Abstract: A method of determining an angle with a beam to terrain for a terrain avoidance system includes receiving first data associated with first returns associated with a first portion of an antenna. The method further includes receiving second data associated with second returns associated with a second portion of the antenna, wherein the first portion is different than, intersects, or includes the second portion. The method further includes determining the angle to terrain using the first data and second data.

Abstract: The present disclosure is directed to systems and methods for providing attenuation alerts for a radar-based terrain warning. A method for providing radar-based terrain warning attenuation alerts may comprise: (a) receiving a radar return; (b) detecting a region of atmospheric disturbance limiting the range of the radar return; and (c) providing a notification of radar-based terrain awareness warning system attenuation in the region of atmospheric disturbance.

Abstract: An aircraft weather radar system can be used with a terrain avoidance system. The aircraft weather radar system is coupled to an antenna. A processor receives radar returns received by the antenna. The processor determines terrain elevation estimates for use with the terrain avoidance system from the radar returns. The terrain elevation estimates are compared to stored terrain elevation data used with the terrain avoidance system to verify position or to check the integrity of the stored elevation data. The processor can be part of a terrain avoidance system, a weather radar system, a navigation system, or can be a standalone system.

Abstract: An aircraft weather radar system can be used with a terrain avoidance system to provide a terrain database. The weather radar system includes a processor and/or other electronics coupled to an antenna. The processor determines terrain data based on weather radar returns received from the antenna. The processor can utilize a variety of techniques for determining terrain data or estimates.

Abstract: A system and method for sensing elevation terrain using an airborne weather radar. Method techniques include sampling first and second radar returns from a weather radar at two portions of an antenna. First radar returns are removed from second radar returns to generate third radar returns for a third portion of the antenna. The third portion of the antenna is included in the second portion but not the first portion. Changes in the third radar return are analyzed to sense elevation of the terrain.

Abstract: A method of detecting obstacles on board an aircraft while in the vicinity (44) of a touchdown point (27, 42), includes the following operations: selecting/determining a path (41) to be followed by the aircraft overflying the touchdown point; the aircraft overflying the touchdown point following the overflight path, and during the overflight recording signals/data delivered by an on-board rangefinder observing a portion of space extending below the aircraft; analyzing the rangefinder data to detect the presence of obstacles and to determine their positions in a terrestrial frame of reference, where appropriate to determine their dimensions; and recording the detected obstacle position data, and dimensions, if any, in a memory.

Abstract: A method and apparatus for at least semi-autonomously controlling a vehicle so as to avoid collisions are provided. A sensor is utilized to scan an area proximate the vehicle for a potential object of collision. The apparatus calculates navigational states of the potential object of collision relative to the vehicle to determine that the vehicle is on a course to enter within a predetermined miss distance relative to the potential object of collision. The apparatus alters the course of the vehicle based on the calculated navigational states.

Abstract: A navigation solution of a navigation system with a Terrain Navigation Module is determined by a procedure including determining a supported position solution and the relative covered path between two height measurements, ascertaining a quality of each active supported position from each active supported position by way of a first quality function, and creating a search area and predetermined positions for each position inside the search area and each relatively stored covered path. The procedure further includes ascertaining a quality of each relatively stored terrain height measurement, and a quality of each reference height, and determining the quality of the position support by a function of all minimum probabilities of all used positions in the search area and supporting the navigation solution ascertained in the Strap Down Module by the navigation filter with the aid of the determined position support and the determined quality of the position support.

Abstract: A mobile radio communication system estimates the positional relationship between an own moving terminal and another moving terminal around a view obstruction. If the absolute value of the difference between detected reception power levels is lower than a first power threshold value, the own moving terminal determines that the other moving terminal is positioned within the visual range of the own moving terminal, the distance from the own moving terminal to the other moving terminal being shorter than a predetermined distance BP, or that the other moving terminal is positioned outside thereof, the distance to the visual range of the own moving terminal being shorter than the predetermined distance BP. Also if the absolute value is higher than or equal to the first power threshold value, the own moving terminal determines in a similar manner.

Abstract: The invention relates to a method of determining an estimated speed of an aircraft relative to ground being overflown by the aircraft, in which use is made of the sum of an acceleration measurement of the aircraft plus a difference value, the difference value being obtained from observation data or signals relating to a region of the ground.

Abstract: A navigation system having a radar altimeter is disclosed. The navigation system comprises a signal processing unit and one or more antennas in operative communication with the radar altimeter and the signal processing unit. The system further comprises a forward looking radar communicatively coupled to the radar altimeter. The forward looking radar and the signal processing unit are configured to provide forward looking radar measurements, radar altitude measurements from the radar altimeter, and datalink communications within a single forward looking radar scanning sequence.

Abstract: A collision and conflict avoidance system for autonomous unmanned air vehicles (UAVs) uses accessible on-board sensors to generate an image of the surrounding airspace. The situation thus established is analyzed for imminent conflicts (collisions, TCAS violations, airspace violations), and, if a probable conflict or collision is detected, a search for avoidance options is started, wherein the avoidance routes as far as possible comply with statutory air traffic regulations. By virtue of the on-board algorithm the system functions independently of a data link. By taking into account the TCAS zones, the remaining air traffic is not disturbed unnecessarily. The system makes it possible both to cover aspects critical for safety and to use more highly developed algorithms in order to take complicated boundary conditions into account when determining the avoidance course.

Abstract: According to the invention, a terrain avoidance maneuver is engaged when the alerts of a given pair of alerts are emitted simultaneously, the triggering of one of the alerts depending on the information provided by a first measurement chain and the triggering of the other alert of the pair relying on information provided by a second measurement chain, distinct from and independent of the first chain.

Abstract: The present invention is directed to a method of positioning perspective terrain on a SVS (Synthetic Vision System) based on a navigation solution, the vertical component of which is calculated utilizing a terrain database and sensing unit (which provides height above terrain). The terrain database provides elevation of terrain above MSL. A sensor, such as a GNSS sensor, may be utilized to calculate the navigation solution. In alternative embodiments, the navigation solution is calculated differently based upon the phase of flight. In one, the vertical component calculation utilizes the sensing unit at or below the sensing unit's rated altitude. In another, vertical component calculation blends the sensing unit with the sensor. The blending may be based upon percentages based upon altitude or utilize filtering such as Kalman filtering. The present invention is particularly advantageous for close to ground operations, insuring perspective terrain will stay consistent with the real world.

Abstract: A spatial data search method, system and apparatus for identifying particular data of significance around a reference vector through the spatial data. The method involves determining a reference vector within a spatial region for which spatial data exists, loading a portion of the spatial data including the data around the reference vector into a memory buffer, and searching the spatial data in a prioritized order. The method, system and apparatus have particular utility in searching geographic data for a terrain awareness and warning system (“TAWS”) and display in an aircraft. Embodiments of the present invention provide advantages over existing sequential and radial search methods, significantly reducing the processing and calculations required and providing faster alerts to pilots.

Abstract: A weather radar system coupled to a weather radar antenna, including a receive circuit for receiving radar returns received by the antenna and a processor for summing portions of the radar return data to obtain a null response. The null response is utilized to determine presence of terrain.

Abstract: A terrain awareness and warning system includes electronics for receiving radar returns and providing terrain and/or obstacle alerts or warnings in response to the radar returns. The electronics receives information from a database and the information is utilized to suppress false alerts or warnings.

Abstract: This method uses for the estimation of a distance, a propagation distance transform considering only the paths which are both accessible to the aircraft taking account of its vertical flight profile and complying with air regulations. The propagated distance Dp is accompanied by a propagated altitude Ap which at all points follows the vertical flight profile of the aircraft, while being greater than the altitudes of these points and complying with the air regulation constraints at these points. This is obtained by subjecting the propagation to compliance with the vertical flight profile of the aircraft, constraints of the elevations of the points of the relief and air regulation constraints.

Abstract: A weather radar system coupled to a weather radar antenna, including a receive circuit for receiving radar returns received by the antenna and a processor for summing portions of the radar return data to obtain a null response. The processor adjusts the phase or power of at least one portion of the radar return data using a steering vector or a tuning vector.

Abstract: A method of identifying a runway is disclosed. A first scan of an area of ground known to include a runway is performed. The first scan is accomplished using a weather radar system at a predetermined position. A first image is obtained from the first scan. The first image is stored in a memory. A second scan of an area of ground proposed to include the runway is performed. The second scan is accomplished using a weather radar system at what is believed to be the predetermined position. A second image is obtained from the second scan. The first image is retrieved from the memory. It is determined whether features in the first image correlate to features in the second image. A runway confirmation signal is sent to a pilot of the aircraft when there is a substantial certainty of correlation between the first and second images.

Abstract: A method and apparatus for terrain mapping and/or obstacle detection for aircraft, including (a) transmitting a non-scanning beam that illuminates the terrain and/or obstacles; (b) receiving a Doppler shifted signal that is Doppler frequency shifted by an amount dependent on an angle between a line of flight of the aircraft and scatterers that reflect the transmitted beam; (c) determining the angle from the Doppler frequency; (d) determining the range of at least some of said scatterers; and (e) determining the azimuth and elevation of the scatterers.

Abstract: Systems and methods for terrain contour matching navigation are provided. In one embodiment, a method for terrain contour matching navigation comprises: receiving at least one sample point representing the position of an aircraft, the at least one sample point including a horizontal position and an altitude sample; correlating a first sample point of the at least one sample point across a reference basket array having a plurality of elements; determining a correlation quality; when the correlation quality does not achieve a pre-determined quality threshold, performing at least one additional correlation of an additional sample point of the at least one sample point across the reference basket array; and when the correlation quality does achieve a pre-determined quality threshold, calculating a position error based on the correlating of the first sample point and any additional correlations of any additional sample points.

Abstract: A method of automatically guiding an aircraft for flight at low altitude determines an LLF (low level flight) trajectory section for following terrain to be overflown by the aircraft. The LLF trajectory section takes account of predictions of the aircraft's mass and speed and climb and descent performance. The LLF trajectory section includes an entry point and an exit point. The LLF trajectory section is integrated between a first trajectory part corresponding to a first phase of flight and a second trajectory part corresponding to a second phase of flight, by providing respectively first and second transition phases. The aircraft is automatically guided so that it successively captures, follows, and leaves the LLF trajectory section.

Abstract: A position estimation system including a first arrangement for providing an image with a known target in a known reference frame. A second arrangement correlates the image with a stored image. The correlation is used to compute an error with respect to a position estimate. In a specific embodiment, the error is referenced with respect to first (x), second (y) and third (z) directions. A target location error is computed with respect to a stored image provided by a target image catalog. The target image catalog includes target geo-locations and digital terrain elevation data. In an illustrative application, the image data is provided by synthetic aperture radar and forward-looking infrared systems. An observation model and a measure noise matrix are Kalman filtered to ascertain a position error in navigation data generated by an integrated inertial navigation and Global Positioning system.

Abstract: A method to control a track gate and a level gate in an altimeter tracking an altitude of an airborne vehicle comprising emitting signals, directed toward a terrain, from the airborne vehicle, receiving terrain echo signals, positioning the track gate to a selected reference amplitude on the rising edge of the terrain echo signals, positioning the level gate to within a selected range of the peak amplitude level of the terrain echo signals, measuring a change in a location of the peak amplitude between sequentially received terrain echo signals, and varying a separation between the track gate and the level gate based on the measured change in the location of the peak amplitude. The terrain echo signals comprise reflections of the emitted signals from the terrain, and each terrain echo signal has a rising edge and a peak amplitude.

Abstract: A method of designing a terrain-following flight profile for an air vehicle. The method includes providing a terrain profile, and transforming the terrain profile into the terrain-following flight profile according to one or more performance parameter of the air vehicle.

Abstract: A system and method for efficient intervisibility determination. The intervisibility determination method of the present invention provides a multiple threat processing capability within a specified area of terrain using a common database. Computation is simplified through the method of processing data posts in the terrain elevation database. By taking integer steps and incrementing distance, x or y, and a predicted elevation value at each step, a small number of operations may be performed. Recomputing a change in elevation value may be reduced. An umbra database provides an enhanced look-up capability for displaying and updating the intervisibility display information. The systems and methods of the present invention may be suitable for use on a vehicle and in mission management activities.

Abstract: The present invention is directed to a system and method for a safe flight display through increasing situation awareness by an optimal presentation, given limited capacity of the system. The system may determine which terrain area needs a detail representation and which area needs a coarse representation. A view-dependent visual error metric may be utilized to define and maintain an error bound and accurately minimize the amount of terrain data being depicted. By performing a breadth-first search on the terrain database, a user can determine amount of geometry to be displayed with limited bandwidth of data presentation. The user may be allowed to scale the application to his/her desired level of detail, given a capacity of the system. Therefore, the system may provide a safe flight display with an anticipated and graceful (all portions of the screen would be given an equal quality representation) degradation in performance upon the choice of the user.

Abstract: A method is disclosed for evaluating the terrain surrounding a radar site. The method comprises to calculate the radar horizon around a radar site from stored terrain elevation information. The information obtained can be used for controlling the scanning profile of the radar, by letting the radar scan above the calculated horizon, and thus avoiding transmitting into the terrain.

Abstract: A method is provided for at least one of detecting and tracking an object within a wide-area. The method including: deploying three or more sensors within the wide-area, each of the sensors having one or more polarized radio frequency waveguides; transmitting polarized radio frequency radiation from at least one source; detecting a reflection of the transmitted polarized radio frequency radiation; and calculating one of a detection or position of an object within the wide-area based on the detected reflection. At least one of the three or more sensors and at least one source can be a mobile platform, which can be manned or unmanned. The three or more sensors can be deployed manually or remotely, such as from a projectile.

Abstract: A system and method for determining the slope of a ground imaged area. The system includes a camera, a memory, and a processor. The camera generates a first and a second image of an area of ground from an aircraft. The memory stores bi-directional characteristic information for associated materials. The processor determines a material type associated with a plurality of the pixels based on a color value of the pixels. The processor retrieves bi-directional characteristic information from the memory for a pixel based on the determined material type. A slope value at a pixel location is determined based on the associated viewing angle values, a determined radiance change value, and the retrieved bi-directional characteristic information.

Abstract: Embodiments of the invention provide a method and apparatus for indicating aircraft height relative to an obstruction in a terrain awareness warning system. The method includes receiving data indicative of geographic features of an obstruction, lateral distance of the geographic feature from an aircraft, height and flight path of the aircraft, calculating a projected height of the aircraft at the location of the obstruction using the data, generating a result signal, and displaying a colored indication on a display screen based on the result signal. The apparatus includes inputs for signals from instruments measuring height, flight path, and location of an aircraft, as well as an input for an instrument providing information about geographic features of terrain surrounding the aircraft. The apparatus includes a means for employing the signals to calculate an effective height of the aircraft relative to the terrain, and a screen display for graphically displaying the results of the calculation.

Abstract: A transponder having a subsystem for providing an altitude alert function signifying a deviation from a set altitude is described. The subsystem includes an input for receiving an altitude deviation limit associated with the set altitude, a CPU receiving updated altitude and determining a difference between the updated altitude and the set altitude associated with the altitude deviation limit, and a transponder subsystem output device for providing the difference between the updated altitude and the set altitude to a user.

Abstract: Embodiments of the invention provide a method and apparatus for indicating aircraft height relative to an obstruction in a terrain awareness warning system. The method includes receiving data indicative of geographic features of an obstruction, lateral distance of the geographic feature from an aircraft, height and flight path of the aircraft, calculating a projected height of the aircraft at the location of the obstruction using the data, generating a result signal, and displaying a colored indication on a display screen based on the result signal. The apparatus includes inputs for signals from instruments measuring height, flight path, and location of an aircraft, as well as an input for an instrument providing information about geographic features of terrain surrounding the aircraft. The apparatus includes a means for employing the signals to calculate an effective height of the aircraft relative to the terrain, and a screen display for graphically displaying the results of the calculation.

Abstract: A method for locating aircraft with respect to airport runways and taxiways, generating and annunciating situational awareness advisories as a function of aircraft state parameters relative to a determination of the aircraft location.

Abstract: A method for recognizing and identifying objects by means of several sensors, particularly using imaging sensors (L, W, V) in the infrared and/or visible wavelength range and radar devices (R) which are based on the generation of a synthetic aperture. According to the invention, generation of the synthetic aperture occurs in accordance with the ROSAR principle, wherein a plurality of antenna elements (A), which the radar device (R) comprises, is placed on the aircraft (F) along its arched contour (K), controlled sequentially and scanned, and wherein the information acquired by the radar devices (R) and the imaging sensors (L, W, V) is subsequently processed, in such a way that optimal imaging of the surroundings of the aircraft (F) is made possible in every viewing direction.

Abstract: A method for calculating a center frequency and a bandwidth for a radar doppler filter is herein described. The center frequency and bandwidth are calculated to provide radar performance over varying terrain and aircraft altitude, pitch, and roll. The method includes receiving an antenna mounting angle, a slant range, and velocity vectors in body coordinates, calculating a range swath doppler velocity, a track and phase swath bandwidth, and a phase swath doppler velocity. The method continues by calculating a range swath center frequency based on the range swath doppler velocity, calculating a phase swath center frequency based on the phase swath doppler velocity, and calculating a level and verify swath bandwidth based upon the track and phase swath bandwidth.

Abstract: A method for incorporating a forward ranging feature into a radar altimeter is described. The method comprises positioning an antenna of the altimeter such that a side lobe of a radar signal radiates from the antenna in a forward direction and processing a radar return from the side lobe to determine a range to a forward object.

Abstract: A terrain clearance measuring radio wave being emitted from an airplane is received, and changes in electric field intensity of the radio wave is input and recorded to a computer, whereby the time of occurrence of a sharply appearing peak value of the changes permits accurate measurement of the point-blank passing time, independent of flight frequency.

Abstract: Methods and apparatus for detecting obstacles in the flight path of an air vehicle are described. The air vehicle utilizes a radar altimeter incorporating a forward looking antenna and an electronic digital elevation map to provide precision terrain aided navigation. The method comprises determining a position of the air vehicle on the digital elevation map, selecting an area of the digital elevation map in the flight path of the air vehicle, based at least in part on the determined air vehicle position, and scanning the terrain representing the selected map area with the forward looking antenna. The method also comprises combining the digital elevation map data for the selected map area with radar return data for the scanned, selected area and displaying the combined data to provide a representation of the terrain and obstacles in the forward flight path of the air vehicle.

Abstract: A flight guidance system providing perspective flight guidance symbology using positioning and terrain information provides increased pilot situational awareness of an aircraft. The guidance system uses a positioning system and a detailed mapping system to provide a perspective display for use in an aircraft. A Perspective Flight Guidance (PFG) symbology set is thereby displayed on a pilot display. The PFG symbology set includes broken line symbols representing an open tunnel and providing flow field data, a half-bracket symbol to indicate that the aircraft is no longer in the open tunnel represented by the broken line symbols and a quickened flight path vector (QFPV) symbol to provide the pilot with predictive flight path information.

Abstract: A transponder having a subsystem for providing an altitude alert function signifying a deviation from a set altitude is described. The subsystem includes an input for receiving an altitude deviation limit associated with the set altitude, a CPU receiving updated altitude and determining a difference between the updated altitude and the set altitude associated with the altitude deviation limit, and a transponder subsystem output device for providing the difference between the updated altitude and the set altitude to a user.

Abstract: A method for incorporating a forward ranging feature into a radar altimeter is described. The method comprises positioning an antenna of the altimeter such that a side lobe of a radar signal radiates from the antenna in a forward direction and processing a radar return from the side lobe to determine a range to a forward object.

Abstract: A ground-based CFIT warning system provides pilots with CFIT alerts. The system is based upon a ground-based tracking system, which provides surveillance of aircraft, such as the AirScene™ multilateration system manufactured by Rannoch Corporation of Alexandria, Va. The system monitors both horizontal and vertical positions of aircraft. When an aircraft has been determined to be operating below safe altitudes, or too close to obstructions, the pilot is provided with a warning. The warning may be delivered via the pilot's voice communications and/or a data link or the like.

Abstract: According to one embodiment of the invention, a system for protecting aircraft includes a plurality of missile warning sensors and a turret mounted near the top of at least one support structure. Each missile warning sensor is operable to detect a missile and the turret is operable to emit a laser beam that is directed toward the missile to divert the missile from its intended flight pattern.

Abstract: Radar coverage maps having blockage, coverage and clutter features available for ease of interpretation are provided using terrain data to establish such features in data sets. The data sets provide a basis for the modified display. Multiple tilts of the radar scan may be represented. Multiple radar zones may be overlapped to provide a mosaic of a region showing areas of no coverage despite overlap.

Abstract: A method for testing a radar system utilizing flight test radar data is described. The method includes time synchronizing measured radar data with a GPS based time marker, storing at least a portion of the time synchronized radar data, storing the GPS data, processing the stored GPS data to correspond with a physical position of an antenna which received the radar data, providing a radar model, and comparing the processed radar model data to the stored radar data.

Abstract: A terrain-awareness system (TAS) provides LOOK-AHEAD/LOOK-DOWN as well as LOOK-UP terrain advisory and warning indications to the pilot of an aircraft of a hazardous flight condition. The TAS includes an airport data base as well as a terrain data base that is structured to provide various resolutions depending on the topography of the particular geographic area of interest. Navigational data from a satellite-based navigational system, such as a global positioning system (GPS), is used to provide a LOOK-AHEAD/LOOK-DOWN and LOOK-UP terrain advisory and terrain warning indications based upon the current position and projected flight path of the aircraft. Since the terrain advisory and the warning signals are a function of the flight path of the aircraft, nuisance warnings are minimized.

Abstract: Embodiments of the invention provide a method and apparatus for indicating aircraft height relative to an obstruction in a terrain awareness warning system. The method includes receiving data indicative of geographic features of an obstruction, lateral distance of the geographic feature from an aircraft, height and flight path of the aircraft, calculating a projected height of the aircraft at the location of the obstruction using the data, generating a result signal, and displaying a colored indication on a display screen based on the result signal. The apparatus includes inputs for signals from instruments measuring height, flight path, and location of an aircraft, as well as an input for an instrument providing information about geographic features of terrain surrounding the aircraft. The apparatus includes a means for employing the signals to calculate an effective height of the aircraft relative to the terrain, and a screen display for graphically displaying the results of the calculation.

Abstract: A phase processor is disclosed which is configured to receive processed radar return data from a left radar channel, a right radar channel, and an ambiguous radar channel. The phase processor comprises a plurality of phase detectors each with an input and a reference input. The phase detectors are configured to determine a phase difference between radar return data received at the input and radar return data received at the reference input.