Abstract: An active channelized antenna system includes an antenna array operable over a multi-octave frequency band to provide one or more antenna output signals. An electronics module includes multiplexer circuitry responsive to the one or more antenna output signals configured to divide an input signal spectrum into a plurality of frequency band components each of less than an octave bandwidth. The electronics module includes a plurality of amplifiers each of less than an octave bandwidth to provide an amplified component signal for a respective frequency band. Combiner circuitry included with the electronics module is configured to combine the amplified frequency band components into a composite signal. A transmission medium such as a coaxial cable, fiber optic line or free space, is configured to transmit the composite signal to a remotely located receiver system. The antenna system may be employed as a repeater system.

Abstract: An active channelized antenna system includes an antenna array operable over a multi-octave frequency band to provide one or more antenna output signals. An electronics module includes multiplexer circuitry responsive to the one or more antenna output signals configured to divide an input signal spectrum into a plurality of frequency band components each of less than an octave bandwidth. The electronics module includes a plurality of amplifiers each of less than an octave bandwidth to provide an amplified component signal for a respective frequency band. Combiner circuitry included with the electronics module is configured to combine the amplified frequency band components into a composite signal. A transmission medium such as a coaxial cable, fiber optic line or free space, is configured to transmit the composite signal to a remotely located receiver system.

Abstract: A local oscillator frequency measurement system for measuring the frequency of a local oscillator of an ESM receiver. The frequency measurement system includes a global positioning system (GPS) receiver (20) for providing a GPS pulse time and time interval signal; a threshold detector (45) responsive to the GPS pulse time and time interval signal for detecting pulses in the GPS pulse time and time interval signal for providing an output indicative of the occurrences of the pulses; a counter (41) clocked by the output of the local oscillator for providing a counter output; a latch (43) for sampling the counter output pursuant to detection of the pulses to provide sampled counts, whereby the sampled counts represent the outputs of the counter at the time the pulses are detected; and a processor (50) for processing the sampled counts to determine the frequency of the local oscillator.

Abstract: A precision direction finding system for making precision angle of arrival estimates for a signal received through two antenna elements separated in space. Phase interferometry is used to determine a precise angle of arrival, with multiple ambiguities due to the periodic nature of the phase difference related to geometric angle. The interferometric ambiguities are resolved using the time difference of arrival (TDOA) of the signal at the two antenna elements. TDOA is measured using leading edge envelope detection for simple pulsed signals, and predetection correlation for phase and frequency modulated signals.

Abstract: A method for use with a long baseline interferometer that unambiguously estimates the angle of arrival of an RF agile signal produced by an emitter. The angle of arrival estimate provided by the method may be used to resolve phase ambiguities inherent in the long baseline interferometer, thereby providing for the unambiguous estimation of the angle of arrival of the RF signal from the emitter. The RF agile signals processed to determine the phase thereof. The phase information contained in the energy radiated by the emitter is then processed to estimate the angle of arrival of the energy. The phase information contained in the RF agile signal is processed using the equations .phi.=(2.pi.fL/c) sin .theta., and .delta. sin .theta.=(c/2.pi.fL).delta..phi., where the phase (.phi.) is measured to a given error (.delta..phi.) to determine the direction of arrival (.theta.) of the energy radiated by the emitter.