With Frequency Modulation Patents (Class 342/128)
  • Patent number: 6531976
    Abstract: 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: Grant
    Filed: September 7, 2001
    Date of Patent: March 11, 2003
    Assignee: Lockheed Martin Corporation
    Inventor: Kai Bor Yu
  • Publication number: 20030020649
    Abstract: A continuous wave radar system includes a transmitter circuit for generating radar transmitting signals, a transmit/receive antenna, coupled to the transmitter circuit by way of a circulator, and a receiver circuit, which is coupled to the transmit/receive antenna by way of the circulator and which is intended to condition radar echo signals of a target object. The radar echo signals are received at the transmit/receive antenna, wherein the circulator serves to pass the transmitting signals, generated by the transmitter circuit, to the transmit/receive antenna and to divert the target object's echo signals, which are received by the transmit/receive antenna, to the input of the receiver circuit.
    Type: Application
    Filed: July 15, 2002
    Publication date: January 30, 2003
    Inventor: Klaus Solbach
  • Publication number: 20030016163
    Abstract: A modulation signal generation circuit performs frequency modulation of a VCO with a triangular wave for operation as an FM-CW radar. A signal processing circuit gives a modulation signal for detection generated from the modulation signal generation circuit to the VCO. A high-frequency signal subjected to frequency modulation in the VCO is transmitted as a radio wave from a transmission antenna and is reflected on a target and the reflected radio wave is received at a reception antenna. The reception signal and the high-frequency signal are mixed by a mixer to provide a beat signal and frequency shift corresponding to a voltage V1 is detected from the frequency of the beat signal. If the voltage V1 of the modulation signal for detection is switched, the frequency shift corresponding to different voltage V1 can be provided and the frequency modulation characteristic can be detected.
    Type: Application
    Filed: July 11, 2002
    Publication date: January 23, 2003
    Applicant: FUJITSU TEN LIMITED
    Inventor: Osamu Isaji
  • Publication number: 20030016165
    Abstract: A system for functional testing in a continuous-wave radar having a transmitter circuit for generating radar transmit signals, a transmit/receive antenna coupled by way of a circulator with the transmitter circuit, and a receiver circuit whose input is coupled with the transmit/receiver antenna by way of the circulator, for processing radar echo signals of a target object received at the transmit/receive antenna. The circulator relays the transmit signals generated by the transmitter circuit to the transmit/receive antenna, and splits off echo signals of the target object received from the transmit/receive antenna to the input of the receiver circuit. An RPC circuit coupled between the output and the input of the receiver circuit suppresses those portions of the transmit signals that are split off from the transmitter circuit and/or reflected from the transmit/receive antenna directly into the receiver circuit.
    Type: Application
    Filed: July 12, 2002
    Publication date: January 23, 2003
    Inventor: Klaus Solbach
  • Publication number: 20020190893
    Abstract: In an FM-CW radar apparatus, while a distance and velocity of a target are measured by simultaneously transmitting an FM modulation wave along a frequency-up direction and an FM modulation wave along a frequency-down direction toward this target, physically-required radar signal measuring time thereof can be reduced by ½.
    Type: Application
    Filed: December 4, 2001
    Publication date: December 19, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventor: Masahira Akasu
  • Publication number: 20020186162
    Abstract: The present invention provides a pulse radar apparatus which is capable of detecting properly an object and measuring a distance up to the object in a short distance even if a leakage signal is contained in a received signal.
    Type: Application
    Filed: December 5, 2001
    Publication date: December 12, 2002
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventor: Shigekazu Okamura
  • Patent number: 6492938
    Abstract: An association method for a multi-slope FMCW radar identifies candidate combinations of frequency components as being correctly or incorrectly associated based on calculated range-rate. Range and range-rate are calculated for various pairs of frequency components emanating from like-polarity slopes of the transmitted waveform, and pairs having similar ranges and range-rates are combined to form candidate associations. The range and range rate of the candidate associations are then computed using all four frequency components, and ambiguous candidate associations are resolved by selecting the candidate associations having similar range rates.
    Type: Grant
    Filed: February 11, 2002
    Date of Patent: December 10, 2002
    Assignee: Delphi Technologies, Inc.
    Inventor: Stephen William Alland
  • Publication number: 20020180632
    Abstract: In an FM-CW radar system, a frequency modulating wave output from said modulating signal generator has a frequency variation skew with respect to a time axis (modulation skew), and the radar system includes a means for varying the modulation skew by controlling the modulation frequency amplitude or modulation period of the modulating signal. The radar system further includes a means for discriminating a signal component varying in response to the variation of the modulation skew, thereby discriminating a signal related to a target object from other signals. In the case of an FM-CW radar system that performs transmission and/or reception by time division ON-OFF control, the radar system includes a means for discriminating a signal which, when the frequency used to perform the ON-OFF control is varied, varies in response to the variation of the frequency, thereby discriminating a signal related to a target object from other signals.
    Type: Application
    Filed: May 24, 2002
    Publication date: December 5, 2002
    Inventor: Osamu Isaji
  • Publication number: 20020180633
    Abstract: In a radar, a coupler extracts a part of a transmission signal as a local signal and a mixer mixes a reception signal from a circulator and the local signal so as to output an intermediate frequency signal which is the frequency difference between the transmission signal and the reception signal. An IF-amplifying circuit amplifies the intermediate frequency signal and an AD converter converts the signal to digital data. A DC-removing unit removes a DC component by subtracting the average from the data and an FFT operation unit performs fast Fourier transform so that the distance to a target and the relative velocity of the target are calculated based on a peak included in the frequency spectrum.
    Type: Application
    Filed: May 29, 2002
    Publication date: December 5, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Motoi Nakanishi, Toru Ishii, Tetsu Nishimura
  • Patent number: 6486826
    Abstract: An arrangement for the precise measuring of the distance with a FMCW radar device having a frequency-variable digitally-actuated oscillator to generate a transmitting frequency which can be tuned over a predetermined frequency range. The digital actuation involves the use of a digital frequency generator which derives in predetermined frequency steps a references signal from a fixed-frequency oscillator signal. The frequency of the frequency-variable oscillator is adjusted in a phase-locked loop linking it to the references signal.
    Type: Grant
    Filed: March 29, 1999
    Date of Patent: November 26, 2002
    Assignee: EADS Deutschland GmbH
    Inventors: Stefan Cramer, Berthold Zimmermann, Rolf Gluth
  • Publication number: 20020154053
    Abstract: 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: Application
    Filed: April 19, 2002
    Publication date: October 24, 2002
    Inventors: Burkhard Schiek, Thomas Much, Michael Kuppers, Uwe Wegemann, Detlef Brumbi
  • Publication number: 20020154051
    Abstract: 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: Application
    Filed: February 25, 2002
    Publication date: October 24, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventor: Sadao Yamashita
  • Patent number: 6469662
    Abstract: This invention concerns a procedure for the elimination of interferences, such as pulses and linear chirps, in a radar unit of the FMCW type. According to the procedure, the useable signal in the form of a beat signal, is subjected to time-frequency division of the type STFT for division of the signal into narrow-band frequency bands. Interference is detected and eliminated in each frequency band, after which the time signal freed from interference and its Discrete Fourier Transform, DFT, are calculated from the time-frequency division in narrow-band frequency bands.
    Type: Grant
    Filed: May 12, 1999
    Date of Patent: October 22, 2002
    Assignee: Celsiustech Electronics AB
    Inventor: Bert-Eric Tullsson
  • Patent number: 6469656
    Abstract: A method is described for detecting moving and/or stationary objects in the path of a vehicle, where the distance and velocity of the reflecting object are determined by using a radar sensor, where the frequency of the signal transmitted is modulated in the shape of a ramp according to a multi-ramp method, and some ramps have a lower slope in the frequency curve. The higher spectral components of the mixed signals from the ramps having the lower slope, which are to be assigned to a distance range of the reflecting object which is greater than the distance range belonging to the ramps having the greater slope, are used to determine the distance, speed and angle of objects.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: October 22, 2002
    Assignee: Robert Bosch GmbH
    Inventors: Klaus-Peter Wagner, Reiner Marchthaler, Bernd Ummer
  • Patent number: 6466159
    Abstract: Radar apparatus in which output RF signals are modulated on an optical signal prior to transmission. Incoming optical echo signals are converted into RF signals using a detector. The original functionality of the radar apparatus is to a large extend retained, including the Doppler processing. The target radar cross section is determined by the wavelength of the optical signal.
    Type: Grant
    Filed: August 4, 2000
    Date of Patent: October 15, 2002
    Assignee: Thales Nederland B.V.
    Inventor: Petrus Johannes Rotgans
  • Patent number: 6445339
    Abstract: This FM-CW radar apparatus comprises a transmitter section, a receiver section, and a signal processing section. The transmitter section transmits a frequency-modulated continuous wave as a transmitted wave. The receiver section receives a radio wave resulting from reflection of the transmitted wave at a target, as a received wave, by a receiving antenna comprising an array of antenna elements, generates a beat signal which is a difference of the transmitted wave and the received wave in each of channels of the respective antenna elements, and converts this beat signal to a digital beat signal by A/D conversion. The signal processing section executes a digital beamforming operation with the digital beat signals and detects the target from the result of the operation.
    Type: Grant
    Filed: October 30, 2000
    Date of Patent: September 3, 2002
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Yukinori Yamada
  • Patent number: 6445336
    Abstract: A radar device in which a much more precise demodulation can be made with an inexpensive circuit, free of the output variation of the frequency-modulated transmission signal. The radar device includes an oscillator which produces and outputs a frequency-modulated electromagnetic wave to a switching circuit by way of a directional coupler. The switching circuit uses switching modulation to radiate the electromagnetic wave from a transmitting antenna. The radiated electromagnetic wave after being reflected from an obstacle is received at a reception antenna. A mixer mixes this reception signal and a local signal fed from the directional coupler to produce a mixing signal which is to be fed to a high pass filter. The high pass filter deletes a low frequency output variation noise which is contained in the mixing signal and which occurs in the frequency modulation in the oscillator. The resulting mixing signal is, with the noise deleted, fed by way of an AC amplifier, to a switching demodulating circuit.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: September 3, 2002
    Assignee: Aisin Seiki Kabushiki Kaisha
    Inventors: Kunihiko Soshi, Shoji Kawata, Mitsuyoshi Saiki
  • Patent number: 6429807
    Abstract: FM-CW radar equipment to solve a conventional problem of failure detection caused by the carrier level of amplitude modulation dispersing too largely to adjust to a constant level within a criterion range. A novel method is applied based on that a noise level greatly varies on occurrence of a failure in radio-frequency circuit. A failure can be detected by comparing the varied noise level with a noise level in normal condition. using this method, FM-CW radar equipment can be configured with a simple structure for detecting a failure in transmission/reception circuit. The equipment provides with a noise-level extraction circuit in radio-frequency circuit, and a comparator for comparing an output of the noise-level extraction circuit with a predetermined criterion value. An alarm is output when the comparator detects the output of the noise-level extraction circuit decreases to less than the predetermined criterion value.
    Type: Grant
    Filed: January 4, 2001
    Date of Patent: August 6, 2002
    Assignees: Fujitsu Limited, Fujitsu Ten Limited
    Inventors: Hideki Shiratori, Naoki Motoni
  • Patent number: 6429804
    Abstract: A target 22 is explored by transmitting an exploration signal 40 at a certain angle while scanning an antenna 23. In the go and return exploration the angle for transmitting the exploration signal is shifted. It is possible to detect the direction of the target 22 with the same accuracy as that in exploration with a more minute angle difference, by combining the exploration results with the angle shifted in a plurality of scans. Relative travel of the target 22 that accompany a plurality of scans is considered as a Doppler shift and a combination of data is used considering the frequency shift. Data that cannot be combined is treated as an unwanted reflective object and the position where unwanted reflecting objects assemble is obtained and the position is determined as a shoulder. The height of a stationary target is determined from the variation in the reflected signal level in an approach to the stationary target.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: August 6, 2002
    Assignee: Fujitsu Ten Limited
    Inventors: Masayuki Kishida, Daisaku Ono, Hirofumi Higashida
  • Patent number: 6420998
    Abstract: A method of detecting and compensating for non-linearities in a microwave radar system in which a transmitted signal, frequency modulated according to a predefined function, is generated using a transmit oscillator, and by mixing the transmitted signal with a received signal reflected by an object, a distance of the microwave radar system from the object is determined. In predefined time windows a predefined constant test control voltage is applied to the transmit oscillator instead of a control voltage effecting frequency modulation, preferably using a test ramp, the voltage/frequency characteristic of a module being updated during the time window in order to generate the function characteristic for frequency modulation taking into consideration the reference signal.
    Type: Grant
    Filed: April 12, 2001
    Date of Patent: July 16, 2002
    Assignee: Robert Bosch GmbH
    Inventors: Klaus Winter, Hermann Winner, Stephan Leinbaum
  • Patent number: 6414628
    Abstract: A radar apparatus mounted on a vehicle includes a detecting section and a fault determining section. The detecting section includes a radar unit and detects a detection object using radar wave radiated from a radar unit toward the detection object and reflected radar wave from the detection target to the radar unit. The fault determining section determines whether any fault has occurred in the radar unit, based on the detecting result of the detection object and a movement distance of the vehicle, and generates a fault detection signal, when it is determined that any fault has occurred in the radar unit.
    Type: Grant
    Filed: January 28, 2000
    Date of Patent: July 2, 2002
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventor: Jun Ashihara
  • Patent number: 6411251
    Abstract: The invention relates to a method for measurement of the radar target cross section of an object with both moving and fixed parts, which method comprises a first measurement with high frequency resolution, from which information can be extracted on modulations in the signal received that derive from moving parts of the object and fixed parts of the object respectively. The invention is characterized in that the method comprises a second measurement with high range resolution, and filtering of the measuring result obtained from the second measurement, which filtering is performed around a certain frequency that is obtained by means of the measuring result from the first measurement. The first measurement is preferably given a high frequency resolution in that it is performed with a narrow-band waveform, and the second measurement is suitably given a high range resolution in that it is performed with a broadband waveform.
    Type: Grant
    Filed: December 8, 2000
    Date of Patent: June 25, 2002
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Tomas Stanek, Roland Jonsson, Jan Hagberg
  • Patent number: 6404378
    Abstract: A device for increasing the dynamic range of frequency-modulated continuous-wave radar includes a transmitter, a send/receive antenna, a receiver circuit and a circulator. The circulator relays the transmission signals of the transmitter to the send/receive antenna and sends the echo signals of a target object to the input of the receiver circuit, which generates on the basis of the transmission signals and echo signals an intermediate frequency signal having a differential frequency corresponding to the distance from the target object. A reflected power canceler circuit equipped with a control amplifier is provided between the input and output of the receiver circuit. The frequency response of the control amplifier is selected so that the degree of suppression drops to a predeterminable extent with an increase in differential frequency above the cut-off frequency of the control amplifier.
    Type: Grant
    Filed: April 24, 2000
    Date of Patent: June 11, 2002
    Assignee: DaimlerChrysler AG
    Inventor: Klaus Solbach
  • Patent number: 6404381
    Abstract: A radar sensor device for detecting the distance and/or the speed of an object relative to the sensor device is provided with an oscillator, which can be frequency detuned through the use of a modulation function. The radar sensor device has a power switch, which can be driven by a power control function, for varying the transmitter power. The sensor device is to be operated in an alternating fashion, through the use of a variable setting of the modulation and power control functions, in at least two different, mutually overlapping operating modes which are tuned to different measuring ranges of the sensor device.
    Type: Grant
    Filed: July 31, 2000
    Date of Patent: June 11, 2002
    Assignee: Siemens Aktiengesellschaft
    Inventors: Patric Heide, Martin Kunert
  • Patent number: 6400311
    Abstract: The inventive radar rangefinder has a transmitting/receiving antenna (22) for surveying a danger area. Said antenna is located in a radome housing (12), on a rotatable platform (18). A reflector is placed at a known distance in order to calibrate the device. This reflector is formed by an auxiliary antenna (24) with a connected delay line (26) inside the randome housing (12). The length of the virtual distance of the reflector produced then corresponds to the velocity factor of the delay line used.
    Type: Grant
    Filed: December 19, 2000
    Date of Patent: June 4, 2002
    Assignee: Honeywell International Inc.
    Inventors: Bertram Kolbli, Peter Lolkes, Axel Konig, Theodor Ohl
  • Patent number: 6396436
    Abstract: The present invention relates to a CW radar method for measuring distances between and relative speeds of a vehicle and one or more obstacles. The present invention further provides that the transmission (s(t)) can be composed of at least four consecutive chirps (A, B, C, D), each having different slopes. The intersection points of all lines in the distance-relative speed diagram from two chirps (A, B) can be calculated from all the ascertained frequency positions K1,n and K2,p. To validate those intersection points, one may observe whether a peak exists in the Fourier spectrum of a third chirp C at a frequency position K3,q, whose assigned line intersects a surrounding area of the intersection point in the distance-relative speed diagram.
    Type: Grant
    Filed: April 7, 2000
    Date of Patent: May 28, 2002
    Assignee: Volkswagen AG
    Inventors: Ernst Lissel, Hermann Rohling, Marc-Michael Meinecke
  • Patent number: 6396435
    Abstract: The invention relates to a method for determining the perpendicular distance between an object and a device whose position varies, in particular a motor vehicle, in the case of which device a first sensor which is arranged on this device emits a signal which is reflected by the object, and this reflected signal is received by this first sensor, in which case the delay time of the signal from transmission to reception is used by the first sensor to determine the distance between the first sensor and the object.
    Type: Grant
    Filed: September 13, 1999
    Date of Patent: May 28, 2002
    Assignee: Mannesmann VDO AG
    Inventors: Norbert Fleischhauer, Gregor Hassler
  • Patent number: 6384768
    Abstract: AN FM pulse Doppler radar apparatus performs pulse modulation of modulating waves having repeatedly increasing and decreasing frequency, transmits thus modulated waves, receives at each range gate having an interval equivalent to a pulse width, reflected waves reflected from an object, determines a distance according to the range gate, and calculates the distance to the object and the relative velocity of the object based on the difference between frequencies of the transmission waves and the received waves. The apparatus includes a velocity determining unit for determining velocity of the radar-mounted vehicle and a comparison-and-detection unit for comparing the detected distance according to the range gate and the distance calculated based on the difference between the frequencies of the transmission waves and the received waves.
    Type: Grant
    Filed: August 10, 2000
    Date of Patent: May 7, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Koichi Kai
  • Patent number: 6384769
    Abstract: The present invention discriminates between moving targets and stationary targets in order to measure distances and speeds of the targets without producing a false target. The invention transmits signals whose modulating frequencies ascend or descend to a target, and receives signals reflected from this target. A frequency spectrum of a beat signal of each target is detected during a modulating frequency ascent period and a modulating frequency descent period. The frequency spectrum of the modulating frequency ascent period and the frequency spectrum of the modulating frequency descent period are used to set a reference spectrum. The reference beat frequencies of either the moving targets or the stationary targets are detected based upon the reference spectrum.
    Type: Grant
    Filed: December 10, 1999
    Date of Patent: May 7, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masashi Mitsumoto, Tetsuo Kirimoto
  • Publication number: 20020044082
    Abstract: 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: Application
    Filed: August 16, 2001
    Publication date: April 18, 2002
    Inventors: Walter Gordon Woodington, Michael Joseph Delcheccolo, Joseph S. Pleva, Mark E. Russell, H. Barteld Van Rees
  • Patent number: 6373427
    Abstract: The invention relates to a radar distance measuring device. An especially linear frequency-modulated high frequency signal is emitted via an antenna and mixed with an echo signal reflected by a target object whose distance is to be determined. The distance of said target object can then be calculated by analyzing the frequency of the mix result. The aim of the invention is to improve the distance resolution or increase the accuracy of measurement. To this end, a first frequency analysis is first carried out to obtain a rough analysis result. Said rough analysis result is used to control a filtering device which then restricts the mix result in its time range to a segment around the frequency of the target object. A discrete Fourier transformation is then carried out for this segment in order to produce an analysis result with a more refined scanning step than the first frequency analysis.
    Type: Grant
    Filed: May 12, 2000
    Date of Patent: April 16, 2002
    Assignee: Mikrowellen-Technologie und Sensoren GmbH
    Inventor: Felix Hohne
  • Patent number: 6369748
    Abstract: A radar system mounted on a vehicle is capable of properly measuring an angle even when a linearity is impaired without increasing a scale of hardware and a load on signal processing, and exhibiting a high performance at a low cost.
    Type: Grant
    Filed: May 23, 2000
    Date of Patent: April 9, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Naohisa Uehara
  • Patent number: 6362777
    Abstract: A Pulse-Doppler radar apparatus is constructed such that an output of an oscillator is divided by a distributor and an on/off switch for generating pulses is coupled to an IF input of a first harmonic mixer, in order to improve precision in measurement of a distance and speed.
    Type: Grant
    Filed: May 26, 2000
    Date of Patent: March 26, 2002
    Assignee: Mitsubishi Denski Kabushiki Kaisha
    Inventors: Kenji Kawakami, Hiroshi Ikematsu
  • Publication number: 20020014989
    Abstract: A method of detecting and compensating for non-linearities in a microwave radar system in which a transmitted signal, frequency modulated according to a predefined function, is generated using a transmit oscillator, and by mixing the transmitted signal with a received signal reflected by an object, a distance of the microwave radar system from the object is determined. In predefined time windows a predefined constant test control voltage is applied to the transmit oscillator instead of a control voltage effecting frequency modulation, preferably using a test ramp, the voltage/frequency characteristic of a module being updated during the time window in order to generate the function characteristic for frequency modulation taking into consideration the reference signal.
    Type: Application
    Filed: April 12, 2001
    Publication date: February 7, 2002
    Inventors: Klaus Winter, Hermann Winner, Stephan Leinbaum
  • Publication number: 20010052872
    Abstract: A radar system which is used for determining optical range includes a frequency analyzer for the analysis of differential frequency signals, which originate from a mixture of the transmitted signal with the received signals, for example reflected from a fog bank. The frequency spectrum images the distance profile of the fog bank.
    Type: Application
    Filed: February 7, 2001
    Publication date: December 20, 2001
    Inventor: Cornelius Hahlweg
  • Patent number: 6320531
    Abstract: An FM-CW radar is provided which may be employed in anti-collision systems or cruise control systems installed in moving objects such as automotive vehicles. The radar analyzes a beat signal in frequency to produce peak frequency components in a modulated frequency-rising range wherein the frequency of a frequency-modulated radar wave transmitted from the radar increases and a modulated frequency-falling range wherein the frequency of the radar wave decreases. If one of peak frequency pairs, each of which is made up of each of the peak frequency components in the modulated frequency-rising range and one of the peak frequency components in the modulated frequency-falling range, lies within a given lower frequency range, the radar identifies the one of the peak frequency pairs as radar data arising from a moving object appearing suddenly in a radar detection zone.
    Type: Grant
    Filed: November 13, 2000
    Date of Patent: November 20, 2001
    Assignee: Denso Corporation
    Inventor: Yukimasa Tamatsu
  • Patent number: 6317074
    Abstract: A frequency modulated continuous wave (FMCW) radar system having a voltage controlled oscillator (VCO) for transmitting a RF signal and a linearizer for linearizing the VCO. The FMCW receives the transmitted RF signal as an input and outputs a signal to a modulator, which successively sweeps the VCO frequency over a defined range. The receiver mixes a return signal with a sample of the transmitted RF signal to derive an IF signal. An adaptive frequency sample clock drives an analog to digital converter to sample and digitize the IF signal, with the clock being derived from the transmitted RF signal.
    Type: Grant
    Filed: June 15, 2000
    Date of Patent: November 13, 2001
    Assignee: Alliant Techsystems Inc.
    Inventor: Lyle H. Johnson
  • Patent number: 6317075
    Abstract: An FMCW sensor in which a transmission signal is generated from a high frequency of a fixed frequency oscillator and a modulated, low frequency of a second oscillator. The modulated frequency is processed in a delay line with a surface wave component to form a reference signal. A transmission mixer with a hybrid coupler having a 90° phase difference and terminated by diodes is employed in a transmission/reception means. A measured signal from the transmission mixer together with the reference signal is interpreted in an evaluation means.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: November 13, 2001
    Assignee: Siemens Aktiengesselschaft
    Inventors: Patric Heide, Martin Nalezinski
  • Patent number: 6317073
    Abstract: An FM-CW radar is provided which may be employed in anti-collision systems or cruise control systems installed in moving objects such as automotive vehicles. The radar produces a first spectrum using a portion of a beat signal in a frequency rising range wherein the frequency of the radar wave increases and a second spectrum using a portion of the beat signal in a frequency falling range wherein the frequency of the radar wave decreases and moves the second spectrum by frequency shifts which are determined as a function of the speed of a radar-mounted vehicle and corrected for compensating various errors involved in measuring the speed of the vehicle to form spectrum groups each consisting of the frequency components moved by one of the corrected frequency shifts and frequency components in the other of the first and second spectra. The radar selects an optimum one of the spectrum groups for use in determining target data.
    Type: Grant
    Filed: September 7, 1999
    Date of Patent: November 13, 2001
    Assignee: Denso Corporation
    Inventors: Yukimasa Tamatsu, Hiroaki Kumon
  • Publication number: 20010035839
    Abstract: FM-CW radar equipment to solve a conventional problem of failure detection caused by the carrier level of amplitude modulation dispersing too largely to adjust to a constant level within a criterion range. A novel method is applied based on that a noise level greatly varies on occurrence of a failure in radio-frequency circuit. A failure can be detected by comparing the varied noise level with a noise level in normal condition. Using this method, FM-CW radar equipment can be configured with a simple structure for detecting a failure in transmission/reception circuit. The equipment provides with a noise-level extraction circuit in radio-frequency circuit, and a comparator for comparing an output of the noise-level extraction circuit with a predetermined criterion value. An alarm is output when the comparator detects the output of the noise-level extraction circuit decreases to less than the predetermined criterion value.
    Type: Application
    Filed: January 4, 2001
    Publication date: November 1, 2001
    Applicant: Fujitsu Limited/ Fujitsu Ten Limited
    Inventors: Hideki Shiratori, Naoki Motoni
  • Patent number: 6278398
    Abstract: A method in which a sensor system with a frequency-modulated signal source an a delay line for generating a time-delay reference signal is implemented. Phase errors are compensated by correcting the modulation (pre-equalization derived from the reference signal. Signals with a long running time are measured and additionally compensated by a computational, subsequent elimination (post-equalization). A high-pass filter is provided to that end.
    Type: Grant
    Filed: August 27, 1999
    Date of Patent: August 21, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Martin Vossiek, Patric Heide
  • Patent number: 6275180
    Abstract: A collision warning system (10) discriminates between objects which pose a threat of collision from those which do not by measuring the relative sightline rate of the object, this being a measure of the rate of change of angular position of the object if the sightline rate is above a threshold value, there is little risk of collision. To measure the sightline rate, a radar source (20) emits microwave frequency radiation which is received by two detectors (22 and 24) after reflection from a target. Signals from the detectors are processed by processing means (26). The processing means determines if the sightline rate of an object is below a certain threshold. If it is, and the relative velocities of the object and the system are such that a collision is likely, a warning buzzer (28) sounds.
    Type: Grant
    Filed: July 27, 1998
    Date of Patent: August 14, 2001
    Assignee: The Secretary of State for Defence, in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventors: Michael Dean, Robert D Hodges
  • Patent number: 6266004
    Abstract: The invention relates to a radar method for an automatic intelligent traffic control (AICC) in a motor vehicle. The use of a frequency modulation continuous wave method (FM-CM) is suggested in order to securely detect the distance to, relative speed and angle of a preceding motor vehicle. It is furthermore suggested according to the invention that when using an A/D converter 5 with 8-bit resolution, the necessary dynamics are generated by means of a level switchover, that the R, V information is generated in FFTs [Fast Fourier Transformations] 6 with blocked R and V-FFTs, that the useful signals are separated from the noise in a detection device 7 by means of a R-dependent adaptive CFAR threshold, that in a track formation 8, the detection is directly assigned to the tracks and that the association of a detection i to a track j is in the process computed as probability r (i, j).
    Type: Grant
    Filed: May 20, 1999
    Date of Patent: July 24, 2001
    Assignee: DaimlerChrysler AG
    Inventors: Wolfram Pannert, Dieter Mann, Wieland Jacobi, Wolfgang Wittekind
  • Patent number: 6255984
    Abstract: FMCW doppler radar, in which a reference signal is generated from the transmit signal via a delay line and a mixer. A measuring signal which is received and mixed with the transmit signal is detected and digitized at the times of the zero crossings of the reference signal. In this way, the measuring signal can be evaluated at time intervals of equal phase of the reference signal. A downstream algorithm enables the generation of a strictly linearly frequency-modulated transmit signal. With this mechanism, phase errors of conventional radar systems are eliminated.
    Type: Grant
    Filed: August 30, 1999
    Date of Patent: July 3, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Bernhard Kreppold, Martin Vossiek, Patric Heide
  • Patent number: 6246359
    Abstract: A signal processing unit detects the azimuthal direction of a target in accordance with the phase difference between signals received by two receiving antennas. Then, by sequentially switching plural transmitting antennas having mutually different beam directions with a switching device, received signals are obtained using each of the transmitting antennas.
    Type: Grant
    Filed: August 25, 1999
    Date of Patent: June 12, 2001
    Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho
    Inventors: Yoshikazu Asano, Shigeki Ohshima
  • Patent number: 6232911
    Abstract: A device for distance measurement by radar comprises a frequency modulated radar-transmitter and -receiver (10) by which a radar beam is directed onto an object to be measured and in which by mixing the transmitted and the received frequency a beat signal (30) is obtained. By use of frequency modulation (16) the frequency of the transmitted radar signal of the radar-transmitter and -receiver is variable periodically according to a saw tooth function. The frequency of the beat signal, due to the travel time of the radar signal reflected by the object, represents a measured value for the distance of the object. A signal processing circuit generates from the beat signal obtained a measured value of the distance. For this purpose the beat signal is fed into a phase control circuit or phase locked loop circuit (66) the output frequency of which makes the measured value of distance.
    Type: Grant
    Filed: January 12, 1995
    Date of Patent: May 15, 2001
    Inventor: Joe Scott O'Conner
  • Patent number: 6225941
    Abstract: An apparatus and method for detecting an object and determining the range of the object is disclosed. A transmitter, coupled to an antenna, transmits a frequency-modulated probe signal at each of a number of center frequency intervals or steps. A receiver, coupled to the antenna when operating in a monostatic mode or, alternatively, to a separate antenna when operating in a bistatic mode, receives a return signal from a target object resulting from the probe signal. Magnitude and phase information corresponding to the object are measured and stored in a memory at each of the center frequency steps. The range to the object is determined using the magnitude and phase information stored in the memory. The present invention provides for high-resolution probing and object detection in short-range applications. The present invention has a wide range of applications including high- resolution probing of geophysical surfaces and ground- penetration applications.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: May 1, 2001
    Assignee: University of Kansas, Center for Research, Inc.
    Inventors: Sivaprasad Gogineni, Pannirselvam Kanagaratnam
  • Patent number: 6218982
    Abstract: A pseudo random noise code is generated synchronously with a reference clock signal. A first forward electromagnetic wave is transmitted in response to the pseudo random noise code. A first echo wave is received which is caused by reflection of the first forward electromagnetic wave at an object. The received first echo wave is converted into a binary signal. A value of a correlation between the binary signal and the pseudo random noise code is repetitively calculated at a predetermined period having a synchronous relation with the reference clock signal. A time interval taken by the first forward electromagnetic wave and the first echo wave to travel to and from the object is measured in response to a timing at which the calculated correlation value peaks. Then, a second forward electromagnetic wave is transmitted in response to a transmitted pulse signal is transmitted. A second echo wave related to the second forward electromagnetic wave is received.
    Type: Grant
    Filed: October 15, 1999
    Date of Patent: April 17, 2001
    Assignee: Denso Corporation
    Inventors: Noriaki Shirai, Yoshiaki Hoashi, Takeshi Matsui
  • Patent number: 6195036
    Abstract: A pulse radar system includes a frequency-agile magnetron comprising an input for giving a feeding voltage of a magnetron tuner. A modulator connected to said magnetron forms pulses of a feeding voltage for the magnetron. A low power signal source also connected to said magnetron generates microwave frequency signals which are given to the magnetron in pauses between pulses. These signals have the frequencies differing from the frequencies of the signals generated by the magnetron and fixed during each period of magnetron pulse repetition. This radar system also includes a signal converter receiving the low power signals reflected by the magnetron. These signals are converted into the signals connected in time to the moments, when the frequencies of the low power source and the frequencies of the magnetron oscillating system coincide with each other. Further, said signals are used for triggering the modulator connected to said converter.
    Type: Grant
    Filed: April 14, 1999
    Date of Patent: February 27, 2001
    Inventor: Mikhail Nikolaevich Zybin
  • Patent number: 6191726
    Abstract: In a procedure for the elimination of interferences of short duration, such as pulses, in a radar unit of the FMCW type, the transmitted and received signals are combined to form a useable signal. According to the procedure, the contribution to the Fourier Transform of the interferences of short duration are filtered out of the Fourier Transform in the frequency domain by an FIR filter with complex coefficients. The procedure requires no additional signal processing between sampling and applying the Fourier Transform, gives very little widening of strong contrasts in the Fourier Transform and is fast and simple to implement in a signal processor.
    Type: Grant
    Filed: May 12, 1999
    Date of Patent: February 20, 2001
    Assignee: Celsiustech Electronics AB
    Inventor: Bert-Eric Tullsson