Abstract: A moving target simulator system for pulse Doppler radar includes a processor for processing received radar signal and transforming the signal into patterned pulses before subjecting the patterned pulses to an 180 degree phase-shift by a phase-shifter. The system also includes a reference signal provided by a corner reflector located in proximity of the simulator. The reference signal and a phase-shifted signal from the simulator are processed by the radar equipped with a phase corrector circuitry to correct a phase drift problem associated with the use of a small antenna with the simulator.

Abstract: Steerable phased array antennas of the tapered type in which the antenna ment power is maximum at the center of the array and tapers off on either side thereof. The phase shifters of each antenna element are of the binary digital type with the number of stages and hence the phase accuracy being maximum for the high power center antenna elements and tapering off on either side thereof. Redundant stages for the binary phase shifters can be provided to increase reliability.

Abstract: Circuitry is disclosed for processing Doppler-shifted radar signals or ot noisy signals which fluctuate widely in frequency. The circuitry includes a dual channel discriminator including a voltage controlled oscillator as part of a feedback loop for frequency tracking of said signals. The discriminator further includes a frequency pass circuit in one channel thereof and a frequency stop circuit in the other channel thereof, with the outputs of these circuits applied to a multiplier. The multiplier output controls the frequency of the voltage controlled oscillator. The voltage controlled oscillator output is heterodyned with the input signals to obtain the heterodyned signals for application to the aforementioned two channels of the discriminator.

Abstract: An electronic detection system for detecting intrusion thru a perimeter eoys a transmission line as a sensing element. In one embodiment, RF energy is transmitted: in another, pulses of DC. In either case, pseudo-random coding of the signals is employed. A preferred emboidiment of the invention utilizes a transmission line consisting of a twisted pair of wires enclosed in a non-deformable insulation and configured for shallow burial to effect concealment. Another shape is disclosed for laying-out over hard ground. A low ohmic ground is included under the line to improve performance. An intruder in the field of the line causes an RF reflection back towards the source, which reflection may be detected by Doppler range-gating techniques.

Abstract: A signal processor circuit including a plurality of similar cascaded stages, each of which is capable of locking onto and tracking a different frequency of a multiple-frequency composite signal applied to the processor. Each of the stages may comprise a frequency locked loop plus a variable frequency stop, wherein the tuning of the variable frequency stop tracks the output of the frequency locked loop. The variable frequency stop circuit passes the non-locked components to the next similar stage which locks onto one of the remaining components.

Abstract: A radar system for measuring an angle of a target. A radar antenna produc at any given instant, one of a pair of directional radar beams. The beams are angularly displaced with respect to each other and overlap within the expected target direction. A code generator sends a train of R-F pulses to the radar antenna. An antenna beam switch, connected between the antenna and the code generator, switches, over a set period of time, every other pulse to one radar beam and the remaining pulses to the other radar beam. The two resulting coded pulse groups differ from each other. A receiver is connected to the radar antenna to receive return signals during a time period which corresponds to a given target range distance. The return signals are auto-correlated with replicas of the transmitted coded signals and the respective correlation outputs are ratio compared with each other to determine exact target angles.

Abstract: A new type of frequency discriminator in which the signal is applied to a ir of channels, one of which includes a frequency pass circuit which may comprise a parallel resonant circuit, and the other a frequency stop circuit which may comprise a resonant trap. The channels also include means to differentially shift the phases of the signals therein by 90.degree.. The two channel outputs are applied to an analog multiplier and the dc value of the output thereof is the discriminator output.

Abstract: An electronic detection system for detecting intruders employs a transmisn line as a sensing element. In one embodiment the transmission line is a modified surface-wave transmission line, for example, a Goubau line which is positioned about the perimeter of the area to be protected. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques. In other embodiments of the invention, the transmission line is an insulated, twisted wire pair or a deformable transmission line. In some instances, the transmission line may be replaced with an active or passive pressure line.

Abstract: A Doppler radar is adapted to respond only to walking human targets by prding means to detect the frequency modulation of the Doppler signals caused by the oscillatory body movements of such walking targets. A frequency locked loop frequency modulation detector is provided for efficient detection of this so-called step frequency modulation, and the detected step frequencies are split into several bands representing targets walking at different step rates. Circuitry is shown for adapting this technique to continuous wave radars or range gated radars.

Abstract: An electronic detection system for detecting intruders employs a transmisn line as a sensing element. In one embodiment the transmission line is a modified surface-wave transmission line, for example, a Goubau line, which is positioned about the perimeter of the area to be protected. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques. In other embodiments of the invention the transmission line is an insulated, twisted wire pair or a deformable transmission line. In some instances, the transmission line may be replaced with an active or passive pressure line.

Abstract: A harmonic frequency generator responsive to an input signal of frequency f hich changes slowly in both frequency and amplitude and characterized in that (1) the output signal (harmonic) amplitude remains proportional to the input signal amplitude and (2) the output frequency nf of the output signal consists soley of one integral (n>1) multiple of the input signal frequency.

Abstract: An antenna beam switching system comprising three antennas whose apertures re disposed in a common plane and which, by means of selective shunting of one or more phase shifters associated with each of the antennas, allows for three dimensional beam switching in at least four directions in space.

Abstract: A pulse train generator comprising a shift register with feedback for proing an output pulse for every m clock pulses applied to the shift register stages. The feedback shift register normally has a maximal length 2.sup.n -1, where n is the number of stages. Clock pulses are applied to the shift register until an all-ONE condition is reached; thereupon, (m-1) additional clock pulses are applied and the states of the register stages can then be sensed. Appropriate gate circuits are added to the shift register, depending upon the sensed register states, to inhibit certain shifts and to insure that the register is returned to the all-ONE condition upon arrival of every mth clock pulse.

Abstract: A pulse train generator comprising a shift register with feedback for proing an output pulse for every m clock pulses applied to the shift register stages. The feedback shift register normally has a maximal length 2.sup.n -1, where n is the number of stages. Clock pulses are applied to the shift register until an all-ONE condition is reached; thereupon, (m-1) additional clock pulses are applied and the states of the register stages can then be sensed. False count correction is obtained by the combination of a detector and an analog integrator.

Abstract: An electronic detection system for detecting intruders employs a transmisn line as a sensing element. In one embodiment the transmission line is a modified surface-wave transmission line, for example, a Goubau line, which is positioned about the perimeter of the area to be protected. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques. In other embodiments of the invention, the transmission line is an insulated, twisted wire pair or a deformable transmission line. In some instances, the transmission line may be replaced with an active or passive pressure line.

Abstract: A signal processing system using balanced processing which involves separng the upper and lower sideband components of a modulation that exists, for example, in a return radar doppler signal, as a result of the motion of scatters and subtracting them.

Abstract: An antenna array radiation pattern switching system suitable for use in re-gated, pulse doppler, radar systems. The antenna array includes first and second antennas, one of which is fed through a fixed phase-shift network while the other is fed through a phase-shift network with double the phase shift of the fixed phase-shift network that can selectively be switched in and out of the feed circuit.

Abstract: A range-gated radar system which includes a phase modulator that modulates n r.f. generator with a signal which may be binary coded. In a preferred embodiment, the binary signal is a periodic signal of 2.sup.N -1 bits per period. Starting at some arbitrary point in the sequence, K contiguous bits are transmitted then M contiguous bits are passed over, then K more bits are transmitted, and so on. The quantities M+K and 2.sup.N -1 have no primary factors in common. The radar system may be a doppler radar system using balanced digital processing which involves separating the upper and lower sideband components of modulation that exist in the return radar signal as a result of the motion of scatterers and subtracting them.

Abstract: A dual frequency moving target radar system having a lower frequency chan which provides relatively good moving target detection in the presence of such obstacles as foliage and precipitation and a higher frequency channel which provides accurate location of targets wherein the Doppler signals from the two channels are correlated to provide suitable target identification which target and clutter are present in the same resolution cell. The Doppler frequency is processed to distinguish the moving target from other returns. Electroacoustic transducers can be used in either of said channels to aid in target identification.

Abstract: An electronic detection system for detecting intruders employs a transmission line as a sensing element. The transmission line is positioned about the perimeter of the area to be protected. An antenna applies pulsed RF energy to the line. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques.