Automatic Range Tracking Patents (Class 342/95)
  • Patent number: 7324041
    Abstract: A method for determining an angle for each of two RF signals at different frequencies and offset from each other. The average angle of a composite signal is obtained from the two RF signals over a frequency difference period by averaging the frequency difference period. The average angle of the composite signal is the dominant signal's angle. The smaller signal's angle is then calculated from the dominant signal's angle, an angle centroid, and the signal voltages for the two RF signals.
    Type: Grant
    Filed: July 12, 2006
    Date of Patent: January 29, 2008
    Assignee: United States of America as represented by the Secretary of the Navy
    Inventor: Shaun David Weatherford
  • Patent number: 7317417
    Abstract: The present invention relates to active sensor applications, and more particularly is directed to efficient systems and methods for detection and tracking of one or more targets. The invention provides a method for receiving signals reflected from one or more targets, processing the received signals and the transmitted signal to compute two or more slices of the cross ambiguity function associated with the signals, and estimating the signal delay and the Doppler shit associated with the targets from the computed slices.
    Type: Grant
    Filed: July 12, 2005
    Date of Patent: January 8, 2008
    Inventors: Orhan Arikan, Ahmet Kemal Ozdemir, Donald Spyro Gumas
  • Publication number: 20070285303
    Abstract: A system and method is presented for detecting and classifying slow-moving and hovering helicopters from a missile's took-down Doppler radar that is compatible with the existing base of Doppler radars. This approach uses definable attributes of a helicopter rotor assembly and its extended Doppler rotor return to differentiate “rotor samples” from other samples (steps 123, 125), extract features such as bandwidth, activity, angle, and shape from the rotor samples (step 127), and classify a potential target as a helicopter or other based on the extracted rotor features and the known attributes of the helicopter rotor assembly (step 129). A target report including a classification target, range, range-rate, and angle of the extended rotor return is suitably passed to a tracking processor (step 121).
    Type: Application
    Filed: June 12, 2006
    Publication date: December 13, 2007
    Inventors: Bernard P. Radza, Joseph Henning, Sunny Ali, John Mincer, Randal Walters
  • Publication number: 20070279276
    Abstract: System for dynamically tracking a position of a target with an antenna in a communication system. The system includes an antenna system (410) configured for generating a sum and difference antenna pattern (201-1, 201-2). A sum RF channel (401) is coupled to a sum channel output of the antenna system. A difference RF channel (402) is coupled to a difference channel output of the antenna system. An RF coupler (422-1) is provided that has a first input coupled to the sum RF channel and a second input coupled to the RF difference channel. One or more coupling control devices (418-1, 418-2) selectively vary an effective coupling value as between the difference channel and the sum channel. An antenna tracking error signal is generated at an output of the coupler.
    Type: Application
    Filed: May 31, 2006
    Publication date: December 6, 2007
    Applicant: HARRIS CORPORATION
    Inventors: James K. Conn, James B. Offner, Larry P. Serulneck, Earl B. Knick, Ron Hash, Ying-Ming Lee, Pete Denney, Joseph A. Elam, Brian A. Smith
  • Publication number: 20070273576
    Abstract: Apparatus and a method utilizing correlation interferometer direction finding for determining the azimuth and elevation to an aircraft at long range and flying at low altitudes above water with a transmitting radar while resolving multipath signals. The signals from the radar are received both directly and reflected from the surface of the water using horizontally polarized and vertically polarized antenna arrays, are digitized and are stored in separate covariant matrices. Eigenvalues for the eigenvectors of the matrices processed on signal samples recorded on horizontally polarized X arrays are compared to the eigenvalues for the eigenvectors of the covariance matrices processed on signal samples recorded on vertically polarized X arrays. Incident field polarization is associated with the antenna array measurements that yield the strongest eigenvalue. The eigenvector and eigenvalues for the strongest signal are selected and used for subsequent signal processing.
    Type: Application
    Filed: May 27, 2006
    Publication date: November 29, 2007
    Inventors: Keith A. Struckman, Robert T. Martel
  • Publication number: 20070252751
    Abstract: A radar apparatus transmits a pulse signal including pulses having at least two different pulselengths in a specific transmit pulse pattern and receives a returning echo signal through a single antenna. A tuning voltage setting timing generator generates a timing of setting a tuning voltage according to a combination of transmission pulselengths and a tuning processor performs tuning operation in a manner suited to a current transmission pulselength based on the tuning voltage setting timing. The radar apparatus may include a tuning voltage alteration decider for deciding whether or not to alter the tuning voltage based on a combination of alternate pulselengths before altering the pulselength of the pulse signal generated by a transmitter and the tuning processor alters the tuning voltage based on the result of decision made by the tuning voltage alteration decider.
    Type: Application
    Filed: April 25, 2007
    Publication date: November 1, 2007
    Applicant: Furuno Electric Company Limited
    Inventors: Masahiro Nakahama, Sae Takemoto, Koji Dai
  • Patent number: 7274324
    Abstract: A path in three-dimensions for an object in flight is determined according to a radar signal reflected by the object. The radar signal is transmitted at an offset angle from horizontal sufficient to capture the object within the transmitted radar signal. The transmitted radar signal is reflected by the object to form a reflected radar signal containing an indication of a position of the object. The reflected radar signal is received and used to determine two-dimensional position information for the object by detection of the indication of the position of the object in the received radar signal. Position information is derived in three-dimensions from the position information in two-dimensions. The path information representative of the path for the object is obtained from the position information in three-dimensions based on an optimization of a curvature of said path information.
    Type: Grant
    Filed: July 8, 2002
    Date of Patent: September 25, 2007
    Assignee: Her Majesty the Queen in Right of Canada as Represented by the Minister of National Defense
    Inventors: Rhonda L. Millikin, Joseph R. Buckley
  • Patent number: 7256729
    Abstract: The invention relates to a method for the observation of a number of objects, which move in a space monitored by a number of sensors, are recorded by the sensors and followed with continuous updating of at least the sensor track defining the kinematics of the object, whereby those provided sensor tracks amongst the sensor tracks from various sensors, which correspond to the same object are automatically assigned to a system track. In order to improve the method with regard to an efficient assignment of the sensor tracks, which is reliable, has a reduced error probability and runs essentially automatically, an assignment of a sensor track to at least one system track is always carried out if a decision on the non-correspondence to the system track can not be securely taken. Subsequently, assigned sensor tracks are continuously monitored for the continued assignment thereof to the assigned system track and on determining the non-correspondence thereof, are removed from said system track.
    Type: Grant
    Filed: June 4, 2003
    Date of Patent: August 14, 2007
    Assignee: Atlas Elektronik GmbH
    Inventor: Jörg Bümmerstede
  • Patent number: 7248206
    Abstract: Unknown alignment biases of sensors of a tracking system are estimated by an iterative Kalman filter method. Current measurements are corrected for known alignment errors and previously estimated alignment biases. The filter time reference is updated to produce estimated target state derivative vectors. A Jacobian of the state dynamics equation is determined, which provides for observability into the sensor alignment bias through gravitational and coriolis forces. The target state transition matrix and the target error covariance matrix are propagated. When a new measurement becomes available, the Kalman gain matrix is determined, the state vector and covariance measurements are updated, and sensor alignment biases are estimated. The state vector, covariance measurements, and estimated sensor alignment biases are transformed to an estimated stable space frame for use in tracking the target and updating the next iteration.
    Type: Grant
    Filed: June 10, 2005
    Date of Patent: July 24, 2007
    Assignee: Lockheed Martin Corporation
    Inventors: Jeffrey B. Boka, Peter J. Mavroudakis, Naresh R. Patel
  • Patent number: 7221307
    Abstract: An active or passive sensor observes a region, and generates evidence of the type of target or object viewed. The evidence is processed to determine the prior probability that the object is of a particular type. The prior probability so determined is thresholded to produce an indication of the presence of multiple targets or objects in a range bin, suggestive of shadowing of a target.
    Type: Grant
    Filed: July 8, 2004
    Date of Patent: May 22, 2007
    Assignee: Lockheed Martin Corporation
    Inventor: Mark A. Friesel
  • Patent number: 7199750
    Abstract: A real-time signal processing engine robustly detects, localizes, tracks and classifies ground targets based on radar signals from a multistatic radar system. The system differentiates between different targets based on an optimized cost function, which can include the total returned normalized pulse energy. The local transmitters/receivers can communicate with each other via the transmitted radar signals.
    Type: Grant
    Filed: April 22, 2005
    Date of Patent: April 3, 2007
    Assignee: BBN Technologies Corp.
    Inventors: John Michael Bourdelais, Ernest Scott Stickels, William Ray Wright, David Earl Norris, Michael Anthony Tiberio, Gary Dana Butler
  • Patent number: 7193557
    Abstract: Tracking objects by receiving a dataframe from a detection sensor device, the dataframe containing a timestamp and data corresponding to each detected object, generating new observation nodes for each detected object, propagating group track state parameters to obtain posterior observable positions and projecting them onto the received dataframe, generating gates for the posterior observable positions and projecting them onto the received dataframe, determining feasible track node and feasible observation node assignments based on the proximity of the new observation nodes to the gates, updating track node state parameters and corresponding scores, performing a multi-frame resolution algorithm to resolve group track nodes into subtrack nodes, determining a set of feasible composite assignments for composite sets of track nodes and observation nodes, updating track node state parameters and corresponding scores, and determining a selected set of joint assignments based on the feasible composite assignments and
    Type: Grant
    Filed: April 29, 2004
    Date of Patent: March 20, 2007
    Assignee: Lockheed Martin Corporation
    Inventors: Michael A Kovacich, Thomas R Casaletto
  • Patent number: 7187320
    Abstract: A target tracking arrangement predicts the state of a target. The predictor may be a Kalman filter. In the presence of a target which is maneuvering, the prediction may be in error. A maneuver detector is coupled to receive residuals representing the difference between the predictions and the target state. The maneuver detector is matched to the predictor or Kalman filter to thereby tend to reduce the undesirable effects of system noise. The matching may be of the frequency response.
    Type: Grant
    Filed: August 27, 2004
    Date of Patent: March 6, 2007
    Assignee: Lockheed Martin Corporation
    Inventor: Robert E. Yang
  • Patent number: 7170443
    Abstract: A method for the evaluation of radar data for fully automatic creation of a map of regions with interference, in which undesirable reflections frequently occur includes the following method steps. The region to be mapped is divided up into cells. The short-lived target tracks that occur in these cells are counted. Statistics are kept, in such a manner that the short-lived target tracks are counted only within a predetermined period of time, while all older short-lived target tracks are left out of consideration. At least one threshold value is predetermined, in such a manner that a cell is considered to have been marked if the short-lived target tracks that are counted in the previous time period exceed the threshold value or values. The map of the current regions with interference results as the totality of the marked cells.
    Type: Grant
    Filed: March 2, 2005
    Date of Patent: January 30, 2007
    Assignee: EADS Deutschland GmbH
    Inventors: Dirk Liebscher, Juergen Altmann, Ulrich Lode, Christoph Schenk
  • Patent number: 7161529
    Abstract: Analysis of electromagnetic (or acoustic) multipath propagation inventively focuses upon the transmitter-to-target propagation (transmitted propagation reaching target via both direct pathway and forward scattered pathway) and the target-to-receiver propagation (re-transmitted propagation reaching receiver via both direct pathway and forward scattered pathway). Transmitter-to-target propagation is calculated using conventional multipath modeling technique. The target's overall scattered field is calculated using the calculated transmitter-to-target propagation in conjunction with qualitative electromagnetic/acoustic target information. Target-to-receiver propagation is calculated using conventional multipath modeling technique and/or the reciprocity principle as applied to the calculated transmitter-to-target propagation.
    Type: Grant
    Filed: May 27, 2004
    Date of Patent: January 9, 2007
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Jerry Rosson Smith, Jr.
  • Patent number: 7079991
    Abstract: The present invention relates to the field of target tracking and more generally to a method employing improved algorithms, which achieve excellent tracking performance for a high-g maneuvering target. The two-model Interacting Multiple Model algorithm and the Interacting Acceleration Compensation algorithm will be modified by introducing adaptive factors through the detection of the normalized innovation squared which is chi-square probability distributed. The implementation results show that the modified algorithms can handle the target sudden maneuver better and are more accurate than the original algorithms.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: July 18, 2006
    Assignee: Singapore Technologies Aerospace Ltd.
    Inventors: Luo Wen Li, Chian Poh Lam
  • Patent number: 7071867
    Abstract: Methods, apparatus, and computer program products are provided for tracking at least one moving target with a radar device without requiring the use of Doppler information. The invention comprises scanning an area with radar signals at a first time to receive a first plurality of target data signals indicative of a position of the target at the first time and determining the position of the target at the first time by collecting the first plurality of target data signals into a first target data grouping, such that the first target data grouping defines a first reference point. Similarly, a second reference point for the target is determined for a second time, and the position of the first reference point is compared to the position of the second reference point to track the moving target. Advantageously, the tracked positions of the moving target may be used to predict a future position of the target at a subsequent time.
    Type: Grant
    Filed: June 25, 2004
    Date of Patent: July 4, 2006
    Assignee: The Boeing Company
    Inventors: Peter S. Wittenberg, Aaron Y. Mosher
  • Patent number: 7046190
    Abstract: A method and apparatus for determining range of a radar target is provided. Signal samples based on returns of a target during tracking are processed to produce a wideband envelope range estimate for components of target motion. The components of target motion include precession and spin motion. Ambiguous phase values are measured. An unambiguous phase value indicative of range is produced from the wideband envelope range estimate and measured ambiguous phase values.
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: May 16, 2006
    Assignee: Raytheon Company
    Inventor: Fritz Steudel
  • Patent number: 7046188
    Abstract: Systems and methods of tracking a beam-aspect target are provided. In embodiments, a target is tracked with a Kalman filter while detections are received. After a detection is missed, the Kalman filter may be concurrently propagated with a blind-zone particle filter until a probability that the target is in a blind zone exceeds a threshold. When the probability exceeds the threshold, the Kalman filter may refrain from further propagating. After a gated detection is received, the blind-zone particle filter and an unrestricted-zone particle filter may be concurrently propagated while a probability that the target is in an unrestricted zone exceeds a threshold. The system may return to tracking with the Kalman filter when a covariance of the unrestricted-zone particle filter falls below a predetermined covariance.
    Type: Grant
    Filed: August 14, 2003
    Date of Patent: May 16, 2006
    Assignee: Raytheon Company
    Inventors: David A. Zaugg, Alphonso A. Samuel, Donald E. Waagen, Harry A. Schmitt
  • Patent number: 7030809
    Abstract: A multiple model (MM) radar tracking filter which controls the weighting applied to outputs of first and second model functions responsive to non-Markovian switching logic, includes the first and second model functions, switching logic receiving unweighted outputs from the first and second model functions and generating first and second weighting signals, first and second multipliers generating respective first and second weighted output signals responsive to received ones of the unweighted outputs of the first and second model functions and the first and second weighting signals, and a feed back loop for providing a feedback signal to respective inputs of the first and second model functions responsive to the weighted outputs of the first and second multipliers. If desired, the MM radar tracking filter may also include a summer for generating a signal output responsive to the weighted outputs of the first and second multipliers.
    Type: Grant
    Filed: November 14, 2003
    Date of Patent: April 18, 2006
    Assignee: The United States of America as representd by the Secretary of the Navy
    Inventors: D. Hugh McCabe, A. Sunshine Smith-Carroll
  • Patent number: 7026981
    Abstract: Analysis of electromagnetic (or acoustic) multipath propagation inventively confines the assessment of multipath propagation to a “surface interactive region” (“SIR”), intermediate the target and transmitter and/or the target and receiver. The down range time of the propagation, translatable to range distance, is related to error associated with such restriction. A SIR scope is selected commensurately with acceptable error. Jointly disclosed (practicable therewith or thereapart) is inventive focus upon the transmitter-to-target propagation (transmitted propagation reaching target via both direct pathway and forward scattered pathway) and the target-to-receiver propagation (re-transmitted propagation reaching receiver via both direct pathway and forward scattered pathway). Transmitter-to-target propagation is calculated using conventional multipath modeling technique.
    Type: Grant
    Filed: May 27, 2004
    Date of Patent: April 11, 2006
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventor: Jerry Rosson Smith, Jr.
  • Patent number: 7026979
    Abstract: A method, apparatus, and computer program product for joint kinematic and feature tracking are presented. Kinematic measurements and feature/class measurements regarding an object are received from a sensor. A probabilistic argumentation operation is performed on the feature/class measurements using information from a knowledge base and a track file ect to generate feature track likelihood scores regarding likely tracks for the object. Kinematic track likelihood scores are generated based on the kinematic measurements and the track file. Joint track likelihood scores are generated based on the feature track likelihood scores and the kinematic track likelihood scores. Joint track likelihood scores are used to generate a multi-frame track measurement association to determine a most likely track for the object. The track file is continually updated with the most likely track for the object, so that the most likely trajectory of the object is obtained.
    Type: Grant
    Filed: December 19, 2003
    Date of Patent: April 11, 2006
    Assignee: HRL Labortories, LLC
    Inventor: Deepak Khosla
  • Patent number: 7026980
    Abstract: Sensors determine the kinematic measurements of a boosting missile, and the information is applied to a plurality of pairs or sets of filters, one of which is matched to the characteristics of a particular target type, and the other of which is general, and not matched to a particular target, for producing from each filter of the set missile position, velocity, acceleration, and specific mass flow rate states, and covariances of those states. From the filtered information, the estimates are made of at least missile mass flow rate, thrust, velocity at stage burnout, and remaining burn time. The likelihood is computed that the states and covariances from the filter sets represent the same target. The largest likelihood is selected as representing the target. In one mode, the estimated parameters are weighted and summed for a composite likelihood.
    Type: Grant
    Filed: March 4, 2005
    Date of Patent: April 11, 2006
    Assignee: Lockheed Martin Corporation
    Inventors: Peter J. Mavroudakis, Jeffrey B. Boka, Naresh R. Patel
  • Patent number: 6999601
    Abstract: A target in a sequence of measurements is tracked by modeling the target with a switching linear dynamic system (SLDS) having a plurality of dynamic models. Each dynamic model is associated with a switching state such that a model is selected when its associated switching state is true. A set of continuous state estimates is determined for a given measurement, and for each possible switching state. A state transition record is then determined by determining and recording, for a given measurement and for each possible switching state, an optimal previous switching state, based on the measurement sequence, where the optimal previous switching state optimizes a transition probability based on the set of continuous state estimates. A measurement model of the target is fitted to the measurement sequence. The measurement model is the description of the influence of the state on the measurement. It couples what is observed to the estimated target.
    Type: Grant
    Filed: September 12, 2003
    Date of Patent: February 14, 2006
    Assignee: Hewlett-Packard Development Company, LP
    Inventors: Vladimir Pavlovic, James Matthew Rehg
  • Patent number: 6995705
    Abstract: The present invention is directed to a system and method for Doppler track correlation for debris tracking in PCL radar applications. The disclosed embodiments describe the systems and methods used in the detection of debris pieces and the association of the Doppler signals from the debris pieces across multiple illumination channels. The present invention also provides computation of debris state vectors and the projection of trajectories to determine debris impact points.
    Type: Grant
    Filed: February 7, 2003
    Date of Patent: February 7, 2006
    Assignee: Lockheed Martin Corporation
    Inventors: Bert L. Bradford, Sandra Lodwig, legal representative, Richard Lodwig, legal representative, Richard A. Lodwig, deceased
  • Patent number: 6982667
    Abstract: A geographical region having an object to be tracked is divided into subregions, where adjacent disposed subregions partial overlap one another and the overlapping portions of adjacently disposed subregions share common states. A transition matrix is used to represent the terrain in a subregion and each subregion can have N geographical states and four (4) additional transition states. A regional tracker is used to estimate state sequences for each new observation of the object. Tracking continues until the process is complete or until the probability that the vehicle is in another new subregion occurs. Tracking performed between adjacently disposed subregions is based, at least in part by, the direction represented by the transition state. Tracking into a new subregion from an adjacently disposed old subregion begins precisely where tracking for the old subregion ended using the states that are common in the overlapping portions of the adjacently disposed subregions.
    Type: Grant
    Filed: June 19, 2002
    Date of Patent: January 3, 2006
    Assignee: SAAB AB
    Inventors: Robert Artebrant, Andreas Tyrberg
  • Patent number: 6959103
    Abstract: Provided is a displacement sensor which allows at least part of the data used from the time of obtaining an image until the time of computing the displacement can be readily verified. In a displacement sensor for automatically extracting a coordinate of a measuring point from an image obtained by using an imaging device according to a prescribed measuring point extraction algorithm, and computing a desired displacement from the automatically extracted measuring point coordinate, the sensor is further provided with the function to edit data used from the time of obtaining the image until the time of computing the displacement for use as display data for an image monitor.
    Type: Grant
    Filed: January 29, 2001
    Date of Patent: October 25, 2005
    Assignee: Omron Corporation
    Inventors: Tatsuya Matsunaga, Masahiro Kawachi
  • Patent number: 6888493
    Abstract: A radar comprising transmitter means for generating bursts of radar pulses, each scan of a radar consisting of a number (Nb) of bursts, the method comprises, for each scan k: a first step, in which a radar cell is pre-selected in a validation gate; a second step, in which a Track-Before-Detect processing is initialized upon the pre-selected cells, using a track filter to construct the validation gate associated to the next scan k+1; the steps being repeated scan to scan. The invention can be applied to surveillance radars, for example with multi-beamforming in elevation, and more generally to all kinds of radars.
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: May 3, 2005
    Assignee: Thales Nederland B.V.
    Inventors: Hans Driessen, Wietze Meijer, Jitse Zwaga
  • Patent number: 6864831
    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 26, 2002
    Date of Patent: March 8, 2005
    Assignee: Raytheon Company
    Inventors: Walter Gordon Woodington, Michael Joseph Delcheccolo, Joseph S. Pleva, Mark E. Russell, H. Barteld Van Rees
  • Patent number: 6856272
    Abstract: Methods and apparatus for early detection and identification of a threat such as individuals carrying hidden explosive materials, land mines on roads, etc. are disclosed. Methods comprise transmitting radar signals in the direction of a potential threat, measuring the energy in reflected signals, dynamically generating a threat threshold value from signals received from multiple areas and comparing the energy in the reflected signals corresponding to different areas to the generated threat threshold value. The threat threshold value may be generated by averaging the weighted reflected energy measured from different areas during a single scan of a region including the different areas. The contribution to the threshold from different areas is weighted in some embodiments as a function of the distance from the transmitter and/or receiver to the particular area. Analysis of areas and treating different areas as segments facilitates accurate analysis and display of threat information.
    Type: Grant
    Filed: December 8, 2003
    Date of Patent: February 15, 2005
    Assignee: Personnel Protection Technoloties LLC
    Inventors: Arthur C. Levitan, Lester Kosowsky
  • Publication number: 20040257266
    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 and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.
    Type: Application
    Filed: July 8, 2004
    Publication date: December 23, 2004
    Inventors: Joseph S. Pleva, Mark E. Russell, Walter Gordon Woodington, Michael Joseph Delcheccolo, H. Barteld Van Rees
  • Publication number: 20040233098
    Abstract: A path in three-dimensions for an object in flight is determined according to a radar signal reflected by the object. The radar signal is transmitted at an offset angle from horizontal sufficient to capture the object within the transmitted radar signal. The transmitted radar signal is reflected by the object to form a reflected radar signal containing an indication of a position of the object. The reflected radar signal is received and used to determine two-dimensional position information for the object by detection of the indication of the position of the object in the received radar signal. Position information is derived in three-dimensions from the position information in two-dimensions. The path information representative of the path for the object is obtained from the position information in three-dimensions based on an optimization of a curvature of said path information.
    Type: Application
    Filed: June 17, 2004
    Publication date: November 25, 2004
    Inventors: Rhonda L. Millikin, Joseph R. Buckley
  • Patent number: 6801156
    Abstract: A monopulse radar system generates elevation and azimuth difference monopulse estimates of the location of targets in each range cell, where the target may be either a single or plural target, each of which is made up of multiple scattering sources. Each azimuth-elevation estimate is based on a transmitted pulse or burst at a given frequency, different from other frequencies in a set of pulses or bursts. A test statistic is generated for each set. The statistic relates to the shape in an azimuth-elevation plane of the cluster of estimates. The test statistic is compared with a threshold to decide whether a single target or plural targets exist in the range cell.
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: October 5, 2004
    Assignee: Lockheed Martin Corporation
    Inventor: Richard Wasiewicz
  • Publication number: 20040183712
    Abstract: Methods and apparatus for early detection and identification of a threat such as individuals carrying hidden explosive materials, land mines on roads, etc. are disclosed. Methods comprise transmitting radar signals in the direction of a potential threat, measuring the energy in reflected signals, dynamically generating a threat threshold value from signals received from multiple areas and comparing the energy in the reflected signals corresponding to different areas to the generated threat threshold value. The threat threshold value may be generated by averaging the weighted reflected energy measured from different areas during a single scan of a region including the different areas. The contribution to the threshold from different areas is weighted in some embodiments as a function of the distance from the transmitter and/or receiver to the particular area. Analysis of areas and treating different areas as segments facilitates accurate analysis and display of threat information.
    Type: Application
    Filed: December 8, 2003
    Publication date: September 23, 2004
    Inventors: Arthur C. Levitan, Lester Kosowsky
  • Publication number: 20040150551
    Abstract: A method for target-tracking of objects via observations from a sensor, wherein a geographical region within which at least one object is present is divided into a predetermined number of states, and the geographical region is divided into subregions so that adjacently disposed subregions all contain a share of states in common. Target-tracking is initiated in a first subregion, whereupon a first observation is associated with the object, and the probable state of the object is estimated. For each new time interval, a new observation is chosen for which a new state is estimated, whereupon the estimated sequence of states in the subregion is updated. When target-tracking is begun in a new subregion, the state history from the preceding subregions is transferred to the new adjacent subregion so that the state estimate in the new subregion is based on the state history in the preceding adjacent subregions.
    Type: Application
    Filed: December 23, 2003
    Publication date: August 5, 2004
    Inventors: Robert Artebrant, Andreas Tyrberg
  • Patent number: 6771205
    Abstract: A combined defense and navigational system on a naval vessel is disclosed. The disclosed system includes a track-while-scan pulse radar which is controlled to provide either navigational information or tracking information on selected targets. Additionally, the disclosed system includes a plurality of guided missiles, each of which may be vertically launched and directed toward intercept of a selected target either by commands from the track-while-scan radar or from an active guidance system in each such missile.
    Type: Grant
    Filed: August 1, 1979
    Date of Patent: August 3, 2004
    Assignee: Raytheon Company
    Inventors: David K. Barton, Benjamin L. Young
  • Publication number: 20040130480
    Abstract: The present invention relates to a system for using signals scattered by targets to determine position and velocity for each of the targets and comprises a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points. Each pair of transmitter and receiver, mono-static or bi-static, is named a measuring facility. The ranges of the transmitters are chosen so that a target at an arbitrary point within the position space can be measured via scattering in the target by at least four, but preferably many more, measuring facilities.
    Type: Application
    Filed: November 10, 2003
    Publication date: July 8, 2004
    Inventor: Hans Hellsten
  • Patent number: 6750806
    Abstract: A method of tracking a target (2) moving in an airspace and a target tracking system (10) for performing the method are described. A search sensor (12) searches a search space at a first clock rate (2&pgr;/&Dgr;T1) and establishes target information in regard to a track (4) flown through by the target (2). Calculation means (16) extrapolate an expected flight path (6) from the target information established and provide flight path data, which describes the expected flight path (8), to a tracking sensor (14), which covers a tracking space (15), and provides this data at a second clock rate (2&pgr;/&Dgr;T2), which is higher than the first clock rate (2&pgr;/&Dgr;T1). When the target (2) reaches the tracking space (15), the tracking sensor (14) is aimed at the expected flight path (6) on the basis of the flight path data provided, the target (2) is detected as soon as it is detectable by the tracking sensor (14), and the tracking sensor (14) is tracked on the target autonomously.
    Type: Grant
    Filed: June 3, 2003
    Date of Patent: June 15, 2004
    Assignee: Oerlikon Contraves AG
    Inventor: Pierre Fischer
  • Publication number: 20040075605
    Abstract: The present invention is directed to a system and method for Doppler track correlation for debris tracking in PCL radar applications. The disclosed embodiments describe the systems and methods used in the detection of debris pieces and the association of the Doppler signals from the debris pieces across multiple illumination channels. The present invention also provides computation of debris state vectors and the projection of trajectories to determine debris impact points.
    Type: Application
    Filed: February 7, 2003
    Publication date: April 22, 2004
    Applicant: Lockheed Martin Corporation
    Inventors: Bert L. Bradford, Richard A. Lodwig, Sandra Lodwig, Richard Lodwig
  • Patent number: 6694044
    Abstract: Portions of an input measurement sequence are classified into a plurality of regimes by associating each of a plurality of dynamic models with one a switching state such that a model is selected when its associated switching state is true. In a Viterbi-based method, a state transition record is determined, based on the input sequence. A switching state sequence is determined by backtracking through the state transition record. Finally, portions of the input sequence are classified into different regimes, responsive to the switching state sequence. In a variational-based method, the switching state at a particular instance is also determined by a switching model. The dynamic model is then decoupled from the switching model. Parameters of the decoupled dynamic model are determined responsive to a switching state probability estimate. A state of the decoupled dynamic model corresponding to a measurement at the particular instance is estimated, responsive to the input sequence.
    Type: Grant
    Filed: September 1, 2000
    Date of Patent: February 17, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Vladimir Pavlović, James Matthew Rehg
  • Publication number: 20040027274
    Abstract: A radar comprising transmitter means for generating bursts of radar pulses, each scan of a radar consisting of a number (Nb) of bursts, the method comprises, for each scan k:
    Type: Application
    Filed: March 27, 2003
    Publication date: February 12, 2004
    Inventors: Hans Driessen, Wietze Meijer, Jitse Zwaga
  • Patent number: 6687606
    Abstract: A method analyzes a plan for scanning the content of a predetermined area. The method includes the steps of: providing a plan for at least one entity (200), the plan including a route and a set of scan points; and assigning an associated score for the plan in order to compare the plan to other plans, the score indicating the quality of the plan.
    Type: Grant
    Filed: February 21, 2002
    Date of Patent: February 3, 2004
    Assignee: Lockheed Martin Corporation
    Inventors: Abha Moitra, Robert M. Mattheyses, Robert J. Szczerba, Louis J. Hoebel, Virginia A. Didomizio, Boris Yamrom
  • Patent number: 6683968
    Abstract: A target in a sequence of measurements is tracked by modeling the target with a switching linear dynamic system (SLDS) having a plurality of dynamic models. Each dynamic model is associated with a switching state such that a model is selected when its associated switching state is true. A set of continuous state estimates is determined for a given measurement, and for each possible switching state. A state transition record is then determined by determining and recording, for a given measurement and for each possible switching state, an optimal previous switching state, based on the measurement sequence, where the optimal previous switching state optimizes a transition probability based on the set of continuous state estimates. A measurement model of the target is fitted to the measurement sequence. The measurement model is the description of the influence of the state on the measurement. It couples what is observed to the estimated target.
    Type: Grant
    Filed: September 1, 2000
    Date of Patent: January 27, 2004
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Vladimir Pavlović, James Matthew Rehg
  • Publication number: 20040008137
    Abstract: Correlating observations of objects in the sky to determine an orbit includes identifying an initially identified object, determining if the initially identified object will be identifiable again, and identifying a subsequently identified object. A determination is then made by comparing characteristics of the initially identified object with the subsequently identified object. If the object correlate to one another a path or orbit of the object can be determined using the characteristics of the initially identified object and the subsequently identified object.
    Type: Application
    Filed: July 12, 2002
    Publication date: January 15, 2004
    Applicant: ITT Industries
    Inventors: Alan W. Hassebrock, J. Wayne Porter
  • Publication number: 20030218565
    Abstract: An adaptive broadcast radar system for tracking targets is disclosed, the radar system includes a transmitter having sub-apertures and a receiver having sub-apertures. The transmitter sub-apertures generate and code a signal waveform. The signal waveform is coded with data about the transmitter, including the degrees of freedom. The receiver receives signals comprising direct path signals and scattered signals correlating to the signal waveforms from the transmitter. The receiver includes a signal processor that regenerates a transmit beam for the coded data, delay, and doppler information from the received signals. The signal processor generates data quads encapsulating the information.
    Type: Application
    Filed: November 28, 2001
    Publication date: November 27, 2003
    Applicant: Lockheed Martin Mission Systems
    Inventor: Robert D. Budic
  • Publication number: 20030189512
    Abstract: A system and method for detecting a target. The inventive method includes the steps of receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component; extracting from the imaginary component information representative of the phase component of the return signal; and utilizing the phase component to detect the target. Specifically, the phase components are those found from the complex range-Doppler map. More specific embodiments further include the steps of determining a power spectral density of the phase component of the return signal; performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray (quadrant channels); and averaging the cross-correlated power spectral density of the low frequency components. In an alternative embodiment, the cross-correlation is performed on the phase component of the range-Doppler map directly.
    Type: Application
    Filed: April 4, 2002
    Publication date: October 9, 2003
    Inventors: Hai-Wai Chen, Harry A. Schmitt, George T. David, Dennis C. Braunreiter, Alphonso A. Samuel, Judith L. David
  • Publication number: 20030174088
    Abstract: This invention relates to an adaptive detection system and method for analyzing range-doppler-azimuth data for target detection. The detection system has a threshold calculator for calculating a threshold value that is based on the standard deviation of the range-doppler-azimuth data and a predetermined probability of detection. The detection system also has a detection module in communication with the threshold calculator to receive the threshold value. The detection module calculates an estimated target amplitude and an estimated noise floor amplitude based on the range-doppler data that is located in a detection window. The detection module detects a target when the difference between the estimated target amplitude and the estimated noise floor amplitude is larger than the threshold value.
    Type: Application
    Filed: March 7, 2003
    Publication date: September 18, 2003
    Inventors: Reza Dizaji, Tony Ponsford
  • Publication number: 20030156056
    Abstract: An HF radar system comprises a transmitting system, a receiving system, a signal processing system and a frequency management/ionospheric sounding system. The transmitting system comprises a transmitting antenna array configured to transmit a beam in a near vertical direction and a transmitting device arranged to drive the transmitting antenna array at frequencies suitable for downward refraction by the ionosphere. The receiving system comprises a receiving antenna array configured to receive returning signals from a target area returning to the receiving antenna array via refraction at the ionosphere. The signal processing system comprises a digital data processing system. The frequency management/sounding system comprises cooperating transmitting and receiving systems sending H-F signals to the ionosphere and analysing the returning signals. Alternatively, the system may have a duplexed antenna array.
    Type: Application
    Filed: January 7, 2003
    Publication date: August 21, 2003
    Inventor: Kenneth H Perry
  • Patent number: 6591146
    Abstract: From a set of possible switching states and responsive to a sequence of measurements, a corresponding sequence of switching states is determined for a system having a plurality of dynamic models, associates each model with a switching state such that a model is selected when its associated switching state is true. A state transition record is determined, based on the measurement sequence. The sequence of switching states is determined by backtracking through the state transition record. Alternatively, the switching state model is decoupled from the dynamic system model. The decoupled switching state model is transformed into a hidden Markov model (HMM) switching state model, while the decoupled dynamic system model is transformed into a time-varying dynamic system model. A solution to the dynamic system model is estimated using a Kalman filter.
    Type: Grant
    Filed: September 1, 2000
    Date of Patent: July 8, 2003
    Assignee: Hewlett-Packard Development Company L.C.
    Inventors: Vladimir Pavlović, James Matthew Rehg
  • Patent number: 6577238
    Abstract: A system 100 is disclosed for monitoring the position of one or more RFID tags 201. The system has a detector 301 incorporating circuitry 304 for detecting changes in the range of an RFID tag 201 from the detector and for triggering an alarm 401 if a detected change in range of an RFID tag 201 exceeds a predetermined threshold or if the RFID radio tag cannot be detected by the detector 301. Range may be detected, for example, by measuring the time of a returned radio signal from a tag 201, by measuring the strength of a returned radio signal from a tag, or by detecting changes in a periodic interval at which energy is transmitted by a tag.
    Type: Grant
    Filed: March 1, 2001
    Date of Patent: June 10, 2003
    Assignee: Tagtec Limited
    Inventors: Howard William Whitesmith, Timothy John Palmer, Alan Edward Ball