Texas Instruments Corporation

Other

Raytheon Company

William C Choate

Rajendra K Talluri

Charles Emil Frey

Anthony K Tyree

David S Ho

Dileep P Bhandarkar

James Anthony Jungmann

A method and apparatus is disclosed for determining the range between two planes, ownship () and target (). Model data () estimating the velocity and position of target () is compared to actual flight path data of the target () passively received by ownship (). The model data () and actual data is compared, and an error measurement is calculated. The model data is also subject to position and velocity constraints (and) which penalize unrealistic estimates. The error measurement and penalties are used to create a perturbation model () which is added to the model data to generate new model data. When the model data () conforms closely to the actual data, a range is computed from the model data ().

Method and apparatus for air-to-air aircraft ranging

A method for inferring precise sensor attitude information in a tracking sensor system begins with storing at a first time a reference image in a memory associated with tracking sensor. Next, the method includes sensing it a second time second image. The sensed image comprises a plurality of sensed feature locations. The method further includes determining the position of the tracking sensor at the second time relative to its position at the first time and then forming a correlation between the sensed feature locations and the predetermined feature locations as a function of the relative position. The method results in an estimation of a tracking sensor pose that is calculated as a function of the correlation. Because the method is primarily computational, implementation requires no new hardware in a tracking sensor system other than that which may be required to provide additional computational capacity.

Method of inferring sensor attitude through multi-feature tracking

A method and system are provided for relating a passive sensor (14) to a geographic environment (42, 44). The passive sensor (14) senses an image (40) of the geographic environment (42, 44). At least one feature (46) is extracted (26) from the image (40). At least one feature is generated (30) from map data (28) representative of the geographic environment. At least one extracted feature is related (22, 32) to at least one generated feature, such that the passive sensor (14) is related to the geographic environment (42, 44).

System and method for relating a passive sensor to a geographic

A method for inferring precise sensor attitude information in a tracking sensor system begins with storing at a first time a reference image in a memory associated with tracking sensor. Next, the method includes sensing at a second time a second image. The sensed image comprises a plurality of sensed feature locations. The method further includes determining the position of the tracking sensor at the second time relative to its position at the first time and then forming a correlation between the sensed feature locations and the predetermined feature locations as a function of the relative position. The method results in an estimation of a tracking sensor pose that is calculated as a function of the correlation. Because the method is primarily computational, implementation requires no new hardware in a tracking sensor system other than that which may be required to provide additional computational capacity.

A method of tracking targets across a sequence of images estimates the range of these tracked objects from the camera. The method assumes the motion of the camera between the successive frames is known. The distance from the sensor to the object is assumed to be much larger than the physical dimensions of the object. The method and system make use of the known sensor motion to generate 'expected images' that are then used to establish a reliable correspondence and track the targets across the image sequence. The method and system use a mean/energy-normalized area correlation technique to establish inter-frame correspondence. With this correspondence, two new methods can estimate the range of the target from the sensor.

Method and system for image-sequence-based target tracking and range

A method and system for covertly determining and predicting air-to-air target data relative to a predetermined position passively senses the target (84) to produce a passive target data set. Next, the method and system transform (14) the passive target data set to produce a transformed passive data set. Then, the system compares (22) the transformed passive data set to a predicted data set (20) to generate a measurement error. By actively sensing (38 and 40) the target for a minimally detectable period (42) of time to produce an active target data set (28), the system applies constraints (28) and therefrom computes penalties (26) that relate to the measurement error (22) to produce a system error. Then, in response to the system error (24) the method and system compute the direction (30) and magnitude (32) for a perturbation or a response (44) to the predicted target data (18). These steps are repeated to covertly determine target data relative to the predetermined position (16) for improved covert air-to-air ranging.

Covert ranging method and system

An emitter location system includes a single carrier based first and second short baseline interferometers, and a long baseline interferometer operatively connected to a computing means. The computing means includes a three level processor. The short baseline interferometers provide phase measurements for level one combination into total phase measurements and estimates of the angle of incidence of the incoming electromagnetic energy. After test for acceptance, the estimated angle of incidence is passed for level two processing which includes the simultaneous processing of the estimated incident angle with the phase measurement of the long baseline interferometer for error correction to provide an improved estimated incident angle. After test for acceptance, the improved angle of incidence measurement is passed for determining the angle of the incident wave for level three processing. Level three processing utilizes the bearing estimates and the carrier position and heading information for an inertial navigation system to relate the information to a fixed coordinate system. Then the location of the emitter is determined using least square method.

Coherent electromagnetic energy emitter locator

Edge maps (40) derived from images are used to compute edge spectra (44), an edge spectrum having a plurality of components (41, 43) corresponding to the angular bins (60) of edge vectors having equal angular widths. Various feature detectors (56) process the edge spectrum to yield information identifying the image. A linear detector correlates a shifted prototype edge spectrum (45) to an input spectrum (44). Nonlinear detectors analyze edge spectra to detect mutually orthogonal edges and edge reversal features (90). Higher level logic (30) is used to select certain detected edge reversal features (90) as the ends of an object (16) depicted in the image.

Method and apparatus for detecting edge spectral features

A CCD imager is provided with an adaptive threshold circuit. The variations in the illumination across the document being read by the imager are compensated for by the adaptive threshold circuit to accurately provide an accurate digital representation of the image on the document.

CCD Imager

A small programmable memory means such as an electrically programmable logic array is incorporated on the chip of a conventional bit addressable random access memory or other cell addressable array circuit. The array has one or more superfluous rows and/or columns of cells held in reserve. Processing and testing of the chip is conducted in a conventional manner. Chips with faulty cells are corrected by programming the memory means with the cell addresses of the faulty cell locations. Subsequently, the memory means will respond to any of these addresses and, through interaction with either the address decoding logic or input/output logic, cause a reserve cell or the contents thereof to be selected instead of the faulty cell.

Fault-tolerant cell addressable array

A small programmable memory means such as an electrically programmable logic array is incorporated on the chip of a conventional bit addressable random access memory or other cell addressable array circuit. The array has one or more superfluous rows and/or columns of cells held in reserve. Processing and testing of the chip is conducted in a conventional manner. Chips with faulty cells are corrected by programming the memory means with the cell addresses of the faulty cell locations. Subsequently, the memory means will respond to any of these addresses and, through interaction with input/output logic, cause the data input and/or output to be steered to or from a reserve cell instead of the addressed faulty cell.

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Dallas, TX, United States of America

William C Choate