An aircraft instrument landing system for use on an aircraft runway to guide approaching aircraft along a glide path comprising in combination first and second directional transmitters to be disposed on the left and right sides of a runway for transmitting radio signals which will overlap including a high frequency oscillator complex for supplying a high frequency output carrier signal from each transmitter and modulator means for each transmitter supplying a pair of different identifiable modul...

This invention provides a thin microwave absorbing wall member using a ferrite plate of which complex permeability is represented substantially by a formula:

A combined microwave and standard ILS system. Course information for at least one of the localizer and glide-slope functions is transmitted in the microwave frequency region, down-converted in the air and mixed into the clearance channels where it overrides standard clearance signals in substantially the same way as with standard ILS course signals on a landing approach. The system is compatible with existing airborne ILS equipment.

A method and apparatus for adjusting the modulation signal levels of overlapping beams which define along points of equal signal levels within the overlap a directional axis which in turn defines a desired navigation course for an airplane or similar maneuverable apparatus. At points offset from the directional axis, one or the other of the modulation signals will be greater in magnitude, depending on the direction of offset. The included angle between the two locus of points representing a pred...

A dual I.L.S. glide slope system for allowing a normal 3.degree. descent path plus an additional 6.degree. descent path which can be used for noise abatement procedures etc. In accordance with the present invention these glide slopes are provided on a single assigned R.F. channel with no inverted courses interposed. The first signal null will occur at 9.degree. elevation when all signals will be zero, producing a "flag" alarm.

A two-frequency capture-effect instrument landing system employs a single localizer antenna array for both course-frequency and clearance-frequency radiation. The composite course and clearance signals are formed by networks that utilize trees of hybrid power dividers to effect unequal power division and distribute the signals to the antenna feeders. Integral monitoring is provided by similar networks, operating backwards in a functional sense, which recombine samples of the RF energy on the ant...

In an antenna array for radiating Instrument Landing System localizer signals, a method for reducing the required number of antenna elements by the combination of average element to element spacing exceeding one wavelength and end-fire directive antenna elements which suppress spurious radiation that would otherwise occur.

A microwave radiometric landing assist system is provided which serves as an aid for landing aircraft, for example, and which may complement the present practice of using visible light sources for runway guidance. The landing assist system of the present invention involves the use of passive metallic objects positioned on the ground in a predetermined pattern. These objects are detected by a microwave radiometric receiving system located in the aircraft, and which likewise may be considered pass...

A receiver system for determining the angle and direction between the longitudinal axis of a vehicle such as an aircraft and the direction of propagation from a source of radiation such as a VHF localizer navigation system. The receiver utilizes a pair of antennas having a mutual spacing determined by the desired accuracy and permitted ambiguities, mounted in the forward section of the aircraft such that one antenna is located on each side of the forward section of the aircraft. The antennas def...

Distance measuring apparatus integrated in an aircraft landing system of the ILS type which utilizes the differential measuring technique wherein a deviation signal is alternately applied and suppressed to a network of lateral aerials of a glide station. The distance measuring apparatus measures the bearing angle of the approaching aircraft with respect to the glide station, and includes at the glide station a pair of lateral aerials associated with the low aerial of the glide station arranged f...