Automatic Range Tracking Patents (Class 342/95)
  • Patent number: 6577269
    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: Grant
    Filed: August 16, 2001
    Date of Patent: June 10, 2003
    Assignee: Raytheon Company
    Inventors: Walter Gordon Woodington, Michael Joseph Delcheccolo, Joseph S. Pleva, Mark E. Russell, H. Barteld Van Rees
  • Patent number: 6538599
    Abstract: 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: Grant
    Filed: November 16, 2001
    Date of Patent: March 25, 2003
    Assignee: Raytheon Company
    Inventor: George Thomas David
  • Patent number: 6512476
    Abstract: An adaptive radar scanning system for an aircraft includes a radar antenna that is angularly movable to scan across a full scan range. A control system operates the radar antenna to scan in an adjusted scan range based on information related to a heading of the aircraft. As a result, the radar system is able to provide more weather information in the direction of a turn, by truncating the scan range of the radar antenna in the direction away from the turn.
    Type: Grant
    Filed: June 21, 2001
    Date of Patent: January 28, 2003
    Assignee: Rockwell Collins, Inc.
    Inventor: Daniel L. Woodell
  • Publication number: 20030006930
    Abstract: A system and method for detecting and tracking a target object, including the calculation of the target object's altitude, is disclosed. During the processing of signals received by a receiver, the system selectively calculates the altitude of the target object from signals modified by an interference effect pattern formed by the signals broadcast by a transmitter, or from the calculation of geometric shapes associated with three or more transmitters and determining the intersection point of those shapes.
    Type: Application
    Filed: May 6, 2002
    Publication date: January 9, 2003
    Applicant: Lockheed Martin Corp.
    Inventors: Richard A. Lodwig, Bonnie L. Adams, Gregory A. Baker
  • Patent number: 6466158
    Abstract: Individual objects are located according to a coordinate system in time-successive patterns and correlated between patterns. The objects are correlated by assigning identifiers to each in both patterns. The locations are transformed by reorientation to their centroid. The average of the transformed coordinate differences is used to adjust the centroid of the objects in a subsequent pattern and the transformed coordinate differences adjusted for the centroid displacement. A figure of merit is taken as the root-mean-square of the adjusted differences and used to determine which possible combination of correlated objects between two patterns is most likely.
    Type: Grant
    Filed: December 8, 2000
    Date of Patent: October 15, 2002
    Assignee: Lockheed Martin Corp.
    Inventor: Marcus Lowell Munger
  • Publication number: 20020113728
    Abstract: Individual objects are located according to a coordinate system in time-successive patterns and correlated between patterns. The objects are correlated by assigning identifiers to each in both patterns. The locations are transformed by reorientation to their centroid. The average of the transformed coordinate differences is used to adjust the centroid of the objects in a subsequent pattern and the transformed coordinate differences adjusted for the centroid displacement. A figure of merit is taken as the root-mean-square of the adjusted differences and used to determine which possible combination of correlated objects between two patterns is most likely.
    Type: Application
    Filed: December 8, 2000
    Publication date: August 22, 2002
    Applicant: LOCKHEED MARTIN CORPORATION
    Inventor: Marcus Lowell Munger
  • Publication number: 20020044081
    Abstract: A radar system (14, 20, 22) generates a plurality of data points (x, y) representative of the position of a tracked object (48), and a representation of an associated path (50, 60) is formed therefrom. At least one quality measure, and at least one heading measure, of said representation, is calculated corresponding to at least one map coordinate (44). The quality and heading measures are stored in memory as a track map. Data from other tracked objects (58) is used to update the track map (38), resulting a plurality of heading values at associated map coordinates (44) that are representative of a path (42) followed by the tracked objects (48, 58).
    Type: Application
    Filed: June 8, 2001
    Publication date: April 18, 2002
    Inventor: Shan Cong
  • Patent number: 6373426
    Abstract: The invention relates to a radar station placed on the surface of the earth, and to a radar system comprising at least two such radar stations. The signal-processing equipment of the radar stations is adapted, at each point of time, to calculate probabilities of target positions and radial target velocity in relation to each individual radar station, based on the signals emitted and received by this station. These calculated values are associated over time, giving cumulative probability measures for target positions and radial velocities in relation to each individual radar station. By providing a system of at least two radar stations, it is possible to calculate the position of a target by associating target positions, such as they are perceived by the different radar stations, with each other by an association of characteristic movements of the target. This is done without having to synchronize the stations.
    Type: Grant
    Filed: June 14, 1994
    Date of Patent: April 16, 2002
    Assignee: Försvarets Forskningsanstalt
    Inventor: Hans Hellsten
  • Publication number: 20020030623
    Abstract: 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: Application
    Filed: June 6, 2001
    Publication date: March 14, 2002
    Inventors: Orhan Arikan, Ahmet Kemal Ozdemir
  • Patent number: 6281833
    Abstract: A timing and control method and apparatus (111) for performing precise range rate aiding includes a range gate delay means (114) for generating an estimate of the range gate delay (135) each pulse repetition interval as a function of the initial range (134) and velocity (133) provided by a processor (104). The range gate delay (135) is converted into a coarse delay (138) defining the integral number of clock cycles preceding the range gate, and a fine delay (139) for positioning a range gate to within a fraction of a clock cycle. Fine temporal control is achieved using programmable delay lines (117) and (118), which retard various control signals, including the system clock signal (131), in accordance with the fine delay (139). A modified signal (126) then drives a counter means (119) which outputs a signal (128) that defines an analog-to-digital sampling window beginning at the elapse of the range gate delay (135).
    Type: Grant
    Filed: November 10, 1999
    Date of Patent: August 28, 2001
    Assignee: Science and Applied Technology, Inc.
    Inventors: Richard C. Pringle, Charles T. McMurray
  • Patent number: 6278401
    Abstract: The present invention is in general related to target type estimation in target tracking systems. The invention enables a low complexity estimation of target type, using, e.g. ESM sensor data, by the introduction of an ambiguity restoring procedure in certain likelihood calculations. The invention further enables the systematic use of target type probability information in the calculation of strobe track crosses and their associated quality which is particularly useful for deghosting purposes. Methods for utilisation of target type probability information in the processes of strobe tracking, association, track quality evaluation and multiple hypothesis tracking are also disclosed.
    Type: Grant
    Filed: November 30, 1999
    Date of Patent: August 21, 2001
    Assignee: SAAB AB
    Inventor: Torbjörn Wigren
  • Patent number: 6262680
    Abstract: There is provided a rocket trajectory estimating method comprising the steps of: measuring a GLOS angle of a flying rocket a tracking system; passing the GLOS angle data through a batch filter to reduce noises; estimating a rocket trajectory on the basis of the GLOS angle data, the noises of which have been reduced; passing the resulting rocket trajectory data through a Kalman filter to reduce biases; and estimating the rocket trajectory again on the basis of the corrected GLOS angle data and the positional information of the tracking system. Thus, there is provide a rocket trajectory estimating method capable of reducing observation errors (noises and biases) of a tracking system of a passive ranging system, which does not have need of any laser range finders, to enhance the accuracy of rocket trajectory estimation.
    Type: Grant
    Filed: July 13, 1999
    Date of Patent: July 17, 2001
    Assignee: Kawasaki Jukogyo Kabushiki Kaisha
    Inventor: Eiichiro Muto
  • Patent number: 6243037
    Abstract: A tracking method for a signal echo system, including generating a plurality of gates for respective propagation modes on the basis of a target state prediction for a dwell time, and generating a target state estimate for the dwell time on the basis of target measurement points which fall within the gates.
    Type: Grant
    Filed: June 18, 1998
    Date of Patent: June 5, 2001
    Assignee: The Commonwealth of Australia
    Inventors: Graham William Pulford, Robert Keith Jarrott, Robin John Evans
  • Patent number: 6239739
    Abstract: Methods of associating a first target track and one of a group of target tracks measured by a radar system, in which the first target track is compared with each of the target tracks in the group of target tracks based on movement between two selected target positions, one in each of the two target tracks. Predetermined maximum numbers of changes in target parameters such as course and speed are assumed to have been able to take place during the movement, and a target parameter for the two positions is allowed to vary while other target parameters are kept constant. A possible range for the varying parameter is determined that is consistent with movement between the two positions, and if a measured value of the varying parameter lies within the range, target tracks are associated with each other.
    Type: Grant
    Filed: September 25, 1998
    Date of Patent: May 29, 2001
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: David Thomson, Benny Bentland, Thomas Kronhamn
  • Patent number: 6212480
    Abstract: An apparatus and method for measuring coefficients of retroreflectance of retroreflective surfaces such as road signs involves use of a modified light based range finder. The apparatus includes a power attenuation factor data base which relates pulse width of received pulses to power attenuation of the transmitted pulses. The range finder calculates target range based on time of flight of light pulses. The apparatus automatically calculates the absolute coefficient of retroreflectance for an unknown reflective surface being measured by comparison of the measurement to a reading with the same instrument of a known reflectance standard.
    Type: Grant
    Filed: January 25, 2000
    Date of Patent: April 3, 2001
    Assignee: Laser Technology, Inc.
    Inventor: Jeremy G. Dunne
  • Patent number: 6211810
    Abstract: In an air traffic control radar system, a processor is described for correlating primary target data received from a target with a target report and a target track, wherein the processor has a search acquisition time that is adapted to the distance of the target from the radar site. The search acquisition time is shorter for more distant targets. The processor can employ a shorter cycle time (time quantum) to establish a correlation between target data and target reports than would otherwise be possible with conventional fixed search acquisition times. The average total dwell time may be reduced while complying with the mandated maximum processing time for more difficult radar reports.
    Type: Grant
    Filed: October 12, 1999
    Date of Patent: April 3, 2001
    Assignee: Raytheon Company
    Inventor: Vincent E. Schirf
  • Patent number: 6137436
    Abstract: A pseudo-noise-modulated spread spectrum is irradiated undirectedly--or, encoded by different modulation, into mutually displaced spatial sectors--and the energy (20) received after reflection at a potential target (13) is cross-correlated, using the pseudo-noise code which is predetermined at the transmission end, in order to provide a spherical monitoring effect which is continuous but which cannot be located in respect of its origin, to provide a warning in particular for marine craft, land vehicles and aircraft against an attacking guided missile as the target (13) to be repelled, and in order to be able to transfer to a target tracker (12) distance and speed information obtained from the correlation product, with the alarm signal, if the alarm sensor (11) is not itself also used as the tracking sensor.
    Type: Grant
    Filed: June 1, 1998
    Date of Patent: October 24, 2000
    Assignee: Diehl Stiftung & Co.
    Inventor: Volker Koch
  • Patent number: 6069581
    Abstract: A radar system is described for use in vehicular applications. The radar system is particularly suited to backup warning systems and side-object warning systems. The radar minimies many of the problems found in the prior art by providing programmable delays and programmable gain. The radar uses a range search algorithm to detect and sort targets at various ranges within the field of view of the radar. Each target range corresponds to a particular delay and gain setting. The radar searches for targets at the various ranges by running a target search algorithm. For each target range, the search algorithm causes the proper time delay and gain setting. Targets within the selected range are detected and catalogued. A display is used to warn the driver of the vehicle of the presence of targets at the various ranges. The warning may be visual and/or audible.
    Type: Grant
    Filed: February 23, 1998
    Date of Patent: May 30, 2000
    Assignee: Amerigon
    Inventors: David Allen Bell, Jimmy Moon Kan Li, Kelvin Chi Lee, Roger Rong Taur
  • Patent number: 6064331
    Abstract: The objectives of the invention are met by an improved radar tracking system and a process of radar tracking. In the improved system and process, an estimate of a target range and a range uncertainity swath from a first radar system is inputted into a second radar system along with a duty factor. The second radar system determines a set of zero eclipse intervals and respective ranges of range pulse repetition frequencies that solves a first set of equations. A usable range pulse repetition frequency is chosen from the results. Next, an estimated target Doppler frequency region and a Doppler uncertainity swath is inputted into the second radar system. The second radar system is instructed to determine a set of clear Doppler frequency region intervals, and respective ranges of Doppler frequency pulse repetition frequencies by solving a second set of equations.
    Type: Grant
    Filed: June 11, 1998
    Date of Patent: May 16, 2000
    Assignee: Boeing North American, Inc.
    Inventors: Louis J. Avila, Prentiss N. Robinson
  • Patent number: 6064330
    Abstract: An apparatus and method for accurately determining a target distance in adverse weather conditions utilizing both LASER and RADAR is disclosed. The radar signals are used to determine an approximate range which is then used as a gating window for the determination of which laser reflection is from the actual target as opposed to a reflection from the atmospheric interference. The method basically comprises the steps of initiating a radar pulse in the direction of a target and receiving a reflection, transmitting a laser signal and receiving a plurality of reflections, determining an approximate range based on the radar signals, and using this approximate range to ascertain which of the laser reflections is from the target. This determination is preferably made by generating a gating signal and gate width from the radar signals and passing the set of laser range signals through the gate to eliminate the false signals and select the signal that survives the gate as the accurate target range.
    Type: Grant
    Filed: May 5, 1998
    Date of Patent: May 16, 2000
    Assignee: Laser Technology, Inc.
    Inventors: Scott Elliott, Eric A. Miller, Jeremy G. Dunne
  • Patent number: 6064333
    Abstract: A phased array radar system for target tracking having a track initiation unit, a track prediction unit, a scheduling unit, a track selection unit, and a transmitter/receiver unit. The track initiation unit initiates new tracks representing detected aircraft targets. The track prediction unit predicts the expected position and the calculated position uncertainty of the target as a function of time and the minimal, maximal and optimal time difference to the next measurement. The scheduling unit performs an independent calculation of a sequence of possible time intervals to the next measurement in accordance with specified conditions, and then performs an intersection operation between the calculated sequences of time intervals in order to calculate the optimal time interval to the next measurement. A track selection unit selects that track which has the shortest remaining time interval, K.sub.i, to the next measurement and decreases the time interval to the next measurement for all other tracks with K.sub.i.
    Type: Grant
    Filed: November 7, 1997
    Date of Patent: May 16, 2000
    Assignee: Telefonatkiebolaget LM Ericsson
    Inventor: Dan Stromberg
  • Patent number: 6055490
    Abstract: An apparatus and method for measuring coefficients of retroreflectance of retroreflective surfaces such as road signs involves use of a modified light based range finder. The apparatus includes a power attenuation factor data base which relates pulse width of received pulses to power attenuation of the transmitted pulses. The range finder calculates target range based on time of flight of light pulses. The apparatus automatically calculates the absolute coefficient of retroreflectance for an unknown reflective surface being measured by comparison of the measurement to a reading with the same instrument of a known reflectance standard.
    Type: Grant
    Filed: July 27, 1998
    Date of Patent: April 25, 2000
    Assignee: Laser Technology, Inc.
    Inventor: Jeremy G. Dunne
  • Patent number: 6018311
    Abstract: A system and method of processing data in a sensor system which receives signal returns from pulsed coherent transmitted signals which are transmitted at a pulse repetition rate and with a pulse repetition interval (PRI). The method includes providing range-filtered data in response to the received signal returns; formatting successive sets of data received during a post detection integration (PDI) interval into a plurality of overlapping coherent processing interval (CPI) data sequences; performing FFT processing on the overlapping CPI data sequences to provide transformed data sequences; performing range-sample CPI processing on the transformed data sequences; and performing noncoherent integration (NCI) processing on output data from the range-sample CPI processed data sequences over a range trajectory in accordance with hypothesized radar-target range rate to provide noncoherent gain-enhanced output data.
    Type: Grant
    Filed: July 14, 1998
    Date of Patent: January 25, 2000
    Assignee: Raytheon Company
    Inventor: George T. David
  • Patent number: 6002358
    Abstract: An apparatus and computer-implemented method of determining a probability that a first track and a second track represent the same physical object.
    Type: Grant
    Filed: August 18, 1998
    Date of Patent: December 14, 1999
    Assignee: Northrop Grumman Corporation
    Inventor: Shiu Ming Tsang
  • Patent number: 5999117
    Abstract: A method for detecting and tracking turns of a maneuvering target comprises the steps of determining first and second radar information of the maneuvering target. The first and second radar information and a set of target speeds are used to determine a set of turn radii for the maneuvering target. The first and second radar information and a set of target arc speeds are used to determine a second set of turn radii for the maneuvering target. The set of turn radii and the set of target speeds define a speed-radius curve, and the second set of turn radii and the set of target arc speeds define an arc speed-radius curve. An intersection of the speed-radius and arc speed-radius curves is located, and the intersection is used to determine whether the maneuvering target has made a turn.
    Type: Grant
    Filed: June 16, 1998
    Date of Patent: December 7, 1999
    Assignee: Northrop Grumman Corporation
    Inventor: Stephen Joseph Engel
  • Patent number: 5959573
    Abstract: A bistatic coherent unlocked radar system and processing method using an advanced waveform that permits bistatic unlocked coherent operation of an unlocked radar transmitter and receiver. The waveform implements intrapulse fine range resolution, pulse to pulse coherency and burst to burst frequency agility to provide for enhanced target detection and robust operation in electronic countermeasure environments. A continuous sequence of pulses at different frequencies is transmitted that may contain an acquisition frequency that is revisited) more times than the other frequencies. Energy reflected from a target is processed to detect energy at the acquisition frequency, for example, over a plurality of range bins and predetermined pulse repetition intervals. A range pattern is generated if the detected energy is above a predetermined threshold. The energy is centroided to indicate the relative angle to the target. The transmitted frequencies contained in the pattern of energy are identified.
    Type: Grant
    Filed: May 22, 1998
    Date of Patent: September 28, 1999
    Assignee: Raytheon Company
    Inventors: Kapriel V. Krikorian, Robert A. Rosen
  • Patent number: 5943003
    Abstract: A radar system for processing a series of radar returns to determine Doppler velocity of an object. Each one of the radar returns is produced in response the object reflecting each one of a series of transmitted radar pulses. The series of radar returns is processed in a sequence of successive dwells. Each one of the dwells has a predetermined number of radar returns. The radar system includes a system clock for producing a series of clock pulses. A range gate is provided for sampling each one of a series of radar returns produced in response to a each one of a series of transmitted radar pulse. The range gate has a time duration equal to an integer number of, N, clock pulse periods. A range gate positioning system initiates the range gate a selected time, .DELTA., after each one of the transmitted pulses. The positioning system determines the selected time, .DELTA.
    Type: Grant
    Filed: November 18, 1997
    Date of Patent: August 24, 1999
    Assignee: Raytheon Company
    Inventor: Dean L. Shollenberger
  • Patent number: 5896102
    Abstract: A cost-effective ultra-wideband radar system capable of locating nearby buried objects such as reinforcing steel rods, pipes, and other objects buried in concrete, soil, behind walls, or in the air. A sequence of ultra-wideband radar pulses e.g. at a plurality of frequencies in a range of about 2 MHz to about 10 GHz are emitted without a carrier and the system detects deflected pulse energy caused by the transmitted pulse whenever encountering a change in the medium i.e. an air to metal change or concrete to metal change. This reflected energy is detected and visually displayed. The range gate delay of the receiver is continuously varied, thus changing the distance from the unit to where the reflected energy would be potentially detected from the target. By continuously sweeping the "depth" of the scan, the operator need only move the unit in two dimensions across the surface to detect objects buried or hidden at varying depths interior to or behind the surface.
    Type: Grant
    Filed: July 28, 1997
    Date of Patent: April 20, 1999
    Assignee: Zircon Corporation
    Inventor: Charles E. Heger
  • Patent number: 5808579
    Abstract: A cell averaging (CA) constant false alarm rate (CFAR) device for use in a radar system which filters noise and clutter from a signal containing a plurality of range cells. A moving window average calculator (MWAC) calculates a moving window average (MWA) for each range cell in a signal. A central processing unit (CPU) estimates a skew factor of a probability density function (PDF) and calculates an offset factor based on information contained in the signal. A multiplying device multiplies the offset factor by the MWA calculated for each range cell and creates a second signal containing a plurality of range cells. A comparator compares each range cell of the second signal to each corresponding range cell of the original signal, selects a the larger value of the two signals, and creates a third signal which is essentially free of noise and clutter.
    Type: Grant
    Filed: December 20, 1996
    Date of Patent: September 15, 1998
    Assignee: Northrop Grumman Corporation
    Inventor: Paul E. Rademacher
  • Patent number: 5781147
    Abstract: An apparatus and method for accurately determining a target distance in adverse weather conditions utilizing both LASER and RADAR is disclosed. The radar signals are used to determine an approximate range which is then used as a gating window for the determination of which laser reflection is from the actual target as opposed to a reflection from the atmospheric interference. The method basically comprises the steps of initiating a radar pulse in the direction of a target and receiving a reflection, transmitting a laser signal and receiving a plurality of reflections, determining an approximate range based on the radar signals, and using this approximate range to ascertain which of the laser reflections is from the target. This determination is preferably made by generating a gating signal and gate width from the radar signals and passing the set of laser range signals through the gate to eliminate the false signals and select the signal that survives the gate as the accurate target range.
    Type: Grant
    Filed: May 9, 1997
    Date of Patent: July 14, 1998
    Assignee: Laser Technology, Inc.
    Inventors: Scott Elliott, Eric A. Miller, Jeremy G. Dunne
  • Patent number: 5757310
    Abstract: The volume of space, in range, azimuth and elevation, over which a conventional Tactical Ballistic Missile (TBM) early warning radar is required to search for incoming missiles is very large. This placed very heavy demands on the radar designer, resulting in large, very high power, low mobility radars, with subsequent vulnerability to ARMs and other defence suppression systems. This invention proposes an alternative approach to a TBM early earning radar which considerably reduces both the design and vulnerability problem, and permits effective TBM early warning radars to be constructed using current technology. This is achieved by moving the radar (1) beyond the front edge of the defended area (2). The increased elevation scan requirements are more than compensated for by a range-adaptive scanning technique which reduces the volume search time by more than 50% compared with a more conventional arrangement.
    Type: Grant
    Filed: April 22, 1996
    Date of Patent: May 26, 1998
    Assignee: Matra BAe Dynamics (UK) Ltd.
    Inventor: Gerald W. Millward
  • Patent number: 5757320
    Abstract: A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with a typical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control.
    Type: Grant
    Filed: December 17, 1996
    Date of Patent: May 26, 1998
    Assignee: The Regents of the University of California
    Inventor: Thomas E. McEwan
  • Patent number: 5745224
    Abstract: A distance measurement device comprises at least one switch for generating a start signal, a distance measurement device for measuring the distance to an object in response to the start signal, a memory device for storing distance data measured by the distance measurement device, the stored data defining a plurality of measurement zones within the full range of distance measurement of the distance measurement device, and a judgement circuit for judging which measurement zone the result of the distance measurement performed by the distance measurement means belongs to from the plurality of measurement zones defined by the distance data stored in the memory device. In accordance with this configuration, division points can be set if an object is placed at an actual division point desired and a switch is pressed. Accordingly, when an operator sets the division point, it is unnecessary to depend on memory, perception, or calculation, and the setting of the division points becomes easier.
    Type: Grant
    Filed: September 28, 1995
    Date of Patent: April 28, 1998
    Assignee: Seiko Precision Inc.
    Inventors: Hajime Oda, Takuma Takahashi
  • Patent number: 5708437
    Abstract: A radar apparatus having a phased array antenna with a large number of transmit and receive modules, a control unit and a video processor. The control unit generates a number of pulse bursts per azimuth-elevation direction, all of which shows slight carrier frequency differences. The video processor determines a doppler spectrum and compared successive spectra for each pulse burst. As a result of the frequency differences, clutter does not show much of a shift while targets which are subject to fold-back in the frequency domain will show considerable shift. A threshold based on a mean spectrum therefore enables detection.
    Type: Grant
    Filed: March 7, 1996
    Date of Patent: January 13, 1998
    Assignee: Hollandse Signaalapparaten B.V.
    Inventor: Bernard Gellekink
  • Patent number: 5610613
    Abstract: A system for obtaining digitized samples of an analog signal at a selectable rate, R. The system includes: a timing generator for producing a train of sampling pulses at a predetermined sampling rate, f.sub.s ; an analog to digital converter for producing a digitized sample of the analog signal in response to each one of the sampling pulses; a processor; and, a selector, for passing each Nth one of the digitized samples produced by the analog to digital converter, where N=f.sub.s /R to the processor. The selector includes a decimator, responsive to a signal, N=f.sub.s /R, representative of the ratio of the sampling rate, f.sub.s, to the digitized signal obtaining rate, R, for producing pulses at the rate, R=f.sub.s /N; and, a register for storing each Nth one of the digitized samples produced by the analog to digital converter, each one of such digitized samples being stored in response to a corresponding one of the pulses produced by the decimator.
    Type: Grant
    Filed: September 15, 1995
    Date of Patent: March 11, 1997
    Assignee: Raytheon Company
    Inventors: Robert W. Hazard, George A. Bouchard, Jeffrey E. Carmella, Michael P. DeMilia
  • Patent number: 5574460
    Abstract: A probe acquisition and display system is disclosed featuring one simple trol for acquiring, tracking, and instantaneously locking for a missile control radar. The system provides for fast initial target acquisition and re-acquisition in the presence of intentional or unintentional interference. A dual trace oscilloscope display is provided with radar tracking (range) gate and a probe is used to touch a target on the display by a radar operator.
    Type: Grant
    Filed: February 3, 1965
    Date of Patent: November 12, 1996
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: John Di Perry
  • Patent number: 5572215
    Abstract: A plurality of threshold detectors is provided to pass analog signals of predetermined and varying threshold values. An analog to digital converter converts these analog signals to binary 1s and 0s. A target detected on each radar beam sweep is a 1 and no target is a 0. These binary numbers are then stored in a reversible up-down counter. At the first signal received, the counter counts up on hits (binary 1) and counts down on misses (binary 0). When the contents of the counter reaches a predetermined count, a target's leading edge is declared. At this time, the counter is then reset and proceeds to count up on misses and down on hits until the aforesaid predetermined count is attained, wherein a trailing edge is then declared.
    Type: Grant
    Filed: April 13, 1967
    Date of Patent: November 5, 1996
    Assignee: Hughes Aircraft Company
    Inventors: Norol T. Evans, Duane R. Ritchie
  • Patent number: 5541605
    Abstract: A cost-effective ultra-wideband band radar system capable of locating nearby buried objects such as reinforcing steel rods, pipes, and other objects buried in concrete, soil, behind walls, or in the air. A sequence of ultra-wideband band radar pulses are emitted without a carrier and the system detects deflected pulse energy caused by the transmitted pulse whenever encountering a change in the medium i.e. an air to metal change or concrete to metal change. This reflected energy is detected and visually displayed. The range gate delay is continuously varied, thus changing the distance from the unit to where the reflected energy would be potentially detected from the target. By continuously sweeping the "depth" of the scan, the operator need only move the unit in two dimensions across the surface to detect objects buried or hidden at varying depths interior to or behind the surface.
    Type: Grant
    Filed: May 30, 1995
    Date of Patent: July 30, 1996
    Assignee: Zircon Corporation
    Inventor: Charles E. Heger
  • Patent number: 5537118
    Abstract: The tracking of moving objects on land, in the air or at sea is effected by means of one or more sensors (S.sub.j.sup.1). The observation space of each sensor is divided into resolution cells (X.sup.1h) forming a grid. The sensors of the same grid are grouped together.A probability estimate (.beta.k) for a moving object being in a cell (Xk) which is an intersection of the resolution cells (X.sup.1h) is produced. For this purpose, the starting points are signals (M.sub.j.sup.1h) delivered by the sensors (S.sub.j.sup.1) and previously selected according to windowing criteria, sets of pairs (F.sub.i (M.sub.j.sup.1h)D.sub.ij.sup.1h) stored in memories (1) and coming from a prior supervised statistical learning, and tracking coefficients (.alpha.k) delivered by an adaptive tracking filter (4) of the PDAF type. After application of this probability (.beta.
    Type: Grant
    Filed: March 28, 1995
    Date of Patent: July 16, 1996
    Assignee: Office National D'Etudes Et De Recherches Aerospatiales
    Inventor: Alain Appriou
  • Patent number: 5525995
    Abstract: In a system for detecting the position and trajectory of a target, Doppler measurements from a bistatic continuous wave radar system are used exclusively to provide information about the target. Radar signals are transmitted to the target by a plurality of transmitters and at least one receiver is provided to receive the signals from the target and make Doppler measurements. A nonlinear least squares estimator is used to estimate the initial target position and a Kalman filter is used to predict the target trajectory from the initial position assumed by the NLS estimator and from the Doppler measurements. The Kalman filter also generates a set of predicted Doppler measurements from the predicted trajectory. The nonlinear least squares estimator is used to compute a correction to the estimated initial position from partial differentials of the initial position and from the differences between the predicted and actual Doppler measurements.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: June 11, 1996
    Assignee: Loral Federal Systems Company
    Inventor: Robert H. Benner
  • Patent number: 5491645
    Abstract: A computer system and method for accurately transforming multiple returns received by multiple satellites from multiple targets into a set of single accurate tracks for each target. Observations from multiple satellites create partial or resulting tracks. These resulting tracks are then correlated with pre-existing base tracks by a series of steps in which resulting tracks are paired with pre-determined base tracks according to a series of criteria. Pairs based on: common observation points and time spans, common satellites, and lack of common satellite, are considered sequentially. The final attempt at correlation consists of pairing each remaining track with each base track and using profile dependent piece correlation of the pairs. Any remaining resulting tracks are then added to the set of base tracks.
    Type: Grant
    Filed: October 13, 1993
    Date of Patent: February 13, 1996
    Assignee: International Business Machines Corporation
    Inventors: Eugene T. Kennedy, Neils H. Hansen
  • Patent number: 5479360
    Abstract: A method for estimating target parameters of a target with respect to a platform such as ownship includes assigning predetermined initial values for the target parameters, wherein the target parameters are part of models having respective model probabilities. The models may include a Kalman filter. The models are updated in response to measured parameters of the target, wherein the measured parameters are different from the ones to be estimated. After a predetermined number of updates, the model having the highest updated model probability may be selected as the winning model. The updated values of the target parameters in the winning model at the time of winner selection are used as the estimated values for the parameters sought to be estimated. The updated parameter values may be refined by restarting the process using the updated values of the winning model as the basis for assigning new initial values for the target parameters.
    Type: Grant
    Filed: December 21, 1992
    Date of Patent: December 26, 1995
    Assignee: Martin Marietta Corporation
    Inventors: Joel F. Seif, Christopher G. Nunno
  • Patent number: 5414643
    Abstract: A multiple hypothesis tracking system (10) which generates a substantially continuous output to a system user. The multiple hypothesis tracking system (10) generates a primary set of tracks (12) which best represents the expected number of targets of interest in a cluster. For multiple sensor applications, a secondary set of tracks is generated having a less probability than the tracks in the primary set. A knowledge of track data is maintained from one scan to a subsequent scan such that tracks can be merged and deleted (14). A universal track file (16) is generated in which track associations from one scan to a subsequent scan are correlated such that the output of the track file remains consistent with respect to the number of tracks.
    Type: Grant
    Filed: June 14, 1993
    Date of Patent: May 9, 1995
    Assignee: Hughes Aircraft Company
    Inventors: Samuel S. Blackman, Robert J. Dempster
  • Patent number: 5400033
    Abstract: This invention comprises the use of integral pulse frequency modulation (IPFM) reaction jet controllers for multi-axis precision tracking of moving objects with flexible spacecraft, and vibration suppression. Two sets of position, rate and accelertion command profiles for multi-axis tracking are disclosed: one for a payload initially facing the zenith and the commands based on a pitch-roll sequence; the other for a payload facing the nadir and the commands based on a roll-pitch sequence. The procedure for designing an IPFM controller for tracking a given, inertial acceleration command profile is disclosed. Important elastic modes of a spacecraft are identified according to their spontaneous attitude and rate response to the minimum impulse bit of the thrusters. The stability of the control-structure interaction is shown to be governed by the ratio of the moments of inertia of the flexible to the rigid portions of the spacecraft.
    Type: Grant
    Filed: February 7, 1994
    Date of Patent: March 21, 1995
    Assignee: Rockwell International Corporation
    Inventor: Hari B. Hablani
  • Patent number: 5396252
    Abstract: A target tracking system (10) comprises sensors (12) which provide data corresponding to a region of interest, the data being time dependent and consisting of amplitudes, ranges and angles. A window (202) is placed around data of interest, the size of the window being determined based on target size, assumed speed and acceleration characteristic, and the window is thereafter broken down into a plurality of smaller windows (208), thereby forming a grid having a nodal point (210) at each corner of the smaller windows. The data within the window is stored in a matrix, and background noise is thereafter minimized by filtering the data past a threshold value (215). The filtered data is analyzed to determine its distance weighted contribution at each nodal point (219), and the weighted distances are summed for each nodal point resulting in a nodal point magnitude for each of the nodal points (220).
    Type: Grant
    Filed: September 30, 1993
    Date of Patent: March 7, 1995
    Assignee: United Technologies Corporation
    Inventor: James A. Kelly
  • Patent number: 5359404
    Abstract: A laser speed detector is described which includes a laser rangefinder which determines the time-of-flight of an infrared laser pulse to a target and a microprocessor-based microcontroller. The device is small enough to be easily hand-held, and includes a trigger and a sighting scope for a user to visually select a target and to trigger operation of the device upon the selected target. The laser rangefinder includes self-calibrating interpolation circuitry, a digital logic-operated gate for reflected laser pulses in which both the "opening" and the "closing" of the gate can be selectably set by the microcontroller, and dual collimation of the outgoing laser pulse such that a minor portion of the outgoing laser pulse is sent to means for producing a timing reference signal.
    Type: Grant
    Filed: September 14, 1992
    Date of Patent: October 25, 1994
    Assignee: Laser Technology, Inc.
    Inventor: Jeremy G. Dunne
  • Patent number: 5331561
    Abstract: A system guides a vehicle along a predefined path by correlating vehicle side range profiles. A lead vehicle gathers side range data using active radiation sources such as light emitting diodes. A microprocessor-based system on board the lead vehicle stores the data into records of a database file, tagging each record to indicate a relative position along the path when the lead vehicle obtained the data. A system on board a follower vehicle gathers its own side range data and also generates a side range profile for the follower vehicle. The follower vehicle's system receives by radio communication the side range profiles from the lead vehicle and, using the tagging information, correlates these profiles with the follower vehicle side range profiles at appropriate points along the path.
    Type: Grant
    Filed: April 23, 1992
    Date of Patent: July 19, 1994
    Assignee: Alliant Techsystems Inc.
    Inventors: William A. Barrett, Donald G. Krantz
  • Patent number: 5325098
    Abstract: A filtering system used in the tracking of a maneuvering target is provid A first filter estimates a partial system state at a time k in terms of target position measurements. A plurality of second filters are each provided with an acceleration model hypothesis from a prior time (k-1) free of position and velocity constraints. Each second filter generates an acceleration estimate at time k and a likelihood at time k that the acceleration model hypothesis is correct. The likelihoods from the second filters are summed to generate a probability vector at time k. A third interaction mixing filter generates the acceleration model hypotheses from prior time (k-1) using the probability vector from prior time (k-1) and the acceleration estimates from prior time (k-1). The third filter also provides an error covariance to the first filter to reflect the uncertainty in the acceleration model hypotheses from prior time (k-1).
    Type: Grant
    Filed: June 1, 1993
    Date of Patent: June 28, 1994
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: William D. Blair, Gregory A. Watson, Theodore R. Rice
  • Patent number: 5313212
    Abstract: A radar system including a Kalman filter that processes radar return signals to produces position, velocity, acceleration, gain and residual error output signals, and a post-processor that processes these signals in accordance with a track filter bias estimation procedure. The procedure computes bias estimates and revised position, velocity and acceleration output signals that are corrected for bias error. The revised output signals are coupled to the radar system to track a target. The track filter bias estimation method computes bias estimates in accordance with the relationship: ##EQU1## where Res, K.sub.1 /K.sub.2, R and T denote the residual, gains, range, and filter cycle time, respectively, and the tilde indicates a sample averaging. The present invention also provides for improved maneuver detection by implementing an acceleration estimation algorithm used to track a maneuvering target. The present invention is applicable in all fields and areas where estimation using Kalman filters is used.
    Type: Grant
    Filed: October 19, 1992
    Date of Patent: May 17, 1994
    Assignee: Hughes Aircraft Company
    Inventor: George J. Ruzicka
  • Patent number: 5311189
    Abstract: The present invention relates to a pulse Doppler radar wherein the phase position of the reflected signals is evaluated as the most important component in addition to the amplitude. Thus a very good resolution results in the range direction and in the velocity direction for the detection of multiple target situations. The invention can be employed particularly for a so-called HPRF radar.
    Type: Grant
    Filed: September 18, 1992
    Date of Patent: May 10, 1994
    Assignee: Deutsche Aerospace AG
    Inventor: Dieter Nagel