Abstract: A commucations navigation system in which data is transmitted and received between a navigation base apparatus provided at a navigation base and a vehicle navigation apparatus provided in a vehicle using communication. The vehicle navigation apparatus is adapted to transmit at least data concerning the current position of the vehicle and the destination thereof to the navigation base apparatus, and the navigation base apparatus stores navigation data in its data base and is adapted to determine a recommended route based on the transmitted data of the current position of the vehicle and the destination thereof and then extract data of the recommended route from the navigation data stored in the data base and transmit the extracted data to the navigation apparatus.

Abstract: Man-machine interface (MMI) for airport traffic control purposes, in particular for safe taxiing and/or approach-departure control at an airport, having a display area on which processes and states at the airport, for example the movements and the current position of aircraft, the switching state of lighting systems, etc., can be displayed and influenced. The display area is designed with a screen whose diagonal is more than 19 inches, preferably more than 21 inches.

Abstract: A landing guidance system is disclosed for use with helicopters or other aircraft during the terminal phase of approach to a marine structure, such as a moving ship at sea. Signals from shipboard pitch and roll position sensors are routed to a signal processor that computes stabilization corrections which, in turn, are applied to a multi-axis electromechanical system that moves internal elements of an optical system to compensate for motion of a shipboard platform resulting in a stabilized optical presentation in inertial space to the pilot of an approaching aircraft. A dual display is provided through the use of a spectral beam splitter that allows both an infrared and visible display to be presented to an approaching pilot. This allows the pilot to use the display with and without night vision devices. The visible energy display to the pilot is color-coded with three distinct colors.

Abstract: A vertical lift aircraft, such as a helicopter, can land in an area with impaired visibility such as fog. Around the landing area is a plurality of laser beam emitters. The emitters project a pattern of laser beams skyward. The helicopter finds the general area by spot-lights pointing up through the fog, or by navigation. As the helicopter approaches, it sends a radio signal, which is detected on the ground. The spot-lights are switched off and the laser emitters are switched on. The helicopter is positioned within the pattern so that the laser beams reflect off of a portion of the aircraft, such as the rotor blades. This forms a visual cue, which the pilot uses to maintain the position of the helicopter relative to the landing area and descends thereto.

Abstract: Monitoring and control apparatus for fail-safe monitoring for normal operation of traffic signal lights provided at an intersection or the like where a plurality of roads intersect. The illumination conditions of respective signal lights are detected using as sensor device, and when the number of illuminated or non-illuminated signal lights is a predetermined number, a normal judgment output of logic value 1 corresponding to a high energy condition is generated while, when the number of illuminated or non-illuminated signal lights is not the predetermined number, an abnormal judgment output of logic value 0 corresponding to a low energy condition is generated. As a result, when a fault in the monitoring apparatus stops the output, the resultant output condition is the same as for a danger condition due to a signal light abnormality, resulting in an extremely safe signal light monitoring and control with excellent fail-safe characteristics.

Abstract: An image processing apparatus and method for identifying a safe landing location on the surface of the moon or planets calculates local average brightness and brightness variance in a neighborhood of each image pixel based on a digital image data obtained with a camera and determines whether each pixel represents a level and flat area based on the local average brightness and brightness variance calculated for each pixel, thereby extracting a desirable landing site.

Abstract: The present invention concerns a device for indicating the position of an aircraft (H) notably a helicopter (H) with respect to a beam (F).In accordance with the invention, said indicator includes fixed first means (6) indicating the position of said aircraft (H), movable second means (7) indicating the position of the beam (F) in a predefined direction with respect to said aircraft (H), and third means (8) indicating which way to steer the aircraft (H) in the predefined direction to capture the beam (F) to said third means (8) being activated only when the aircraft (H) has crossed the beam (F) completely and is outside it.

Abstract: An Automatic Long-Life Infrared Emitter & Locator System which may be used to locate persons in need of assistance or marked objects is disclosed. Since the emitter (10) operates continuously and emanates infrared radiation (21) that can not be seen by the user, no affirmative action is required to activate the emitter (10). One of the preferred embodiments of the present invention (10) includes a flexible plastic or rubber housing (12) having an opening (15) that is specially shaped to fit over and to finly grasp a conventional electrical battery (16). A lens (18) residing on the top of the housing (12) passes invisible energy issuing from an infrared emitting diode (20) deployed beneath it. The diode (20) is connected to the battery (16) by leads (19) through a pulse control circuit (22). This circuit (22) produces intense and regular spikes of energy that cause the diode (20) to flash over a period of many weeks.

Abstract: Systems and methods for an integrated approach lighting system are described. An integrated approach lighting system includes a threshold bar and a plurality of lighting towers. The systems and methods provide advantages in that pilots are given a precise three dimensional visual reference to the aircraft's position relative to the runway's centerline, threshold crossing and height above the airfield. This provides the pilot with a higher concentration of visual information to insure faster decision making and an easier, more accurate and safe approach to landing.

Abstract: An Airport Guidance System and Method which provides for GNSS compatible seamless airport guidance capability is disclosed. The computer system provides a automated lighting 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 lighting control, travel path information management processes which allow for the intelligent control of airport lighting systems. True airport independent processing is achieved when the ECEF coordinate reference frame is utilized. The lighting 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: An electrical strip of infrared radiating elements which is powered by a battery and rolled up on a wheel and has many advantages over the present device. The first is visibility. It is highly visible at over three miles and the system is a 3/4" strip with LEDs placed every meter and on both sides that is rolled up on a reel. To deploy the marker the strip can be staked or held at one end while the strip is simply unrolled of the reel. The PIRM is self packing and, if packaged to do so, can automatically roll itself up. The PIRM can be operated either by a switch on the reel or remotely, by laser remote control or by a switch on the reel. The flashing pattern is completely programmable. The pattern can be used as a wind direction indicator. The speed it flashes can be used to indicate how hard the wind is blowing or how dangerous the landing zone is.

Abstract: In this application are disclosed a variety of improvements to the original system. These improvements provide for greater utility, effectiveness, and ease of manufacturing of the laser visual landing aid system.

Abstract: A microprocessor-controlled airfield lighting control and monitoring system having bi-directional communication between the controlling microprocessor and the airfield lights and/or sensors. The system also includes a metal container for the remote control microprocessor and an improved attachment arrangement for the power transistor associated therewith. A DC power supply is connected to the remote controller microprocessor and has an integrated circuit adapted to sense a threshold voltage, which causes the power transistor to short around the associated power source.

Abstract: A wake turbulence avoidance light system is provided including an aircraft runway with a periphery including a pair of long parallel side edges and a pair of short end edges. Also included is a plurality of light assemblies mounted along at least one of the side edges of the runway in spaced relationship. A plurality of sensors are adapted for indicating a point on the runway at which a plane has departed. Finally, control circuitry is connected between the light assemblies and the sensors for indicating a location of the point by illuminating a light assembly adjacent thereto, as detected by the sensor.

Abstract: A method and system for visually guiding a vehicle to an approach corridor and subsequent landing, parking, or docking zone. As a vehicle approaches the designated landing, parking, or docking zone, the pilot is visually guided into the approach corridor by one or more pairs of guidance light units. Each guidance light unit has at least an affirmative color light segment and a negative color light segment. The affirmative color light segment indicates affirmative approach, landing, parking, or docking conditions and the negative color light segment indicates negative approach, landing, parking, or docking conditions. The colored light segments of the guidance light units are positioned and oriented such that the affirmative color light segment either corresponds with the approach corridor or provides visual guidance to assist the pilot in guiding the vehicle into the approach corridor by defining outwardly extending guidance corridors.

Abstract: A microprocessor-controlled airfield series lighting circuit communications system and method allows bi-directional communication between the controlling microprocessor and the airfield lamps. The bi-directional communications signals are formed by using a modulated radio-frequency signal that is transmitted through a circuit containing many transformers having their primary windings connected in series. Respective secondary windings of the transformers are connected to various devices, such as lamps or sensors. A high frequency signal is imposed on the series-connected primary windings to control the lamps. The frequency of this signal is selected to be able to be detected on the secondary side of the transformer. A remote controller is connected to the secondary of each transformer to receive the control signal and selectively switch power obtained from the transformer secondary to the respective connected device.

Abstract: A remote control device for an automotive vehicle wherein a transmitter (10) is received in a holder (2), with side-marker lights and taillights staying on, to connect holder-side contacts (3, 4) to transmitter-side contacts (16, 17), and the transmitter (10) is removed from the holder (2) to disconnect the transmitter-side contacts (16, 17) from the holder-side contacts (3, 4). A differentiating circuit (21) detects the disconnection of the transmitter-side contacts (16, 17) from the holder-side contacts (3, 4) by the removal of the transmitter (10) in the on position of the side-marker lights and taillights, and a timer (22) clocks a predetermined timer time over which LEDs illuminate manipulation keys (12) of the transmitter (10). Only the removal of the remote control transmitter from the holder permits the manipulation keys to be readily illuminated.

Abstract: A system for enhancing navigation or surveillance in low visibility conditions is realized by employing one or more ultraviolet radiation sources, a receiver which is capable of producing output signals from which a two dimensional image of the received radiation can be constructed, and a display device for displaying such image. In one preferred embodiment the ultraviolet radiation source is co-positioned with a critical marker such as a runway beacon or hazard beacon. The ultraviolet radiation emanates from the source, preferably modulated to form a repetitive, characteristic signal, propagates through the low visibility atmosphere, and received by the ultraviolet imaging receiver. In another preferred embodiment, an ultraviolet radiation source is placed at or near the ultraviolet imaging receiver, that is, onboard the same vehicle or at the same fixed location. One or more reflectors are co-positioned with the critical markers.

Abstract: An automatic control system for a series circuit, in particular for airport signaling lights, physically separated from the work circuit feeding the lights and galvanically separated from the latter, includes a computer; several Main Stations each containing several Main Modules, each controlling several Remote Modules which check and act on a single airport light, each of said Main and Remote Modules having firmware boards; a full duplex transmission network linking the computer with the Main Stations; each Remote Module has externally two pairs of electric terminals of which one pair is connected to the secondary of an insulating transformer making part of the work circuit and the other pair is connected to a light or a group of lights being controlled, the two pairs of electric terminals being connected to each other by electrical leads, wherein connected in series to one of the electrical leads is a coil which is magnetically coupled to a Hall sensor of the Remote Module; and further including an electron

Abstract: The present invention includes an airfield lighting and control system for energizing at least one airfield control device and containing a ground fault detection system, comprising: (1) at least one airfield control device; (2) an AC electrical circuit conducting an AC signal and connected to said at least one airfield control device; (3) an inductive device, in electrical contact with said AC electrical circuit, which comprises (a) an inductive coil having an input pole and an output pole, and being loaded by a capacitor; (b) a driver winding for the inductive coil, the driver winding adapted to sense AC current flow through the inductor coil; (c) a sampling resistor connected to the driver winding and adapted to detect AC current in the form of a voltage across the sampling resistor; (d) signal processing circuitry comprising: (1) an inverting amplifier adapted to amplify the voltage; and (2) a phase shifter adapted to shift the phase of the voltage; and (e) a power amplifier connected to the signal proces

Abstract: A control system includes at least one guiding device including a long range guiding water jet generator having a plurality of first nozzles each projecting a jet of water upwardly and a first illumination apparatus projecting a plurality of beams of light upwardly each in concert with the jet of water projected from each of the first nozzles so as to guide the flight vehicle along a predetermined direction when the flight vehicle is located at a longer distance relative to the guiding device and a short range guiding water jet generator having a plurality of second nozzles each projecting a jet of water upwardly and a second illumination apparatus projecting a plurality of beams of light upwardly each in concert with the jet of water projected from each of the second nozzles so as to guide the flight vehicle along the predetermined direction when the flight vehicle is located at a shorter distance relative to the guiding device.

Abstract: The invention provides a layered modulation data communication systems characterized by numerous, asynchronous data transmitters operating on a power line. Data is modulated onto relatively low frequency subcarriers. Subcarriers are used to modulate carriers centered on a common frequency. The subcarriers are frequency division multiplexed. Data is recovered by demodulating the subcarriers from the carriers and subsequently demodulating the data from the subcarriers.

Abstract: A light unit has a strobe operated flash tube and a non-strobe peripheral lamp immediately beneath the flash tube; a switch can turn the unit off, operate either light or enable the pilot of an aircraft to signal the light unit to operate the flash tube or to turn off the flash tube and operate the non-strobe peripheral lamp, by means of a radio receiver having a local oscillator midway between two standard distress frequencies. The light unit may have infrared or other color lenses. A ribbon assists establishing a pattern of light and/or colors to mark a landing site and indicate wind direction.

Abstract: A microprocessor-controlled airfield lighting control and monitoring system having bi-directional communication between the controlling microprocessor and the airfield lights and/or sensors. The system also includes a metal container for the remote control microprocessor and an improved attachment arrangement for the power transistor associated therewith. A DC power supply is connected to the remote controller microprocessor and has an integrated circuit adapted to sense a threshold voltage, which causes the power transistor to short around the associated power source.

Abstract: In an arrangement for supervising and controlling field light units (20) at an airport, a regulator provided with a monitoring unit for power supply and for monitoring the light units is arranged individually for each light unit (18,20) to regulate the light intensity of the light units and to receive information as to their operational status. In a preferred embodiment, each light unit comprises two separate light sources that can be alternately and separately connected into circuit in case of failure to either of the light sources. Each light unit is provided with an electronic unit including a regulator, monitoring unit, and modem for power supply to the light unit and for monitoring the operation of the light unit. Each light unit is individually addressable from a control central for the airport. A ground traffic control system can be integrated into the field lighting system by connecting suitable presence detectors to the system.

Abstract: A runway marker has a pair of upwardly converging reflectant planar panels facing approximately in opposite directions. In its correct attitude on a support surface the panels slope at 2.degree.-6.degree. to the vertical if the marker is intended for assisting the landing of fixed wing aircraft and at 8.degree.-10.degree. to the vertical if the marker is intended for assisting the landing of helicopters. The reflectant panels are preferably retroreflectant.

Abstract: A method and apparatus for determining the presence of a burned out lamp of a traffic signal is disclosed. The current applied to one or more banks of traffic signals and the voltage applied across such traffic signal banks are measured simultaneously. An electrical characteristic, such as impedance, of such traffic signal banks, is measured for each pattern of switch settings which control lamp illumination for signalling as they occur. Such characteristic is stored for each of the unique patterns which are repeated over and over again to control traffic. Such previously stored characteristic provides a baseline characteristic for each successive pattern of illumination of the lamps. With each pattern change, such characteristic is measured and compared with the previous baseline characteristic for the pattern to determine if a lamp has burned out.

Abstract: A runway lighting system comprises a series runway transmission line providing current to a plurality of runway lamps. A failed lamp indicator (FLI) connects across the terminals of each lamp to determine when the lamp is malfunctioning. When the FLI determines that a lamp is malfunctioning, the FLI transmits a malfunction signal, during a specific time period defined in lamp address circuitry in each FLI, onto the existing series runway transmission line. A circuit status analyzer (CSA), which forms part of the vault computer, receives the malfunction signal, noting the time period during which the signal was received. The CSA then accesses an internal ROM look-up table to determine which FLI sent the signal.

Abstract: A pattern of light is projected from multiple sources located on an aircraft to form two clusters. The pattern of each cluster changes as the aircraft flies above and below a predetermined nominal altitude. The initial patterns are two horizontal, spaced apart lines. Each is capable of changing to a delta formation as either the altitude or the terrain varies. The direction of the delta cues the pilot as to the direction of corrective action.

Abstract: A docking target (10) includes three concentric circles (C1, C2, C3) each comprising a plurality of different color light emitting diodes (D1, D2, D3) spaced about the circumference of each circle (C1, C2, C3). During vehicle approach, each circle appears initially as a light spot, then a continuous ring of light and finally a plurality of independent light points at defined distances of the vehicle (14) from the station (12) so that the operator can determine distance of the vehicle (14) to the target (10). The light emitting diodes (D1, D2, D3) on each circle, when visible, provide attitude information of the vehicle (14) with respect to the station (12) by the intensities of the light emitting diodes (D1, D2, D3) and the geometric shape produced thereby so that the operator can adjust the attitude of the vehicle (14) with respect to the station (12).

Abstract: A method and apparatus for aiding a landing aircraft. Three differently-colored beams of laser light are produced and transmitted, one of the beams of laser light being transmitted in a plane containing the direction from which the aircraft is approaching. Another of the beams of light is transmitted on one side of the plane, and the third of the beams of light is transmit on the other side of the plane. The pilot of the aircraft can determine whether the aircraft is on the plane or to the one side or the other by the color of the light the pilot receives. If desired, at least one of the colored laser beams that is transmitted toward one side of the plane can be broken into a plurality of adjacent fan-shaped beams, the light in at least one of the fan-shaped beams being interrupted intermittently.

Abstract: In an arrangement for supervising and controlling field light units (20) at an airport, a regulator provided with a monitoring unit for power supply and for monitoring the light units is arranged individually for each light unit (18,20) to regulate the light intensity of the light units and to receive information as to their operational status. In a preferred embodiment, each light unit comprises two separate light sources that can be alternately and separately connected into circuit in case of failure to either of the light sources. Each light unit is provided with an electronic unit including a regulator, monitoring unit, and modem for power supply to the light unit and for monitoring the operation of the light unit. Each light unit is individually addressable from a control central for the airport. A ground traffic control system can be integrated into the field lighting system by connecting suitable presence detectors to the system.

Abstract: A beacon device for alerting friendly personnel on land, sea or air, from close proximity up to several miles, that the beacon location is also friendly, is contained in an upright case that has an least one infra-red (IR) light emitting diode and a visible light emitting diode clustered together at the top of the case, from which overlapping IR and visible light beacons emanate upward when the case is upright and means including one or more switches on the device or remote from the device are provided for controlling electric power to the diodes. In a preferred embodiment an adjustable collar surrounding the clustered diodes is moveably attached to the case and is moveable downward on the case to intercept less of the overlapping beacon light so that the elevation angle (.theta.) of the beacon is relatively low and is moveable upward on the case to intercept more of the overlapping beacon light so that the elevation angle (.theta.) of the beacon is relatively high.

Abstract: Apparatus for indicating to a vehicle or craft a desired path of travel, comprising a body including a plurality of systems adapted to emit electromagnetic radiation over a desired path, means partially to mask electromagnetic radiation emitted by at least some of the systems, and means to rotate the systems whereby the systems and mask means provide continuous and flashing electromagnetic signals for indicating a desired path for a vehicle or craft. The apparaus is particularly suitable for guiding helicopters during landing.

Abstract: The invention relates to a method and an installation for providing an aircraft with alignment guidance during the approach stage. At least three flashing lights are disposed on either side of the runway and directed towards an approaching aircraft. The beam directions and the timing of the light flashes are such that the pilot of an aircraft lying on the axis of the runway sees the two lights closest to the runway flash simultaneously, whereas the pilot of an aircraft that is too far to one side or the other of the axis of the runway sees a series of light flashes that appear to be running towards the axis of the runway.

Abstract: A disc arrangement is provided for positioning about airport lights for inhibiting erosion and suppressing foliage.

Abstract: A portable warning light system is made up of a main frame member which is pivotally mounted on a trailer, a pair of light bars are pivotally connected on the main frame for movement in a plane parallel to the frame between a retracted or travel position and an extended position, and the main frame can be selectively positioned at different angles between the vertical and horizontal.

Abstract: Optical guidance system for the night landing of aircraft on a landing area along a determined approach path, which comprises two horizon reference luminous bars (1, 2) disposed in alignment with each other in a horizontal direction substantially perpendicular to the approach path, and two azimuth overshoot indicating lamps, respectively to the left (5) and to the right (6), located at the outer ends of the pair of horizon reference bars and provided with masks (8) in order that they can only be seen by the aircraft if the latter overshoots the approach path in azimuth to the left and to the right respectively.

Abstract: A spectral analyzer and direction indicator system (10) is disclosed and includes optical channels (20,30,40) for providing detected optical information indicative of incidence direction and spectral content of incident radiation. Each optical channel includes a reflector element (11,17,23) having a non-ruled section (11a, 17a, 23a) and a spectrally dispersing ruled section (11b, 17b, 23b); an analytical optical system (13,19,25); and a detector array (15,21,27). For each reflector element the non-ruled section is tilted in one or two directions relative to the ruled section. The disclosed spectral analyzer and direction indicator system is advantageously utilized as an aircraft based sensor in an aircraft landing system having ground based lasers (29L, 29R, 33L, 33R, 37L, 37R) directed into the landing approach path.

Abstract: A ground light or beaconing system for a landing strip having at least one loop of lamps connected in series. Said loop is supplied by a solar cell, via a regulating circuit ensuring the preheating of the lamps while also maintaining a current flowing in the loop adapted to its operation.

Abstract: An improved runway lighting system comprises a first set of runway lights providing illumination in one direction along the runway, a second set of runway lights providing illumination in the opposite direction along the runway and a switching unit for switching on either the first set of lights or the second set of lights, depending on the direction of approach of incoming aircraft. A control unit provides current pulses along existing runway circuitry to operate the switching unit. Circuitry in the switching unit determines which set of lights to illuminate based upon the amplitude and duration of the current pulse. A selector switch may also be provided in the control tower to remotely operate the control unit.

Abstract: The landing approach aid for aircraft exhibits, on the one hand, triple mors (4,6) on the landing field. On the other hand, the aircraft (1) is provided with a spotlight, a television camera in the vicinity of the spotlight (at 3) and a device for displaying and/or evaluating the recorded television images. (FIG. 1).

Abstract: A portable infrared landing site illumination system is provided for fixed ing and rotary wing aircraft having night vision capabilities as provided by the Army's second generation goggles (PVS-5) or the third generation goggles (ANVIS). The system employs special markers assembled from readily available disposable components and a simple above ground mounting stake. Also provided is a special laser illuminator which operates in several modes to assist all phases of the landing operation.

Abstract: A traffic signal made up of a conventional stop and go configuration of lamps and switching means with an improved lamp control and improved lamps. The lamps are of the incandescent type, preferably having two filaments. The filaments are connected to a source of electrical current. The current is supplied through an electronic circuit providing electrical current of a first polarity alternately to one of the filaments and electrical current a second polarity alternately to the second filament. It has been discovered that this alternate energizating of the filaments gives a scanning effect that is more conspicuous and has greater attention getting qualities under all viewing conditions.

Abstract: A computerized flight inspection system is disclosed. The system of the present invention may be utilized to generate an accurate reference location with respect to an airport runway for an aircraft having an inertial navigation system. A selected geometric pattern having a highly unambiguous autocorrelation function is placed on at least one end of the runway. A video line scanning camera mounted to the aircraft is then utilized to scan the geometric pattern in a line generally perpendicular to the line of flight. The output of the video line scanning camera is then correlated with a stored reference pattern to generate a signal indicative of the detection of the geometric pattern on the runway. A laser altimeter is mounted to the aircraft and utilized to generate an accurate signal indicative of the aircraft altitude with respect to the runway pattern. The outputs of the correlation circuit and the laser altimeter are then utilized to correct data from the inertial navigation system.

Abstract: A passive type forward/aft indicator for mounting on an aircraft refueling tanker. The indicator providing the appearance of an ascending liquid thermometer for guiding an aircraft to be refueled. The indicator providing proper longitudinal positioning underneath the tanker. The indicator can be used equally well for space docking and other types of rendezvous missions.

Abstract: An active, electro-optical display system for use on fixed-wing, land-based airport runways, is disclosed for remotely guiding a pilot during visual approach and landing of an aircraft. Conventional Microwave Landing System (MLS) ground-transmitted data is air-derived on board the aircraft and data-linked to a ground receiver to produce a continuous digital data signal indicative of aircraft slant range, elevation and azimuth relative to the desired landing position. The resulting data signal is electrically coupled to a signal processor governed in accordance with control guidance laws to produce three discrete signals indicative of the magnitude and direction of the descent rate error, the flight path acceleration, and the lateral drift rate of the aircraft relative to the intended landing area.

Abstract: A glide slope indicator system in which light from an incoming aircraft's landing light is shaped by spherical/cylindrical lens combination into a line image which strikes a linear photodiode array. By determining which photodiode in the array the center of the line image strikes, the glide slope angle can be determined. An appropriate signal is communicated to the pilot via a pair of indicator lights mounted on the runway depending upon whether the aircraft is above, below or on the desired glide slope angle.

Abstract: A diffuse incandescent runway marker light apparatus has a housing with a visible light diffusing plate mounted in one end and an infrared light diffusing plate mounted in the other end, and a pair of incandescent light sources mounted in the housing and aimed toward the respective housing end plates. A switch, when flipped to a first position, turns on one light source for producing visible illumination and turns off the other light source. The switch, when flipped to a second position, turns off the one light source and turns on the other light source for producing infrared illumination. In such manner, the appropriate type of illumination for marking the runway for overt or covert landing operation may be selected. When the switch is flipped to a third position, both light sources are turned off.

Abstract: A runway collision avoidance system having warning devices is provided for the safety of aircraft taxiing, taking off, and landing. The system is capable of detecting ground traffic and obstacles including aircraft, maintenance vehicles and wildlife that may encroach upon an active runway during low visibility conditions or when visual observation is impaired. The system includes an electromagnetic transmitter positioned beyond one end of a runway which directs a continuous beam of high frequency radio signals, for example microwaves, longitudinally along the full length of the runway. A plurality of electromagnetic receivers positioned beyond the other end of the runway pick up the transmitted signals and apply them to a balance circuit and then to a comparator circuit. With a clear runway, the transmitted signals are received without interruption and the receiver outputs remain balanced or equal.