Abstract: A traffic radar unit capable of looking past the lead vehicle of oncoming traffic and discovering and identifying a violator employs master and slave antennas having diverging boresights that provide overlapping relative power density radiation patterns. The radar return signal from a target of interest is received by each antenna to produce two independent Doppler signals of the same frequency which are processed by respective master and slave signal processing channels. In the illustrated embodiment, a reference boresight is established in the overlapped patterns such that a target position along the reference boresight occurs at the time that the amplitudes of the two Doppler signals are equal. Controllable high pass filters whose passbands are shifted upwardly in response to return signals of increasing amplitude attenuate stronger, lower frequency interfering signals.

Abstract: Frequency domain, pulse compression CW radar apparatus comprises a frequency synthesizer which provides RF and IF CW signals and linear frequency modulator (LFM) which provides a saw tooth LFM ramp signal with the f.sub.LFM. A mixer combines the f.sub.LFM signal with the f.sub.RF signal to provide a CW radar signal having a frequency, (f.sub.RF +f.sub.LFM) for transmitting by a transmitter. A receiver receives time-delayed CW radar return signals reflected, for example, from clutter at a one range and from a target at another range. A second mixer down-converts the clutter and target return signals to an intermediate frequency for processing and a third mixer extracts the f.sub.LFM signal from the intermediate frequency clutter and target return signals to provide, in a frequency-time domain, rectangular wave, clutter and target signals.

Abstract: A passive interrogator label system is disclosed which transmits a first signal to, and receives a second signal from a remote, encoding transponder. In the preferred embodiment, the transponder is a passive, surface acoustic wave device which receives the first signal, processes this signal and transmits, in reply, the second signal which includes a unique identification code. The passive interrogator label system incorporates a means and method for compensating for variations in signal delays within the transponder due to changes in ambient temperature as well as manufacturing tolerances of the transponder. The method includes the steps of measuring the difference in delay times between two successive delay taps in the transponder and using this difference as a standard for determining the differences in delay times between other successive taps in the same transponder.

Abstract: A monitor for an electronic TACAN (ELTA) includes a 16-way switch whereby samples of the r.f. signal fed to each TACAN antenna element are fed via a common lead 30 to (a) means for r.f. phase correlating the samples with the transmitter generated signals, and (b) means for determining the relative phse and amplitude of the low frequency modulations in the sampled signals.

Abstract: A method for computer aided simulation of complete radar systems under evaluation of the instantaneous power and frequency information comprises the steps of providing a simulation signal representing the instantaneous power spectrum of the transmitter modifying said signal in accordance with the propagation and spreading path to be simulated and in addition modifying said signal in accordance with preselected target properties, modifying the previously modified signal in accordance with particular properties characteristic of the receiver and associated components to be simulated, such as amplifier characteristics, filters, mixers, Doppler stages, analog-to-digital conversion and calculating statistical moments of the first and second order of the resulting signal such as the expectancy value and its variance and indicating the same.

Abstract: A corner radar reflector that backscatters cross-polarized returns from a linearly polarized source is formed by three mutually perpendicular surfaces forming a concave structure. At least one of the surfaces has a depolarizing characteristic. The depolarizing surface is comprised of a grid of thin mutually parallel wires closed spaced. These wires reflect the parallel tangential component of the incident field but do not reflect the orthogonal component. Beneath the wires is a sheet of microwave absorbing material to absorb the energy that was not reflected by the wire grid.

Abstract: A system and method for automatically pointing a microwave antenna at a desired satellite in geosynchronous earth orbit from a remote location, such as encountered in a well logging, is disclosed. The system uses a truck borne, gimbal mounted antenna and a computer arranged to automatically control and drive servo motors connected to the gimbal mounts of the antenna. Accurate pointing with minimal human intervention is achieved.

Abstract: Interrogator/receiver apparatus is disclosed for transmitting a first signal to, and receiving a second signal from a remote transponder. In the preferred embodiment, the transponder is a passive, surface acoustic wave device which receives the first signal, processes this signal and transmits, in reply, the second signal which includes a unique identification code. The interrogator/receiver apparatus includes (1) a common RF unit for generating the first (interrogation) signal and (2) a plurality of transmitter/receiver heads, each remote from, and coupled to the common signal generator, for transmitting the first signal to, and receiving the second signal from a transponder or transponders in its vicinity.

Abstract: A radar detector capable of discriminating a prescribed radar signal from other undesired radar or interference signals by mixing an incoming electromagnetic wave radar signal with a local signal whose frequency varies with time within a fixed range of frequency repeatedly at regular periods, thus providing a beat signal; temporarily stopping the frequency sweep in response to appearance of dc components alone in the beat signal when the incoming radar signal matches the local signal in frequency; and watching the length of time for which the incoming radar signal matches the local signal in frequency. The reception of the prescribed radar signal is indicated using a sound-generating unit such as a speaker or a light-emitting unit.

Abstract: A satellite communications system and method of communication which results in increased frequency-reusage within assigned frequency bands and allows for a reduction in satellite transponder requirements per unit of bandwidth employed. The disclosed system employs a satellite in a geostationary orbit having transponders and one or more large-aperture, high-gain antennas that provide a broad-area beam for a relatively wide service area and for transmitting to and receiving signals from N narrow-area beams for N respective sub-areas, the sub-areas corresponding to the high-traffic nodes. Both beam types operate in the same allocated frequency bands but with opposite linear or opposite handed circular polarizations, or, alternatively, with arbitrarily determined portions of the allocated frequency band pairs with dual polarization so that the allocated frequency spectrum is used at least N+1 times.

Abstract: A multiple range interval clutter cancellation circuit for MTI radars is disclosed, for assuring cancellation of narrow band clutter in the second or further range interval, while preserving wideband cancellation in the nearer range intervals and economizing on the number of fill pulses. The circuit includes two clutter cancellers. One canceller has a relatively narrow band clutter rejection bandwidth, and effectively a higher number of fill pulses in relation to the clutter rejection bandwidth and effective number of fill pulses for the second canceller. The outputs of the two cancellers are subjected to an AND gate function, such that only targets which pass through the clutter rejection bandwidth of both cancellers are reported as a target. The circuit obtains the elimination of returns from ambiguous range interval clutter with less transmitted energy and time than conventional canceller circuits.

Abstract: A radar return suppressor for use in concealing and camouflaging mobile targets such as trucks, artillery and like vehicles. One or more lengths of a support member attachable to the target and components support and position a radar signal attenuator between the target and the anticipated radar source. In one embodiment, the attenuator is a multiplicity of closely spaced flexible plastic strands having radar signal absorbing material dispersed in the strands to form a labyrinth to entrap and absorb the radar signal. In a second embodiment the labyrinth of strands is replaced by an intertwined plastic vine-like structure secured in the support member for absorbing the energy of the radar signal.

Abstract: An adaptive radar system is presented which is capable of identifying interference frequencies and changing the system operating frequencies to permit radar operation in portions of the frequency spectrum that are free of interference. A time-integrating optical receiver or electronic FFT is employed to detect those frequencies where interference occurs thereby cueing the radar system to noise-free portions of the frequency spectrum. A digital computer processes the information from the optical or electronic FFT receiver to control system operation at those frequencies where interference has not been detected.

Abstract: Described is a pulse radar apparatus having a repetition period containing m wobbles. The pulse radar apparatus is provided with: a transmitting and receiving unit (2), whereby the received target echoes are sampled and digitized; an n-point DFT processing unit (3); a threshold circuit (4); and a cluster combiner circuit (5) comprising means to form a cluster covering one single target using the signals obtained from the threshold circuit (4). Due to the wobbles, additional information arises in the DFT spectra. From the range, azimuth, local maximum values of the DFT spectrum and the associated output channel number of the DFT processing unit (3), a classification unit (6) determines whether a target is a multiple-time-around target. The classification unit (6) is also able to determine the target doppler frequency, even if this frequency exceeds the average pulse repetition frequency.

Abstract: A digital scan converter comprises an A/D converter; an input buffer; a random access memory; a write address generator; a plurality of read address generators; an address switch circuit composed of a first address switch means for switching the addresses from the write address generator and the read address generators and delivering the addresses via an address signal line to the random access memory, and alternately switching a first address signal line for transmitting the address from the write address generator and a common signal line for commonly transmitting the addresses from the plurality of the read address generators for connecting one of said switched lines with the address signal line, and a second switch means for switching in succession the connection between the common signal line and a plurality of second signal lines respectively connected with the plurality of the read address generators for transmitting the addresses; a plurality of output buffer; an output switch circuit having a third s

Abstract: A radar system having a common antenna for transmitting and receiving signals conventionally includes a branch duplexer which is bulky and inconvenient.By using a waveguide section having an antenna port at one end and a receiver port at the other, and including a protection unit comprising p.i.n. diodes these difficulties are reduced. The diodes prevent transmitted energy from a magnetron reaching the receiver port but allow received energy, because of its lower amplitude, to pass.

Abstract: A modification is presented to improve radar systems, which normally tracks a single target, to enable them to perform a simultaneous search of a large space volume while maintaining track of a selected target. This modification entails an operating process in which a search is conducted with a controlled search pattern and search time so that the antenna is as close as possible to the tracked target position at the search conclusion and antenna slewing time is mimimized. Finally, the present procedure can be implemented while adding as little as a thousand words of memory to the radar system.

Abstract: A radar detecting system comprises an antenna for receiving radar signals, a sweep generator for producing a sweep signal over a predetermined range of frequencies and at a predetermined rate and a mixer for mixing the sweep signal with the received radar signal for producing intermediate frequency (IF) signals. A bandpass filter passes only those IF signals within a predetermined frequency band and a detector responds to the IF signals passed by the bandpass filter by producing corresponding output pulses. A control circuit is responsive to a pair of output pulses being produced for each of three successive cycles of the sweep signal and to both the first pulse and the second pulse of each pair of pulses occurring at the same time intervals respectively relative to the corresponding cycle of the sweep signal for producing a warning signal.

Abstract: In a radar enhancing transponder, apparatus for determining the percent of modulation on a received signal and apparatus for determining the percent of modulation on a signal transmitted by the transponder, with means for comparing the percentages to develope an error signal which is used to control the modulation in the transponder so that the percent of modulation on the return signal remains the same as that on the received signal.

Abstract: A flat plate reflector at one station, responsive to ambient vibrations, is illuminated by a narrow beam of radio frequency waves transmitted from a second location, the transmitted waves being modulated in direct proportion to the ambient vibrations and reflected back to the second station for analysis.