Abstract: The present invention relates to a system for sweeping a laser beam in a preset pattern, while, at the same time, directing the pattern to any area in a predetermined scanning area. The invention is particularly useful in LADAR applications. In one version of the invention, a series of optical prisms are arranged in concentric tubes so that the prisms have a common optical path. The tubes and, hence, the prisms, may be independently rotated by precision electric motors coupled to gear rings on the tubes.

Abstract: An apparatus to determine the three-dimensional location of an airborne platform relative to a target area using two separate antenna assemblies positioned on the airborne platform. The first antenna assembly is adapted to transmit energy downward toward a surface location directly beneath the airborne platform, while the second antenna assembly is adapted to transmit energy forward towards the target area remote from the surface location. A single transmitter is associated with both of the antenna assemblies for transmitting signals toward the surface location and the target area. A receiver coupled to the antenna assemblies receives and detects the signals corresponding to the transmitted energy as reflected by the target area and the surface location. A radar processor is coupled to the receiver and is adapted to determine the range between the airborne platform and the surface location and determine the three-dimensional height of the target area from the detected signals.

Abstract: A winged bomb is launched from a launch aircraft and glides to a target. During the glide the winged bomb follows a calculated guide path stored in a on board computer, with correction generated by the computer using data from an altimeter and global positioning receiver. Near the termination of the glide a television camera is activated and transmits signals to a remote location from which final correction are manually generated and transmitted by radio to the bomb. The bomb is designed with low radar cross section.

Abstract: One aspect of the invention relates to a laser ranging system.

Abstract: A baro altitude and terrain warning system with an integrity monitoring function which uses a radar altimeter to generate instantaneous altitude signals used to confirm the validity of a baro altitude signal, generated by a baro altimeter and an expected terrain clearance signal, provided by the terrain warning system, and for generating an alert when insufficient correlation exists between such signals.

Abstract: In missile guidance systems, knowledge of the target's flight policy and doctrine, along with an analysis of local topographic features, are used in a minimum commitment guidance policy. By assuming certain objectives of the target, paths may be defined by evaluating the degree of detection avoidance provided by the terrain adjacent to the various paths. To maximize the probability of intercept, a missile may be guided in a direction covering the most likely of these paths for periods while the target is hidden. The paths are then reevaluated each time the target is detected. For highly maneuverable targets that are capable of executing violent changes in direction and speed, the topography-aided guidance system maximizes the probability that the target can escape the missile intercept envelope.

Abstract: The invention is a method and apparatus for generating navigation data.

Abstract: A sensor system for providing a cartographic overlay on a displayed sensor image for a current location within a selected region. The sensor system includes a sensor for generating the sensor image and a location device for generating a location signal corresponding to the current location of the sensor. Additionally, the system includes a storage device in electrical communication with the location device wherein the storage device electronically stores cartographic data for the selected region. The cartographic data consist of titles and symbols for known objects in the region. The storage device is operative to generate a map data signal corresponding to the cartographic data based on the location signal. The system further includes a display in electrical communication with the sensor and the storage device for presenting a final image. The display produces a final image that consists of the sensor image superimposed with cartographic data based upon the map data signal.

Abstract: A missile includes a fuselage with a roll axis and a nod axis perpendicular to the roll axis, and a conformal window mounted to a forward-facing end of the fuselage. There is a sensor system with a field of regard through the window and a line of sight, and a sensor system pointing mechanism affixed to the airframe and upon which the sensor system is supported. The sensor system pointing mechanism includes a gimbal structure having a first degree of rotational freedom about the roll axis and a second degree of rotational freedom about the nod axis, and a linear translational mechanism connected to the sensor system. The linear translational mechanism is operable to translate the sensor system away from the window with increasing angular deviation of the line of sight of the sensor system from the roll axis. Preferably, the translational mechanism is a slider-crank mechanism.

Abstract: A clear air turbulence (CAT) detection system performs a nested grid modeling algorithm to detect CAT along the flight path of an aircraft. The aircraft stores coarse simulation information and utilizes the information to perform large scale weather modeling over a large grid. On board sensors are utilized to generate observational information to model atmospheric conditions within a smaller grid, nested within the larger grid, and including the flight path of the aircraft. A nowcast predicting turbulence along the flight path in the near future alerts the pilot to the likelihood of encountering clear air turbulence. A data link may be utilized to receive coarse simulation data or observational data from sources external to the aircraft. Additionally, the coarse simulation information may include turbulence forecast data and the observational information is used to refine the turbulence forecast to more accurately predict clear air turbulence along the flight path of the aircraft.

Abstract: A positioning and ground proximity warning method for vehicle includes the steps of outputting global positioning system signals to an integrated positioning/ground proximity warning system processor; outputting an inertial navigation solution to an integrated positioning/ground proximity warning processor; measuring air pressure, and computing barometric measurements which is output to the integrated positioning/ground proximity warning processor; measuring time delay between transmission and reception a radio signal from a terrain surface, and computing radio altitude measurement which is output to the integrated positioning/ground proximity warning processor; accessing a terrain database for obtaining current vehicle position and surrounding terrain height data which is output to the integrated positioning/ground proximity warning processor; and receiving the position, velocity and time information or said pseudorange and delta range measurements of said global positioning system, the inertial navigation s

Abstract: An image sensor attached to an aircraft generates an image. The image includes a runway and other objects. The edges within the image are detected and Nav Data is used to predict the coordinates defining the runway. The predicted coordinates and the detected edges are correlated to determine the location of the runway within the image. The location of the runway within the image is then used to determine the lateral and vertical deviation of the aircraft relative to the runway.

Abstract: In a method for the piloting of an aircraft, enabling low-altitude flight by setting up a tangent with the relief to be overflown, the aircraft pilot determines the goals to be attained on a cartographic screen. This is done in enabling a computer, using altimetrical data, to define a ground profile and then a set of straight lines at a tangent to said ground profile. A method of this kind has the advantage of enabling an optimized flight plan to be reconfigured directly, when the pilot comes up against a threat that makes it necessary to change the pre-set flight plan. Application to military transport aircraft.

Abstract: Methods and apparatus providing model-based feature tracking for location assessment of a sensor platform, or tracking of a feature are disclosed wherein a series of predictive models are developed to predict a location of features in subsequently acquired sensor data. Feature location data acquired by a sensor in a previous platform position assessment is used to build a model corresponding to anticipated feature locations in data acquired for a present platform position assessment.

Abstract: An arrangement for coordinating positional and angle information made on separate relatively moving platforms, such as aircraft, having independent coordinate systems, uses measurements of a common reference made on both platforms. The measurements are transmitted to a common location. Measurements made at a first time are processed to determine two of three coordinate transformation angles. After a period of time, a second set of measurements is used to determine the third coordinate transformation angle. In a particular embodiment of the invention, the direction of motion of one of the platforms is controlled to be orthogonal to a coordinate axis of the other platform. When the coordinate transformation is determined, it can be used to coordinate or align navigation instruments, weapons, or the like. In one embodiment of the invention, a missile is directed toward a target, in a situation in which the target is viewed from the missile and another moving vehicle.

Abstract: An aircraft including an approach and landing system, including a navigation unit for providing navigation information, a weather radar unit for providing radar information, a processor which receives navigation information from the navigation unit and information from the weather radar unit, the processor unit providing an output representing information concerning the aircraft in accordance with the provided navigation information and radar information, a memory for storing information representing a scene, the processor unit correlating the stored scene information with the output representing information concerning the aircraft to provide a mapped scene, a display unit for displaying the output of said processor and the mapped scene, and a steppable frequency oscillator for providing a signal which is stepped in frequency to the weather radar unit, thereby providing an increased range resolution.

Abstract: A method and apparatus for performing on-board corrections to the computed navigation variables of an inertial system on an aircraft while flying over a body of water. Onboard instruments, including a barometric altimeter and a radar altimeter, measure the vertical distance of the aircraft above an ellipsoidal model of the earth and above the body of water respectively. An on-board computer calculates the differences between such heights over a plurality of points along the path the aircraft travels over the water as indicated by its inertial navigation system. The differences are compared with a map of the undulation of the geoid encompassing the region to determine the deviation of the navigated course from the true course. Appropriate corrections to the aircraft's inertial system may then be made to reduce error.

Abstract: An automatic target acquisition and tracking system has been developed for a focal plane array seeker. The automatic target acquisition is achieved by three independent target acquisition algorithms, viz., the maximum likelihood classification, the video spatial clustering, and the target-to-interference ratio. Each algorithm operates asynchronously and provides independent target detection results. Target information is then combined hierarchically in a probabilistic fashion and prioritized. The highest priority target is handed off to a dual mode tracker consisting of a minimum absolute difference correlation tracker and a centroid tracker. The dual mode tracker subsequently provides a feedback signal to a proportional navigation system or other guidance/control system for directing the flight path of a munition.

Abstract: A terrain referenced navigation system utilizing a five-state kalman filter with a filter distribution based on a fixed grid approach. The five-state kalman filter utilizes an aircraft's altitude, East velocity, East acceleration, a South velocity and South acceleration. The database of the terrain referenced navigation system also utilizes a state variable indicating whether the aircraft is headed over water or land. The accuracy of the terrain referenced navigation system is improved by ignoring filter coefficients over water. The invention provides increased computational efficiency and accuracy by predicting inertial navigation parameters in the line of flight of an aircraft within a circle error of probability at predetermined filter locations within the circle error of probability. The difference between actual and predicted values are then used to compute a new estimate. The method is repeated until the removal of the most divergent filter at each pass results in a single best filter.

Abstract: The invention provides an array of standard infrared aiming lights mounted n an aircraft and used occasionally by pilots wearing infrared goggles to enhance perception of terrain features on low flying missions.

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: An AWTSS is shown to be made up of an improved synthetic aperture radar (SAR) for generating radar maps with various degrees of resolution required for navigation of an aircraft and detection of ground targets in the presence of electronic countermeasures and clutter. The SAR consists, in effect, of four frequency-agile radars sharing quadrants of a single array antenna mounted within a radome on a "four axis" gimbal with a sidelobe cancelling subarray mounted at the phase center of each quadrant. Motion sensors are also mounted on the single array antenna to provide signals for compensating for vibration and stored compensating signals are used to compensate for radome-induced errors. In addition, a signal processor is shown which is selectively operable to generate radar maps of any one of a number of desired degrees of resolution, such processor being adapted to operate in the presence of clutter or jamming signals.

Abstract: A vehicle mounted radar tracking system monitors vehicle heading rate, vehicle heading acceleration, vehicle roll rate and vehicle pitch rate, and provides a turn detect signal in response to heading rate, heading acceleration, roll rate or pitch rate being in excess of corresponding enable threshold magnitudes. In response to the turn detect signal, the tracking system dead reckons the positions of targets being tacked, and tracking system parameters are varied to make it more responsive to target motion. The turn detect signal is removed in response to heading rate, heading acceleration, roll rate and pitch rate being less than corresponding disable threshold magnitudes, and the tracking system is returned to normal operation.

Abstract: A vehicle mounted radar system has an antenna (12) which rotates about a reference axis (19). During angular movement of the antenna with respect to the reference axis, a radar indicated target azimuth (.phi.') is modified to provide a corrected target azimuth (.phi.) which is substantially indicative of the actual or true target azimuth. A tracking system (25) uses a predicted radar indicated target position (P.sub.n+1 (x,y)) for target tracking and correlation. The tracking system uses a smoothed target position (STP(x,y)), indicative of actual target position, for providing a visual display (39) of target track.

Abstract: The extraction of radar targets, in particular airplanes or cruise missiles, from clutter is typically based on the target's velocity relative to the ground. Equipment using this principle is usually referred to as a doppler processor or moving target indicator. In situations where severe clutter is encountered, as for example where a look-down radar is trying to find low-flying cruise missiles, extraction of the target solely through its velocity relative to the ground is generally unsatisfactory. A similarly situated human observer looking down can recognize a target both from its motion and the characteristic shape of a fuselage with wings. The principle of this "shape recognition" or "pattern recognition" is here applied to radar by utilizing the so-called radar signature of the target.

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 navigation system contains a modified Kalman filter processor which continuously receives both TERCOM and SITAN control information so that the operation of the SITAN processing is effectively continuously optimized. The system employs an over flight terrain data storage map to which position and altitude signals are coupled for extracting both elevation and slope information from the stored map. The extracted elevation and slope data are coupled, together with the outputs of baromatic and radar altimeter sensors and estimated altitude and position data outputs from the navigation unit, to a correlation/modified Kalman filter processor.

Abstract: An apparatus incorporating recursive estimators, more particularly apparatus for measuring the state of a dynamic system using a recursive estimator for modelling the dynamic behavior of the system, and navigation systems using a recursive estimator for navigation integration. Also disclosed are novel methods of updating the inputs to the estimators of such apparatus and systems.

Abstract: A warning device, for a helicopter with a tail rotor and a mechanical protection device therefor, for giving during emergency power-loss landings a flare signal to the pilot to initiate flare followed by a tail/ground contact warning signal when the helicopter tail approaches too closely the ground. The warning device comprises in one embodiment a height-finder with two switchable transmitting/receiving antennas mounted at the helicopter tail to produce respectively, when switched into use, a height-finding beam backwards and obliquely downwards or forwards and obliquely downwards. Height signals obtained initially using antenna 40 are processed by computing means and initiate at a predetermined initial flare altitude a flare warning signal whereafter height signals from antenna 26 are used to determine the sink rate of the tail and in dependence upon this sink rate and the instantaneous height, a warning signal is initiated if this corresponds to a predetermined relative relationship.

Abstract: An aircraft is equipped with a system of the FM-CW type including an on-board radio altimeter which cooperates with a transponder/beacon located at A. The radio altimeter is adapted for the measurement, alternately with the measurement of the altitude H, of the distance D in relation to point A, and of the angle .beta. in relation to a horizontal axis (46) linked to the transponder. The radio altimeter includes two aerials and a supplementary processing chain for the measurement of angle .beta.. The transponder is equipped with a base with two receiving/transmitting aerials (25, 27), switched alternately to sequentially operated circuitry in the transponder. Furthermore, the exact position of the aircraft within the vicinity of point A is determined by at least two measurements of distance D and of the angle .beta. in relation to the aerial base of the transponder.

Abstract: An automatic landing system for landing remotely piloted flying vehicles ng a predetermined path and at a predetermined point. The system includes an autopilot carried by the flying vehicle for measuring the parameters of attitude, airspeed, and heading and for comparing the measured parameters with the inputted parameters for the desired attitude, airspeed and heading. The autopilot adjusts the vehicle controls to make it conform to the desired attitude, airspeed and heading when deviations therefrom are detected. The system includes a radar transmitter and receiver means disposed on a stabilized double gimbal for measuring the actual heading and distance from the vehicle to the radar transmitter and receiver on a continuous basis.