Abstract: A system which receives a pseudonoise sequence signal quantizes the signal during a fixed interval of time and passes the quantized signal to a plurality of correlation channels. Each of the correlation channels rotates the incoming phase modulation at a different fixed rate to cancel out a corresponding component of offset frequency. The outputs of the correlation channels are examined to determine whether acceptable correlation has been attained and, if so, which channel provides the best frequency compensation.

Abstract: A system which receives a pseudonoise sequence signal quantizes the phase of the received signal in digital form as in-phase and quadrature digital signals. A digital correlator correlates the digital signals against the stored pseudonoise code sequence and separately accumulates the results. The accumulated results are vector added and a peak detector is utilized to determine the time of arrival of the signal. At the same time, the accumulated results are used by an arctangent calculator to derive a phase signal, which is gated as an output when the time of arrival is determined. An embodiment in a phase monopulse radar system collects the signals from four antennas spaced as pairs in both azimuth and elevation to determine the azimuth and elevation phase differences of the received signal. In this embodiment, a single digital correlator is utilized, the inputs to which are time multiplexed.

Abstract: A system which utilizes a digital correlator to determine the time of arrival of a received pseudonoise sequence. At the same time, the incoming pseudonoise sequence is quantized to higher resolution and passed through a digital delay line with a total delay of slightly greater than the duration of the pseudonoise sequence itself. From the time of arrival measurement, a clock strobe timing is established to do active correlation on the delayed received sequence as it emerges from the delay line. The results of the active correlation are accumulated and/or added to obtain the amplitude of the received signal.

Abstract: A continuous phase shift modulation system wherein, for each of the in-phase and quadrature components, adjacent half-cosine pulses of the same polarity are joined by a continuous transition modulation signal which maintains continuity of the waveform and at least its first derivative. When this occurs, the other component signal is adjusted to maintain constant the vector sum of the component signals.

Abstract: A stand-alone digital processor based system includes a five-output state digital filter provided with magnitude and time data relative to a received TACAN signal. Threshold detection is provided for validating the received signal magnitude. The filter outputs produce phase signals which are combined in the digital processor, in accordance with an algorithm, to generate bearing data. The bearing data is stored and scaled prior to updating a display.

Abstract: A digital tacan system which provides improved bearing and range accuracy and allows faster acquisition. In computing, both bearing and range updates are maintained current using a Kalman filter. Portions of the computation may be performed in an on-board computer with the remainder done is a special purpose computer capable of being implemented using a few custom made MOS/LSI chips.