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: A radar tomography apparatus and method determines one or more material properties of an object at a first number of positions distributed within a region of interest of said object. The apparatus includes one or more transmitters that transmit radiation, in particular microwave radiation, in the direction of the region of interest of the object, a plurality of receivers that receive radiation reflected from or transmitted through the region of interest of the object, a processor that processes the received radiation, said processor including a forward solver that determines electromagnetic field values at a second number of positions distributed in the region of interest from the received radiation.

Abstract: A method includes: generating a frequency-modulated continuous signal, an emission sequence being formed of successive ramps centered on a carrier frequency; fixing a modulation band ?F and the duration Tr of a recurrence in such a way that at the range limit, a reception ramp appears shifted by at least one given frequency with respect to the corresponding emission ramp, on account of the propagation delay for the outward-return journey to a target kTr+?, k being an integer and ? a duration less than Tr; demodulating the signal received by the signal emitted, the resulting signal including a first sinusoid at the frequency ?Fdim=(1?(?/Tr)·?F and a second sinusoid at the frequency ?Fd=(?/Tr)·?F; sampling the resulting signal and performing a first fast Fourier transformation on this resulting signal over the duration of each emission ramp; detecting in the resulting spectrum the spectral lines appearing at the frequencies ?Fd and ?Fdim, and performing the vector sum of these two spectral lines after resetting

Abstract: Doppler-inspired methods for signal generation and frequency up-conversion are provided that are compatible with CMOS technology. In accordance with an embodiment, a circuit is provided that includes two input signals that can propagate on artificial transmission lines in opposite directions, resembling the relative movement of source and observer in Doppler frequency shift; and an output signal combiner. By controlling the characteristics of the transmission lines and the input signal frequencies, the harmonic generation of active devices is utilized and combined to provide the desired high-frequency component at the output.

Abstract: A method of radar-imaging a scene in the far-field of a one-dimensional radar array, comprises providing an array of backscatter data D(fm, x?n) of the scene, these backscatter data being associated to a plurality of positions x?n, n=0 . . . N?1, N>1, that are regularly spaced along an axis of the radar array. The backscatter data for each radar array position x?n are sampled in frequency domain, at different frequencies fm, m=0 . . . M?1, M>1, defined by fm=fc?B/2+m??f, where fc represents the center frequency, B the bandwidth and ?f the frequency step of the sampling. A radar reflectivity image 1 (?m?, ?n?) is computed in a pseudo-polar coordinate system based upon the formula (2) with formula (3) where j represents the imaginary unit, formula (A) is the baseband frequency, FFT2D denotes the 2D Fast Fourier Transform operator, ?m?, m?=0 . . . M?1, and ?n?, n?=0 . . .

Abstract: According to one embodiment, a weather radar apparatus includes a transmitting/receiving unit configured to transmit a radar wave to an observation target and receive a reflected wave, a distribution unit configured to distribute a received signal of the reflected wave to a main path and at least another path, an extraction unit configured to extract, from a signal of the other path, an interference wave signal extracted from another radio station, and a removing unit configured to remove the interference wave signal extracted from a signal of the main path.

Abstract: A frequency modulation continuous wave (FMCW) system includes a first memory receiving a clock signal and storing voltage digital values of I FMCW signals, a second memory receiving the clock signal and storing the voltage digital values of the Q FMCW signals, a first digital-to-analog converter (DAC) connected to the first memory and receiving the clock signal for converting the voltage digital values of the I FMCW signal to a first analog voltage, a second digital-to-analog converter (DAC) connected to the second memory and receiving the clock signal for converting the voltage digital values of the Q FMCW signal to a second analog voltage, an I low-pass filter connected to the first DAC smoothing the I FMCW signal and a Q low-pass filter connected to the second DAC smoothing the Q FMCW signal.

Abstract: A method comprises transmitting a radar signal into an target area, receiving reflected portions of the radar signal from the target area, and processing the reflected portions of the radar signal. The step of processing comprises windowing analog signals representative of the reflected portions of the radar signal, performing a fast Fourier transform on the windowed analog signals to produce an FFT result for each window, and obtaining the average of the FFT results from consecutive windows. In accordance with the method, a user receives indication from an indicator that a golf ball is present in the target area when the average of the FFT results corresponds to characteristics of the golf ball. The system comprises a radar transceiver, a processor for processing reflected portions of the radar signal, and an indicator indicating to the user a golf ball present in the target area.

Abstract: To generate a pulse for ranging, a kernel is convolved with a spreading sequence. The spreading sequence is parametrized by one or more ordered (length, sparsity) pairs, such that the first sparsity differs from the bit length of the kernel and/or a subsequent sparsity differs from the product of the immediately preceding length and the immediately preceding sparsity. Alternatively, a kernel is convolved with an ordered plurality of spreading sequences, all but the first of which may be non-binary. The pulse is launched towards a target. The reflection from the target is transformed to a received reflection, compressed by deconvolution of the spreading sequence, and post-processed to provide a range to the target and/or a direction of arrival from the target.

Abstract: A method for estimating a target angle of a wideband signal received on an electronically steered antenna array includes: generating spatial frequency data from the received wideband signal; stabilizing the spatial frequency data to a beam steering direction; compressing the stabilized spatial frequency data to a plurality of frequency range bins; calculating a monopulse discriminant from the stabilized spatial frequency data; and calculating the target angle using the monopulse discriminant.

Abstract: A method for operating a radar, having the following steps: determining first and second differential signals from a first and second transmitted frequency-modulated signal and received components of the first and second transmitted frequency-modulated signal reflected by a plurality of objects; determining in each case one first and one second chirp signal for each first and the second differential signal, the first chirp signal corresponding to the double differentiation of the phase of the first and the second differential signal with respect to time; assigning one of the first differential signals to one of the second differential signals, based on a correspondence of the first chirp signal, that is assigned to the one first differential signal, to the second chirp signal that is assigned to the one second differential signal; and determining the separation distance and/or the relative speed of one of the objects, based on the one first differential signal and the one second differential signal assigned t

Abstract: A new approach to radar imaging is described herein, in which radar pulses are transmitted wi th 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: A system includes a multi-system approach to detecting concealed weapons and person borne improvised explosive devices (PBIED). A first and second radar system operate at different center frequencies to provide, respectively, isolation of a target of interest from clutter and fine detail information on the target, such as whether the target is a living person, whether a concealed object may be present, material composition of the object, and shape, size, and position of the target relative to the system. Circular polarized radar beam may be used to distinguish a suspect object from within a crowd of people. Radar image of the object may be overlaid on visual image of a person carrying the object. Radar tracking of the object is coordinated with visual tracking of the target provided by a camera system, with visual display and tracking of the target overlaid with the radar information.

Abstract: The invention provides a method for obtaining the object-plane field without a pure theoretical estimation or a direct experimental measurement of a point spread function (PSF) of an imaging system. Instead, at least two image-plane fields have to be recorded. It is essential that the resolutions of the system producing the images have to be quite different from each other. Although both PSFs of the system are unknown, the recording conditions have to be chosen so that the second PSF could be expressed via the first PSF. Two integral equations—(1) a convolution of the object-plane field with the first PSF and (2) a convolution of the object-plane field with the second PSF (expressed via the first PSF)—can be reduced to one functional equation in the Fourier space. The reverse Fourier transform of the solution of this equation is the object-plane field.

Abstract: A process is provided for analyzing a radar signal using CLEAN to identify an undetected target in sidelobes of a detected target. The process includes obtaining system impulse response data of a waveform for a point target having a signal data vector based on a convolution under conjugate transpose multiplied by a target amplitude vector plus a noise vector, estimating the target amplitude vector, and applying a CLEAN Deconvolver to remove the detected target from the data signal vector based on the estimate amplitude vector absent the detected target and an amplitude vector of an undetected target. The process further includes building a detected target vector with the amplitude estimate vector, setting to zero all elements of the detected target vector except at an initial time, and recomputing the amplitude estimate vector by a Reformulated CLEAN Detector.

Abstract: Disclosed herein are systems, methods, and non-transitory computer-readable storage media for radio phase retrieval. A system practicing the method gathers first data from radio waves associated with an object observed via a first aperture, gathers second data from radio waves associated with the object observed via an introduced second aperture associated with the first aperture, generates reduced noise data by incoherently subtracting the second data from the first data, and performs phase retrieval for the radio waves by modeling the reduced noise data using a single Fourier transform. The first and second apertures are at different positions, such as side by side. This approach can include determining a value Q which represents a ratio of wavelength times a focal ratio divided by pixel spacing. This information can be used to accurately measure and correct alignment errors or other optical system flaws in the apertures.

Abstract: A logging system and method for measuring propped fractures and down-hole subterranean formation conditions including: a radar source; an optical source; an optical modulator for modulating an optical signal from the optical source according to a signal from the radar source; a photodiode for converting the modulated optical signal output from the optical modulator to the source radar signal. A transmitter and receiver unit receives the source radar signal from the photodiode and transmits the source radar signal via at least one antenna attached to the casing and in communication with at least one photodiode into the formation and receives a reflected radar signal. A mixer mixes the reflected radar signal with the source radar signal to provide an output. This can describe fractures connected to the wellbore and differentiate between the dimensions of the two vertical wings of a propped fracture.

Abstract: An orthogonal frequency division multiplexing (OFDM) receiving apparatus, including a receiving unit, a subcarrier demodulation unit and a signal output processing unit, is provided. The receiving unit is for receiving an RF signal to generate a set of discrete signals. The subcarrier demodulation unit is coupled to the receiving unit, and used for demodulating a set of discrete signals to obtain a complex signal. The signal output processing unit is coupled to the subcarrier demodulation unit, and used for capturing and outputting real parts of the complex signal.

Abstract: A method for processing return radar waveforms in response to transmitted radar waveforms. The method includes receiving, with a processor, a return radar waveform having a Doppler shift larger than Doppler tolerance. The method also includes separating, with the processor, the return radar waveform into a plurality of shortened waveforms. The method also includes compressing, with the processor, each of the plurality of shortened waveforms with a shortened form of the return radar waveform. The method also includes summing, with the processor, the plurality of compressed, shortened waveforms by computing a Doppler Fourier transform for each radar range bin of the return radar waveform using the plurality of compressed, shortened waveforms.

Abstract: In a method for detecting an object with an FMCW (frequency modulated continuous wave) ranging system a superior accuracy and resolution is obtained by determining the strongest sinusoidal component in the frequency spectrum and removing the determined component from the spectrum, repeating the preceding step at least once, adding one of the components determined in the two preceding steps to the spectrum, re-determining the then strongest sinusoidal component in the spectrum and removing the re-determined component from the spectrum, repeating the preceding step for each remaining of the determined sinusoidal components, and repeating the last two steps until a desired degree of convergence is reached.

Abstract: Detecting and grading the state and evolution of wake turbulence caused by an aircraft is made on the basis of radar signals reflected by this turbulence, these signals being analyzed through analysis cells of given dimension in terms of distance and bearing. A first preliminary detection step detects and locates turbulence in a cell. A second step determines the strength of the detected turbulence, while a third step determines the age of the detected turbulence as well as the geometric parameters which characterize it. This method makes it possible to detect wake turbulence and to determine at one and the same time the position and the strength of the latter as well as its stage of evolution.

Abstract: A method examining an object using millimeter-wave signals includes: (a) providing at least two millimeter-wave signal sources; (b) transmitting at least two millimeter-wave signals having at least two different frequencies from the signal sources illuminate the object; (c) in no particular order: (1) determining whether a return reflected signal is above a threshold level; [a] if yes, processing the return signal to identify object shape; [b] if not, processing another return signal; and (2) determining whether a return intermodulation product or harmonic signal is detected; [a] if yes, processing the return signal to identify object nature; [b] if not, processing another return signal; (d) determining whether checked all return signals; (1) if not, processing another return signal; (2) if yes, proceeding to step (e); (e) determining whether results are satisfactory; (1) if not, changing frequency of at least one of the wave signals; (2) if yes, terminating the method.

Abstract: A signal processing method includes transforming a received NLFM waveform from a first domain to a second domain, multiplying the transform of the received NLFM waveform with a complex conjugate of a low-pass filtered and transformed reference signal, and inverse transforming a product of the multiplication from the second domain to the first domain.

Abstract: A method and apparatus of determining a wave height directional spectrum of an ocean wave field using the intermediate-frequency (IF) signal from marine radars with a rotating antenna, using either a fully coherent or a standard non-coherent transmitter/receiver modified for coherent-on-receive use. The method may include receiving the IF radar ocean surface echo signal for a series of transmit pulses, at a sequence of azimuthal antenna positions, and a number of antenna rotations covering several minutes, then generating a matrix of complex IF signal samples from these, deriving phases for each sample, generating the difference in phase for consecutive azimuths, then Doppler shifts, and finally radial velocities.

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

Abstract: A method and apparatus for detecting objects located underground. In one advantageous embodiment, a detection system detects objects having electrical non-linear characteristics located underground. The detection system comprises a transmitter unit, a receiver, and a processor. The transmitter transmits a plurality of pulsed radio frequency signals having a first frequency and a second frequency into a ground. The receiver monitors for a response radio frequency signal having a frequency equal to a difference between the first frequency and a second frequency, wherein the response radio frequency signal is generated by an object having the non-linear conductive characteristics in response to receiving the plurality of electromagnetic signals. The processor is connected to the transmitter unit and the receiver, wherein the processor controls an operation of the transmitter unit and the receiver, wherein the object is detected when the response radio frequency signal is detected by the receiver.

Abstract: The present invention is directed to an improved radar system that produces high range resolution while using existing narrow processing bandwidths and sampling rates to achieve a low cost radar product that is particularly useful for moving targets. The present invention uses a small number of closely spaced Linear Frequency Modulated Chirps. In one embodiment typically 2, 3, 4 chirps are used. Each frequency is sampled at a rate commensurate with the narrower bandwidth, corrected for motion, Time Aligned and combined to produce a single wide-band chirp but achieved using the lower sample rate commensurate with the narrower transmitted waveform.

Abstract: A distance measuring apparatus comprising a transmission antenna to radiate a transmission radio wave; a reception antenna to receive a reflected signal from a target; an analog-to-digital converter to perform an analog-to-digital conversion for converting a reception signal; and a signal processing unit to process the converted signal and to detect the target, in which a transmission frequency of the transmission radio wave to be radiated is switched at a timing synchronized with a sampling frequency of the analog-to-digital conversion, the transmission frequency is switched in accordance with an arbitrary pattern within a frequency band, and the reception signal is rearranged in order on the basis of the arbitrary pattern at a time of the transmission to then be subject to a radar signal processing.

Abstract: A method of processing an input signal to perform frequency analysis is disclosed. The input signal comprises a desired signal and an interference signal. A crosslation is performed to generate a representation of the frequency content of the input signal. The representation comprises initial crosslation values predominantly corresponding to interference and subsequent crosslation values corresponding to the desired signal. For the crosslation values corresponding to interference, a maximum value and slope are calculated. These are used as parameter indicators of the interference and also to identify which values should be discarded in the processing of the desired signal. With the crosslation values corresponding to interference discarded, the remaining crosslation values are processed to calculate properties of the desired signal.

Abstract: Radar system for providing an aircraft with a facility for in use at least detecting another aircraft in at least one monitorable zone within a region surrounding of that aircraft, wherein the system comprises for each monitorable zone at least one subsystem comprising one transmitter for sending an electro-magnetic probe signal and at least one receiver for receiving a reflection of that probe signal, wherein the transmitter is arranged to send the probe signal in a direction that is static with respect to that aircraft.

Abstract: This disclosure provides a radar device including a transmission module for sequentially transmitting two or more kinds of pulse signals having different pulse widths by a predetermined transmitting pattern, a memory module for storing a predetermined number of pulse reply data corresponding to each kind of the pulse signals, the predetermined number being number of transmissions of the kind of the pulse signals, a pulse integrating module for performing pulse integration of the pulse reply data stored in the memory module for each kind of the pulse signal, and an image generating module for generating a radar image using the results of the pulse integration.

Abstract: A signal processing apparatus for a radar transceiver, which receives a reflected signal generated by a target object in response to a frequency modulated transmission signal, and generates a beat signal having a frequency difference between the transmission signal and a reception signal, includes: an azimuth angle detection unit that detects an azimuth angle of the target object on the basis of a peak signal in a frequency spectrum of the beat signal; a peak signal extraction unit that prioritizes extraction of a peak signal corresponding to a predetermined azimuth angle range and a predetermined relative distance range of the target object; and a target object detection unit that detects the target object from the extracted peak signal.

Abstract: A judging and controlling part 110 comprises an operation mode judging unit 111, a pulse width selecting unit 112, and a band limiting width selecting unit 113, wherein the operation mode judging unit 111 receives a signal of a gear state from a predetermined controlling device in a vehicle, and then judges the operation mode thereof. Based on a result of the judgment at the operation mode judging unit 111, the pulse width selecting unit 112 and the band limiting width selecting unit 113 control a wide band impulse generating part 120 and a band width limiting part 150, respectively.

Abstract: A three-dimensional imaging radar operating at high frequency e.g., 670 GHz radar using low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform, is disclosed that operates with a multiplexed beam to obtain range information simultaneously on multiple pixels of a target. A source transmit beam may be divided by a hybrid coupler into multiple transmit beams multiplexed together and directed to be reflected off a target and return as a single receive beam which is demultiplexed and processed to reveal range information of separate pixels of the target associated with each transmit beam simultaneously. The multiple transmit beams may be developed with appropriate optics to be temporally and spatially differentiated before being directed to the target. Temporal differentiation corresponds to a different intermediate frequencies separating the range information of the multiple pixels.

Abstract: A step frequency inverse synthetic aperture radar (ISAR) includes a transmitter configured to transmit a transmission pulse at a transmission frequency to a near earth object (NEO), the transmission frequency having a frequency range comprising a starting frequency, an ending frequency, and a step size; a receiver configured to receive a pulse response from the NEO, the pulse response corresponding to the transmission pulse; and a computer configured to determine a 3-dimensional image of the interior of the NEO from the pulse response.

Abstract: A method and apparatus for determination of a Doppler frequency shift 30 between a transmitted signal 4 and a received signal 20 resulting from this transmitted signal. A plurality of relative frequency shifts are carried out, in each case by a real frequency shift value, in that either at least one shifted discrete amplitude spectrum 8 of the transmitted signal 4 and at least one shifted discrete amplitude spectrum 22 of the received signal 20, or a plurality of shifted amplitude spectra of the transmitted signal 4 or of the received signal 20 are produced. Quality measures are determined for these frequency shifts, indicating the quality of the match between the shifted signals. That quality measure which corresponds to the highest quality of the match is determined, and the frequency shift value associated with this quality measure is equated to the Doppler frequency shift 30 to be determined.

Abstract: A method comprises transmitting a radar signal into an target area, receiving reflected portions of the radar signal from the target area, and processing the reflected portions of the radar signal. The step of processing comprises windowing analog signals representative of the reflected portions of the radar signal, performing a fast Fourier transform on the windowed analog signals to produce an FFT result for each window, and obtaining the average of the FFT results from consecutive windows. In accordance with the method, a user receives indication from an indicator that a golf ball is present in the target area when the average of the FFT results corresponds to characteristics of the golf ball. The system comprises a radar transceiver, a processor for processing reflected portions of the radar signal, and an indicator indicating to the user a golf ball present in the target area.

Abstract: An embodiment of the invention includes a step of transmitting an OFDM waveform including several frequency carrier signals transmitted simultaneously, the frequency carrier signals being coded in order to improve the Doppler response. An embodiment of the invention includes a step of receiving the echoed waveform from the target. The initial phase of each frequency carrier signal is recovered from the echoed waveform. The recovered initial phase of each frequency carrier signal is cyclically shifted in order to compensate for the Doppler effect and subsequently decoded. A compressed pulse is synthesized from the decoded initial phases.

Abstract: A system and method for generating alert signals in a detection system is described. The system compares data extracted from signals received via receive antenna beams with stored scenarios and determines whether to generate an alert signal based upon the results of the compare operation. The comparison of data extracted from received signals with stored scenarios can be accomplished by using one or more latches to process the extracted data from the received signals. In one embodiment, raw detections are pre-processed to generate so-called field of view (FOV) products. The FOV products are then provided to a tracker. In another embodiment, rather than pre-process the raw detections, the raw detections are instead provided directly to a tracker which processes the raw detections to provide products including, but not limited to, relative velocity and other parameters.

Abstract: A pulsed compression noise correlation radar uses noise modulation and pulse compression technology to scramble recognizable transmit signal characteristics and reduce transmit energy. The pulsed noise correlation radar advantageously uses pulse compression technology, a pulsed linear frequency modulated noise correlation mixer, and a new and innovative noise fused waveform to automatically correlate the pulsed linear frequency modulated (LFM) noise waveform with the received signal. The pulsed noise correlation radar apparatus and system now make it possible to effectively reduce transmitting power, preserve high band widths through oversampling in the receiver, and achieve multi-channel array frequency diversity. A secure pulsed compression noise correlation radar system and methods for undetected target detection with pulsed noise correlation radar and a pulsed LFM fused noise waveform are also provided.

Abstract: Disclosed is a method, means for and computer program for enhancing range and azimuth resolution in a two-dimensional (2D) image generated by a frequency modulated continuous-wave (FMCW) radar for providing enhanced situational awareness in autonomous approach and landing guidance (AALG) system by forming and displaying a two-dimensional (2D) model of landing conditions from received range and azimuth real beam radar (RBR) signals by rendering one or more target locations and amplitudes in both range and azimuth, selecting a region of interest from the displayed 2D model to enhance the one or more target locations in the selected region of interest, selectively applying range and azimuth resolution enhancement using a first and second beamforming approach or applying azimuth only resolution enhancement by using just the second beamforming approach to obtain an one or more accurate target location estimations and combining the enhanced one or more target locations to render an enhanced 2D image.

Abstract: A method includes correlating a plurality of samples of a waveform into a correlation domain to provide a mainlobe defined by a first subset of a plurality of pulse-compressed samples and a plurality of sidelobes defined by a second subset of the plurality of pulse-compressed samples. A weight is calculated for at least one of the pulse-compressed samples, and one of a plurality of SVA filter values is selected to apply to the at least one pulse-compressed sample based on the calculated weight of the at least one pulse-compressed sample. The SVA filter values include one, one minus a quotient of one-half divided by the calculated weight of the at least one sample, and a scale factor having a value greater than zero and less than or equal to one. The selected SVA filter values are applied to the at least one pulse-compressed sample.

Abstract: Signal processing is used to detect transient signals in the presence of noise. Two embodiments are disclosed. In both embodiments, the time series from a remote sensor is broken into a number of short time series. The power spectrum of each short time series are then calculated along with the mean noise level. The moments of each peak in every power spectrum are calculated and the peak with the largest power selected from each power spectrum. A histogram of the moments from these selected peaks is generated and normalized to become a measured PDF. In addition, a pre-determined PDF is derived, in the same method as above, from theoretically calculated noise, numerically simulated noise, or measured noise. Comparison between the measured and pre-determined PDF's establish the detection of a transient signal. The first embodiment compares the area between the measured and pre-determined PDF's against a threshold to determine detection.

Abstract: A method includes: generating a frequency-modulated continuous signal, an emission sequence being formed of successive ramps centred on a carrier frequency; fixing a modulation band ?F and the duration Tr of a recurrence in such a way that at the range limit, a reception ramp appears shifted by at least one given frequency with respect to the corresponding emission ramp, on account of the propagation delay for the outward-return journey to a target kTr+?, k being an integer and ? a duration less than Tr; demodulating the signal received by the signal emitted, the resulting signal including a first sinusoid at the frequency ?Fdim=(1?(?/Tr)·?F and a second sinusoid at the frequency ?Fd=(?/Tr)·?F; sampling the resulting signal and performing a first fast Fourier transformation on this resulting signal over the duration of each emission ramp; detecting in the resulting spectrum the spectral lines appearing at the frequencies ?Fd and ?Fdim, and performing the vector sum of these two spectral lines after resetting

Abstract: There is disclosed a system and method for detecting targets. A transmitter may transmit a first inverse transform signal, the first inverse transform signal derived from a reference image of a first reference target at a first aspect angle. A receiver may receive a return signal reflected from a scene. A detector may determine, based on the return signal, if an object similar to the first target at the first aspect angle is detected within the scene.

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 frequency modulated continuous wave (FMCW) radar is described. The radar includes a first discriminator for receiving a portion of the swept frequency signal generated by a frequency sweep generator and for producing a reference difference-frequency signal of frequency equal to the difference between the frequency of the swept frequency signal and the frequency of a time displaced swept frequency signal derived from the swept frequency signal. An analogue-to-digital converter is provided for sampling the target difference-frequency signal at a rate derived from the frequency of the reference difference-frequency signal. A processor (88) for determining frequency components of the digitized target difference-frequency signal is arranged to determine for at least one frequency component of the digitized target difference-frequency signal any phase difference between frequency sweeps of said swept frequency signal. The radar may be used for detecting foreign object debris (FOD) on runway surfaces and the like.

Abstract: An image processor includes an optical processor and a microwave processor. The optical processor is configured to extract optical image information from optical image data provided by a sensor, the optical image data representing an optical image of an object. The microwave image processor is configured to produce microwave image data representing a microwave image of the object in response to the extracted optical image information and microwave measurements provided by a microwave imager based on illuminating the object with microwave radiation.

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 multi-port junction is fed with a frequency-stepped source and has one of its ports connected to an antenna that can serve either as a transmit-and-receive antenna or as a receive antenna only, with the outputs of the multi-port junction being used to estimate a complex reflection coefficient for each frequency of interest. The subject system requires no IF stages, down-conversion mixers or oscillators, and therefore may be provided adjacent each antenna at low cost. An embodiment involving co-located separate transmit and receive antennas is used to minimize the power requirements for the multi-port junction, whereas in a third embodiment, an array of transmit/receive antennas is used, fed by the same RF source but in which digitally-controlled phase shifters are used for beam-forming purposes.