US 5,208,601 A · All-weather precision landing system for aircraft in remote areas

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. In a preferred embodiment, two (portable) reflectors are utilized in conjunction with an conventional linearly polarized wave airborne radar system (e.g., standard modern weather radar), requiring no modifications to the airborne equipment while still providing an inexpensive means to obtain precise visual indication of glide slope and approach vector information.

Claims15

Dependent claims

An all-weather landing system for aircraft comprising:

radar means housed in an aircraft;
a plurality of passive 90.degree. dihedral corner reflectors positioned in a predetermined array for producing two-bounce reflected signals from incident transmitted signals from said radar means without substantial ground reflections, each reflector producing a reflected signal of the same rotational sense as the incident signal, such that at least two dihedral reflectors are positioned a distance D apart along an axis adjacent an aircraft runway and parallel to said runway centerline, said two dihedral reflectors' vertex junctions being oriented generally perpendicular to said runway surface such that reflected beam signal strength maximums in the plane bisecting each dihedral angle respectively are directed at differing angles with respect to said runway surface to produce a narrow upper reflected beam pattern and a lower reflected beam pattern envelope resulting in a median beam angle along an equal power intersection of said narrow upper and lower reflected beam patterns corresponding to the desired glide slope for said runway;
and
reflection signal processing circuitry means in said aircraft for processing reflected signals from said dihedral reflectors to provide an indication of said approach vector and glide slope of said aircraft.

1 more element

Dependencies are inferred from the claim text.

All-weather precision landing system for aircraft in remote areas

Life of this patent

All-weather precision landing system for aircraft in remote areas

Life of this patent

Abstract

Claims15