Abstract: A terrain reference navigation system for an aircraft, surface vessel or subsurface vessel utilizing three sets of geo-physical correlation data. A kalman filter is used to correlate terrain data, electromagnetic data and gravimetric data with the output of a digital map of terrain, electromagnetic field and gravity. An optical disk stores the digitized data for sections of the globe. A Best of 3 selection process decides based on the errors in the kalman filter whether to accept the prediction of the terrain system, electromagnetic system or gravity system. An inertial navigation system uses the results of the Best of 3 selection to update aircraft, surface vessel or sub-surface vessel position and velocity and provide a more accurate positional estimate.

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.

Abstract: A system (10) and method for matching a set of detected points (26) to a reference constellation (20). A programmable processor (14) receives detected coordinate locations from a sensor (16) and reference coordinate locations from a reference storage device (12). The processor (14) performs a coordinate transformation from the reference coordinate frame to the detected coordinate frame and contructs a table of possible matches. Potential matches are found from the possible matches which have their difference vectors below a predefined threshold. These possible matches are then placed in a match matrix histogram (30) which is further refined to eliminate all but the best matches. The final matching then may be used to find a particular aimpoint (24) in the detected constellation (26).

Abstract: An airborne system is disclosed for determining the position of an aerial vehicle. According to the invention, a first memory is provided containing the general characteristics of different types of discrete landmarks and a second memory containing the geographic position of such landmarks on the ground to be flown over, a device for extracting, from the signals delivered by sensitive means, the general characteristics of said different types of discrete landmarks located on the ground being flown over, and a device for computing from the signals delivered by said sensitive means the relative positions of said vehicle with respect to said recognized landmarks, which it feeds to Kalman filter means.

Abstract: The recoverable airborne instrument module is implemented using an aerodynamic housing which has at least one moveable control surface thereon. In operation, the recoverable instrument module is carried aloft by balloon to enable its instrument package payload to perform a series of meteorological measurements. The exterior housing of the recoverable instrument package has an aerodynamic shape, such as a delta wing airframe with a controllable rudder. A navigation circuit contained within the housing references the radio frequency transmissions of a plurality of beacons to determine the altitude and geographic position of the instrument package. This information, as well as data identifying the location of at least one predetermined landing site is used to dynamically calculate a flight path to controllably descend the instrument module to a selected one of these landing sites.

Abstract: A method and apparatus are described for image matching, particularly for increasing match information in scene matching navigation systems. The invention correlates a sequence of sensed images with a reference map and stores the resultant correlation surfaces. The correlation surfaces are then added so that match point correlations combine coherently by superposing the individual correlation surfaces using short term accurate navigation data. As a result, a composite correlation surface is formed in which the values at the peak (or antipeak) position add up and the effective match area is greatly increased. Both peaks and antipeaks are then detected to determine a match point and provide a navigation position update.

Abstract: A method of using a method for navigating and updating of navigation for aircract under utilization of sensor image processing and reference store data, for purposes of automatic or assisted landing is disclosed.

Abstract: A method for navigation and updating of navigation for aircraft uses range image processing and a reference store, segmentizing the range image data are segmentized in order to obtain a particular pattern of type features for purposes of classifying particular types of objects across which the craft flies; extracting particular signature features including localized elevational jumps and determining the position of the craft by correlating a plurality of features and their spatial orientation to each other as extracted with corresponding stored reference information in order to provide a maximum fit that is indicative of deviation of the flight from a flight path as identified by the reference information.

Abstract: A method for aircraft navigation which includes, sensor signal processing with refernce data. The method provides for sensing and range finding the elevational profile underneath the craft. Those elevational data are fed to a segmentizing and type classifying unit whose output in turn is fed to a classifying unit, and that the position of the craft is determined by comparing the segmentized overflight strip with corresponding topographic features in reference information.

Abstract: A method of aligning two images of the same scene by matching features in a first image to features in a second image is disclosed. The method comprises identifying edges of objects in the first image using two different processes. The edges identified using both processes are compared and combined into one image representing confirmed edges which are readily identified in other images of the same scene. A template is then formed from the confirmed edges which is matched to a subregion of the second image.

Abstract: A device for correcting the flight path of an air to surface missile and ding said missile to a target. A first map of a strip of ground which is transverse to the direction of flight is provided on a rotatable drum along with a second map of a strip of ground which is parallel with the direction of flight. A live image of the ground over which said missile is traveling is projected first through the first map to provide a position fix of the missile in range and azimuth relative to a target and after a correction has been made to the flight path of the missile, the live image of the ground is projected through the second map to provide guidance correction to direct the missile to the target.

Abstract: A method of identifying and detecting remote objects by transmitting wave energy and receiving wave energy reflected from the object. Separate signal parameters pertaining to the wave energy received are processed forming a measured signature of the object. The measured signature is compared with a number of prestored signatures having the same signal parameters relating to known objects of interest. A recording is made of which prestored signatures correspond to the measured signature within predetermined tolerances. Subsequent transmission and reception of wave energy is used for updating the separate parameters and the measured signature. The updated measured signature is compared with the recorded prestored signatures for updated recording of a smaller number of prestored signatures corresponding to the updated measured signature within the predetermined tolerances.

Abstract: The image pipeline for a vision system includes a series of digital image processing boards controlled by a computer. A video camera generates from a laser beam reflected from the target surface an RS-170 analog video signal which is converted to a digital signal for processing. Bins of digitizing parameters suitable for several target surface reflectivities are stored in computer memory. The appropriate bin is selected from histogram data of pixel intensity levels generated by one of the image processing boards using digitizing parameters from a reference bin. Improved imaging, especially of black surfaces, is achieved by scanning a laser beam to generate a light stripe over a number of image frames using the digitizing parameters from the selected bin and integrating the data from the successive frames using the image processing boards.

Abstract: A drift correction mechanism for a vehicle (e.g. aircraft) navigation system makes use of a digital map data base, in order to correct for errors in position estimates, so that the estimated flight path of the aircraft will more closely track its actual flight path, and thereby effectively compensate for the long term error to which the navigation system is subjected. During the flight, altimeter readings are periodically carried out in order to generate elevation values that are representative of the actual elevation of the terrain over which the aircraft is flying. These elevation values are then used as inputs to a digital map database, from which elevation profile contour lines of respective elevation values may be derived. At the time that a respective altimeter reading is effected, the position estimate output of the aircraft's navigation system is also sampled.

Abstract: An item of interest may be located in a scene image by scanning a reference image containing the item (extracted from a previous image of the scene for example) over the scene image and, for each position of the reference image, correlating corresponding pairs of pixels from the reference and scene images. Herein, to avoid inaccuracies due to bright spots say affecting a small portion of the scene image, for each position of the reference image, all the pixel pairs are correlated and an average similarity value assigned to that reference image position.

Abstract: A system which combines intensity area correlation is disclosed for use with terrain height radar and infrared emissivity systems to give a simultaneous three-mode map matching navigation system. The infrared system senses passive terrain emissions while the height finding radar measures the time between transmission of a radar signal to the ground and receipt of a radar return. The intensity correlator uses the radar returns to sense changes in the reflection coefficient of the terrain. Map matching all three modes simulanteously provides an accurate, highly jam resistant position determination for navigation update.

Abstract: A method of navigation and serial guidance under utilization of elevational data correlation, wherein a correlator compares terrain specific elevational reference data, with actually acquired and processed altitude data, is improved by using a millimeter wave sensor operating in the atmospheric window of about 94 gigahertz; and being operated during cruising by back and forth scanning in a substantially vertical down direction across a prescribed flight path; occasionally the sensor is pivoted about a horizontal axis, for scanning in the forward direction in a forward search mode for purposes of target acquisition.

Abstract: Certain man-made structures located in a complex background, such as railroad ties, telephone poles, and fences are detected by a flying craft, using a low powered structure resonant radar system. The radar system transmits a radar signal which includes wavelengths of the same order of magnitude as twice the spacing of the elements of the man-made structure or grating multiples thereof, and transmits them in a plurality of different directions and frequencies. Reflections of the transmitted radar are received and structural resonance backscatter is detected wherein the backscatter amplitude at the resonant frequency is much higher than that at adjacent frequencies or that of the clutter background, indicating the presence of the search-for type of structure. The bright structural resonance backscatter can then be exploted by the structure resonant radar for guidance, homing, etc.

Abstract: A method of processing images taken by an endoscope having insertion section, bending section and operation section including a step of entering a first image of an object taken by the endoscope having the bending section situated in a first position, a step of entering a second image taken by the endoscope having the bending section situated in a second position, after moving the bending section into the second position by operating an operation member, the first image being partially overlapped with the second image, a step of detecting a positional relation between the first and second positions by detecting the movement of the bending section, a step of deriving a distance between corresponding points on the first and second images, a step of deriving three dimensional information of the object, and a step of displaying a three dimensional image of the object in accordance with the three dimensional information.

Abstract: An aircraft microwave altimeter system has a threshold detector with two parallel channels that provide two sets of output signals at two different levels of sensitivity. The signals at the higher sensitivity are supplied to a display whereas those at the lower sensitivity are supplied to a navigation system. A comparator indicates a fault in the system if the two sets of output signals differ by more than a predetermined amount.

Abstract: A method and apparatus for the identification of spatial patterns that occur in two or more scenes or maps. Each pattern comprises a set of points in a spatial coordinate system collectively represented by the geometrical figure formed by connecting all point pairs by straight lines. The pattern recognition process is one of recognizing congruent geometrical figures. Two geometrical figures are congruent if all the lines in one geometrical figure are of the same length as the corresponding lines in the other. This concept is valid in a spatial coordinate system of any number of dimensions. In two- or three-dimensional space, a geometrical figure may be considered as a polygon or polyhedron, respectively. Using the coordinates of the points in a pair of congruent geometrical figures, one in a scene and the other in a map, a least squares error transformation matrix may be found to map points in the scene into the map.

Abstract: A contour line generator for identifying and displaying real time elevation contour lines for use with a moving map display. A plurality of data points neighboring a selected data point are compared to determine the presence or absence of a contour line. An average elevation is computed and applied to address a contour memory, having stored therein the elevations at which contour lines are desired to be displayed. The resultant logic signals are applied dynamically to override normal display data when a contour line is to be generated. The system provides programability for flexibility in modifying contour line intervals.

Abstract: A technique for the real-time computer generation of visual scenes of rolling terrain and sea waves is based on a view ray approach wherein an azimuth sweep is defined and an image profile is generated by incrementing range steps from the view point but employs a data base which is an on-line math model consisting of a summation of cosine functions rather than a grid data base. Math models are generated separately for both land and sea elevation posts for the scene to be generated. A horizontal field of view is defined as a predetermined number of increments between sweeps perpendicular to a boresight from a view point, and a vertical field of view is defined as a predetermined number of increments between view rays perpendicular to the boresight from the view point. The change in range is incremented along the boresight from the view point, and for each range increment, the view ray is stepped down by an increment corresponding to an incremental change in the tangent of the view angle.

Abstract: A method of navigating an airborne vehicle using observation of linear features such as roads, railroads, rivers or the like. Maps of linear features in several discrete areas along an intended flight path are prepared and entered into an on-board computer memory. The vehicle typically uses an inertial navigation system during flight from the origin to the first mapped area. Imaging sensors and on-board processing detect linear features as the vehicle approaches or passes over them. The sensed feature pattern network is compared to the reference mapped feature network to update the inertial navigation system to generate guidance commands. Frequent updates at other mapped areas keep the vehicle on course. This system is also capable of navigation updates from single linear features when the flight path is fairly well known, and of tracking a linear feature for terminal guidance. In these cases, only a small number of feature parameters need to be stored, rather than an area map.

Abstract: Improved radar guidance system for the navigation apparatus of an aircraft s it flies over substantially flat terrain with random and different features. The system is generally made up of an airborne radar altimeter, a video signal processor and a master processor. The altimeter transmits a series of pulses at predetermined time intervals for impacting a plurality of spaced points along the aircraft ground track. The echo signal of each pulse-impacted point processor divides the amplified signal into corresponding signals. A comparator of the signal processor transforms one of the divided signals into a constant output. A track and hold arrangement of the signal processor correlates the delayed leading edge of the comparator output with the other of the divided signals so as to determine a point of intersection therebetween.