Abstract: An antenna feed for a TACAN circular array. A power divider divides a source of radio frequency signals into zero, first and ninth order mode signals. A second power divider divides the zero mode input signal into a plurality of output signals each driving a pair of elements of the TACAN array. A second conventional matrix of radio frequency components receives the first and ninth mode excitation signals. A phase combining network combines the first and ninth mode signals so as to produce a plurality of signals each driving a pair of antenna elements. An output hybrid coupler combines the zero phase mode with the phase combined signals to produce the required TACAN azimuth antenna pattern.

Abstract: The invention provides a method and apparatus for detecting specialized meteorological conditions, in particular a microburst. The detector is localized so as to process radar return signals from regions in which aircraft are particularly vulnerable to microbursts. The detector includes a Doppler radar and an intelligent processor. Doppler radar returns are stored in an array wherein the contents of each cell identify the wind velocity parallel to propagation path. A pattern matching process identifies the existence of a microburst, maximum wind velocity associated with the microburst, and the location of the center. By tracking the microburst center as a function of time, the microburst velocity and direction can be determined, allowing prediction for microburst location in the future. Based on observed microburst lifetimes, the expected duration of the microburst can also be predicted.

Abstract: An aircraft locating system identifies on a TV format radar display the position of a specific aircraft based on an RF transmission from the aircraft on an RF channel. The locating system includes at least a pair of receive stations located within several miles of an airport and separated by a base line which is in near proximity to at least one runway at the airport or a theoretical extension thereof. Each receive station includes a passive receiver for determining a bearing angle to a source of RF on the RF channel for generating a signal representative of the bearing angle.The locating system further includes a processor which is responsive to bearing angle signals derived from the receive stations for generating line count and line delay information. The line count and line delay information correlate a position determined by the bearing angle signals from at least a pair of receive stations with a frame of reference of the TV display.

Abstract: The apparatus of this invention is a system for providing frequency synchronization and predictable phase output of the transmitted signals of a multi-channel frequency division multiplexed communications system.