Abstract: GPS satellite (4) ranging signals (6) received (32) on comm1, and DGPS auxiliary range correction signals and pseudolite carrier phase ambiguity resolution signals (8) from a fixed known earth base station (10) received (34) on comm2, at one of a plurality of vehicles/aircraft/automobiles (2) are computer processed (36) to continuously determine the one's kinematic tracking position on a pathway (14) with centimeter accuracy. That GPS-based position is communicated with selected other status information to each other one of the plurality of vehicles (2), to the one station (10), and/or to one of a plurality of control centers (16), and the one vehicle receives therefrom each of the others' status information and kinematic tracking position. Objects (22) are detected from all directions (300) by multiple supplemental mechanisms, e.g., video (54), radar/lidar (56), laser and optical scanners. Data and information are computer processed and analyzed (50,52,200,452) in neural networks (132, FIGS.

Abstract: A Traffic Alert and Collision Avoidance System (TCAS) uses a dual bandwidth receiver to achieve extended range operation. During normal operations TCAS radio signals are filtered by a bandpass filter which passes all TCAS radio signals of interest. When extended range operation is desired the TCAS radio signals are filtered by a more narrow bandpass filter. The narrower filter passes only selected TCAS radio signals and improves the signal to noise ratio and thus allows detection of selected TCAS radio signals at extended range. The TCAS system switches between the normal mode and the extended range mode to detect and track aircraft at both near and far distances.

Abstract: Proximity radar mounted in a vehicle determines the location of other vehicles. Other vehicles detect their own positions and broadcast those positions to all surrounding vehicles. Vehicle position data is plotted on a moving map so the driver can see the location of other vehicles, in some cases with an icon color which matches vehicle color(s). A driver can open a communication link with drivers who are projected to constitute a collision threat. A fixed radar unit can be positioned at blind intersections and broadcast vehicle location information for vehicles not equipped with the ability to track their own locations.

Abstract: A system, method, apparatus, and computer program product for avoiding aircraft collisions with stationary obstacles. The aircraft is provided with a simplified uncluttered onboard display of all objects which are in or proximate to the projected path of the aircraft at its particular altitude plus or minus a predetermined increment, such as 100 feet constituting a hazard zone. The display presents the hazards in that zone in geographical relationship to the position and path of the aircraft. In addition to the obstacles in the hazard zone the display may also present topographical features of the underlying terrain. This information is in the form of a muted presentation of a topographical moving map. As the aircraft approaches a hazard in the hazard zone the presentation of the obstacles or hazards within the zone is enhanced to draw increasing attention of the pilot.

Abstract: The invention is an electronic system for warning helicopter pilots of the presence of electric power lines during landing. The system detects electromagnetic fields created by electricity flowing through the power lines. When the helicopter is closer than a predetermined distance from the power line, visual and audio alarms alert the pilot of the danger. When the helicopter is a safe distance from the power line, the alarms reset.

Abstract: An emergency vehicle proximity warning and communication system including a transmitter mechanism situated in an emergency vehicle and adapted to emit an activation signal via free space. Further provided is a receiver mechanism situated within another vehicle and adapted to actuate upon the receipt of the activation signal via free space. An emergency citizen band radio receiver is connected to the receiver mechanism and is adapted to receive emergency instructions from a driver of the emergency vehicle upon the supply of power thereto. To ensure the driver is given proper indication and instruction, the emergency citizen band radio receiver is further adapted to playback a prerecorded warning message upon the supply of power thereto in combination with the lack of receipt of emergency instructions from the driver. Also included is a switch mechanism situated within the receiver housing and coupled to the receiver mechanism and the emergency citizen band radio receiver.

Abstract: A Traffic Alert and Collision Avoidance System(TCAS) antenna is mounted on a selected forward portion of an aircraft thereby extending the effective forward range of the TCAS. The antenna and ground plane are tilted relative to conventional TCAS antennas thereby aligning a peak of the antenna's radiation pattern along the aircraft's level line of flight. The resulting increased gain directed forward of the aircraft increases the forward range of the TCAS for both receiving and transmitting TCAS signals. The invention is also useful to extend the range of other aircraft systems including transponders. Alternate embodiments include tilting a conventional TCAS antenna mounted on a middle portion of the aircraft.

Abstract: An aircraft local-area augmentation system that employs a differential global positioning system (GPS) to assist aircraft (102) landing is disclosed. One or more GPS ground stations (120), each including at least two GPS receivers (122) and a datalink transmitter (126), calculate and transmit GPS correction data to an aircraft (102). An aircraft (102) employs a GPS receiver (106) for receiving ranging signals (112) from GPS satellites (108), and a datalink receiver (116) for receiving GPS correction data and other information from a GPS ground station (120). The aircraft (102) further includes a data processor (110) for determining a global position of the aircraft (102) as a function of the aircraft GPS pseudorange data and the GPS correction data. The system minimizes the introduction of non-common errors by the use of double-differencing calculations using multiple combinations of satellite (108) and GPS ground station receiver (122).

Abstract: The invention is a method for determining the relative position and velocity of a second vehicle with respect to a first vehicle. The method is practiced on board the second vehicle and utilizes a plurality of satellite transmitters and an inertial measurement unit on the second vehicle. The first vehicle has available a plurality of data items consisting of the first vehicle's measured position, measured velocity, and specific-force acceleration. The second vehicle has available data items consisting of the second vehicle's measured position, measured velocity, specific-force acceleration, autonomous position, autonomous velocity, autonomous position correction, and autonomous velocity correction. The measured position and measured velocity are determined utilizing the radio signals from a plurality of satellite transmitters and the specific-force acceleration is obtained from an inertial measurement unit.

Abstract: A collision judging system for a vehicle includes a sensor for detecting a relative speed between a subject vehicle and an object, and a judging section for judging a possibility of collision of the subject vehicle with the object based on the relative speed. In the collision judging system, when an output from the differentiating device exceeds a preset value, a signal indicative of a command to prohibit the judgment of the possibility of collision in the judging section is outputted from the prohibiting-signal outputting device, thereby avoiding the unnecessary judgment of the possibility of collision in the judging section.

Abstract: A system for coding and transmitting traffic alert and collision avoidance data between vehicles (A, B and C) traveling within a given airspace (12). The airspace is divided into a grid of volume elements (14a, 14b . . . 14i), each of which is assigned a unique pseudonoise (PN) code. A vehicle (A) traveling through the airspace determines its position using signals from Global Positioning System (GPS) satellites. The vehicle's position places it within one of the volume elements in the airspace. A Traffic Alert and Collision Avoidance System (TCAS) transmitter (38) on the vehicle creates a navigation message that describes the position of the vehicle. A collision avoidance signal is then generated by modulating a carrier signal with the PN code representing the volume element containing the transmitting vehicle and with the navigation message. The collision avoidance signal is transmitted on a common communications channel using time-multiplexing based on a pseudorandom sequence.

Abstract: The invention provides a system and a method for detection of oil spills and icebergs at sea and for aiding the navigation of ship traffic to avoid collisions between ships and icebergs. A constellation of polar orbiting satellites is used to determine the position of icebergs and oil spills within an observation area, and this information is transmitted to a data processing center which also receives information concerning the position of ships within the observation area. The data processing center uses this information to evaluate the likelihood of collisions between ship and icebergs and sends warning signals to the ships, alerting them to the danger. The data processing center also correlates the position of ships and oil spills to determine the likely cause of the latter.

Abstract: A system (400) for positioning and navigating an autonomous vehicle (310) allows the vehicle (310) to travel between locations. Position information (432) is derived from global positioning system satellites (200, 202, 204, and 206) or other sources (624) when the satellites (200, 202, 204, and 206) are not in the view of the vehicle (310). Navigation of the vehicle (310) is obtained using the position information (432), route information (414), obstacle detection and avoidance data (416), and on board vehicle data (908 and 910).

Abstract: An aircraft location and identification system, including a first position determining portion located aboard a transmitting aircraft for determining a first set of present positional and tracking information is described relative to said transmitting aircraft. A transmitting portion is included for transmitting the first set of present positional and tracking information to a receiving aircraft. A second position determining portion, which is located aboard the receiving aircraft, determines a second set of present positional and tracking information relating to the receiving aircraft. A computing portion is located aboard the receiving aircraft and/or a ground based facility. The computing portion utilizes present and past values of the first set of present positional and tracking information to derive a corresponding first probabilistic future tracking configuration of the transmitting aircraft.

Abstract: A high performance, real-time control sequencer is disclosed which incorporates a unique state matrix logic. This real-time control sequencer performs rapid resolution of control processed state transitions and the required control actions as a function of detected external events and the current control process state. The control sequencer's micro-instructions present event and current state data as inputs to a state matrix logic and initiate state matrix operations. The state matrix, in turn, outputs data defining and initiating the next control process state, required process control actions to be performed by the control sequencer microcode, process status, and event response or control output data. The real-time, event-driven data processor invention provides greater flexibility for reconfiguring event patterns to be detected and responses desired.

Abstract: In a vehicle which sets a target vehicle-interval distance, and can execute auto-cruise control for controlling the vehicle speed so as to maintain the target vehicle-interval distance, when the auto-cruise control is not executed, a vehicle-interval distance to be set by a driver is detected together with the vehicle speed at that time. A plurality of sets of the vehicle speed and vehicle-interval distance data are accumulated, and the relationship between the vehicle speed and the vehicle-interval distance is calculated. Upon execution of the auto-cruise control, a vehicle-interval distance corresponding to the vehicle speed at that time is obtained from the calculated relationship, and the obtained vehicle-interval distance is set to be the target vehicle-interval distance.

Abstract: A method and system are disclosed for improved collision avoidance of two locomotives by periodically receiving on each locomotive digitally encoded data to determine its geographical location, speed and direction of travel by means of an onboard global positioning system receiver. A first data frame including this data is created on each locomotive. Each locomotive periodically broadcasts to the other digitally encoded signals containing the first data frame. A second data frame is created on each locomotive from the received digital signals from the other locomotive containing the second locomotive's geographical location, speed and direction of travel and locomotive identification. The data frames are processed and displayed onboard each locomotive to determine if the other is a collision candidate. If so, collision avoidance procedures are automatically initiated, including initiation of aural and visual alarms at a first selected distance and the reduction of speed at a second selected, closer distance.

Abstract: An automatic brake control system produces a warning before automatically making the braking action of a driving vehicle according to the velocities of the driving vehicle and the vehicle ahead. The system calculates the desired vehicle distance according to the velocities of the driving vehicle and the vehicle ahead, and sets a warning distance which is longer than the desired vehicle distance. The warning distance is set in accordance with the driver's feeling. According to the present invention, the system is prevented from producing undesirable warning.

Abstract: An anti-collision system detects conditions of an object preceding a source vehicle, and parameters indicative of operating conditions of the source vehicle, and controls the source vehicle so as to prevent a collision with the object, based on the detected conditions of the object and the detected operating conditions of the source vehicle. The system estimates a path of travel of the source vehicle, based on the detected parameters, and sets an area of travel of the source vehicle to a first predetermined area lying about the estimated path of travel. Further, the system estimates a path of movement of the object, based on the detected conditions of the object, and sets an area of movement of the object to a second predetermined area lying the estimated path of movement. The system calculates a possibility of collision, based on the set area of travel and area of movement, to thereby control the velocity of the source vehicle.

Abstract: An automatic dependent surveillance (ADS) system for tracking aircraft includes a GPS navigation receiver for determining the position of an aircraft, a Mode S transponder for transmitting the position of the aircraft, and a Mode S receiving station for receiving the aircraft's position and for determining the position of the transmitting aircraft relative to other aircraft and the ground. The Mode S position information is broadcast as a squitter on a random time basis having a present average transmission rate, or in response to an interrogation signal from a Mode S receiving station. The Mode S receiver can be another aircraft, an en route ground station, and/or a terminal ground station. The en route ground station can include a multi-sector receiving antenna with each sector connected to a separate Mode S receiver. The terminal ground station can include an omni-directional antenna connected to a Mode S receiver.

Abstract: A horizontal miss distance filter system (220) is provided for inhibiting resolution alert messages from an air traffic alert and collision avoidance system (210) to a pilot's display (230). The horizontal miss distance filter employs a parabolic range tracker (10) to derive a range acceleration estimate (11) utilized to discriminate intruder aircraft (110) having non-zero horizontal miss distances. The horizontal miss distance calculated from the range data provided by the parabolic range tracker is compared with a bearing based horizontal miss distance provided by a bearing based tracker (22). The smaller of the two calculated horizontal miss distances defines a projected horizontal miss distance which is compared with a threshold value. Any resolution alert for intruder aircraft whose projected horizontal miss distance is greater than the threshold will be inhibited unless it is determined that the encounter involves a maneuver of one of the aircraft.

Abstract: An antenna arrangement on a host aircraft for generating power signals related to a direction from which a transponder reply signal is received from a threat aircraft. The arrangement includes first and second monopole antenna elements arranged along a first axis of the host aircraft, third and fourth monopole antenna elements arranged along a second axis of the host aircraft, with the second axis being orthogonal to the first axis, a first quadrature combiner coupled to the first and second monopole antenna elements for generating first and second signals from the received reply signal, and a second quadrature combiner coupled to the third and fourth monopole antenna elements for generating third and fourth signals from the received reply signal. The respective power levels of the first, second, third and fourth signals are related to the direction from which the reply signal is received from the threat aircraft.

Abstract: The method embodying the invention comprises the periodical drawing up and transmission, on board an aerodyne, of a tracking message comprising a code identifying the aerodyne and navigational data, to an air surveillance station for a geographical area, permanent monitoring by said station and reception of tracking messages transmitted by the aerodynes in the vicinity, determination of their respective future paths within said geographical area, detection by said station of the risks of collision of each aerodyne with a relief obstacle, and drawing up by said station of the avoidance commands to be performed by the pilot of the aerodyne and transmission of these commands to the pilot. This method does not implement any specific autonomous system, while providing a high degree of security.

Abstract: A target electronic system forms part of a marker beacon. The target system ids in detecting the marker beacon upon deployment. A seeking electronic system for locating the target system may be mounted on an air vehicle, land vehicle, sea vehicle, or backpack. The target system, upon deployment of the marker beacon, sends out signals identifying the marker beacon's use, identity, and direction. The seeking system then responds by querying the target system of its distance. The target system then responds to this query. The seeking system then has the option of sending a signal to have the target system initiate the activation of a flare. The activated flare can then be used for visual and infrared detection.

Abstract: This invention relates to a system to alert an aircraft pilot of the presence and general location of other aircraft that might constitute a collision threat to the pilot's aircraft. A first and second antenna on the upper paid lower surfaces of the aircraft each operate in first and second modes characterized by respective first and second directivity conditions. The first and second antennas directly receive pulse signals from a source in order to determine the relative time of arrivals and thus the relative altitude of the source to the aircraft. Analysis means compares amplitudes of responses in the first and second modes to provide an angle indicating signal without having to generate radio signals other than those already being generated by equipment in the other aircraft in response to ground ATC interrogation.

Abstract: In a collision avoidance communication system and method, equipped aircraft (12) and ground control stations (18) which represent nodes of an RF communication network (22). A radar system (16) determines locations of equipped aircraft (12) and unequipped aircraft (14) within an airspace (10). The ground control station (18) couples to the radar system (16) and the network (22) to receive location data for the aircraft (12, 14). These location data are merged in an object list (142). The ground control station (18) displays objects from the object list (142), broadcasts surrogate location data (84) for unequipped aircraft (14) over the network (22), and broadcasts control data (100, 116) describing weather conditions, geographic features, and the like, over the network (22). Equipped aircraft 12 receive aircraft location data (84) and control data (100, 116) from the network (22). Each equipped aircraft (12) determines its own location.

Abstract: A vehicle location system and method whereby the position coordinates of a vehicle are made available to other vehicles or to fixed locations by transmission of a data message containing position coordinates of the vehicle. The time slot in which the data message is transmitted is uniquely assigned to each transmitting vehicle as a function of its position in a grid segment with respect to a reference waypoint assigned to that grid segment. Position information in latitude and longitude is provided to each receiving vehicle, together with a precise timing signal, by the Global Positioning System (GPS), or by the Global Orbiting Navigational Satellite System (GLONASS), or by both systems. A synthetic latitude function and a synthetic longitude function provide a periodic mapping of a specific time period onto areas represented by grid segments charted on the global surface. These synthetic functions are initiated and controlled by the precise timing signal from the GPS or GLONASS systems.

Abstract: An automatic brake control system produces a warning before automatically making the braking action of a driving vehicle according to the velocities of the driving vehicle and the vehicle ahead. The system calculates the desired vehicle distance according to the velocities of the driving vehicle and the vehicle ahead, and sets a warning distance which is longer than the desired vehicle distance. The warning distance is set in accordance with the driver's feeling. According to the present invention, the system is prevented from producing undesirable warning.

Abstract: Communication devices and communication network techniques are employed to meet safety-critical, operational requirements for train location and control in railroad and public transit applications. On-board and trackside communication radios participate in a synchronous, time-slotted communication network, providing contentionless and highly responsive access to all participants. Encrypted, validated, and error protected communication links provide reliable and redundant transfer of information among the train, trackside, and control station radios. Spread spectrum communication techniques enable range measurements between all participants. These wireless communication links relay train range measurements to control or processing stations and relay control information (principally speed commands) from the processing stations to the trains. High resolution position location is determined along elevated, at-grade, and in-tunnel tracks using wireless methods and sparse device placement.

Abstract: An obstacle avoidance apparatus including a target data generator for outputting observation values of a target, a static obstacle driver for expressing a static obstacle by a turning acceleration of the target, a characteristic amount extractor for outputting characteristic amounts for representing first control amounts of a destination direction and a static obstacle avoidance by the turning acceleration, and a control amount determiner for outputting a second control amount of the target based on the first control amounts. A three-dimensional obstacle is expressed by the turning acceleration looked at from the target and the control amount for avoiding the obstacle until the target reaches a destination is determined.

Abstract: A route predicting apparatus for monitoring a flying target and predicting a route thereof. Even if the target is hidden by mountains or other obstacles thus preventing observation for a certain time, a reliable route prediction is carried out by utilizing the fact that a route of the target is restricted by geographical features. The apparatus comprises an observation unit for observing a target and outputting an observed value thereof, a terrain information unit for outputting characteristic parameters of stored terrain information, a prediction unit coupled to receive the observed value and the characteristic parameters of terrain information for performing a fuzzy inference to output a predicted observed value of the target, and a learning adjustment unit coupled to receive an error signal between a predicted observed value at the current time predicted a unit time before and a real observed value at the current time for adjusting the prediction unit by using a neural network.

Abstract: A system for sea navigation which features a plurality of ships located in a single high density area (for example port) and a control center for this area using a common transmission channel. The ships are equipped to transmit data about their speed, heading and position, which are displayed on a panoramic screen fitted on all ships and in the control center. The control center has priority access to this common channel to send general interest messages or special messages to all or some of the equipped ships.

Abstract: An apparatus includes an inter-vehicle distance sensor for measuring a distance from a self vehicle to a vehicle traveling ahead, and a relative speed is calculated on the basis of the inter-vehicle distance data detected by the inter-vehicle distance sensor. When a variation of the relative speed is small, it is recognized that a vehicle is present ahead of the self vehicle. An acceleration/deceleration is obtained from a stored acceleration/deceleration basic map on the basis of a difference between the inter-vehicle distance and a target inter-vehicle distance, and the relative speed with the vehicle ahead, and an acceleration/deceleration correction coefficient is calculated from a correction map set with adjustment constants in correspondence with the measured inter-vehicle distance. An acceleration/deceleration is calculated by multiplying the acceleration/deceleration with the correction coefficient.

Abstract: A proximity warning device for aircraft responds solely to transmissions from transponders. The host aircraft has a host transponder and a signal is generated therein and coupled to the device to indicate transmission of a host reply. Selective suppression is implemented based on presence of an SSR beam which is indicated by the signal. Suppression pulses have a fixed duration but randomly selected intervening durations. Data collection proceeds without regard for suppression or the presence of host replies. The shaping of data collection intervals free of interference from suppression provides for improved efficiency for later data decoding and processing. The signal is used to specially mark collected data generated by a host reply. The ability to discriminate between host and other replies allows completely new performance monitoring functions. In one case, the health of the receiver is deduced from the amplitude of host replies.

Abstract: A vehicle anti-collision device comprising a laser rangefinder mounted inside a vehicle near to a windshield thereof. The distance of the vehicle from a leading vehicle is constantly calculated and sampled at predetermined time intervals, enabling the closing velocity of the vehicle with respect to the leading vehicle to be calculated. A digital speedometer is provided for determining the self-speed of the vehicle whereby the safety time between the two vehicles may be calculated. The safety time is displayed and an audible alarm is sounded in the event that the calculated safety time is less than a predetermined threshold. Preferably, the rangefinder is coupled to the vehicle's steering mechanism so as to be responsive to a turning radius of the vehicle in order that the rangefinder may distinguish between two vehicles travelling in the same lane and in different lanes, respectively.

Abstract: A method for controlling the distance between moving vehicles can be used irrespective of the type of distance detection. The driver interventions which occur in the course of a currently-maintained distance control are detected and evaluated. For this, control devices, which are actuated in the course of the normal travel mode, for example the accelerator pedal, the brake pedal, the indicator lights, etc. are monitored. Conclusions are made as to the driver's current preferences from an evaluation of detected actuations and the driver's reaction time included in the currently calculated set distance is accordingly adaptively corrected. In this manner, dead times are minimized and the most rapid possible adaptation of the distance between vehicles to changing driving behavior of the driver is achieved. As a result, a significantly improved acceptance of a corresponding automatic distance control can be detected.

Abstract: An airport surface traffic surveillance and automation system addresses a wide variety of airport surface conflict scenarios using a combination of runway-status lights, controller alerts, and enhanced controller displays. Runway-status lights, composed of runway-entrance lights and takeoff-hold lights, provide alerts directly to pilots and vehicle operators, to prevent runway incursions before they happen. Controller alerts are used to direct a controller's attention to existing conflicts between aircraft on or near the runways. Enhanced displays present symbology to describe aircraft position, size, direction and speed of motion, altitude, aircraft flight number, and equipment type. Aircraft on approach to runways are also depicted on the displays.

Abstract: This invention provides automatic longitudinal control of vehicles on highways, including speed control and protection against collision. The invention also provides for lane changing, following highway directional changes, route control, and transitions between the operator-controlled and the automatically controlled states. The invention is ideally configured to be employed jointly and cooperatively with previously developed means of automatic lateral control. Groups of permanent magnets are embedded in the highway surface at regular intervals. Permanent magnet sensors are installed in vehicles so that proximity and polarity indications of embedded magnets are obtained as a vehicle proceeds along the highway.

Abstract: An anti-collision system for vehicles includes a speed sensor for sensing the speed of the vehicle, a space sensor for measuring the distance of the vehicle from an object, a computer for computing a danger-of-collision distance to the object, an alarm actuated by the computer when the sensed distance of the object is equal to or less than the danger-of-collision distance compared by the computer, and a brake light actuated upon the actuation of said alarm. The system also includes a control panel having parameter presetting means for presetting preselected parameters concerning the vehicle, the vehicle driver, and the environment, which are utilized by the computer for computing the danger-of-collision distance to the object.

Abstract: A warning system for predicting collision between two or more relatively moving objects, comprising a position determination element for determining at a predetermined frequency for each one of the objects a respective location in space relative to a fixed frame of reference so as to produce successive frames of positional data for each object and a memory element coupled to the position a determination element for storing the successive frames of positional data. A path analysis element is coupled to the memory element and is responsive to successive respective locations of each of the objects for computing a trajectory for each object relative to the fixed frame of reference while an intersection analysis element coupled to the path analysis element and responsive to each one of the computed trajectories predicts whether two or more trajectories will intersect. A warning element is coupled to the intersection analysis element for warning respective ones of the objects of an impending collision.

Abstract: A collision avoidance system for sea navigation comprises, for each equipped ship, a transmitter that repeatedly transmits the geographic coordinates, course and speed of its own ship and a receiver that sends a display device similar data received from other ships. These received data are displayed, mostly in the form of symbols, on the panoramic screen of the display device.

Abstract: The disclosed system has, for each equipped ship, a transmitter that repetitively transmits the geographical coordinates, speed and course of its own ship. Furthermore, it transmits an identification code of any nature serving as an address for the exchange of messages. If it wishes to make concerted arrangements with other surrounding ships in order to perform maneuvers, it sends encoded messages taken out of a glossary.

Abstract: The present invention is concerned with a system in which when the altitude of a subject aircraft becomes lower than a predetermined altitude, a warning limit value is reduced or made equal to zero on the minimum altitude side whereby a useless alarm based on response signals delivered from other aircraft staying in or taxiing in the airport are suppressed.

Abstract: The range from which a collision avoidance system at an Own station can receive SSR interrogations and reply messages from Other stations, is extended by utilizing P2 pulses for timing TOA measurement in the event P1-P3 pulse pairs are unavailable from the scanning main beam or its side lobes. The amplitude of the P2 pulses in the SLS radiation pattern being greater than the P1-P3 side lobes of the main beam over an angular sector of about 60.degree. centered on the main beam can insure reception of P2 pulses at much greater ranges than P3 pulses contained in the main beam side lobes can be reliably received. Using P2 timing, interlaced Mode A and Mode C reply messages contained in a main beam burst reply sequence are separated into two "families" of TOAs, the Mode C (altitude) TOAs always being longer than the Mode A TOAs by 13 .mu.sec. A "true" TOA is obtained by subtracting an appropriate time period from the TOA of each family, from which identity, altitude and range information is readily derived.

Abstract: An improved air traffic control (ATC) system which utilizes traffic alert and collision avoidance systems (TCAS) as a component together with a flight control computer of an aircraft autopilot, a data radio and an interactive touch screen display device to produce a system for allowing easy trailing of another aircraft on trans-oceanic flights and to reduce landing delays at busy airports under IFR conditions.

Abstract: A passive aircraft Traffic alert and Collision Avoidance Device (TCAD) is based on sensing and responding to transponder replies of other aircraft to SSR interrogations. In order to avoid masking other aircraft replies by the host transponder TCAD repeatedly and randomly suppresses the host transponder and simultaneoulsly listens for other aircraft replies. Suppression on each occasion is effective for an equal and predetermined duration which is much longer than a typical replay, in a preferred embodiment the suppression/listen duration is 725 .mu.s. In this embodiment the time between successive suppression/listen occasions is random between 725 .mu.s. and 5.025 ms. with an average value of about 2.9 ms. Digital signal processing is used to detect and discard garbled or overlapping replies. Each valid reply, exhibiting a minimum pulse amplitude, is decoded and correlated with a calibrated range parameter and given a time tag.

Abstract: A craft tracking and collision avoidance system is disclosed. The system allows the positions of a plurality of craft, either on land, sea, or air, or space, to be monitored. Each craft determines its own position using an existing position determining system such as LORAN or GPS. Each craft then transmits a radio frequency signal into which position information, preferably identifying information, and other messages, have been encoded. Each craft broadcasts its position, identifying information and other messages on a regular basis without the need for any interrogation signal. The broadcast position and identification information can be received by other craft and, since each craft has determined its own position, can be used to determine the proximity and identity of other craft, and if the craft are on a collision course.

Abstract: An integrated real-time information dissemination system for aircraft within a predetermined range of an air traffic control facility (ATC), includes airborne components for receiving ground-disseminated data concerning dynamic conditions, such as air traffic and meteorological conditions, and for storing data concerning static features, such as terrain and moving map features, within the range of the ATC. An airborne computer and display is provided in a subject aircraft for generating a continuously updated integrated graphic display of representations of the dynamic and static conditions. The graphic display is egocentric with respect to the ATC until the subject aircraft has been identified to the ATC, after which the graphic display is egocentric with respect to the subject aircraft. The airborne computer includes a computer program for detecting potential collisions with the dynamic or static features and for issuing a warning based upon the level of collision threat.

Abstract: A microwave signal detector system provides a visual indication of the relative bearing of a remote source of microwave energy. An antenna for receiving said microwave energy includes a plurality of microwave-sensitive elements arranged in a planar circular array for receiving pulses from all azimuth directions. Each microwave sensing element is adapted to monitor energy received in a predetermined angular sectors and includes a horn element and a microwave energy responsive diode disposed within said horn element. The diode is connected as part of a voltage divider to develop a noise signal corresponding to the microwave energy received at each sector resulting from vibrations in the diode which occur at an audio frequency. The resultant developed noise signal is digitized and compared to a predetermined threshold to provide an output control signal when the developed signal exceeds the value of the threshold. The output signal drives an LED indicator.

Abstract: In a Traffic Alert and Collision Avoidance System (TCAS), response to interrogations can result in normal, multipath (image), and mixed multipath (potential image) tracks. The method for reducing the number of false tracks includes the steps of selecting a track to be updated from an existing track list. The selected track has the shortest measured range within the highest priority category track. A reply which has not yet been utilized is selected which has parameters which are within predetermined windows of the selected track parameters. (The predetermined windows are equal to or smaller than the windows for lower priority targets.) The selected track is updated using .alpha..beta..gamma. range squared filter, and the selected reply is marked as used. After all tracks are updated, the unused replies are tested to generate new tracks. Then all the tracks are examined to insure that predetermined track category criteria are met, otherwise the track is recategorized.