Automatic Range Tracking Patents (Class 342/95)
  • Patent number: 5309159
    Abstract: A method of and a system for scanning a scene for the purpose of classifying a plurality of moving objects located in the scene and having an average distance between them, including the steps of performing a sweep of the scene, during the sweep, producing a multiplicity of detections of at least one portion of the scene at a rate such that a distance traveled by the moving objects between detections is small with respect to the average distance, and calculating, from the multiple detections, two-dimensional motion information for at least some of the moving objects.
    Type: Grant
    Filed: February 19, 1992
    Date of Patent: May 3, 1994
    Assignee: Israel Aircraft Industries Ltd.
    Inventors: Nahum Shahaf, Moshe Meidan
  • Patent number: 5289189
    Abstract: A method of reducing tracking errors in an area comprised of touching surveillance regions which involves; transmitting a plurality of signals into a region, receiving signals scattered from the region and analyzing the received signals using a processing means, to produce target measurements; dividing each region into a number of zones comprising an edge zone at each edge of said region and one or more center zones; associating target measurements with appropriate zones; apportioning said measurements into data blocks on a storage means such that each pair of adjoining edge zones form a single data block and each central zone forms a data block; updating target tracks in each data block using said target measurements; allocating target tracks from each data block to the correct region; and displaying the tracks on a visual display means. A separate list of tracks for those targets contained in the edge track zone of touching regions is maintained.
    Type: Grant
    Filed: May 29, 1992
    Date of Patent: February 22, 1994
    Assignee: The Commonwealth of Australia
    Inventor: Samuel B. Colegrove
  • Patent number: 5260709
    Abstract: A system and method that uses differential computation of position relative to a global positioning system (GPS) coordinate system and the computation of an optimum weapon flight path to guide a weapon to a non-moving fixed or relocatable target. The system comprises an airborne platform that uses a navigation subsystem that utilizes the GPS satellite system to provide the coordinate system and a synthetic array radar (SAR) to locate desirable targets. Targeting is done prior to weapon launch, the weapon therefore requires only a navigation subsystem that also utilizes the GPS satellite system to provide the same coordinate system that the platform used, a warhead and a propulsion system (for powered weapons only). This results in a very inexpensive weapon with a launch and leave (autonomous) capability. The computational procedure used in the platform uses several radar measurements spaced many degrees apart. The accuracy is increased if more measurements are made.
    Type: Grant
    Filed: December 19, 1991
    Date of Patent: November 9, 1993
    Assignee: Hughes Aircraft Company
    Inventor: Michael V. Nowakowski
  • Patent number: 5254999
    Abstract: A video signal processor for a radar system includes A/D converters for receiving radar signals to digitize the signals at a predetermined speed, direct averagers for writing signals included in the predetermined size of azimuth among the digitized radar signals into different memories according to the azimuths and for averaging signals corresponding to the same range gates, cell average processors having a microcomputer and a RAM for cell-averaging the output of the direct averagers with the processing program down-loaded from a main controller, an extractor for extracting only target data from the output of one of the cell average processors, a radar video processor controller for generating various control signals, and a communication processor for performing the data transmission and reception between the main controller and the radar video processor controller of the radar system.
    Type: Grant
    Filed: January 22, 1993
    Date of Patent: October 19, 1993
    Assignee: SamSung Electronics Co., Ltd.
    Inventor: Sang-yoon Lee
  • Patent number: 5214433
    Abstract: An apparatus and method for tracking maneuvering and non-maneuvering targ in the presence of stochastic acceleration are provided. The apparatus and method utilize a two-stage Kalman estimator, the first stage of which is a bias-free filter providing target position and velocity estimates, and the second stage of which is a bias filter providing estimates of target acceleration. These two filters act together to provide parallel processing calculations thereby achieving high speed target state determination. During target maneuvers, the output of the second stage is used to correct the output of the first stage. In the absence of maneuver, the second stage is turned off and the first stage provides the target position and velocity estimates.
    Type: Grant
    Filed: June 17, 1992
    Date of Patent: May 25, 1993
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Ali B. T. Alouani, William D. Blair, Theodore R. Rice
  • Patent number: 5150125
    Abstract: A pulse Doppler radar altimeter designed to resolve the ambiguous range problem associated with the use of a pulse repetition interval, which is less than the aircraft altitude, includes a radar transmitter configured to transmit first and second series of pulses where the first series has a pulse repetition interval slightly different from the pulse repetition interval of the second series. At a time when the first series is being transmitted, the receiver electronics including a range gate and a tracker searches for ground returns and positions the range gate in time coincidence with the detected ground return. Control then shifts so that the second series of pulses is transmitted and a determination is made whether overlap of the range gate with the ground return from the second series corresponds to the same altitude as when the first series was involved.
    Type: Grant
    Filed: December 24, 1990
    Date of Patent: September 22, 1992
    Assignee: Honeywell Inc.
    Inventor: James R. Hager
  • Patent number: 5148175
    Abstract: Range gate delay is effected by serially connected coarse and fine programmable delay lines. The radar transmit trigger pulse is propagated through the programmable delay lines to provide a delayed trigger pulse. The delayed trigger pulse triggers a range gate generator for generating the range gate. The delay effected by the coarse and fine programmable delay lines is controlled from the system CPU. The range gate generator comprises a D-type flip-flop with the Q output thereof connected as the input to a further programmable delay line. The delayed trigger pulse sets the flip-flop and the output of the further programmable delay line resets the flip-flop. The range gate is provided by the Q output of the flip-flop. The width of the range gate is determined by the delay set into the further programmable delay line by the system CPU.
    Type: Grant
    Filed: July 5, 1991
    Date of Patent: September 15, 1992
    Assignee: Sperry Marine Inc.
    Inventor: Thomas M. Woolfolk
  • Patent number: 5144316
    Abstract: A method and apparatus for generating a track data set corresponding to a plurality of objects. A system employing the invention receives reports, e.g. radar echoes, from the plurality of objects over a time interval, partitions the time interval into subintervals or time bins, and sorts the returns into the time bins. In each bin, the reports are very close to one another in time, so that, in correlating the reports in each bin to the tracks, one can use the reports to form the necessary search tree, rather than using the tracks. Doing so increases efficiency if the number of reports per time interval significantly exceeds the number of tracks.
    Type: Grant
    Filed: December 20, 1991
    Date of Patent: September 1, 1992
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Jeffrey K. Uhlmann, Miguel R. Zuniga
  • Patent number: 5132688
    Abstract: A pulsed doppler radar system having an improved detection probability, comprising an antenna unit, a transmitter for transmitting a signal through the antenna unit, a receiver for receiving a signal reflected by a target through the antenna unit to provide a reception signal. A processing unit which receives the reception signal from the receiver determines, in accordance with a range of the target and a signal-to-noise ratio and bandwidth of the reception signal, an optimum integration number which maximizes the detection probability and performs coherent integration on the reception signal by the number of times equal to the determined optimum integration number thereby outputting a signal having a predetermined level. Such a signal is fed to a display and an image of the target is displayed on a display.
    Type: Grant
    Filed: February 27, 1991
    Date of Patent: July 21, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Akihiro Shima, Takahiko Fujisaka, Yoshimasa Ohashi
  • Patent number: 4992795
    Abstract: To make an "intelligent" selection, in a radar, of the piece of information transmitted to the tracking unit by the extractor, in case of saturation, a method comprising the first step of selecting a set of N attributes (x.sub.1, x.sub.2, . . . x.sub.N) defining the plots given by the extractor. Then quantifying each attribute, in defining intervals in the range of values taken by the attribute and associating, with each N-tuple formed by a combination of values of the attributes, an estimated value of validity of the corresponding plot. Further, for each plot transmitted by the extractor, searching for the N-tuple that corresponds to it, in order to associate the estimated value of validity, assigned to the N-tuple, with the plot.
    Type: Grant
    Filed: October 10, 1989
    Date of Patent: February 12, 1991
    Assignee: Thomson-CSF
    Inventors: Jean-Luc Lassallette, Guy Desodt, Eric Potier
  • Patent number: 4975705
    Abstract: A target detector (1) for detecting targets provided with transmitter means (3, 5) for simultaneous generation of different electromagnetic waves having different frequencies which are transmitted by means of an emission and detection device (2). The target detector is also provided with receiving means (3, 4, 5) for obtaining, by means of the emission and detection device (2), target signals comprising target information received at different frequencies. A signal processing unit (15, 16, 17) is provided for processing the target signals in combination to obtain target-representing signals.
    Type: Grant
    Filed: July 12, 1989
    Date of Patent: December 4, 1990
    Assignee: Hollandse Signaalapparaten B.V.
    Inventors: Bernard Gellekink, Cornelis M. Jansen
  • Patent number: 4973968
    Abstract: A radar system for determining first time around targets from multiple time around targets using two radar pulse trains of different pulse repetition intervals and thresholding means. Echos from pulses at each pulse repetition interval being compared to determine first time around targets from subsequent time around targets. The radar system uses thresholding levels to determine an echo and is less prone to problems of coincidence gate clashing with high duty cycles.
    Type: Grant
    Filed: February 22, 1989
    Date of Patent: November 27, 1990
    Assignee: Plessey Overseas Limited
    Inventor: David L. Hurd
  • Patent number: 4862177
    Abstract: A processor adapted for use in conjunction with a monopulse radar system for discriminating between ground and airborne moving targets and comprising: Doppler filter circuits for detecting moving targets; angle measurement circuits which respond to the received sum and elevation difference signals so as to provide an indication of the relative angle of each moving target and of the ground; and means for identifying a detected target as a ground or an airborne target as a function of whether the angle of the target is substantially the same as or different from that of the ground.
    Type: Grant
    Filed: November 25, 1974
    Date of Patent: August 29, 1989
    Assignee: Hughes Aircraft Company
    Inventor: Sung Y. Wong
  • Patent number: 4816833
    Abstract: Post detection processing for a pulse doppler surveillance radar is disclosed wherein target reports having ambiguous ranges along with those containing unambiguous ranges are used for tracking targets. The tracking includes a maneuver recognition mechanism for adaptively weighting the range, range rate, and X and Y coordinate driving errors as a function of the maneuvering and non-maneuvering operations of the target.
    Type: Grant
    Filed: June 16, 1987
    Date of Patent: March 28, 1989
    Assignee: Westinghouse Electric Corp.
    Inventors: Kenneth H. Ferguson, Bobby J. Gatlin, Philip Real, Joseph L. Conroy, James P. Ehrman
  • Patent number: 4743907
    Abstract: A radar system for low-level target tracking comprises a first and a second radar apparatus, both apparatus operating at their own frequency, but employing one and the same tracking antenna. A target being tracked in range and angle coordinates by the first radar apparatus can be tracked in angle coordinates by the second apparatus and in range by the first radar apparatus when the target arrives within the range of the second radar apparatus. A preferred digital embodiment of this system is obtained by utilizing a common signal processing unit including a matched filter.
    Type: Grant
    Filed: May 5, 1986
    Date of Patent: May 10, 1988
    Assignee: Hollandse Signaalapparaten B.V.
    Inventor: Bernard Gellekink
  • Patent number: 4673938
    Abstract: A modification is presented to improve radar systems, which normally tracks a single target, to enable them to perform a simultaneous search of a large space volume while maintaining track of a selected target. This modification entails an operating process in which a search is conducted with a controlled search pattern and search time so that the antenna is as close as possible to the tracked target position at the search conclusion and antenna slewing time is mimimized. Finally, the present procedure can be implemented while adding as little as a thousand words of memory to the radar system.
    Type: Grant
    Filed: September 5, 1985
    Date of Patent: June 16, 1987
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventors: Robert A. Phillips, Calvin A. Cassidy
  • Patent number: 4646097
    Abstract: A precision distance measuring equipment (DME/P) receiver for detecting an RF signal including at least one interrogation pulse is described. The DME/P receiver includes first and second signal processing channels. The first processing channel includes a wideband filter, of bandwidth BW1, for receiving the processed RF signal and in response thereto generating a wideband (FA) mode signal proportional to the logarithm thereof. The second signal processing channel includes a narrowband filter, of bandwidth BW2, for receiving the processed RF signal and in response thereto generating a narrowband (IA) mode signal proportional to the logarithm thereof, the bandwidth BW2 of the narrowband filter being within the bandwidth BW1 of the wideband filter.
    Type: Grant
    Filed: May 6, 1985
    Date of Patent: February 24, 1987
    Assignee: E-Systems, Inc.
    Inventor: Dennis D. King
  • Patent number: H1122
    Abstract: A process that derives estimates of range and range-rate during the radar ack of an object, when the radar employes a linear frequency modulated waveform. FM waveforms at the radar wavelength are transmitted. The frequency of the radar echos are measured and the difference between the incoming frequency of radar echos and the local oscillator frequency is estimated. The signal is decomposed into Range and Range rate. Implementation of the decomposition device can either be a sequence of stored software or a hardwired processor.
    Type: Grant
    Filed: June 24, 1991
    Date of Patent: December 1, 1992
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Richard E. Pavek