Fast Fourier Transform (fft) Patents (Class 342/196)
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Patent number: 6646589Abstract: An FMCW radar is provided which may be employed in automotive anti-collision or radar cruise control systems. In a distance measuring mode, only one of channels is used to sample a beat signal continuously, thereby allowing a sampling frequency to be increased up to Nc times that in an azimuth measuring mode and a sweep time in which a transmit signal sweeps in frequency upward and downward cyclically to be minimized. This causes half the sampling frequency to be higher than a frequency component arising sufficiently from a distant target present outside a preset radar range, thereby eliminating an error in detecting the distant target as being located inside the preset radar range.Type: GrantFiled: September 12, 2002Date of Patent: November 11, 2003Assignee: Denso CorporationInventor: Kazuma Natsume
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Publication number: 20030206129Abstract: A method (100) for coherent change subtraction of mission and reference synthetic aperture radar (SAR) data (20′,20″) is provided. The method (100) forms (102) mission and reference images (22′,22″) from the mission and reference SAR data (20′,20″), registers (122) the mission and reference images (22′,22″) on a common plane to form registered mission and reference images (24′,24″), and forms (124) the registered mission and reference images (24′,24″) into at least one patch (26) containing mission and reference data (28′,28″). The method (100) then processes (126) each patch (26) by removing (130) linear phase terms (34) from the mission data (28′), trimming (142) non-overlapping spectra of the mission and reference data (28′,28″), and balancing (144) phases and amplitudes of the mission data (28′).Type: ApplicationFiled: May 6, 2002Publication date: November 6, 2003Inventor: Kenneth Fell Obenshain
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Patent number: 6636174Abstract: System and method for detection and tracking of targets, which in a preferred embodiment is based on the use of fractional Fourier transformation of time-domain signals to compute projections of the auto and cross ambiguity functions along arbitrary line segments. The efficient computational algorithms of the preferred embodiment are used to detect the position and estimate the velocity of signals, such as those encountered by active or passive sensor systems. Various applications of the proposed algorithm in the analysis of time-frequency domain signals are also disclosed.Type: GrantFiled: June 6, 2001Date of Patent: October 21, 2003Assignee: Altratek Inc.Inventors: Orhan Arikan, Ahmet Kemal Ozdemir
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Publication number: 20030193431Abstract: A system for processing radar data from two or more areas of interest is provided, such as for simultaneously processing vehicle speeds in the opposite lane in front of the patrol vehicle and in the opposite lane behind the patrol vehicle. The system includes an antenna signal processor that receives radar data from one or more radar antennae and generates speed data for a first vehicle travelling in a first direction relative to a radar observation point and a second vehicle travelling in a second direction relative to the radar observation point. A display generator system receives the speed data and user-entered display control data, and generates user-readable display data based on the speed data and the user-entered display control data.Type: ApplicationFiled: June 2, 2003Publication date: October 16, 2003Inventors: John L. Aker, Alan B. Mead, Robert S. Gammenthaler, Robert V. Vanman
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Patent number: 6633252Abstract: A radar-plow drillstring steering system comprises a steering plow and a measurements-while-drilling instrument for mounting just behind the drill bit and downhole motor of a drill rod. The instrument includes a radar system connected to upward-looking and downward-looking horn antennas and a dielectric-constant sensor. The steering plow includes four pressure pads radially distributed around the outside surface and their associated servo motors. A coordinated control of the pressure pads allows the steering plow to push the drillstring and drill bit up-down-left-right. The antennas and sensor are embedded in respective ones of the pressure pads and are used to electronically and non-invasively probe a coal seam to locate its upper and lower boundary layers. The dielectric-constant sensor provides corrective data for the up and down distance measurements. Such measurements and data are radio communicated to the surface for tomographic processing and user display.Type: GrantFiled: November 4, 2002Date of Patent: October 14, 2003Inventors: Larry G. Stolarczyk, Gerald L. Stolarczyk
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Patent number: 6630900Abstract: The invention relates to a system suitable for a remote interrogation of passive transponders using chirp signals for interrogation. The transponder preferably has an encoding unit (11), a calibrating unit (12) and a measuring unit (13) each with a plurality of parallel channels (11.1 to 11.5, 12.1 and 13.1 to 13.2). The encoding unit and the calibrating unit are preferably jointly incorporated with a common delay line (14) on the same SAW chip. The interrogation signals received in the transponder via an antenna (10) are delayed characteristically and code-specifically, in particular in the encoding and calibrating unit. Decoding in the interrogation station is preformed by discrete Fourier transformation of the response signal and subsequent evaluation of the spectrum. To correct general disturbing influences on the delay of the response signal, said signal is calibrated using a single calibrating component in the response signal.Type: GrantFiled: May 3, 2002Date of Patent: October 7, 2003Assignee: Hera Rotterdam B.V.Inventors: Roland Stierlin, Roland Küng
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Publication number: 20030184470Abstract: A radar system achieves adjustment of a time-change characteristic of a frequency-modulating voltage signal to a voltage-controlled oscillator for determining a transmitting signal such that the time-change characteristic of the frequency-modulating voltage signal is changed by a minute amount and the frequency spectrum of a beat signal is determined. The adjustment is performed so that the shape of a bulge in signal intensity included in the frequency spectrum is the sharpest.Type: ApplicationFiled: March 17, 2003Publication date: October 2, 2003Applicant: Murata Manufacturing Co., Ltd.Inventors: Toru Ishii, Motoi Nakanishi, Tetsu Nishimura
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Publication number: 20030179128Abstract: The determination of separation (R) and relative speed (v) of at least one object which is distant from an observation point can be achieved by sending electromagnetic signals from the observation point, with a frequency shift over a modulation range (fSweep), in the form of signal segments (A, B) during a measuring interval, with a frequency separation (fShift) from each other which are transmitted alternately, the echo signals from which are detected after reflecting from the object. The phase difference (&Dgr;&phgr;) of the echo signals arising from each signal segment (A, B) is detected. Said determination occurs with short reaction time and high precision whereby the signal segments (A, B) are transmitted with a stepwise shift each time by a frequency step (fIncr) over the modulation range (fSweep) and at least one sampled value for determination of the phase difference (&Dgr;&phgr;) for each signal segment is taken.Type: ApplicationFiled: March 4, 2003Publication date: September 25, 2003Inventors: Ralph Mende, Hermann Rohling, Marc-Michael Meincke
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Publication number: 20030164792Abstract: A method of recognising a radar target comprises producing a sequence of Doppler spectra of radar returns form a scene and producing therefrom a sequence of Doppler feature vectors for a target in the scene. Hidden Markov modelling (HMM) is then used to identify the sequence of Doppler feature vectors as indicating a member of a particular class of targets. HMM is used to identify the sequence of Doppler feature vectors by assigning to each feature vector an occurrence probability by selecting a probability distribution or state from a set thereof associated with a class of targets, multiplying the occurrence probabilities together to obtain an overall probability, repeating for other probability distributions in the set to determine a combination of probability distributions giving highest overall probability for that class of target, then repeating for at least one other class of targets and selecting the target class as being that which yields the highest overall occurrence probability.Type: ApplicationFiled: January 23, 2003Publication date: September 4, 2003Inventors: Mohammed Jahangir, Keith M Ponting
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Patent number: 6611225Abstract: A radar signal processing apparatus has a range gate for extracting range gate data sequences from a memory, a first frequency extraction section which extracts a beat frequency corresponding to a target by performing frequency analysis by FFT at a low computation load and with low frequency measurement accuracy on all range gate data sequences extracted by the range gate, a second frequency extraction section which extracts a beat frequency corresponding to the target by performing frequency analysis by FFT at a high computation load and with high frequency measurement accuracy only on the range gate data sequence from which a beat frequency has been extracted by the first frequency extraction section, and a distance and speed derivation section which obtains the relative distance and the relative speed of the target on the basis of the beat frequency extracted by the second frequency extraction section.Type: GrantFiled: May 3, 2002Date of Patent: August 26, 2003Assignee: Mitsubish Denki Kabushiki KaishaInventors: Masashi Mitsumoto, Takahiko Fujisaka, Koichi Kai
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Publication number: 20030156054Abstract: A radar system is capable of transmitting necessary information through a very small amount of data from a radar device to a host device via a bus with a limited bandwidth. A radar sensor generates a beat signal between a transmission signal and a reflected signal from a target. A signal processor determines a spectrum of the beat signal and compresses the data indicating the spectrum. The resultant compressed data is transmitted to the host device via a bus. The host device decompresses the received data thereby reproducing the spectrum data. The host device then detects the target on the basis of the reproduced spectrum data.Type: ApplicationFiled: February 7, 2003Publication date: August 21, 2003Applicant: Murata Manufacturing Co., Ltd.Inventors: Toru Ishii, Tetsu Nishimura, Motoi Nakanishi
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Publication number: 20030156057Abstract: In a method for HPRF-radar measurement of the range and Doppler frequency of at least one target, a transmit signal is generated which consists of two pulse sequences that are interleaved on a pulse to pulse basis, and have the same pulse repetition frequency PRF and the same transmit frequency. The pulses of a first one of the two pulse sequences have a linearly increasing phase value with a fixed phase difference &phgr;1n (greater than zero) from pulse to pulse with &phgr;1n≧0, while the pulses of the second pulse sequence have a linear increasing phase value with a fixed phase difference &phgr;2n which differs from &phgr;1n. The two received base band signals of each individual pulse sequence are Fourier transformed, and the amplitude peaks of the resulting two Fourier spectra are determined.Type: ApplicationFiled: November 25, 2002Publication date: August 21, 2003Inventors: Hermann Rohling, Wilhelm Guener, Hans Hommel, Dieter Nagel
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Publication number: 20030156055Abstract: An inventive frequency modulated continuous wave (FMCW) radar system realizes both of a quick detection of higher relative speed provisional target and a sure detection of smaller relative speed provisional target. The number of detection cycles used for a paring validity check (a test to see if a detected target or a pair of frequencies is an actual target or a pair for an actual target) is set in response to the relative velocity.Type: ApplicationFiled: February 19, 2003Publication date: August 21, 2003Inventors: Yukimasa Tamatsu, Hiroaki Kumon
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Patent number: 6608585Abstract: A high-definition radar imaging system and method receives image data and adaptively processes the image the data to provide a high resolution image. The imaging technique employs adaptive processing using a constrained minimum variance method to iteratively compute the high-definition image. The high-definition image I is expressed in range and cross-range as I(r,c)=min&ohgr;HR&ohgr;, where &ohgr; is a weighting vector and R is a covariance matrix of the image data. A solution for I(r,c) is approximated by i) forming Y=[x1 . . . xK]T/{square root over (K)} where x1 . . .Type: GrantFiled: February 28, 2002Date of Patent: August 19, 2003Assignee: Massachusetts Institute of TechnologyInventor: Gerald R. Benitz
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Patent number: 6608586Abstract: A method of removing RFI from a SAR by comparing two SAR images on a pixel by pixel basis and selecting the pixel with the lower magnitude to form a composite image. One SAR image is the conventional image produced by the SAR. The other image is created from phase-history data which has been filtered to have the frequency bands containing the RFI removed.Type: GrantFiled: July 25, 2002Date of Patent: August 19, 2003Assignee: Sandia CorporationInventor: Armin W. Doerry
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Publication number: 20030151544Abstract: A radar device precisely detects a target in short time intervals by detecting a true peak frequency with high accuracy via a calculation which does not require a large amount of computation. A discrete frequency spectrum of a beat signal multiplied by a window function is determined, and values of signal strength at two discrete frequencies which are, respectively, higher and lower than a peak frequency of the discrete frequency spectrum of the beat signal and which are adjacent to the peak frequency. The frequency difference between the discrete peak frequency of the beat signal and the peak frequency of the window function is then determined from the ratio between the values of signal strength at those two discrete frequencies adjacent to the peak frequency. Thus, the true peak frequency of the beat signal is determined with a high frequency resolution.Type: ApplicationFiled: February 3, 2003Publication date: August 14, 2003Applicant: Murata Manufacturing Co., Ltd.Inventors: Tetsu Nishimura, Motoi Nakanishi, Toru Ishii
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Patent number: 6603423Abstract: A ROSAR wire detection method is based upon ROSAR focusing of entire segments of wire. By generating a wire reference signal comprised of a sum of coherent reference signals, the basis for reliable wire detectability is provided.Type: GrantFiled: January 18, 2002Date of Patent: August 5, 2003Assignee: EADS Deutschland GmbHInventors: Helmut Klausing, Horst Kaltschmidt
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Publication number: 20030142000Abstract: A system and method for efficient phase error correction in range migration algorithm (RMA) for synthetic aperture radar (SAR) systems implemented by making proper shifts for each position dependent phase history so that phase correction can readily be performed using the aligned phase history data during batch processing. In its simplest form, the invention (44) is comprised of two main parts. First (60), alignment of the phase error profile is achieved by proper phase adjustment in the spatial (or image) domain using a quadratic phase function. Second (62), the common phase error can be corrected using autofocus algorithms. Two alternative embodiments of the invention are described. The first embodiment (44a) adds padded zeros to the range compressed data in order to avoid the wrap around effect introduced by the FFT (Fast Fourier Transform). This embodiment requires a third step (64): the target dependent signal support needs to be shifted back to the initial position after phase correction.Type: ApplicationFiled: January 30, 2002Publication date: July 31, 2003Inventor: Kwang M. Cho
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Publication number: 20030132874Abstract: A method for exciting an antenna with a waveform having a burst width and pulse width scaled proportionately with a selected range scale and a temporal filter to address any ambiguities in range resulting from the transmission of a signal in accordance with the novel waveform. The inventive filtering method includes the step of scanning a beam including a plurality of pulses of electromagnetic energy. The step of scanning the beam includes the step of outputting a beam excited by a waveform having a burst width and pulse width scaled proportionately with a selected range scale. Reflections of these pulses are received as return signals. The returns are processed to extract range in range rate measurements. The range and range rate measurements are compressed to form a plurality of range bins. The pulses are selectively weighted to reduce sidelobes resulting from a subsequent Fast Fourier transform (FFT) operation.Type: ApplicationFiled: January 16, 2002Publication date: July 17, 2003Inventors: Kapriel V. Krikorian, Robert A. Rosen
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Patent number: 6593874Abstract: In a radar, a frequency-modulated transmission signal whose frequency varies in time is generated. The gain-frequency characteristics of an IF signal which represents a beat signal between the transmission signal and a reception signal has its peak at or below one half of the sampling frequency of an AD converter. The gain-frequency characteristics of an IF amplifier circuit is determined so that the gain increases as the frequency increases at or below the frequency corresponding to the peak, the ratio of change in the gain relative to change in the frequency becomes smaller at short distances for which a saturation of a mixer is caused, and the gain is reduced at DC and in the vicinity of DC.Type: GrantFiled: February 25, 2002Date of Patent: July 15, 2003Assignee: Murata Manufacturing Co., Ltd.Inventor: Sadao Yamashita
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Publication number: 20030128149Abstract: Methods and systems are provided for characterizing an overhead line. A radar signal is propagated in a region that includes at least a portion of the overhead line and a reference object, which may, for example, be a ground surface, growth over a ground surface, or another overhead line. A reflected radar signal is received from the overhead line and the reference object. A determination is made of a geometric relationship between the overhead line and the reference object, such as by determining a minimal separation between the overhead line and the reference object.Type: ApplicationFiled: October 21, 2002Publication date: July 10, 2003Applicant: Hot/Shot Radar Inspections, LLCInventors: Gilbert F. Miceli, Michael Parisi
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Publication number: 20030128154Abstract: A radar performs accurate and appropriate pairing even if peaks of approximately identical signal intensities or even if a plurality of peak groups having identical representative beam bearings exist in the frequency spectrum. First, the peak frequency of a peak which appears in the frequency spectrum is determined for each of an up-modulating interval and a down-modulating interval in predetermined beam bearings, and signal-intensity profiles in the beam bearings are extracted with regard to a plurality of beam portions which are adjacent to the beam bearings. Next, the correlation level between the signal-intensity profiles at the up-modulating interval and the down-modulating interval is determined, and pairing is performed in sequence starting from the profiles having a higher correlation level.Type: ApplicationFiled: January 2, 2003Publication date: July 10, 2003Applicant: Murata Manufacturing Co., Ltd.Inventors: Motoi Nakanishi, Toru Ishii, Tetsu Nishimura
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Patent number: 6590519Abstract: A radar source is configured on a vehicle, which may be an airborne vehicle such as a helicopter. An arrangement of at least one computer system is provided in communication with the radar source and configured to accept instructions from an operator and to operate the radar source. As the vehicle moves in the vicinity of a subterranean volume along a navigation path, a radar signal is propagated with the radar source into the subterranean volume. A reflected radar signal from a subterranean object within the subterranean volume is received. Physical characteristics of the subterranean object are ascertained from the reflected radar signal.Type: GrantFiled: March 9, 2001Date of Patent: July 8, 2003Assignee: Hot/Shot Radar Inspections, LLCInventors: Gilbert F. Miceli, Michael Parisi
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Publication number: 20030122703Abstract: The invention detects a ghost occurring due to mispairing, reflections from a wall, or the like, and improves the ability of a radar to track targets when actual relative velocity changes by more than a certain value. If a stationary target is present within a prescribed region centered about a moving target, the stationary target is excluded from output data by determining it as being a target resulting from mispairing due to the detection of guardrail posts or similar structures. Further, a moving target that is expected to collide with an eligible target is also excluded from the output data by determining it as being a target resulting from mispairing due to the detection of a target having many reflecting points. For a moving target showing an unlikely relative velocity, pairing with some other peak is attempted by determining the moving target as being a target resulting from mispairing due to the detection of a plurality of moving targets moving in the same direction.Type: ApplicationFiled: December 9, 2002Publication date: July 3, 2003Inventors: Masayuki Kishida, Sadanori Matsui, Yasuhiro Sekiguchi, Tokio Shinagawa, Daisaku Ono
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Patent number: 6587073Abstract: A method for the processing of a frequency signal especially for utilization in the evaluation of a distance measurement by means of pulsed electromagnetic waves or of frequency-modulated continuous waves on the basis of the radar principle. The frequency signal is divided into at least two frequency ranges corresponding to two main components of the frequency signal, the frequency signal in each of the two frequency ranges is then subjected to a separate Fourier transform, the Fourier transform applied to the frequency signal in the first frequency range resulting in a corresponding first complex time signal and the Fourier transform applied to the frequency signal in the other frequency range resulting in a second complex time signal. The second time signal is complex-divided by the first time signal which produces a third time signal, and the third time signal is then subjected to a Fourier transfer, the result being a processed frequency signal.Type: GrantFiled: April 19, 2002Date of Patent: July 1, 2003Assignee: Krohne Messtechnik GmbH & Co. KGInventors: Burkhard Schiek, Thomas Much, Michael Küppers, Uwe Wegemann, Detlef Brumbi
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Publication number: 20030117311Abstract: A Doppler radar apparatus includes a first oscillator for generating a first sweep signal to repeatedly sweep a predetermined frequency range periodically; a second oscillator for generating a second sweep signal having sweep properties identical to those of the first sweep signal, the second oscillator 41b starting sweep before the first oscillator finishes frequency sweep; a power combiner for combining the first and second sweep signals to generate a transmission signal; a switch for receiving, as inputs, the first and second sweep signals, and switching an output between the first and second sweep signals synchronously with the timing when sweep with each of the first and second sweep signals is terminated; and a mixer for mixing a reception signal coming from a part of the transmission signal reflected in a target and received, and an output signal from the switch with each other to produce an output signal from the mixer.Type: ApplicationFiled: June 14, 2002Publication date: June 26, 2003Applicant: MITSUBISHI DENKI KABUSHIKI KAISHAInventor: Mikio Funai
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Publication number: 20030117312Abstract: In an FM-CW radar system, regarding peaks appearing in the frequency spectrum of a beat signal in an FM-CW radar, groups of consecutive peaks in beam bearings within a predetermined frequency difference are regarded as being caused by reflected waves from a single target, and based on a combination of a peak group in an up-modulating interval and a peak group in a down-modulating interval, a relative distance to a target and its relative speed are determined.Type: ApplicationFiled: December 6, 2002Publication date: June 26, 2003Applicant: Murata Manufacturing Co., Ltd.Inventors: Motoi Nakanishi, Toru Ishii, Tetsu Nishimura
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Publication number: 20030117310Abstract: A plurality of sub-antennas in a two-dimensional plane antenna 11 or the like receive milliwaves from concerned object 20. AnA/D converter 12 converts the received signal to digital data. A signal processor 13 executes signal processing on the digital data for displaying images on a monitor 15. Prior to the measurement, a calibration signal source 14 generates a calibration signal. A phase compensator 133 in the signal processor 13 obtains phase compensation data, and compensates measurement data.Type: ApplicationFiled: December 10, 2002Publication date: June 26, 2003Applicant: NEC CORPORATIONInventors: Takeshi Kikuchi, Hitoshi Nomi
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Publication number: 20030117313Abstract: The present invention relates to a radar device and, particularly, to a radar device mounted on a vehicle to be used for a collision alarm and the like. The invention provides a radar device that has a unit for removing the FMAM noise without lowering the signal detection sensitivity. The radar device transmits a frequency modulation signal by switching the frequency modulation signal with a first switching signal, receives a signal reflected from a target object, switches the reception signal with a second switching signal, mixes the switched reception signal with the transmission signal, and further mixes the mixed signals with a third switching signal thereby to obtain a beat signal. The radar device obtains a distance to the target object and a relative speed of the target object from the beat signal.Type: ApplicationFiled: December 6, 2002Publication date: June 26, 2003Applicant: Fujitsu Ten LimitedInventor: Osamu Isaji
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Patent number: 6583754Abstract: A vehicle speed sensing system includes an RF transceiver coupled to an antenna for transmitting an RF signal towards the terrain over which the vehicle moves and for receiving a reflected Doppler signal therefrom. The transceiver generates a time-domain in-phase reference signal I and a time-domain quadrature signal Q which is offset in phase by 90 degrees from the reference signal I. A digital signal processor which receives the I and Q signals, and uses a complex fast Fourier transform routine to convert the time domain I and Q signals to frequency domain values I(f) and Q(f). The digital signal processor further processes the I(f) and Q(f) values and generates a speed a direction signal which is unaffected by vehicle vibrations.Type: GrantFiled: October 31, 2001Date of Patent: June 24, 2003Assignee: Deere & CompanyInventors: Karl-Heinz O. Mertins, Jerry Dean Littke, William Flavis Cooper, Rick Allen Worrel
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Publication number: 20030112173Abstract: As to a beat signal of a received wave, for instance, a plurality of FFT-based frequency spectra of every FM rise zone are accumulated in an accumulation unit. A judgment unit judges a valley section from the plurality of frequency spectra accumulated. A peak frequency extraction unit acquires, as beat frequencies of different targets, respective beat frequencies of peak sections located at both sides of the valley sections judged.Type: ApplicationFiled: April 1, 2002Publication date: June 19, 2003Applicant: Fujitsu LimitedInventors: Tetsuo Seki, Osamu Isaji
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Publication number: 20030107512Abstract: A system for detecting and avoiding interference with radar signals in wireless network devices is described. The receiver circuit of the device receives incoming 5 GHz traffic. Such traffic could comprise both WLAN traffic as well as radar signals from radar systems. The incoming packets are treated as an input event, and are screened to be examined as radar pulses. Radar pulses are identified using the length of the detected event. The radar pulses are examined using frequency domain analysis, and the packet train is examined to find gaps between radar pulses. The periodic nature of the packet is determined using frequency domain and time domain analysis to calculate the period of the pulse train. Particular intervals within the pulse train are analyzed using threshold numbers of periodic pulses within the interval and threshold power levels for the pulses. The calculated period information is used to identify the radar source and screen non-radar traffic.Type: ApplicationFiled: December 31, 2001Publication date: June 12, 2003Inventors: William McFarland, Chaohuang Zeng, Deepak Dhamdhere
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Patent number: 6577267Abstract: A device for non-contractual measurement of the speed of an object moving over a surface comprises a means for radiating a signal of fixed frequency at an angle onto the surface in or against the direction of motion, said angle being variable by the movement of the object, and for receiving a Doppler-shifted signal reflected at the surface. A means is provided for combining a plurality of reflected Doppler-shifted signals, which are received in temporal succession, so as to produce a combined spectrum. The device for non-contractual speed measurement additionally comprises a means for detecting from the combined spectrum the spectral portion having the highest or lowest frequency and exceeding a predetermined signal power, and a means for deducing the speed from the frequency of the detected spectral portion.Type: GrantFiled: December 26, 2000Date of Patent: June 10, 2003Assignee: Fraunhofer-Gesellschaft Zur ForderungInventors: Stefan Moedl, Norbert Weber, Josef Sauerer
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Patent number: 6577269Abstract: A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone.Type: GrantFiled: August 16, 2001Date of Patent: June 10, 2003Assignee: Raytheon CompanyInventors: Walter Gordon Woodington, Michael Joseph Delcheccolo, Joseph S. Pleva, Mark E. Russell, H. Barteld Van Rees
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Patent number: 6577265Abstract: A multi-stage processing system receives data from signals that indicate information related to scatterers, such as signals from a Doppler scanning system. The multi-stage processing system tracks allowed processing time for the data. The multi-stage processing system performs a first stage of processing for the data to generate first estimates of spectral moments for the signals. The multi-stage processing system performs additional stages of processing for the data as the allowed processing time permits and stops the additional stages of processing for the data when the allowed processing time expires. The additional stages of processing may comprise generating second estimates for at least some of the spectral moments. The additional stages of processing may use methods having increasing complexity and accuracy.Type: GrantFiled: January 9, 2002Date of Patent: June 10, 2003Assignee: University Corporation for Atmospheric ResearchInventors: Shelly D. Dalton, Lawrence B. Cornman, Robert K. Goodrich, Nathaniel Beagley
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Publication number: 20030102998Abstract: A radar system and a characteristic adjustment method for the radar system are provided, in which a control voltage waveform of a voltage controlled oscillator for frequency-modulating a sending signal can be set in a short time without increasing the required amount of memory. In adjusting time-varying characteristics of a voltage signal for frequency modulation on a voltage controlled oscillator determining a sending frequency, the time-varying characteristics of the voltage signal for frequency modulation are adjusted to optimize a form of a protrusion in signal intensity included in a frequency spectrum of a beat signal.Type: ApplicationFiled: November 21, 2002Publication date: June 5, 2003Inventors: Toru Ishii, Motoi Nakanishi, Tetsu Nishimura
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Patent number: 6570526Abstract: A device for measuring the speed reached and the distance covered by a moving user or object has a Doppler radar sensor that may be secured to the moving user or object and is made of a microwave strip transmission line sensor (1) that generates measurement signals and supplies them to an evaluation unit (2) with a sender that transmits the evaluated data to a separate processing and display unit (8).Type: GrantFiled: July 10, 1998Date of Patent: May 27, 2003Inventors: Tilmann Noller, Stephan Jurende, Arno Unkrig, Robert Götz, Horst Kaltschmidt, Rupert Christl
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Publication number: 20030090406Abstract: A ground penetrating radar comprises a signal generator, a return signal processor, gating means and antenna. The signal generator is a dual frequency synthesiser that generates a stepped frequency master signal and a tracking signal offset by an intermediate frequency. The return signal processor is a dual channel quadrature receiver that mixes down a return signal and a sample of the master signal to intermediate frequency using the tracking signal. The signal generator is pulsed by the gating means and the return signal is gated at the same frequency. Hollow pyramidal antennas are also described that have an ultrawide band bowtie structure with antenna electronics located within one antenna element. A method of operating the radar is also described.Type: ApplicationFiled: October 17, 2002Publication date: May 15, 2003Inventors: Denis Longstaff, David Noon, Christhoper John Leat, Glen Francis Stickley, Mikhail Cherniakov
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Publication number: 20030085835Abstract: A scan type radar device capable of detecting a lateral position of a target even if a peak showing the lateral position of the target irregularly fluctuates in the lateral direction as well as reducing the mis-pairing. The former is achievable by changing a reference value of the lateral fluctuation of the target when all the past and present target data fluctuate to an extent exceeding the reference value. The latter is achievable by forecasting a representative peak position at this time in both of up-beat and down-beat from the peak position data at the preceding time and carrying out the past-correspondence grouping of the up-beat and the down-beat at this time in the vicinity of the position of the representative peak forecast this time; the pairing being carried out by using the representative peak calculated by the past-correspondence grouping.Type: ApplicationFiled: November 7, 2002Publication date: May 8, 2003Applicant: Fujitsu Ten LimitedInventors: Sadanori Matsui, Tokio Shinagawa, Masayuki Kishida, Daisaku Ono
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Publication number: 20030080895Abstract: A vehicle speed sensing system includes an RF transceiver coupled to an antenna for transmitting an RF signal towards the terrain over which the vehicle moves and for receiving a reflected Doppler signal therefrom. The transceiver generates a time-domain in-phase reference signal I and a time-domain quadrature signal Q which is offset in phase by 90 degrees from the reference signal I. A digital signal processor which receives the I and Q signals, and uses a complex fast Fourier transform routine to convert the time domain I and Q signals to frequency domain values I(f) and Q(f). The digital signal processor further processes the I(f) and Q(f) values and generates a speed a direction signal which is unaffected by vehicle vibrations.Type: ApplicationFiled: October 31, 2001Publication date: May 1, 2003Inventors: Karl-Heinz O. Mertins, Jerry Dean Littke, William Flavis Cooper, Rick Allen Worrel
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Patent number: 6538599Abstract: A radar system and radar processing method includes a number of aspects for providing improved function. The system and method may employ one or more of the following aspects: timely range-velocity (range-Doppler) compensation for target nonstationarity by integration along hypothesized range-Doppler trajectories, allowing noncoherent integration over an elongated time interval; noncoherent integration of an enlarged signal set obtained from overlapped coherent processing intervals (CPIs); hypothesized joint multiple accelerations used to generate multiple hypothesized range-Doppler trajectories; and sliding window integration to increase data output rates with use of large noncoherent integration intervals (NCIs). These aspects allow for improved signal-to-noise ratios, for acquisition and tracking of targets at longer ranges, and for improved target parameter estimation.Type: GrantFiled: November 16, 2001Date of Patent: March 25, 2003Assignee: Raytheon CompanyInventor: George Thomas David
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Publication number: 20030052814Abstract: To measure the absolute speed of a body 100 moving relative to the ground 33 using an onboard speed sensor 1, a radar wave is transmitted towards the ground by an antenna with a wide aperture angle. The wave reflected by a reflecting obstacle on the ground and the transmitted wave are mixed and the frequency content of the low frequency signal obtained is determined. The speed of the moving object and the height of the transmitter and receiver antennas above the ground can then be measured by adjusting a theoretical curve to the time-varying evolution of the Doppler frequency corresponding to the reflecting obstacle.Type: ApplicationFiled: August 2, 2002Publication date: March 20, 2003Inventors: C?eacute;line Corbrion, Jacques Lewiner, Thierry Ditchi, Eric Carreel
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Publication number: 20030052813Abstract: An FMCW radar is provided which may be employed in automotive anti-collision or radar cruise control systems. In a distance measuring mode, only one of channels is used to sample a beat signal continuously, thereby allowing a sampling frequency to be increased up to Nc times that in an azimuth measuring mode and a sweep time in which a transmit signal sweeps in frequency upward and downward cyclically to be minimized. This causes half the sampling frequency to be higher than a frequency component arising sufficiently from a distant target present outside a preset radar range, thereby eliminating an error in detecting the distant target as being located inside the preset radar range.Type: ApplicationFiled: September 12, 2002Publication date: March 20, 2003Inventor: Kazuma Natsume
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Publication number: 20030048214Abstract: A wideband adaptive digital beamforming technique for maintaining a high range resolution profile of a target in motion in the presence of jamming utilizes a sequence of adaptively calculated narrowband jamming cancellation weights. The adaptive weights are calculated such that the desired frequency dependent gain is maintained toward the target center. These adaptive weights tend to preserve the range profile quality and low range sidelobes. This technique also tends to eliminate signal cancellation problems as well as adaptive weight modulation effects.Type: ApplicationFiled: September 7, 2001Publication date: March 13, 2003Inventor: Kai Bor Yu
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Publication number: 20030048216Abstract: An FM-CW radar system comprises a modulating signal generating means for changing a modulating signal to be applied to a FM-CW wave, a calculating means for calculating a distance or relative velocity with respect to a target object by performing processing for detection by fast-Fourier transforming a beat signal occurring between a transmitted signal and a received signal, and a control means for determining a detection range based on the calculated distance, and for performing control to change the modulating signal, wherein the modulating signal is changed by changing one parameter selected from among a modulation frequency, a triangular wave frequency, and a transmit wave center frequency. The detection range is set to a distance obtained by adding a prescribed distance to the shortest distance detected, or to a distance obtained by subtracting a prescribed distance from the distance of a fixed object.Type: ApplicationFiled: October 22, 2002Publication date: March 13, 2003Inventor: Masayuki Kishida
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Patent number: 6531976Abstract: A wideband adaptive digital beamforming technique for maintaining a high range resolution profile of a target in motion in the presence of jamming utilizes a sequence of adaptively calculated narrowband jamming cancellation weights. The adaptive weights are calculated such that the desired frequency dependent gain is maintained toward the target center. These adaptive weights tend to preserve the range profile quality and low range sidelobes. This technique also tends to eliminate signal cancellation problems as well as adaptive weight modulation effects.Type: GrantFiled: September 7, 2001Date of Patent: March 11, 2003Assignee: Lockheed Martin CorporationInventor: Kai Bor Yu
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Patent number: 6529157Abstract: An improved radar signature evaluation apparatus for measuring and evaluating the radar signature for an aircraft, missiles, and other vehicle. The radar signature apparatus includes an instrumentation system for generating radar cross section data for the vehicle being evaluated and a computer for processing the radar cross section data and a printer for printing various plots derived from the radar cross section data.Type: GrantFiled: February 11, 2002Date of Patent: March 4, 2003Assignee: The United States of America as represented by the Secretary of the NavyInventors: Dean L. Mensa, Andre C. Bati, Kenneth Vaccaro, Long D. To, Robert E. Dezellem, David P. Wirtz
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Publication number: 20030038742Abstract: A system for determining the scan type of a signal, such as a radar signal, includes a scan detector, a transformer (e.g., an FFT algorithm), a correlator, and a decision block. The signal is received and processed by the scan detector. The scan detector provides an envelope signal, representing the scan type of the received signal. The envelope signal is transformed, typically from a time domain signal to a frequency domain signal, by any of several processes including a Fourier transform, a Laplace transform, an FFT, or a DFT. The transformed envelope signal is compared to several scan data sets by the correlator. Each scan data set represents a particular scan type. If the decision block determines that the comparison between the transformed envelope signal and a scan data set meets (or exceeds) a degree of similarity, the scan type of the received signal is determined to be the scan type of that scan data set.Type: ApplicationFiled: July 23, 2002Publication date: February 27, 2003Inventor: Thomas H. Greer
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Publication number: 20030038741Abstract: A system for determining the scan type of a signal, such as a radar signal, includes a scan detector, a transformer (e.g., an FFT algorithm), a correlator, and a decision block. The signal is received and processed by the scan detector. The scan detector provides an envelope signal, representing the scan type of the received signal. The envelope signal is transformed, typically from a time domain signal to a frequency domain signal, by any of several processes including a Fourier transform, a Laplace transform, an FFT, or a DFT. The transformed envelope signal is compared to several scan data sets by the correlator. Each scan data set represents a particular scan type. If the decision block determines that the comparison between the transformed envelope signal and a scan data set meets (or exceeds) a degree of similarity, the scan type of the received signal is determined to be the scan type of that scan data set.Type: ApplicationFiled: August 27, 2001Publication date: February 27, 2003Inventor: Thomas H. Greer
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Patent number: 6522284Abstract: A method and system for identifying an anomaly in an electrically insulative component of a structure, such as an insulator on a utility or telecommunications pole, are provided. Locations for the structure and electrically insulative component are identified. A radar signal is propagated towards the electrically insulative component with a radar antenna while the radar antenna is motion along a navigation path in the vicinity of the structure. A reflected radar signal is received from the electrically insulative component, from which a determination is made whether the electrically insulative component contains the anomaly.Type: GrantFiled: December 20, 2000Date of Patent: February 18, 2003Assignee: Hot/Shot Radar Inspections, LLCInventors: Gilbert F Miceli, Michael Parisi