Abstract: An aircraft guidance system uses radar imaging to verify airport and runway location and provide navigation updates. The system is applicable to flight operations in low visibility conditions.

Abstract: An aircraft guidance system uses radar imaging to verify airport and runway location and provide navigation updates. The system is applicable to flight operations in low visibility conditions.

Abstract: An aircraft guidance system uses radar imaging to verify airport and runway location and provide navigation updates. The system is applicable to flight operations in low visibility conditions.

Abstract: A radar based terrain and obstacle detection device for aircraft detects obstacles and terrain ahead of the aircraft. An alert is sounded if the obstacle or terrain is above a clearance plane positioned ahead of the aircraft.

Abstract: A method and apparatus for improving resolution of targets in a monopulse radar beam.

Abstract: A method for removing clutter related frequency components from power spectrums generated from weather radar return signals to provide improved windshear detection capability. Weather radar return signals are synchronously detected and digitized to provide i and q time domain sample sequences. The i and q time domain sample sequences are passed through a window function and then transformed to frequency domain sequences by a Fast Fourier Transform. A power spectrum is generated from the frequency domain sequences. The spectrum is subjected to a Spectral Gaussian Envelope Discrimination (SGED) process in which the spectral envelope is scanned to identify any lobe therein having a slope greater than a predetermined minimum. A first pseudo-Gaussian sigma, calculated from the width and maximum amplitude of any such lobe, is compared with a second pseudo-Gaussian sigma, calculated from known conditions.

Abstract: A distributed network that compensates for the effects of interelement coupling in a multielement antenna array is inserted between the output of an antenna array and the inputs of a receiver system. Within the distributed network are a plurality of couplers interconnected by transmission lines serving as phase shifters. The coupling factors of the various couplers and the lengths of the transmission lines are selected so as to apply voltage components of specific amplitudes and phase to the antenna ports. The values of the amplitudes and phases of these voltage components are such as to neutralize the components of the voltages at the output of the antenna array which are caused by the spatial couplings between the elements of the antenna array.

Abstract: A direction finding receiving system for use on a protected aircraft in which a signal from an ATCRABS transponder on an intruder aircraft is received has been described incorporating a four element interferometer type antenna array, reversing switches, individual receivers, a phase detector and a processor for processing the outputs of the phase detector. The invention overcomes the problem of correcting for the difference in phase delay of signals passing through the receivers.