Abstract: This disclosure relates to multi-element antenna clusters or arrays for the reception and transmission of radio waves for direction-finding, navigation aid and emitter and/or receiver location purposes. In particular, it relates to arrangements of multiple antennas whereby the direction of propagation (arrival or departure) of a wavefront is determined from a combination of the amplitudes of phasor (or total individual antenna output) differences between pairs of antennas, said arrangements being along certain geometrical patterns, such as a circle, an ellipse, a polygon, an open straight line, etc., with at least one longest dimension measuring more than one wavelength of the incident or departing wave. Although described in terms of electromagnetic waves and hence antennas as receiving sensors or radiators, this invention in reality applies to any other form of propagating waveborne energy, such as acoustic, ultrasonic, seismic, etc.

Abstract: This disclosure relates to multi-element antenna clusters or arrays for the reception and transmission of radio waves for direction-finding, navigation aid and emitter and/or receiver location purposes. In particular, it relates to arrangements of multiple antennas whereby the direction of propagation (arrival or departure) of a wavefront is determined from a combination of the amplitudes of phasor (or total individual antenna output) differences between pairs of antennas, said arrangements being along certain geometrical patterns, such as a circle, an ellipse, a polygon, an open straight line, etc., with at least one longest dimension measuring more than one wavelength of the incident or departing wave. Although described in terms of electromagnetic waves and hence antennas as receiving sensors or radiators, this invention in reality applies to any other form of propagating waveborne energy, such as acoustic, ultrasonic, seismic, etc.

Abstract: The disclosure relates to methods and apparatus for separating radio signals arriving from different directions and for multiplexing signals intended for receivers dispersed in different directions. The methods and apparatus employ a plurality of antennas with spacing and individual feedline characteristics designed so that a modulation is imparted to each of a plurality of incident signals, for receiving antennas, and radiated signals for transmitting antennas, the modulation level of each signal being determined by the direction of propagation of the signal and by the spacing between antenna pairs. Accordingly, the orientation of lines connecting pairs of antennas as well as the spacing between antennas are set to inhibit the modulation in a particular direction, or to strip a particular modulation off a signal incident from a selected direction.

Abstract: The disclosure relates to methods and apparatus for facilitating the accurate measurement of Doppler frequency shift induced on a one-way-propagated signal wave either by deliberate on-platform controlled actual or simulated motion of a receiving antenna means, or by relative motion between transmitting and receiving platforms, or by both. The methods and apparatus of this invention are directed to the suppression of identifiable components of a composite modulation process on a sinusoidal carrier, for the purpose of retaining, for separate detection, measurement or transmission, the result of any of the aforementioned frequency-shift inducing processes.

Abstract: The disclosure relates to methods and apparatus for combining a multiplicity of diversely received replicas of a signal originating in the same remote transmitter. The disclosed methods and apparatus apply, in particular, to digitally modulated sinusoidal prime-carriers or subcarriers, and base the final decision about which of the code alphabet symbols is present in each bit-symbol time slot on either: a) the maximum value of a decision index for each code alphabet letter indicated in/for the same bit time-slot by parallel bit-by-bit detection of the diverse replicas of the signal, the decision index being defined as a function only of the pre-video (IF carrier or subcarrier) signal-to-noise power ratios of the various signal replicas that yield the same code alphabet letter; or on b) bit-by-bit detection of the maximal ratio combination of the video (or pre-bit-detection) bit-stream waveforms out of the prime-carrier or subcarrier exponent (i.e., phase or frequency) demodulators.

Abstract: The disclosure relates to methods and apparatus for separating radio signals arriving from different directions and for multiplexing signals intended for receivers dispersed in different directions. The methods and apparatus employ a plurality of antennas with spacing and individual feedline characteristics designed so that a modulation is imparted to each of a plurality of incident signals, for receiving antennas, and radiated signals for transmitting antennas, the modulation level of each signal being determined by the direction of propagation of the signal and by the spacing between antenna pairs. Accordingly, the orientation of lines connecting pairs of antennas as well as the spacing between antennas are set to inhibit the modulation in a particular direction, or to strip a particular modulation off a signal incident from a selected direction.

Abstract: The disclosure relates to methods and apparatus for combining a multiplicity of diversely received replicas of a signal originating in the same remote transmitter. The disclosed methods and apparatus apply, in particular, to digitally modulated sinusoidal prime-carriers or subcarriers, and base the final decision about which of the code alphabet symbols is present in each bit-symbol time slot on either: a) the maximum value of a decision index for each code alphabet letter indicated in/for the same bit time-slot by parallel bit-by-bit detection of the diverse replicas of the signal, said decision index being defined as a function only of the pre-video (IF carrier or subcarrier) signal-to-noise power ratios of the various signal replicas that yield the same code alphabet letter; or on b) bit-by-bit detection of the maximal ratio combination of the video (or pre-bit-detection) bit-stream waveforms out of the prime-carrier or subcarrier exponent (i.e., phase or frequency) demodulators.

Abstract: This disclosure relates to multi-element antenna clusters or arrays for the reception and transmission of radio waves for direction-finding, navigation aid and emitter and/or receiver location purposes. In particular, it relates to arrangements of multiple antennas whereby the direction of propagation (arrival or departure) of a wavefront is determined from a combination of the amplitudes of phasor (or total individual antenna output) differences between pairs of antennas, said arrangements being along certain geometrical patterns, such as a circle, an ellipse, a polygon, an open straight line, etc., with at least one longest dimension measuring more than one wavelength of the incident or departing wave. Although described in terms of electromagnetic waves and hence antennas as receiving sensors or radiators, this invention is reality applies to any other form of propagating waveborne energy, such as acoustic, ultrasonic, seismic, etc.

Abstract: The disclosure relates to methods and apparatus for separating radio signals arriving from different directions and for multiplexing signals intended for receivers dispersed in different directions. The methods and apparatus employ a plurality of antennas with spacing and individual feedline characteristics designed so that a modulation is imparted to each of a plurality of incident signals, for receiving antennas, and radiated signals for transmitting antennas, the modulation level of each signal being determined by the direction of propagation of the signal and by the spacing between antenna pairs. Accordingly, the orientation of lines connecting pairs of antennas as well as the spacing between antennas are set to inhibit the modulation in a particular direction, or to strip a particular modulation off a signal incident from a selected direction.

Abstract: The disclosure relates to methods, algorithms and apparatus for direction-of arrival (DOA) measurement/computation based on long-baseline, phase-difference, paired-antenna interferometry and on DOA-computing array processing algorithms. Specifically, methods and algorithms based on direct, cyclically unambiguous estimation of the cosine of the DOA are described for resolving the cyclic ambiguities in long-baseline, phase-difference paired-antenna interferometers, and for steering the computations to the vicinities of the solutions in computation-intensive array processing algorithms, thereby reducing computation load and time. The invention enables the design of DOA-determination systems and radio navigation aids that combine desirable characteristics (such as high resolution and accuracy, simpilicity, low cost, self-calibration, etc.) of different methods of extracting/computing DOA data from the outputs of antenna elements that are positioned in diverse arrangements for realizing complementary apertures.

Abstract: The disclosure relates to methods and apparatus for separating radio signals arriving from different directions and for multiplexing signals intended for receivers dispersed in different directions. The methods and apparatus employ a plurality of antennas with spacing and individual feedline characteristics designed so that a modulation is imparted to each of a plurality of incident signals, for receiving antennas, and radiated signals for transmitting antennas, the modulation level of each signal being determined by the direction of propagation of the signal and by the spacing between antenna pairs. Accordingly, the orientation of lines connecting pairs of antennas as well as the spacing between antennas are set to inhibit the modulation in a particular direction, or to strip a particular modulation off a signal incident from a selected direction.

Abstract: The disclosure relates to methods and devices for separating and suppressing an interfering or jamming signal which is the strongest of a plurality of linearly combined signals and which carries modulation including at least amplitude modulation. The methods and devices collapse the frequency spectrum of the strongest signal to substantially a single frequency and filter out that single frequency.

Abstract: The disclosure relates to radar methods and systems for directionally selective detection of objects and determination of the distances to the objects. A rectangular-wave frequency-shifted radar signal is employed. This radar signal may be generated by inducing a directionally dependent Doppler shift which permits directionally selective detection. Higher and lower frequency portions of the returned radar signal are separately frequency converted and phase compared to determine range. In a preferred embodiment, a collision avoidance system for automobiles is provided.

Abstract: An apparatus or method, for characterizing carrier waves according to the direction in which the carrier waves are transmitted or received, comprises radiating or receiving from a position which is moved repetitively along a line of motion having a predetermined, fixed location in a frame of reference. The radiating or receiving position may be moved so that at least one of the speed and direction of motion is abruptly changed. The radiating or receiving position may be moved back and forth along two non-parallel, straight lines of motion, whereby elevational and aximuthal angles of propagation are determinable solely responsively to the amplitude of the frequency shift induced by the changes in direction of the motion along the lines of motion.

Abstract: This invention relates to interference suppression or reduction means in receiving systems, and more particularly to apparatus for suppressing interference in receiving equipment by locally inducing a sufficiently large frequency difference between a desired signal and an undesired signal arriving from a different direction at the receiving site.

Abstract: A method and apparatus for tracking and position determination includes generating carrier waves in transmitters; radiating said carrier waves; receiving said radiated carrier waves; imparting or simulating a motion, or motions, to radiators, reflectors or/and receiving antennas, within the locality of each, in such a way as to induce direction-dependent frequency modulation in each signal delivered to the receiving detectors; detecting said modulation on each received signal; and using measured parameters of said detected modulation to track the location of one or more of the said transmitters, reflectors or/and receivers and determine the corresponding position coordinates thereof. The actual or simulated motion of the radiators reflectors or antennas may have a uniform velocity along at least two straight, non-parallel lines.

Abstract: Interference in the overlapping of at least two transmission transmitters areas of a co-channel multiple signal broadcasting system is suppressed by an asymmetrical radio frequency carrier deviation in one given direction of one of the two transmitters and an asymmetrical radio frequency carrier deviation in a direction opposite to the one given direction of the other of the two transmitters. The oppositely directed asymmetrical carrier deviations create a .+-. 2.5 kHz rms carrier frequency offset from the nominal carrier frequency in a manner which is compatible with present FCC regulations.