Abstract: An air traffic surveillance and communication system for air traffic controllers, includes a plurality of ground based first radio transceivers located in specific geographic sectors, respectively, and having a first frequency channel for supporting party-line digital voice and a second frequency channel dedicated to supporting a digital data channel for down-linking dependent surveillance data and for both up-link and down-link data communications. The first and second frequency channels are paired such that each time a frequency change is commanded by the ground both the first and second frequency channels will be automatically tuned to a new air-ground frequency paid. The system also includes a plurality of aircraft based second digital radio transceivers, one located in each aircraft. Each second radio transceiver has corresponding first and second frequency channels and a navigational data source on each aircraft.

Abstract: In a system for locating a plurality of objects and obstructions and for detecting and determining the rolling status of moving objects, such as aircraft, ground vehicles, and the like, in the area of an airport, a short-range radar network is provided having at least three radar stations. Via simple stationary non-rotating transmitting antennas with coherent time-pulsed microwaves or other microwave signal forms, a large sector in the azimuth of about 90.degree. is illuminated, and the associated fixed receiving antennas, which have fixed subdivided sector characteristics, with one receiving channel per subsector, also receive signals from the other stations for bistatic measurements. The separation of the signals of individual stations is effected by selecting different frequencies, or alternatively, a time triggering of transmitted signals and receiver gates or by station-specific modulation codes. Illumination zones are chosen so there are no shadow zones caused by, e.g., buildings.

Abstract: The radar target simulator serves for the training of air traffic controllers. It comprises a radar device (10) detecting the approach area of a runway, and a display device (17) for displaying the real targets detected by the radar device (10). The display device generates an approach line corresponding to an ideal approach. The instructor position comprises a simulation device (18) for generating simulation targets moving continuously depending on flight parameters of a simulated airplane, which have been inputted. The real targets detected by the radar device (10) and the simulation targets are displayed together on the display device (17). The simulation device (18) is used to check the correctness of the adjustment of the radar device (10). Therefore, an airplane performing an ideal approach is simulated on the display device (17) and it is detected whether there are any deviations of the simulation target from the approach line displayed on the display device.

Abstract: An airport vehicle identification system for improving airport traffic management and collision avoidance, includes a ground surveillance radar and a plurality of low power frequency translators located in spaced relationship about the surface of the airport. The radar system transmits a conventional radar signal for target detection and a beacon interrogation signal for target detection. Each translator is designed to bandshift the interrogation signal to a frequency value compatible with the vehicle transponder, and transmit the bandshifted interrogation signal to the vehicle transponder. Each frequency translator is bi-directional and receives a transponder reply signal indicative of vehicle identity and bandshifts the reply signal to a frequency value compatible with the ground surveillance radar and transmits the bandshifted reply signal to the ground radar.

Abstract: There is provided an aircraft position monitoring system for monitoring the position of aircraft in a ground station. An air-borne sub-system mounted in the aircraft acquires, automatically and periodically, monitor data including data on the aircraft position, ID and FOM. The acquired monitor data is transmitted to the ground station via a satellite communication line or a data communication line. In the ground station, the monitor data sent from the aircraft is sent to a monitoring device and a tracking processing unit. The resultant data is displayed on a display device. The tracking processing unit collates the input monitor data with track data in a track file prepared on the basis of flight schedule data of the aircraft, and determines presence/absence of correlation therebetween by referring to FOM data in the monitor data. On the basis of the determination result, the existing track file is updated or a new track file is prepared. Thus, the tracking processing of each aircraft is performed.

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: An airport vehicle identification system includes a ground surveillance radar system which radiates both a conventional radar signal and a beacon interrogation signal. The radar receives i) a backscatter signal from the skin returns of a target and ii) an encoded ID signal indicative of the target identity. The encoded ID signal is transmitted by a vehicle (e.g., an aircraft) mounted transponder in response to receiving the beacon interrogation signal. The transponder can be located within an external vehicle light housing such as an aircraft collision avoidance light. This invention fills the critical void in airport traffic control of providing ground controllers with electronic airport surface surveillance data which includes both vehicle position and identity.

Abstract: A process for reducing the likelihood of runway incursions wherein the major components of an aircraft are individually tracked by radar instead of tracking only the overall image of the aircraft to more accurately predict possible runway incursions due to the rapid and accurate indication of any change in aircraft orientation during each sweep of the radar.

Abstract: A method and apparatus for monitoring moving vehicular traffic, especially adapted for the detailed profiling and counting of airport usage by aircraft employing Doppler radar and sound generated by target aircraft. A primary parabolic reflector operated in the Cassegrainian mode with respect to Doppler radar radiation, employed in combination with a hyperbolic sub-reflector constructed so that it will reflect the radar radiation but remain transparent to sound waves is used to propagate and receive radar radiation, and to receive sound waves emanating from a target aircraft. Sound waves emanating from the target are received by the parabolic reflector and directed toward the parabolic reflector's primary focus where they strike a microphone placed at the primary focus of such reflector. The signal from the microphone and the information from the Doppler radar unit are processed by a central processing unit to provide a variety of information relating to the target aircraft.

Abstract: A multipurpose system provides radar surveillance for air traffic control purposes. The system includes four separate active phased-array antennas, each with .+-.45.degree. coverage in azimuth, from 0.degree. to 60.degree. in elevation. Each antenna element of each phased-array antenna is coupled by a low-loss path to the solid-state amplifier associated with a transmit-receive (TR) module. Each antenna produces a sequenc of pencil beams, which requires less transmitted power from the TR modules than a fan beam, but requires more time beacuse the pencil beam must be sequenced to cover the same volume as the fan beam. In order to scan the volume in a short time, the PRF is responsive to the elevation angle of the beam, so higher elevation angles use a higher PRF. Low elevation angle beams receive long transmitter pulses for high power, and pulse compression is used to restore range resolution, but the long pulse results in a large minimum range within which targets cannot be detected.

Abstract: A technique is disclosed for multiple sensor tracking which distributes data association and filtering processing among multiple processing entities but coordinates the track estimates such that track states and covariances represent the equivalent of a centralized estimate. The object of the invention is to establish and maintain a single system track for a single aircraft in a distributed processing environment. This is achieved through communication of track information among processing entities which process a single sensor's inputs. Continued updating and re-broadcasting of process data are performed between the multiple sensor's processing entities.

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: 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.

Abstract: It describes a Microwave Landing System wherein.The means for surveillance of the transmissions from the various MLS stations are centralized in a single central station which then commands the various MLS stations. The connection between the central station and the MLS stations is assured by a network of optical fibers.

Abstract: The system comprises a central station assuring the generation of the microwave signals which must be transmitted by the different stations of an MLS. The signals thus generated in a centralized way are distributed to the different stations via an optical fiber network, the stations then assuring only the amplification and transmission of the signals.

Abstract: A method and apparatus for monitoring moving vehicular traffic, especially adapted for the detailed profiling and counting of airport usage by aircraft employing Doppler radar and sound generated by target aircraft. A primary parabolic reflector operated in the Cassegrainian mode with respect to Doppler radar radiation, employed in combination with a hyperbolic sub-reflector constructed so that it will reflect the radar radiation but remain transparent to sound waves is used to propagate and receive radar radiation, and to receive sound waves emanating from a target aircraft. Sound waves emanating from the target are received by the parabolic reflector and directed toward the parabolic reflector's primary focus where they strike a microphone placed at the primary focus of such reflector. The signal from the microphone and the information from the Dopple radar unit are processed by a central processing unit to provide a variety of information relating to the aircraft.

Abstract: A system for transmitting aircraft beacon information received by a secondary surveillance radar through telephone lines to a remote display includes a digitizer connected to the radar for preparing a serial file of data records containing position and identification information of the beacons detected by each sweep of the radar. This information is transmitted through the telephone lines to a remote computer where it is displayed.

Abstract: The locations of aircraft on a first approach to a first runway are displayed on a line substantially parallel to a second approach to a second runway, the second runway converging with the first runway. The distances of aircraft on the first approach from a threshold of landing for the first runway are computed. These distances are used to draw a symbol of aircraft on the first approach onto the line parallel to the second approach at the distances from a threshold of landing for the second runway. The "mirror image" of aircraft displayed on the line parallel to the second approach will aid air traffic controllers in staggering aircraft approaching an airport on converging runways.

Abstract: The method consists mainly in re-creating, from an incoming radar recurrence (R, R'), a corrected recurrence (R.sub.c, R'.sub.c) that has the same characteristics (notably the same sampling frequency and number of samples) but with the samples re-positioned temporally to make the necessary range correction.

Abstract: Transponder reply rate limiting employing a circular memory queue to store the times of prior responses up to the limits of circular memory queue capacity. Separate circular memory queues contain the times of (1) long replies, and both (2) long or short replies. Each circular memory queue has a pointer and several offset indicators which are spaced from the pointer to the time entry positions at predetermined intervals according to corresponding preestablished criteria. After each transponder reply, the time of the reply is entered in the circular memory queue at a next pointer location. Eartimes, i.e., earliest allowable response times, are repeatedly determined and compared to time elapsed from a selected reference time. When the current time exceeds the eartime, for a given inquiry signal, a response signal is generated by the transponder electronics and is transmitted to the inquiring ground station. Eartimes are based upon predetermined criteria of allowable response rates in selected time periods.