Abstract: A wide band clock controlled delay line for reading-in short pulses at high peed and reading them out at low speed comprises in one embodiment an array of charge coupled photon detectors (CCPD's) and a CRT circuit for generating and scanning an electron beam across a short persistence phosphor face to thereby excite the phosphor to emit radiation with an intensity proportional to the electron current in the scanning electron beam. The scanning rate for the beam is sufficient to operate on short pulses from a wide band system. An input signal driver applies an input signal to the CRT circuit to control the intensity of the electron beam, and a lens collects and focuses the light emissions from these phosphors on to the array of CCPD's. A clock pulse generating circuit generates clock pulses at a much slower rate than the scanning electron beam steps from one CCPD to the next for stepping out the charge stored in the array into an adding circuit.

Abstract: An improved antenna and interference-cancelling system for improving signal ampling, particularly in side-lobe canceller system operating in a multiple-interference-source environment. An antenna is constructed as a circularly symmetric lens having loosely coupled feed elements disposed around the periphery of the lens. Each feed element acts as a high-azimuth-gain antenna which permits signal reception from all directions. The lens, when connected to couple the receiving feed elements to a side-lobe canceller, permits the canceller to discriminate against clutter and scattered signals and resolve interference sources in angle so that all canceller loops do not receive signals from all other interference sources, while still providing interference samples from all directions.

Abstract: A doppler-tolerant pulse-compression code generator for generating a plurty of approximately orthogonal codes which will prevent radar interference and suppress jamming. These codes are generated by phase-coding the frequency-band steps and also altering the time-sequence of the frequency steps of a step-approximation to a linear FM chirp pulse.

Abstract: A digital pulse compression processor for reducing the processing loss in rget-echo signals caused by sampling time errors comprising a first processing channel for sampling the echo signal in accordance with pulses from a first clock signal and a second processing channel for sampling the echo signal in accordance with pulses from a second clock signal at the same sampling frequency as the first clock signal but with its pulses interlaced, in time, approximately midway between the pulses of the first clock signal to ensure that the largest sampling error will be one-quarter of a sampling period or less. The sampled signals in each channel are then digitized and compressed, and then processed to form the compressed signal envelope. The resultant signal envelopes from each channel are multiplied together to form a low-sidelobe narrow output pulse.

Abstract: A scanning radar system having the capability of taking a number of succeve looks at the same range and angle resolution cells with several millisecond time intervals between looks. The scanning radar system includes a pulsed transmitter, a receiver, and an array of energy beam radiators having individual beam paths with associated centerlines. A commutator switch and a duplexer sequentially connect a different one of the radiators to the pulsed transmitter at the beginning of each pulse repetition period and to the receiver during the subsequent interval between pulsed transmissions. A motor rotates the array of radiators as a unit to cause the beam path centerlines to rotate and scan the field of view.

Abstract: A system for integrating weapon control radars which operate at the same or ifferent frequency bands, and for permitting every weapon control radar, for example on a ship, to lock through every weapon control antenna, thereby enabling all radars to be used against all targets, includes interconnecting broad-band antennas that can be time - and/or frequency-shared by all the radars. Each antenna has a coaxial monopulse feed at the various bands of operation. Each antenna also includes a switch for time-sharing the radars either simultaneously or sequentially into the antenna. A second switch for each antenna sends the radar outputs associated with each antenna to a control system for that antenna and its associated weapon launcher.

Abstract: A pulse compression decoder which oversamples by two the signal elements of received phase-coded signal, performs a pairwise average on the signal elements at intervals equal to 1/2 the width of a signal element, reverse-codes the pairwise averages, combines the pairwise averages to form a sub-accumulation signal, and performs a pairwise average on the sub-accumulation signals at intervals equal to 1/2 the width of a signal element to produce a compressed pulse having a high peak-to-side lobe ratio.

Abstract: A pulse expansion and compression system, especially useful for radar ranging, comprising a pulse coder for expanding an input pulse and a pulse compressor of the matched-filter type. The coder consists of a plurality of delay stages into which the input pulse is fed, a discrete Fourier transform (DFT) circuit to which the output signals of the delay stages are fed, a time-dispersionmeans (TDM) comprising an arrangement of delay stages for differently delaying the output signals from the DFT, and a coherent summer for adding the real and imaginary parts of the signals from the TDM. The summer output is fed to a phase modulator and then to the transmitter.The echo signals are conjugated, time-inverted, and passed through the same DFT as the input pulse signal. The outputs of the DFT are then passed through a TDM of the same type as the first TDM, but this time in time-inverted order.

Abstract: The invention is a configuration of digital open-loop cancelers, each of ch uses a batch window sampling technique, for decorrelating a main input signal from a plurality of auxiliary input signals by using one or more iterations of cancellation. The main signal includes a desirable signal and undesirable interference signals. The auxiliary signals include the undesirable interference signals which are correlated with the interference of the main signal. Samples of the main signal and a first auxiliary signal are fed to a first digital canceler. The canceler batches them, (forms the samples in a group) and measures the correlation between the main signal and auxiliary signal. This measurement, or weight, is applied to each of the samples of the auxiliary signal which were used to establish the weight. The weighted auxiliary samples are subtracted from the main input signal to produce an output residue signal that is uncorrelated with the auxiliary signal.

Abstract: A circuit for processing the azimuth error video signal of a monopulse rever in an aircraft to separately but simultaneously display the heading and position of the craft. The azimuth error signal is simultaneously applied to a sample-and-hold (SAH) circuit, a delay means and a one-shot multivibrator (MV). The MV opens the SAH to accept the first ground-transmitter signal in a sequence, the SAH charging a capacitance to the magnitude of the signal, and then prevents the SAH from accepting any further signals in the sequence. The output of the SAH is subtracted from the delayed signal to obtain a video signal indicative of aircraft position, and the output of the first subtracter is subtracted from the delayed signal to obtain a video signal indicative of the aircraft heading.

Abstract: A system for measuring, in conjunction with a GCA radar, the crab angle of n aircraft which is making its landing approach above a runway. A loop antenna mounted on the craft transmits an audio-frequency electromagnetic wave to two sets of crossed receiving loops, each set mounted at one side of the runway. A line joining the centers of the loops makes a 45.degree. angle with the plane of each loop. The outputs of the loops in each set are subtracted from each other, amplified, detected and rectified and then differentiated to provide a pulse output indicating the zero point of the subtraction, i.e., the time when the H-field vector is at an angle of 45.degree. to the plane of each of the loops in the set providing the zero-indicating pulse output. The zero-indicating pulse outputs are fed to a time interval counter which determines the time interval between them.

Abstract: A system for measuring, in conjunction with a GCA radar, the crab angle of n aircraft which is making its landing approach above a runway just prior to touch-down. Two doppler radars are placed, one on each side of the runway at equal spacings from the center line of the runway, with their antennas facing each other. The doppler radars function at very nearly the same frequency. The average doppler frequency of the echo received by each radar is determined and the frequencies are subtracted from each other. The difference in doppler frequency and the ground velocity of the aircraft are coupled to a computer which solves an equation to provide the value of the crab angle of the aircraft.The result can be radioed to the aircraft so that an adjustment in yaw can be made to zero the crab angle before touch-down.

Abstract: A moving-target indicator system uses adaptive loop cancellers for cancelg clutter. Each adaptive-loop canceller uses multiple memories and a switching circuit. The switching circuit switches each memory into the circuit to allow each of the memories to develop a weight W for a different selected range interval on a pulse-to-pulse basis.

Abstract: An aircraft landing system which provides a pilot a perspective view of a nway on which he intends to land under zero visibility conditions. The system includes a multiplicity of microwave transmitters spaced at known intervals along both sides of a runway and a timing generator which causes the microwave transmitters to transmit in sequence. The aircraft contains a monopulse receiver which provides conventional azimuth angle video information to a CRT display and also provides range video information to a Y sweep generator. The latter Y sweep generator generates a sweep voltage for the Y axis of the CRT display which is of sufficient length to display all transmitted pulses from all microwave transmitters in sequence with the correct relative spacing between microwave transmitters.

Abstract: A digital open-loop canceller is used to decorrelate one signal from anot in such applications as coherent sidelobe cancellers and moving target indicators. The invention measures the correlation between a complex main input signal and a complex auxiliary input signal in digital form. It divides the correlation coefficient by the average value of the auxiliary signal magnitude squared, multiplies the ratio by the auxiliary signal and subtracts the result from the main input signal to cancel correlated components.

Abstract: An improved interference cancelling system and technique for optimizing sal sampling, particularly in a side-lobe canceller system operating in a multiple signal environment. A plurality of auxiliary antennas provide samples of the interference environment for cancelling interference received by a main radar antenna. At least one of the auxiliary antennas is rotated in a circle in a horizontal plane for causing modulation of the interference residue. The component modulated with the frequency of rotation in the residue is compared in phase with the rotation modulation frequency to derive a signal for automatically moving the antenna to a position in the horizontal plane where the residue modulation is substantially eliminated. At that position the cancellation is maximized for the particular geometry of interference sources at that time.

Abstract: A pulse-compression MTI doppler radar system includes an antenna, a transter, a coded modulator, a receiver and a display. The coded modulator is connected to the transmitter and has at least two waveform generators for coding pulses having low cross-correlation. A pulse-compression filter having at least two pulse compressors for providing pulse compressed signals is connected to the receiver. Each pulse compressor is matched autocorrelatively to a different one of the waveform generators. An MTI processor has two MTI processing channels which are responsive to the pulse-compressed signals and provide an output to the display.

Abstract: A multi carrier-frequency pulsed radar system in which each carrier-frequy reflected radar signal is separately processed by parallel receiver branches. The output of each receiver branch is multiplied together to form the product of the separate receiver outputs, which product is then displayed on a plan-position-indicator (P.P.I.) display.

Abstract: A non-coherent, non-doppler, MTI radar system has its cancellation notch adened to include a selected range of target velocities. The apparatus includes a transmitter/receiver for transmitting and receiving short pulses in the nanosecond range. Also included is apparatus for generating multiple MTI responses having cancellation notches at different target velocities and multiplying the responses together to obtain a broadened cancellation notch.

Abstract: 1. In a signal jamming device, first and second transducers physically displaced relative to each other said transducers having substantially identical signal coupling characteristics on the basis of direction to a selected distant object, means for coupling said transducers whereby signals received by one transducer are emitted by the other and vice versa, and differential impedance means connected to said means for coupling for producing phase shift of signals emitted by one transducer relative to signals emitted by the other transducer.