to dual polarization radar systems. In some embodiments, the clutter component of the signal can be transformed to noise. An interpolation procedure can then be used to recover the transformed part of the weather. A unique filter can be designed to use for both H and V channels for dual-polarization parameter estimation. In addition, the filter can be directly extended for staggered PRT 2/3 sampling scheme.