Abstract: Apparatus for detecting the position of a vessel in a broadcast image of the radar scan in a radar monitored area includes a television monitor for displaying a broadcast image of a radar scan of the area, and a controllable reflector for varying reflection of the radar waves impinging thereon from the monitoring radar to produce identifiable signal components in the broadcast image of the radar scan received on the television monitor. This controllable reflector may be actuated by the vessel operator to vary the reflection of the radar waves and produce variations in the broadcast image to enable the operator to identify the position of the vessel in the radar scan image appearing on the monitor. The monitoring installation includes a monitoring radar transmitter/receiver, and a television transmitter televising an image of the radar scan. Desirably, it includes a scan converter which receives the signals in polar coordinate form and provides rectangular raster signals with X and Y coordinates.

Abstract: A remote radar phase calibrator that provides radar phase measurement and libration. A trihedral or dihedral reflector placed in the radars field of view provides an amplitude calibrated phase stable signal to the radar. Movement of the reflector head-on to the radar provides a phase angle measurement that varies as a function of the radars transmitted wavelength and the distance the reflector is moved.

Abstract: An all-weather aircraft landing system includes a plurality of ground based passive 90.degree. dihedral reflectors for producing two-bounce reflected signals without ground reflections, and an airborne radar system which may transmit and receive "same sense" circularly polarized radiation, while completely rejecting "opposite sense" polarization returns or else utilizing them to indicate weather conditions. Radar clutter from objects such as rain, buildings and trees which produce opposite sense reflections are rejected by the "same sense" receiver or switched to an "opposite sense" receiver to provide weather/obstacle condition information. By properly orienting a plurality of 90.degree. dihedral angle reflectors of a particular size in a predetermined array pattern and tilt-angle adjacent a runway, the reflections from airborne radar signals are processed and displayed to provide a visual means for determining glide slope deviation and approach vector of the landing aircraft.

Abstract: An even-bounce reflector for calibrating the orthogonal polarizations of a radar system. A segment of a cylindrical reflector is fixed to a flat plate reflector with the angle between the segment of a cylinder and a flat plate being substantially 90 degrees.

Abstract: An array of twenty corner reflectors with each corner reflector consisting f three mutually perpendicular reflecting planes whose intersection lie at a common point. The twenty corner reflectors are, in turn, configured to provide omni-directional reflection to incoming electromagnetic waves, while maintaining strong reflection characteristics.

Abstract: An array of reflectors of electromagnetic waves comprising a plurality of trihedral reflectors (10 to 17) arranged about a vertical axis (21) with each reflector orientated about its major axis (22) so that the plane bicseting the angle between two panels (18) is vertical and with adjacent reflectors turned through 60 degrees about their major axes (22) relative to one another, characterised in that the reflectors (10 to 17) are tilted relative to said vertical axis (21) of the array with the adjacent sides (37) of adjacent reflectors diverging so that the major axes (22) of the reflectors are directed from the vertices (19) at the required angles of elevation. Preferably, the horizontal sides (24) of alternate reflectors (14 to 17) at the top terminate closely adjacent to corners of intermediate reflectors (10 to 13). The sides (37) of adjacent reflectors diverge towards the bottom to form triangular gaps (38) therebetween.

Abstract: A radar reflector provides an enhanced radar cross section pattern in one plane and this improved radar detectability in that plane. The radar reflector comprising a trihedral corner reflector arrangement having three planar faces at right angles to each other, a first planar face substantially triangular in shape having a right angle representing a common vertex, second and third planar faces joined at inner edges of the second and third planar faces to form a center line extending from the common vertex and each joined to the first planar face at straight sides extending from the common vertex such that the reflector is symmetrical about the center line, the center line being shorter than the two straight sides.

Abstract: An aircraft structure for the minimization of microwave energy reflection from the aircraft back to a receiver. The provision of structural configurations and materials operate to reduce microwave energy reflection toward its source or another receiver located at a level below the aircraft and laterally or forward thereof.

Abstract: A new type of passive trihedral corner reflector is described which rotates the polarization of a reflected microwave beam by 90.degree. and thereby permits a reflected radar beam to be more easily distinguished by the interrogating radar system from the random reflections from nearby objects, i.e., clutter. Rotation of the incident beam is provided by locating a passive polarizing or "twist" grid of closely spaced thin parallel wires spaced above one conducting surface by air or by a dielectric to give an electric spacing from the surface of about 0.25 .lambda.. The spacing of the wires is less than 0.25 .lambda. so that the wires constitute a reflecting surface for signals polarized parallel to the wires. The reflector can have triangular or square sides which are mutually orthogonal. In a preferred embodiment the reflector is tipped forward by 35.degree. from a reference horizontal plane and tilted clockwise in a vertical reference plane by 15.degree. to optimize reflections.

Abstract: A radar reflector (4, 5) comprises a hollow, generally spherical or conical radar transmitting housing (6) containing a radar reflecting assembly (10) having a number of trihedral cube corner reflecting elements arranged in strings one above the other and with a number of the strings arranged side-by-side around the inside of the housing (6). The radar reflecting assembly (10) may comprise strings of reflecting elements with the origins of all of the reflecting elements lying on and being arranged around a frusto-conical surface and with all of the reflecting elements facing outwards. Preferably, the radar reflecting assembly (10) comprises at least three strings of single or double-handed helical reflecting element arrays (20) arranged side-by-side.

Abstract: A method for producing a spherical radar reflector containing triple reflectors and composed of identically shaped eighths of a sphere is described. The eighths of the sphere consist of foam material and their plane surface, which are in contact with each other, are constructed to be reflecting. The eighths of the sphere are individually expansion molded in appropriate molds and the plane surfaces of the eighths of the sphere are covered with material reflecting radar rays. This material can consist of metal foils or can be a mixture of an adhesive and of metal particles which are uniformly distributed in the adhesive.

Abstract: A reflecting target device usable in space or on earth in the testing and simulation of weapons and other energy radiating space hardware. The disclosed embodiment includes an icosahedral reentrant cavity structure providing both infrared and radio-radar frequency retroreflective capability through the use of corner reflectors, conductive grid wires and coating layers. Launch-related apparatus are also described.

Abstract: A corner radar reflector that backscatters cross-polarized returns from a linearly polarized source is formed by three mutually perpendicular surfaces forming a concave structure. At least one of the surfaces has a depolarizing characteristic. The depolarizing surface is comprised of a grid of thin mutually parallel wires closed spaced. These wires reflect the parallel tangential component of the incident field but do not reflect the orthogonal component. Beneath the wires is a sheet of microwave absorbing material to absorb the energy that was not reflected by the wire grid.

Abstract: A system to provide warning whenever unreliable data is being received by an airborne receiver for a microwave landing system. The received data is tested against certain criteria to determine validity. The received data is also tested to determine whether it was received via a direct path or via a multipath reflection. A validity counter records the percentage of valid data received. A multipath counter records the length of time data is received via direct path relative to the length of time data is received via multipath. Both counters control warning flags to cause a warning to be generated whenever the counter contents are below threshold values. The validity counter is set to an upper limit when its count crosses the threshold in a positive direction and is set to a negative limit when its count crosses the threshold in a negative direction.

Abstract: This invention allows for the use of safety apparatus at the front and rear of the automobile, which serve as an addditional pair of "eyes" for the driver. The apparatus comprises a security system for the prevention of automobile collisions. The apparatus at the front of the automobile is connected to the front wheel system or to the steering mechanism by an appropriate rotary device which revolves so that the beams or waves do not encounter vehicles in oncoming lanes going in the opposite direction. The electronic safety apparatus emits beams or waves whose length is automatically regulated to correspond to weather conditions and to the speed of the vehicle so as to ensure safe braking distance.