Abstract: A vehicle locator includes an on-board computer and a ground penetrating radar mounted on the vehicle that is communicably connected to the on-board computer. A reflective landmark is located at a known location along the path of the vehicle. The reflective landmark includes reflective elements arranged to encode data. The ground penetrating radar transmits signal energy and detects reflected signal energy reflected by the reflective landmark and communicates encoded data representative of the reflected signal energy to the on-board computer. The on-board computer decodes the encoded data and thereby determines the location of the vehicle.

Abstract: A portable sensor calibration target includes a frame assembly, a first panel, and a second panel. The frame assembly may include three legs and a plurality of frame edges that is configured to form a first frame and a second frame and is configured to be held at a pre-selected height above ground by the legs. The first panel is removably attached to the first frame in an unfolded position, and includes a plurality of boards and a plurality of hinges connecting the plurality of boards. The first panel is configured to fold at the plurality of hinges into a folded position. The second panel is removably attached to the second frame adjacent to the first frame. The first panel and the second panel meet to form an edge, which is detectable by a detection system of a vehicle for calibrating the detection system.

Abstract: This invention is a novel retroreflective traffic stripe comprising a widely spaced repeating pattern of linear light turning prisms over cube corner retroreflective prisms in a critical optimal configuration. The light turning prisms comprise at least two exposed surfaces, one approximately vertical facing the headlights of oncoming traffic, and another opposing the first and sloped by approximately 45 degrees. The approximately vertical surface efficiently accepts light from the headlights and transmits such light to the sloped surface which totally internally reflects such light downward onto an array of cube corner retroreflective prisms, which totally internally reflect such light in approximately the reverse direction.

Abstract: An apparatus interfaces with a light stanchion associated with a runway. The apparatus can include a first interface for attaching to the light stanchion, second interface for attaching to runway light, and a radar reflective member. The radar reflective member can be a corner reflector. The radar reflector can be part of set of reflectors arranged in accordance with visual approach slope indications or precision approach path indications.

Abstract: A system and method include scanning a light detection and ranging (LIDAR) device through a range of orientations corresponding to a scanning zone while emitting light pulses from the LIDAR device. The method also includes receiving returning light pulses corresponding to the light pulses emitted from the LIDAR device and determining initial point cloud data based on time delays between emitting the light pulses and receiving the corresponding returning light pulses and the orientations of the LIDAR device. The initial point cloud data has an initial angular resolution. The method includes identifying, based on the initial point cloud data, a reflective feature in the scanning zone and determining an enhancement region and an enhanced angular resolution for a subsequent scan to provide a higher spatial resolution in at least a portion of subsequent point cloud data from the subsequent scan corresponding to the reflective feature.

Abstract: An apparatus and method for joint calibration of vision and radar sensors for an autonomous device is disclosed. The apparatus may include a spherical portion and a cutout portion. The cutout portion may be formed within the spherical portion and have three equal surfaces. Additionally, the apparatus may include a trihedral reflector positioned within the cutout portion.

Abstract: An apparatus is disclosed which may serve as a target for calibrating a camera. The apparatus comprises one or more planar surfaces. The apparatus includes at least one fiducial marking on a planar surface. The set of all planar markings on the apparatus are distinguishable.

Abstract: A conforming radar reflector that includes a thin, metallic reflector layer with a plurality of corner reflectors formed or molded. The shape and orientation of the corner reflectors on the reflector layer produce a strong radar return signal and enable the reflector to bend and conform to the shape of a support object or surface. The corner reflectors are recessed cavities with three converging reflecting surfaces oriented 90 degrees apart from each other and attached at their adjoining edges. Adjacent corner reflectors are rotated and offset approximately 60 degrees. When viewed from the front, six adjacent corner reflectors are aligned in radial pattern each with one vertex pointing to a common center. Disposed between the outer perimeter edges on adjacent corner reflectors is flexible intermediate section that acts as a living hinge that enables the reflector layer to be bent along the intermediate section to conform to an outer surface.

Abstract: The apparatus of the present invention provides on-board detection systems such as automotive CAS radars the ability to react to small aspect ratio targets at an off angle to the road greatly increasing the ability of the operator of a vehicle to avoid a collision with cyclists, motorcycles, mobility devices, pedestrians and other difficult aspect ratio targets. The apparatus of the present invention is passive and can be adapted to a number of mounting schemes covering a broad spectrum of small aspect ratio targets. Examples include mounting the apparatus to the frame of a bicycle, the fender of a motorized mobility device, a motorcycle or attached to the crutch or walking stick of a pedestrian.

Abstract: An inflatable dummy target fittable into a carrier missile capable of being released from the carrier missile during exo-atmospheric flight; upon release, the dummy target or portion thereof is capable of being inflated and manifest characteristics that resemble GTG missile characteristics, wherein the GTG missile characteristics include IR signature, RF signature and GTG missile.

Abstract: A conforming radar reflector that includes a thin, metallic reflector layer with a plurality of corner reflectors formed or molded. The shape and orientation of the corner reflectors on the reflector layer produce a strong radar return signal and enable the reflector to bend and conform to the shape of a support object or surface. The corner reflectors are recessed cavities with three converging reflecting surfaces oriented 90 degrees apart from each other and attached at their adjoining edges. Adjacent corner reflectors are rotated and offset approximately 60 degrees. When viewed from the front, six adjacent corner reflectors are aligned in radial pattern each with one vertex pointing to a common center. Disposed between the outer perimeter edges on adjacent corner reflectors is flexible intermediate section that acts as a living hinge that enables the reflector layer to be bent along the intermediate section to conform to an outer surface.

Abstract: The invention provides a reflective material, adapted for the efficient retro-reflection of radiation emitted by radar, the material comprising a multiplicity of reflective entities which are typically embedded in a substrate, the multiplicity of reflective entities being comprised in at least one reflective surface or electrically conducting surface, and the at least one reflective surface or electrically conducting surface comprising an electrically conductive coating, a high permittivity material, a foil, a film or a fabric formed from electrically conducting fibres or filaments. The reflective entities may comprise discrete shaped entities, most preferably di- or tri-hedral shaped entities, which are preferably embedded in a high permittivity medium. More preferably, the reflective entities are comprised in the machined surface of a reflecting substance comprising a polymeric sheet material which is machined to provide an irregular patterned surface.

Abstract: A passive wireless tag assembly comprises a plurality of antennas and transmission lines interconnected with circuitry and constructed and arranged in a Van Atta array or configuration to reflect an interrogator signal in the direction from where it came. The circuitry may comprise at least one surface acoustic wave (SAW)-based circuit that functions as a signal reflector and is operatively connected with an information circuit. In another embodiment, at least one delay circuit and/or at least one passive modulation circuit(s) are utilized. In yet another embodiment, antennas connected to SAW-based devices are mounted to at least one of the orthogonal surfaces of a corner reflector.

Abstract: An apparatus is described for measuring the earth surface movement by means of SAR images; the apparatus comprises at least one SAR radar (10) placed on a satellite or on an aeroplane and at least one electromagnetic wave reflector (1) placed on an earth surface portion to be measured. The at least one SAR radar comprises means (11) for transmitting an electro-magnetic signal (60) onto said reflector and means (12) for acquiring the electromagnetic signal (61) reflected from the reflector; said SAR radar is adapted to acquire reflected signals along ascendant (50) and descendant (51) orbits. The reflector comprises, in a single piece, a first trihedron (2) configured for reflecting the signal transmitted by the SAR radar along ascendant orbits (50) and a second trihedron (3) configured for reflecting the signal transmitted by the SAR radar along descendant orbits (51).

Abstract: The present invention relates to a decoy for deceiving Doppler radar systems. The decoy comprises a corner reflector, where at least one of the surfaces (1) is arranged to be able to obtain a varying reflectivity for radar radiation with a modulation frequency, which in the reflected radiation causes Doppler sidebands of an extent that is usual for the radar application.

Abstract: A biconic radar reflector permits boats to be seen on large ship radars. The biconic radar reflector may give a continuous azimuth lobe and a wide elevation lobe in order to maximize the probability of being seen on a ship radar. The biconic radar reflector may give a solid 360 degree azimuth lobe and a wide 80 degree elevation lobe. The biconic radar reflector may give improved detection probability, as compared to conventional corner reflectors, especially in the case of heavy rain clutter, where right circular return is 20 dB over the rain clutter. The biconic radar reflector may be made of two truncated conic sections, facing each other along a vertical axis so that a 90 degree angle is between them.

Abstract: A system and a method for detecting an intrusion in an area by disposing a plurality of corner reflectors therein, interrogating and receiving successive response signals therefrom, and operating a control unit, coupled to a radar, the control unit being operative to compare and detect a change in returned signals for each one interrogation. A change to the returned signals, say above a certain threshold of change, may be proof that an intrusion had taken place.

Abstract: The invention proposes to provide distraction spoofing even on modern infrared, radar and dual-mode guided missiles (4) by production of a decoy chain (20). The chain (20) is formed by a plurality of apparent targets which are switched successively, for example by firing of individual chaff submunitions (2.1-2.5). The deployment takes place before or during the search phase of the missile and can in this case, for example, be carried out using the reverse walk-off principle or at the same time simultaneously or successively and in the form of a pattern. This ensures that the decoys (2.1-2.5) act initially in the greatest selected range zone away from the target (3). The spoofing chain (20) created in this way results in the missile (4) having to carry out a series of time-consuming analysis processes on its way to the target (3).

Abstract: A modular RCS (Radar Cross Section) and IR (Infra-Red) signal generation device includes: a plastic bag which is normally stored in a folded state, and inflated when gas is introduced into the bag as desired; a radar reflector received in the plastic bag, the radar reflector being configured in a multi-hedral reflector structure having a reflection characteristic similar to that of a naval vessel to be protected; hot air tubes formed through the plastic bag, hot air being capable of generating IR signals by flowing through the hot air tubes; and connection patches positioned on one of the surfaces of the plastic bag at the points where the ends of the hot air tubes intersect with the surfaces, respectively, the connection patches being adapted to be attached to those of adjacent modular RCS and IR signal generation devices, respectively, so as to interconnect the hot air tubes with those of the adjacent modular RCS and IR signal generation devices.

Abstract: A buoyant target comprises an inflatable structure with a drogue chute attached to the periphery of the bottom of the inflatable structure. The drogue chute is an open flexible structure with a bottom end weighted with ballast to deploy it, and with ports through its side to permit water to flow into and out of it. A radar reflector device is attached inside the inflatable structure. The radar reflector device comprises a plurality of mutually orthogonal radar reflective surfaces having central reflection vectors pointed at predetermined directions.

Abstract: The present invention relates to a decoy for deceiving radar systems, especially Doppler radar systems. The decoy comprises a corner reflector, where at least one of the surfaces (1) is arranged to be able to obtain a varying reflectivity for radar radiation, especially with a modulation frequency which in the reflected radiation causes Doppler sidebands of an extent that is usual for the radar application.

Abstract: A radar reflector which can be deployed from an aircraft and is intended to fly freely after deployment, and which includes multiple reflector surfaces that are essentially plane in an operative state and which issue in pairs in opposite directions from an essentially plane base plane. The radar reflector before deployment can be stored compactly, packed up into the minimum possible volume. This facility for packing the radar reflector up has been achieved in that its reflecting main surfaces have each been divided up by means of specially aligned buckled folds into a plurality of parts which can be folded in towards one another when the reflector is to be folded up.

Abstract: A radar reflector which can be deployed from an aircraft and is intended to fly freely after deployment, and which includes multiple reflector surfaces that are essentially plane in an operative state and which issue in pairs in opposite directions from an essentially plane base plane. The radar reflector before deployment can be stored compactly, packed up into the minimum possible volume. This facility for packing the radar reflector up has been achieved in that its reflecting main surfaces have each been divided up by means of specially aligned buckled folds into a plurality of parts which can be folded in towards one another when the reflector is to be folded up.

Abstract: A radar decoy having radar reflectors disposed in the interior of the inflated canopy of a descending parachute as a first set of four corner reflectors, and a second set of corner reflectors disposed on the exterior of the canopy integral with the first set of corner reflectors, to form an octahedron of eight corner reflectors. The radar decoy is pliable and folded with the parachute for stowage in the interior of a canister. When loaded on a vehicle flying in a trajectory, the canister may open at a point P on the trajectory, to release the parachute, and thereby deploy the radar decoy to become operative.

Abstract: A rocket tube for housing a reloadable rocket motor is connected to a spacer element and a wire-rider element. A sensor target for reflecting radar signals is screwably attached to the rocket tube. The sensor target is provided with a plug for effectively sealing one end of the rocket tube with the other end of the rocket tube being utilized to reload a rocket motor upon completion of a test firing. A guide wire is threaded through the wire-rider element with the guide wire serving as a travel path. The rocket tube, spacer element, and wire-rider element are connected in an easily assembled, aerodynamic manner that allows for multiple radar tests using the same components within a brief time period.

Abstract: A heat seeking missile decoy device mounted on a military vehicle to change the infrared signature of the military vehicle. The device is at ambient temperature when stored on the military vehicle. When a heat seeking missile is fired at the military vehicle, the decoy device deploys and increases in temperature, changing the infrared signature of the vehicle and causing a hot spot away from vulnerable components of the vehicle. The hot spot radiates in the infrared in an area that is away from vulnerable parts of a military vehicle, drawing the heat seeking missile toward it. The termination trajectory of the heat seeking missile is at the end of the decoy device and not the vulnerable parts of the military vehicle. The energy required to heat the device is passive waste energy from the vehicle engine exhaust.

Abstract: In a countermeasure system for an aircraft, a countermeasure module includes a chamber. Countermeasure equipment is housed in the chamber of the countermeasure module. An attachment mechanism allows for releasable attachment of the countermeasure module to an aircraft. A flight mechanism is provided on the countermeasure module for returning the countermeasure module to a location, such that when an aircraft to which the countermeasure module is attached reaches a desired airborne position, the attachment mechanism releases the countermeasure module from the aircraft, and the flight mechanism on the released countermeasure module returns the countermeasure module to the location.

Abstract: An apparatus for detection of any intruder passing through an electronic wall is disclosed. The electronic wall is formed by a millimeter-wave radar positioned at one end of the wall and a plurality of combinations of plane reflectors and retroreflectors placed along the floor of the wall as well as on structures at both ends. The wall is formed of a plurality of electromagnetic beams with each beam having two segments, one between the radar antenna and a plane reflector and the second segment between the plane reflector and a retroreflector. A sufficient number of beams inhabit the wall volume to make traversing the wall by an intruder without detection essentially impossible, even though the intruder should attempt such detection avoiding methods as crawling under or jumping over the assumed locations of the beams. The primary means of determining that an intruder is traversing the wall is the detection of one or more electromagnetic beams being partially or completely blocked.

Abstract: A guide marker includes a substrate and a radio-wave reflecting unit for reflecting radio waves at certain intensity in all directions in a virtual plane, including the incident direction of the radio waves, the radio-wave reflecting unit being provided in the surface of the substrate. The radio-wave reflecting unit includes a concave and convex portions provided in the substrate or radio-wave reflectors which resonate at the frequency of incident radio waves and which reflect the radio waves in the incident direction. The radio-wave reflectors are mounted on the substrate. A visual guide marker device includes one of a light-reflecting component having a reflection characteristic and a light-generating component which self-generates light, and a guide marker including a dielectric material.

Abstract: The present invention provides an electromagnetic reflector comprising a deployable support frame carrying at least one sheet element designed to form a reflective surface when in the deployed state, wherein the support frame comprises a band that is suitable for being packaged in a folded state and that is suitable for returning to a deployed state in the absence of external constraint, the band being in the form of three rings that are orthogonal in pairs, and the reflector further comprising eight generally triangular panels of sheet material.

Abstract: The present invention relates to a device forming an electromagnetic reflector comprising a deployable support frame (100) carrying at least one cloth element (200) designed, in the deployed state, to form a reflective surface, the device being characterized by the fact that the deployable support frame (100) comprises at least one deployable arm (120) that is telescopic.

Abstract: An array of corner reflectors is used to provide a retro-reflector for a large range of incident angles. A novel orientation of the individual corner reflectors is used. This allows the interior of a first corner to remain visible while the interior of a second corner becomes visible. This may be done while maintaining a phase coherence between the contributions of the first and second corner reflectors. Phase coherence ensures constructive interference among the returns from the first and second corner reflectors. Coherence is achieved by an arrangement which places the interior vertices of the corner reflectors close to each other. One such arrangement also places the peak return from one corner reflector acting as a dihedral between the locations of the dihedral and trihedral returns of a second corner reflector. This arrangement results in a substantially uniform and strong retro-return. Phase coherence may be maintained over a desired range of elevation angles.

Abstract: Method and apparatus for a miniature omni-directional corner reflector (MOCR) and an array thereof. In one aspect, the invention comprises the application of MOCRs in an amorphous configuration to produce a reflective coating. The geometry, matter, and size dictate the principle behavior of the MOCR to reflect incident electromagnetic radiation back toward the source of illumination. The omni-directionality topology, miniature size, and powder form of individual MOCRs eliminates the need for a particular orientation of individual MOCRs when applied as a reflective coating or layer to a desired object or structure.

Abstract: A fast deployment and retrieval system permits the rapid deployment of a decoy in seconds in response to an incoming threat, thus eliminating the necessity of pre-deployment, with retrieval permitting reeling in and deployment of the decoy a number of times during a mission in response to threats, and a commensurate reduction in life cycle cost. Upon detection of an incoming threat by a warning receiver, a controller coupled to a transmission releases a brake that is utilized to control the speed of deployment, whereas upon retrieval, the transmission drives a motor for retrieval of the decoy. The system is thus reusable, fast reacting, and also minimizes range penalty considerations because the decoy is only deployed when needed. In one embodiment, the system accommodates both a towing cable and a fiber-optic signal cable in which apparatus for unwinding of the cables is mechanically ganged together so that the cables pay out at the same rate.

Abstract: A guide marker includes a substrate and a radio-wave reflecting unit for reflecting radio waves at certain intensity in all directions in a virtual plane, including the incident direction of the radio waves, the radio-wave reflecting unit being provided in the surface of the substrate. The radio-wave reflecting unit includes a concave and convex portions provided in the substrate or radio-wave reflectors which resonate at the frequency of incident radio waves and which reflect the radio waves in the incident direction. The radio-wave reflectors are mounted on the substrate. A visual guide marker device includes one of a light-reflecting component having a reflection characteristic and a light-generating component which self-generates light, and a guide marker including a dielectric material.

Abstract: The present invention relates to a device forming an electromagnetic reflector comprising a deployable support frame (100) carrying at least one cloth element (200) designed, in the deployed state, to form a reflective surface, the device being characterized by the fact that the deployable support frame (100) comprises at least one deployable arm (120) that is telescopic.

Abstract: The present invention provides an electromagnetic reflector comprising a deployable support frame carrying at least one sheet element designed to form a reflective surface when in the deployed state, wherein the support frame comprises a band that is suitable for being packaged in a folded state and that is suitable for returning to a deployed state in the absence of external constraint, the band being in the form of three rings that are orthogonal in pairs, and the reflector further comprising eight generally triangular panels of sheet material.

Abstract: The invention is a radar decoy which electronically simulates objects by generating radar detectable signals over the entire microwave frequency range. The simulator includes a series of tuned, spaced diode networks for generating carrier suppressed doppler side bands. Each diode network operates at a single, different frequency. The diode networks are enclosed by a corner reflector which modulates the amplitude and the phase of an impinging radar signal. The diode networks are controlled by a switching network which turns the diodes on and off at a desire frequency to produce a doppler frequency shift and thereby simulate moving objects.

Abstract: An apparatus for the detection of any intruder passing through an electronic fence is disclosed. The electronic fence is formed by a millimeter wave radar positioned at one end of the fence and a plurality of reflectors placed along the floor of the fence as well as on a structure at its far end. The fence is formed of a plurality of electromagnetic beams traversing between the radar antenna or antennas and each of the reflectors. A sufficient number of beams inhabit the fence volume to make traversing the fence by an intruder without detection essentially impossible. The radar reflection from the intruder's person is used to report the location of an intruder attempting to traverse the electronic fence near the radar end and is the secondary means of detection at greater ranges where breaking of one or more electromagnetic beams constitutes the primary means of detection.

Abstract: A detection system for small water craft, such as a kayak. Radar reflective material is incorporated in the surface of the kayak or other water craft, and also is incorporated in surface areas of water craft accessories, such as cushion, life vest or paddle. When the smaller water craft is in the vicinity of a larger aircraft which may be radar equipped so that there is danger of a collision or where the water craft is in a position where it would want detection as part of a rescue effort or the like, the water craft is oriented so that the radar reflective surface would reflect radar back to the sending source, thus better enabling detection. Also, the paddle or other water craft accessory could be positioned so as to reflect the radar waves. Further, the paddle or other accessory could be oriented to reflect the radar waves back to the source, or do so intermittently, in the event that the radar system is programmed to ignore a constant reflective signal.

Abstract: Three reflector plates comprising: a lateral reflector plate having two half plates each opposingly placed across a rotation supporting shaft introduced therebetween, a longitudinal reflector plate having two half plates each opposingly placed across the rotation supporting shaft therebetween, and a bottom reflector plate placed at the central portion of the rotation supporting shaft, wherein these three reflector plates are brought into mutual orthogonal intersection at their diameters, and the rotation supporting shaft is provided with an inclination supporting hole with an inclination of a "detection design angle", thereby enabling to maintain the detection design angle when in use and enabling to easily assemble into the shape for use even in case of emergency, and further enabling the reflector plates to be stacked flat one upon another and stored free from bulkiness when not in use.

Abstract: An apparatus and method for providing small size, high gain corner reflection of radio frequency signals for use in military and commercial applications. Conventional corner reflector practice is combined with electronic amplifying reflection devices such as the superregenerative amplifier to provide an array of antennas and amplifiers spread over each planar surface of a corner reflector. The specific antenna used may be selected from a plurality of various antenna types depending on the application. As in a conventional corner reflector, the amplified signal is reflected at the same angle and in the opposite direction of the incident signal.

Abstract: A microwave radar reflector includes three, substantially planar networks whose reflectivity or transmissivity may be controlled. The three networks are arranged as a trihedron with an open angle. An additional network, whose reflectivity or transmissivity may be separately controlled, is located at said open angle of the trihedron. With the additional network controlled to be transmissive and the other networks having their characteristic modulated between reflective and transmissive, the reflector will return a modulated message when the reflector is illuminated.

Abstract: Retroreflective target for laser ranging embodying at least one hollow cube corner retroreflector constituted by three reflective surfaces which are substantially planar and perpendicular to each other and intersect at three edges which are substantially orthogonal and converge at an apex (S), the cube corner retroreflector being associated with a geometrical normal at the same angle to each of the edges, the target including a reference point (O) substantially on the normal on the opposite side to the reflective surfaces at a distance e..sqroot.

Abstract: A cube-corner retroreflector for laser telemetry corrects speed aberration .delta. and has three substantially orthogonal mirror surfaces defining three substantially orthogonal edges converging at an apex. Each edge is associated with the surface substantially orthogonal to it. The shape of each surface is at least approximately that of a portion of a cone whose axis is coincident with the associated edge. The generatrices of this portion of a cone have a non-null average generatrix slope relative to a plane perpendicular to the axis of the portion. The average .alpha..sub.0 of the average slopes of the surfaces at least approximately satisfies the equation:.alpha..sub.0 .about.0.2.delta./kwhere k is a predetermined parameter dependent on the number, the geometry and the refractive index or indices or the media constituting the interior volume of the retroreflector.

Abstract: There is disclosed herein a system for reflecting electromagnetic radiation emanating from a doppler-based radar source toward the source whereby at least a portion of the difference between the emanating and reflected signal is continuously varied between preselected limits by causing the reflector to oscillate along the beam axis. The reflector is moved between approximately 0.001 and 0.250 inches and at a frequency mix ranging between about 2,000 Hz and 15,000 Hz. The reflector is mounted to a reciprocating system which is provided to drive the reflector.

Abstract: A coating composition for the attenuation of the reflection electromagnetic radiation and particularly electromagnetic radiation have a wavelength of greater than 800 nm including the near infrared is described. The composition comprises a chromophore capable of absorbing up to about 95% of the electromagnetic radiation having a wavelength greater than 800 nm. Optionally, the composition may comprise microbeads that serve the purpose of also scattering the electromagnetic radiation.

Abstract: A technique for determining the spin history of kinetic energy penetrator projectiles. The method employs a special dihedral plug fitting in the rear (tracer well) of the penetrator projectile that produces a modulation of the tracking radar's signal. This signal is recorded and analyzed to yield the rotation rate of the projectile as it travels down range.

Abstract: A spacecraft for geodetic applications designed to travel along a trajectory in an orbital plane around a planet, embodying at least one cube corner retroreflector designed to face the planet at least temporarily and having an apex, a normal, and three faces which are substantially orthogonal with respect to one another, to within an arcminute, forming three dihedral angles at substantially equal angular distances from this normal, the effective diameter of this cube corner being at least 3 centimeters, the apex being located, relative to the center of mass of the spacecraft, at a distance whose projection on an imaginary line joining the center of mass to the center of the planet remains at all times at a known value to within variations of less than 5 centimeters.

Abstract: An apparatus for use, for example, as a runway radar signal reflector, for reflecting incoming radar signals, which includes a reflector for reflecting the radar signals, a chamber through which the incoming signals pass on the way to the reflector, and a mechanism for periodically creating a plasma in the chamber so as to prevent the incoming radar signals from being reflected.