Abstract: The surveillance system provides a means to measure Time Difference of Arrival (TDOA) and decode identification of signal source transmissions. TDOA and identification information received from a minimum of two receiving means is used to supplement non-cooperative surveillance systems (e.g., primary radar, acoustic sensors) with target identification. The system uses a Line Of Position technique to determine position. The system can be implemented as a standalone multilateration surveillance system, which provides signal source position determination when reception is available from a minimum of two receiving means. The system provides position aiding when implemented to supplement non-cooperative surveillance systems.

Abstract: In an air traffic control radar system, a processor is described for correlating primary target data received from a target with a target report and a target track, wherein the processor has a search acquisition time that is adapted to the distance of the target from the radar site. The search acquisition time is shorter for more distant targets. The processor can employ a shorter cycle time (time quantum) to establish a correlation between target data and target reports than would otherwise be possible with conventional fixed search acquisition times. The average total dwell time may be reduced while complying with the mandated maximum processing time for more difficult radar reports.

Abstract: A passive millimeter-wave imaging system (10) is disclosed that provides a full 360° instantaneous azimuthal field-of-view (54) image of a scene. The imaging system (10) makes use of a spherical Luneburg lens (12) and a series of millimeter-wave direct detection receivers (24) configured in a ring (16) around the lens (12), and positioned at the focal plane of the lens (12). The series of receivers (24) are positioned on a plurality of consecutive sensor cards (14), where each card (14) includes a certain number of the receivers (24). The receivers (24) define a one-dimensional focal plane array with limited obscuration, and thus give a 360° instantaneous field-of-view (54) of a slice of the scene. Processing circuitry (32), including a multiplexing array interface for multiplexing the signals from the receivers (24), are positioned on an outer ring (34) outside of the sensor card ring (16).

Abstract: An improved traffic alert and collision avoidance method and device wherein TCAS data is augmented by higher resolution radar data. By using radar to search out targets, altitude information can be developed for those aircraft not equipped with altitude reporting transponders. The improved accuracy also allows angle/angle perspective display of air traffic and thus provides enhanced situational awareness.

Abstract: A method and system providing a computer human interface for use by an air traffic controller supported by various GNSS compatible control and management commands. A data entry capability allows the controller to select various GNSS based commands such as arrival and departure clearances to effectively control and manage the flow of traffic using GNSS and its augmentations. GNSS is used as the primary air and surface position and navigation sensor. GNSS compatible travel paths are utilized in clearances, navigation and for conformance and traffic flow monitoring purposes. Two display views enable the controller to observe the traffic situation on one display view, while other display views are predominately utilized for the presentation of control and management system commands, warning alerts, messages and other functions. Controller to Pilot Data Link Capability (CPDLC) for clearances is utilized in conjunction with clearance acknowledgments being generated aboard the cleared aircraft.

Abstract: An Airport Guidance System and Method which provides for GNSS compatible airport guidance capability is disclosed. The computer system provides automated navigation functions based upon GNSS based position and spatially compatible databases. The system and method utilize precise GNSS compatible zones, the Earth Centered Earth Fixed (ECEF) WGS-84 coordinate reference frame, GNSS compatible local coordinate frames such as local and state plane grids, zone-based automated airport control, travel path information management processes which allow for the intelligent control of airport traffic. True airport independent processing is achieved when the ECEF coordinate reference frame is utilized. The navigation methods and processes are applicable to vehicles and aircraft operating in a controlled airport space envelope as well as other remote user sites with or without the assistance of air traffic controller.

Abstract: The invention comprises a mulli-wave radar system for obtaining first target position information of a flying object by capturing and tracking the flying object from a maximum detection distance, a stereo-camera system for taking over the tracking of the flying object in the vicinity of a landing point by acquiring the first target position information of the flying object from the milli-wave radar system, and obtaining second target position information having higher precision than the first target position information, and a controller for managing the first target position information of the milli-wave radar system and the second target position information of the stereo-camera system, controlling the milli-wave radar system to capture and track the flying object to the vicinity of the landing point, and controlling the stereo-camera system to capture and track the flying object at the time of landing of the flying object.

Abstract: An airfield hazard automated detection device having a radar for scanning the airfield for obstacles and an automated target recognition system, operably connected to the radar, for comparing the images of the scans of the obstacles to images of known potential hazards and for instructing a directed imaging system to verify the potential hazard by scanning the potential hazard and indicating the result.

Abstract: A method for designing an aircraft to ground communications system identifies a plurality of unique functions in the communications system. The components, hardware and software, necessary to implement each of the plurality of unique functions are isolated such that the components for implementing a specific function are partitioned to allow independent testing and certification of the hardware and software components for each unique function.

Abstract: A system and method updates flight management files in accordance with the present invention and provides a retrievable record of the flight performance of an aircraft. A flight management computer is positioned on board the aircraft and interfaces and provides flight critical data received from flight navigation database files to a plurality of aircraft navigation and operational components located throughout the aircraft. A ground data link unit includes a data store that accumulates and stores flight performance data. A spread spectrum transceiver coupled to the data store transmits the stored flight performance data and uploads navigation database files over a spread spectrum communication signal. A controller is operatively connected to the data store, spread spectrum transceiver and flight management computer and receives the uploaded flight navigation database files and transfers the database files to a flight management computer.

Abstract: A system and method for providing a retrievable record of the flight performance of an aircraft is disclosed and includes a ground data link unit that obtains flight performance data representative of aircraft flight performance during flight of the aircraft. An archival data store is operative to accumulate and store flight performance data during flight of the aircraft. A spread spectrum transceiver is coupled to the archival data store and includes a transmitter that is operative after the aircraft completes its flight and lands at an airport to download the flight performance data that has been accumulated and stored over one of a plurality of sub-band frequency channels of a spread spectrum communication signal. The frequency is chosen based upon the position of the aircraft determined by an onboard global positioning system. An airport based spread spectrum receiver receives the spread spectrum communication signal from the aircraft and demodulates the signal to obtain the flight performance data.

Abstract: A system and method of the present invention provides a retrievable record of the flight performance of an aircraft and allows exchanging of data to and from an aircraft. A ground data link unit obtains flight performance data. A spread spectrum transceiver is coupled to an archival data store that has accumulated and stored the flight performance data. The spread spectrum transceiver downloads both the flight performance data and data messages over the spread spectrum communication signal as the aircraft approaches the destination airport and after the aircraft completes its flight and lands at the airport. An airport based spread spectrum transceiver receives the spread spectrum communication signal and demodulates the signal to obtain the data messages and flight performance data. A ground based processor coupled to the airport based spread spectrum transceiver receives at least the data message for subsequent processing.

Abstract: A data management system and method that enables acquisition, integration and management of real-time data generated at different rates, by multiple, heterogeneous incompatible data sources. The system achieves this functionality by using an expert system to fuse data from a variety of airline, airport operations, ramp control, and air traffic control tower sources, to establish and update reference data values for every aircraft surface operation. The system may be configured as a real-time airport surface traffic management system (TMS) that electronically interconnects air traffic control, airline data and airport operations data to facilitate information sharing and improve taxi queuing. In the TMS operational mode, empirical data shows substantial benefits in ramp operations for airlines, reducing departure taxi times by about one minute per aircraft in operational use, translating as $12 to $15 million per year savings to airlines at the Atlanta, Georgia airport.

Abstract: A display and methodology visually rendering digital data link communications between aircraft and other aircraft or ground stations. The display may be a TCAS type aircraft display residing in the aircraft cockpit visually displaying the digital data link communications. The display may also be used at a ground location, such as at an air traffic control (ATC) center. Visually displaying the digital data link communications allows a pilot to obtain situational awareness by monitoring the digital communications between aircraft, and may be used in combination with or replace monitoring the voice communications being exchanged over the voice channels. In one embodiment, conversation balloons are associated with aircraft symbology on the display. In another embodiment, messages are arranged in the timeline that can be viewed live, or retrieved via the historical representation of previous messages. A scroll bar is provided as a cursor control device to select messages for display.

Abstract: In a path determining section, an optimum path is calculated based on detection/storage information of a position detector, airport surface information storage section, aircraft information storage section and knowledge information storage section according to an instruction request from a request information input section of an aircraft and is indicated by a path indicator of the aircraft. Further, a collision determining section calculates the possibility of collision on the optimum path obtained in the path determining section according to the coordinates and traveling directions of all of the aircraft based on the above detection/storage information and a warning is indicated by a warning indicator of the aircraft.

Abstract: A collision avoidance system utilizes a satellite navigational system to continuously determine object motion parameters relative to the earth's surface and exchanges this information with other objects. The system calculates collision potential with other objects that are stationary or in motion based on the exchange of the motion parameters. Evasive actions are calculated with congested space and altitude floor taken into account. The system determines collision potential between two or more objects or can utilize a single ground monitor to perform the collision potential calculations between all participating objects.

Abstract: The present automated vehicle travel path determination system which computes a travel path for a vehicle from an origination point to a destination point based on the operating characteristics of the vehicle as well as phenomena extant in the multidimensional space, which phenomena have an impact on the cost of operation of the vehicle. This vehicle travel path determination system can concurrently consider a plurality of vehicle operating characteristics in selecting the travel path. The travel path is optimized for a weighted selection of a number of cost factors, which weighted selection represents a desired combination of cost factors for the operation of this particular vehicle. This vehicle travel path determination system also considers the time varying nature of the phenomena that exist within the multidimensional space and the impact these time varying phenomena have on the vehicle as it traverses the travel path.

Abstract: An aircraft control system which assist in determining aircraft arrival orders and intervals, reduces controller's workloads, and ensures safe aircraft flight operation are provided.

Abstract: An apparatus and techniques for correlating crossing targets in an air traffic control system is described. The technique utilizes a target/track correlation made on the basis of three conditions: (1) separation distance between a target pair; (2) target polarity and (3) a value of a threshold separation value indicator.

Abstract: A method for traffic monitoring, particularly at airports, is disclosed including the localization of a traffic object is carried out by direction finding and by additional information. The radio communication between the traffic object and a control center is recorded and fed to a speech recognition unit on the side of the control center; an identification phrase transmitted together with the message of the traffic object is identified in the speech recognition unit on the side of the control center and allocated to the localized traffic object; and that the allocated identification of the localized traffic object is continuously maintained, the source of the identification being on the side of the traffic object.

Abstract: A method of radar imaging moving objects, especially ground traffic at airports, uses inverse synthetic aperture radar (ISAR). The two-dimensional location distribution of backscatter centers of the object is detected. A plurality of range bins are provided for suppressing of interference, created because of Doppler shifts, in microwave images represented in the form of pixels. Only those pixels are considered to be active which exceed a defined intensity threshold value, which had previously been determined as a fixed fraction of the maximally present pixel intensity. A range area with interference is determined with the aid of a method wherein the threshold is exceeded and wherein the number of active pixels in the individual successive range bins is counted, and wherein image opening is performed in the detected interfered range area, which consists of a succession of a single or several repeated "erosions" and "dilatations".

Abstract: An apparatus and computer-implemented method of determining a probability that a first track and a second track represent the same physical object.

Abstract: The surveillance system provides a means to measure Time Difference of Arrival (TDOA) and decode identification of signal source transmissions. TDOA and identification information received from a minimum of two receiving means is used to supplement non-cooperative surveillance systems (e.g., primary radar, acoustic sensors) with target identification. The system uses a Line Of Position technique to determine position. The system can be implemented as a standalone multilateration surveillance system, which provides signal source position determination when reception is available from a minimum of two receiving means. The system provides position aiding when implemented to supplement non-cooperative surveillance systems.

Abstract: An MTI radar system transmits pulses with variable interpulse time periods and is structured with a lattice filter to process return signals to identify targets while substantially rejecting static and moving clutter. The MTI radar system also operates to reject adverse effects of transmitter instability in the processing of return signals. The MTI radar system is applied as an airport traffic control in which aircraft are detected as targets.

Abstract: A plurality of control terminals are arranged to a plurality of control sections. Flight plan data of each control target aircraft is stored in a flight plan data management unit. The present positions of the control target aircraft are checked and acquired by an aircraft position information acquisition unit. The control states of the control target aircraft are managed by a control progress information management unit. The history of control of each control target aircraft is stored in a control progress information storage unit. A control target aircraft prediction unit predicts control target aircraft after a predetermined time on the basis of the control progress information and flight plan information. A control terminal assignment processing unit increases/decreases the number of control terminals on the basis of the prediction result and determines a control terminal for controlling control target aircraft.

Abstract: A broadband transmitter element, located at a remote object, transmits a broadband signal at a prescribed transmission time. A broadband receiver element, located at a base platform spaced from the remote object, receives electromagnetic radiation during a reception search window. The broadband receiver element stores information characterizing the broadband signal. A synchronizer synchronizes the broadband transmitter element with the broadband receiver element for timing the transmission and reception. A processing device derives an estimated time of flight for the broadband signal to travel from the remote object to the base platform, and a correlation detector, located at the base platform, identifies the remote object and the arrival time of the broadband signal by correlating the stored information with signals received during the reception search window.

Abstract: This invention is a system that monitors many performance parameters and many aircraft operational parameters, and broadcasts this information along with aircraft identification, audio, video, global positioning and altitude data, to a world wide two-way rf network. This information is monitored and recorded at a remote, centralized location. At this location, this information is combined with archived data, ATC data, weather data, topological data, map data, and manufacturers' data. Analysis of this combined data allows identification of problems and generation of advisories. Six types of advisories are generated: maintenance, safety of flight, flight efficiency, flight separation, safe to fly and safe to take off. In the event of a crash the remotely recorded data provides an instant indication of the cause of the crash as well as where the crashed plane can be found. Use of this invention allows replacement of the current, on-board flight data recorders thus saving costs and weight.

Abstract: An apparatus and method for discriminating between false images created by multipath and an aircraft of interest in an air traffic control environment by maintaining a three-dimensional database in the area of interest of the air traffic control environment, the three-dimensional database including a position of a radar radiation source, three-dimensional positions, orientations, and sizes of fixed reflectors and three-dimensional positions, orientations, and sizes of non-fixed reflectors; receiving return radar radiation from an unknown object; classifying the unknown object as an aircraft of interest if the return radiation from the unknown object correlates with previous returns; and classifying the unknown object by searching for a plurality of candidate reflectors and if a sum of the distances between the plurality of candidate reflectors is approximately equal to a distance between the unknown object and the radar radiation source, classifying the unknown object as a false image created by multipath.

Abstract: A method and system supporting seamless 3-dimensional operations in a multi-dimensional environment using orbiting satellite compatible coordinate references and databases. The system includes a control and management element and an aircraft/surface vehicle element. The two elements utilize a common worldwide coordinate reference frame and a common time reference for its operation. Precise collision detection, navigation and 3-dimensional situational awareness functions are performed using precise vector processing algorithms in combination compatible databases. Seamless air and ground operations are supported in such a fashion that the overall processing mathematics are directly applicable anywhere around the globe, only the specific databases need change for any given site. No regional distance scaling corrections or discontinuity compensations are required from site to site anywhere around the globe. Such a system greatly simplifies the operation of airports and other 4-dimensional environments.

Abstract: Air traffic surveillance and communication system for air traffic controllers includes a plurality of ground based first digital radio transceivers, each first digital radio transceiver being 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 pair.

Abstract: A user interface apparatus for an electronic operation strip control system for supporting control services by presenting electronic operation strips used in airport control to a plurality of controllers who carry out airport terminal radar control services and entering control services previously distributed and associated with each other, including an information display device and an instruction input device provided for each controller. Operation strip control information items necessary for respective distributed control services are obtained and inputted into an information processing section, where the items are edited and processed in correspondence with the distributed control services and in accordance with contents of instructions from an instruction input device.

Abstract: A GNSS Based Multi-Dimensional Control and Management System for vehicles operating in a multi-dimensional environment is disclosed. GNSS compatible techniques provide for a seamless airport independent four (4) dimensional vehicular management capability. The system utilizes precise 3-dimensional maps, the Earth Centered Earth Fixed (ECEF) WGS-84 coordinate reference frame, local coordinate frames such as local and state plane grids, zone-based management processing, automated airport lighting control, collision prediction and avoidance processing, 4-dimensional waypoint navigation, and air traffic control and vehicle situational awareness through global management processes that allow for the safe and efficient management of an airport in the air and one the ground. The management methods and processes are also applicable to vehicles and aircraft operating in the airport space envelope as well as other remote user sites with or without the assistance of the air traffic controller.

Abstract: A radar detection system includes a transmitter and a receiver. The transmitter generates a pulse including a first subpulse generated at a first predetermined frequency and a second subpulse generated at a second predetermined frequency. At least one of the first and second subpulses include a digitally adjusted rise time and fall time, each of the rise time and fall time being separately adjustable independent of the other to provide for the relative lowering of transmission power above and below the first and second predetermined frequencies. The transmitter then transmits generated first and second subpulses at the respective first and second predetermined frequencies, as digitally adjusted in rise and fall time.

Abstract: An aircraft landing determination apparatus and method for determining landing status of an aircraft by tracking arriving aircrafts and providing a unique runway assignment therefor. The aircraft landing determination apparatus includes a target processor, a track administrator, and a track reporter. The target processor culls multiple target tracks from a target data transmission provided by a target sensor. The track administrator receives the target tracks, selects at least one arrival track therefrom, and allocates a unique runway assignment to each arrival track. The track reporter receives the arrival track and runway assignment, prepares a track report thereabout, and transmits the track report to a position monitoring apparatus.

Abstract: An aircraft N-number control system includes a receiver for receiving aircraft identification information signals representing alphanumeric characters corresponding to an aircraft. A microprocessor operating in accordance with stored programming instructions processes the received aircraft identification information signals into alphanumeric codes, determines whether there is a substantial similarity between the alphanumeric codes representing two aircraft and generates an output signal representing the alphanumeric codes only if there is no substantial similarity. The alphanumeric codes representing the aircraft are displayed on a air traffic controller's radar screen in response to the output signal.

Abstract: A coherent signal generated at a precise frequency determined by an atomic clock is transmitted by a moveable object. A receiver station compares the frequency of the coherent signal received from the moving object with a second coherent signal generated at the same precise frequency by an atomic clock in the receiver to determine the radial component of the velocity of the moveable object relative to the receiver as a function of the doppler shift of the transmitted signal. Low cost, low power, miniature atomic clocks with an accuracy of 10.sup.-11 make possible accurate measurements of velocities of only centimeters per second. Such velocity measurement can be used to enhance radar tracking in air traffic control and collision avoidance systems.

Abstract: An airport surface traffic system is provided which detects targets moving on an airport surface and automatically adds ID codes thereby reduces the controlling duties of an air traffic controller and elevates safety of an aviation control. An airport surface traffic system comprises airport surface monitoring radars which detects targets moving on an airport surface, ASDE target detector which detects targets by an output signal of the airport surface monitoring radars, a second monitoring radar which receives response signals from airplanes and from an airport monitoring radar which controls airport, ASR/SSR target detector which detects targets, ID code addition apparatus which adds an ID code to targets based on a signal from FDP which stores flight schedule data of airplanes and a multi-function display which displays targets.

Abstract: In accordance with the principles of the invention, a surveillance radar is provided with a rotating, frequency squinting, end-fed slotted array antenna, which is caused to transmit a plurality of different carrier frequency pulses for successively illuminating specific antenna beam positions during rotation of the antenna. Upon reception of each radar signal return, a signal processor responsive to the frequency of each transmitted pulse and the mechanical pointing angle of the antenna at the time of transmission of each pulse, will determine the frequency dependent squint angle for the transmitted pulse and combine that angle with the instantaneous mechanical pointing angle of the antenna at the time of the pulse transmission, to determine the actual beam pointing angle for each pulse at the time of its transmission. A video signal processor groups together the pulse signal returns from physically adjacent ones of the actual beam pointing angles for common processing, i.

Abstract: An airport runway incursion warning system for monitoring air and ground traffic at an airport. The system is optimally used with an aircraft that has an electronic tag or interrogation system that stores identification information regarding the aircraft, and an RF transponder for receiving interrogation signals and for transmitting the identification information in response thereto. A radar system comprises a plurality of radar sensor units disposed at predetermined installation sites adjacent to a runway. Each radar sensor unit typically has an interface processor and telemetry electronics for communication, although hard-wired communication paths may be used. An RF/telemetry interface is provided for communicating with the radar sensor units when the interface processor and telemetry electronics are used. The RF/telemetry interface is also used to transmit the interrogation signals to the aircraft and receive the identification information therefrom.

Abstract: An improved airport control/management system for controlling and managing the surface and airborne movement of vehicular and aircraft within a defined and selected airport space envelope of an airport, the traffic, comprising apparatus for establishing a precise 3-dimensional digital map of the selected airport space envelope, the map containing GNSS positioning system reference points, a computer with a monitor screen for receiving and displaying the 3-dimensional map, transmit and receive radio equipment located on at least one vehicle/aircraft in the airport space envelope to generate and transmit continuous GNSS-based location reports a receiver associated with the computer to receive the reports from the vehicle/aircraft, programming associated with the computer and using the reports to superimpose 3-dimensional image corresponding to a path of the vehicle/aircraft onto the 3-dimensional map, apparatus associated with the 3-dimensional map for generating airport control and management signals as a funct

Abstract: An apparatus for monitoring the position of multiple objects in a space including a target supervisor, a location supervisor, and a hazard monitoring supervisor. The tracking supervisor receives target data from a sensor, characterizes and tracks selected objects, and provides a target output having multiple features respective of the selected objects. The location supervisor characterizes and displays multiple features in the space, and provides a location output having the aforementioned features therein. The hazard monitoring supervisor detects and responds to a predetermined hazard condition, and provides a detectable notice of such hazard condition, responsive to the target output and the location output. A data logger for selectively retains the target output, the location output, or both. The position monitoring apparatus has six modes: full operation, non-airport-surveillance-radar, isolation, set-up, adaptation, and simulation.

Abstract: An airspace management system and method includes an alternate quick look mode display option which allows a user to designate a specific geographic region for display in a specified area on a display screen. Within this specified area, which can encompass a portion or all of the display screen, radar plot data is displayed for at least one aircraft for which input radar information is received. Symbols can be assigned to aircraft to differentiate friend and enemy aircraft; colors can be assigned to differentiate friend and enemy aircraft and plots; and radar-measured height information can optionally be displayed. In this quick look mode, near real-time positions for all aircraft within the quick look mode window are displayed, since selection of the quick look mode window bypasses normal time-consuming tracking information processing.

Abstract: An improved airport control/management system for controlling and managing the surface and airborne movement of vehicular and aircraft within a defined and selected airport space envelope of an airport, the traffic, comprising apparatus for establishing a precise 3-dimensional digital map of the selected airport space envelope, the map containing GNSS positioning system reference points, a computer with a monitor screen for receiving and displaying the 3-dimensional map, transmit and receive radio equipment located on at least one vehicle/aircraft in the airport space envelope to generate and transmit continuous GNSS-based location reports, a receiver associated with the computer to receive the reports from the vehicle/aircraft, programming associated with the computer and using the reports to superimpose 3-dimensional image corresponding to a path of the vehicle/aircraft onto the 3-dimensional map, apparatus associated with the 3-dimensional map for generating airport control and management signals as a func

Abstract: A system for identifying the location of an aircraft on the surface of an airport includes a plurality of low power FM transmitters located along the boundaries of runway and taxiways. Each transmitter provides an FM signal having a common carrier frequency and each FM signal is encoded with unique information indicative of the position of the transmitter on the airport surface. Aircraft and other vehicles containing a conventional FM receiver "capture" only the strongest signal and process the "captured" signal to determine which transmitter was the source of the signal and hence where the aircraft is on the airport surface.

Abstract: The present invention relates to an airplane detection system to surely detect an airplane moving along a runway or a taxiway. The system employs a wheel detection sensor for providing a wheel detected output when emitted electromagnetic waves are blocked by the wheels of the airplane and a fuselage detection sensor for providing a fuselage detected output when receiving the reflection of the emitted electromagnetic waves from the fuselage of the airplane. According to the output signals from both the sensors, the system detects the airplane.

Abstract: Monitoring an area with the aid of a frequency-modulated continuous-wave radar includes emitting a frequency-modulated continuous-wave transmitting signal with at least one transmitting antenna having a directional pattern whose main azimuthal direction depends on the frequency of the transmitting signal. Related to a predeterminable direction, an azimuthal region is selected, and in the selected region, an azimuthal swivelling of the directional pattern of the transmitting antenna is carried out by changing the frequency of the transmitting signal. Also in the selected region, each azimuthal value is assigned a frequency value of the transmitting signal. The selected region is divided into a predeterminable number of azimuthal increments adjoining one another, and in each of the increments, a monotonous change of the frequency of the transmitting signal occurs.

Abstract: The surveillance radar device comprises, in combination, a fixed antenna for providing electronic scanning of space in bearing in the horizontal plane, a transmit source and microwave frequency transmit/receive means with a circulator, a transmit channel, a receive channel and means for subdividing the receive channel into a sum signal and at least one difference signal. A first and a second receiver element with frequency change respectively receive the sum and difference signals, and provide numerically coded outputs. Processing means process numerical signals from the first and second receiver elements for the radar detection of objects in the zone under surveillance.

Abstract: A millimeter wave radar is placed on an aircraft and several radar targets are placed near a runway. The targets are discrete objects, each having a relatively localized radar cross section, a unique signature or a unique range bin, and a position which is accurately known. Targets should be spread over the length of the runway. Radar corner reflectors and active or passive repeaters are preferred. The locations of the radar targets with respect to the runway can be transmitted to the aircraft, or they can be stored on board. On board memory requirements can be reduced by requiring all airports to select one of only a few standard target placement patterns, or even only one. Targets are inexpensive, as are radars whose only precision requirement is in range, and not in azimuth or elevation angles. Range to at least three targets in the radar's field of view is all that is required for an on-board computer to determine the aircraft's location.

Abstract: The invention relates to a method for monitoring an area by a plurality of economical radar systems. These systems operate with CW modulation at low transmission power and can therefore be fully realized in semiconductor technology. The area is divided into base cells that are directly contiguous without gaps.

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.