Abstract: A bit plane partitioned graphics display system prioritizes large numbers of classes of information prior to relaying the information to the color lookup table. This allows the color lookup table to process only 12 or less bits of information at a time.

Abstract: A radar capability display apparatus utilizing radar theory equations which are stored in a computer to relate the measured characteristics of interference signals in radar return echoes to determine the amount of radar performance degradation that the interference signals create. These loss of performance factors which are obtained at each antenna beam angle and range, are displayed on the radar's screen as the radar capability display.

Abstract: A pulsed Doppler radar mounted adjacent to the tip of a helicopter rotor blade for sensing obstacles in the helicopter path. The rotor tip velocity shifts the frequency of radar echos so that, through pulsed Doppler radar techniques, the echos from obstacles can be separated from clutter.

Abstract: In a communications system including a transmitter and a receiver with a multiple antenna array having null steering apparatus attached thereto, a desired signal and an identifier signal are summed and utilized to frequency-shift key (FSK) modulate a carrier prior to transmission, the desired signal including bits of data delayed a predetermined period relative to the identifier signal and the identifier signal including the bits of data summed with a pseudo random signal and substantially reduced in amplitude relative to the desired signal, which transmitted signal is received in the null steering apparatus where the pseudo random signal is removed from the identifier signal and the data is utilized to FSK modulate a carrier to produce a reference signal, which reference signal is utilized to cause the null steering apparatus to have high response to the desired signal.

Abstract: A transponder including a receiver and transmitter for receiving an interrogation signal and transmitting a coherent response with circuitry for modulating the coherent response to include a predetermined coded complex phase and/or amplitude shift therein to convey information, such as the identity of the transponder.

Abstract: In a null steering array antenna having a main antenna characterized by a radiation pattern with a relatively narrow main lobe and a plurality of secondary antennas forming a sub-array for providing a null in the direction of an undesired signal, a null steering device is associated with each secondary antenna and coupled to receive a portion of the signal from the main antenna for producing a null at each secondary antenna in the direction of the main lobe. The plurality of null steering devices are gated or otherwise activated so as not to operate on signals which are to be nulled by the main null steering apparatus.