Abstract: A spin stabilized, earth orbitting satellite having a phased array antenna capable of radiating a plurality of steered electromagnetic beams to predetermined earth locations. The antenna array extends around the satellite and is made up of individual elements which are energized through semiconductor diode devices by electron beams. The electron beams are controlled by fields having the same frequency as the spin frequency of the satellite.

Abstract: A traffic radar device has a microprocessor controlled system for facilitating the Doppler signal processing. Related circuits enable the Doppler signal to be gathered on a digital basis and arrayed in the memory of the microprocessor unit. The array is then examined and by executing a predetermined algorithm, a decision is made as to whether or not a series of samples of Doppler signals, comprises within the array, represents a valid signal suitable for display as a number indicative of speed of a target vehicle.The microprocessor also controls a tracking filter system over the expected Doppler frequency range and has a duty factor modulation and tunable notch to facilitate the filter operation.The radar device includes a range control that limits the range of the detection of the target vehicle without affecting the detection of the platform vehicle speed.

Abstract: An object location system wherein signals are transmitted or received via more than one transmit station and wherein the objects receive signals from the transmit stations or transmit signals for reception by the treatment stations within a data base region and wherein location coordinates are established in response to the signals received by the transmit stations or in response to the signals received at the object from the transmit stations at a predetermined number of geographic locations within the data base region by positioning the object receiver or transmitter at each of the predetermined geographic locations. The objects are located within the data base region by comparing location coordinates determined in response to signals received at the transmit stations or in response to signals received at the objects with the established location coordinates.

Abstract: An orientation system adapted to be mounted within a vehicle, comprising a display including a rotational heading indicating compass card fabricated from an image retaining fluorescent display panel responsive to bearing data signals generated by selected ones of a plurality of light emitting diodes.

Abstract: A Loran-C receiver cycle detector is disclosed which processes Loran-C signal pulses on a cycle-by-cycle basis of the carrier frequency and generates an output for a specific carrier cycle. Due to received noise, sampling techniques are used to create a histogram which is analyzed to provide feedback used to accurately locate a tracking point on each Loran-C pulse.

Abstract: To eliminate fixed echoes at the receiver of a pulse radar, incoming i-f signals are demodulated, subjected to Doppler filtering, centered and bottom-clipped to eliminate those whose amplitudes lie below a certain threshold. The centering operation and/or the magnitude of the threshold are controlled automatically as a function of the amplitude of the incoming signals as measured upstream of the Doppler filter.

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: Radar tracking or homing units employing three or more primary radiators and utilizing an arrangement of a sum-difference network and signal processing stage to form sum, difference and cross-related or cross-term signals and to effect correction of errors introduced due to the presence or apparent presence of two targets with the resolvable radar volume, using a stipulated method of signal processing.

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: An array of antennas is sequentially sampled by digital commutation means provide a synchronous display of a synthesized antenna array pattern of reception on a cathode ray tube indicator. The commutation means and digital means for generating sine and cosine signals operate from a common oscillator source. Digital means are provided to advance or delay the phase relation of the pattern or of a strobe line with respect to the CRT sweep to effect rotation thereof into azimuthal alignment. Automatic bearing readout is digitally accomplished when alignment is achieved.

Abstract: A null pattern technique for reducing the effect of an undesired interfering signal in a data link channel, using an accepted monopulse tracking arrangement in a novel mode, such that the source of such interfering signal can be caused to be placed at the null of the antenna pattern used, thus greatly increasing the desired-signal-to-interfering-signal ratio without necessitating a physically large antenna.

Abstract: A method and apparatus for eliminating multiple-time echoes from the output signal train of random PRF pulse Doppler radar system. A multiple-time echo is recognized by calculation of the absolute value of the difference between the last two phase pulses received in each range gate (bin). That absolute value is compared to the average of the preceding N absolute value. A multiple-time echo is present if the last absolute value is higher by a predetermined amount than the average of the preceding N absolute values. A logical switch provides automatic switching to substitute a previous phase pulse in a corresponding range gate when the phase pulse of a range gate is determined to be altered by presence of a multiple-time (non-coherent) echo signal.

Abstract: 1. In passive detection and tracking apparatus, in combination, a plurality of directional signal obtaining means for obtaining from radiant energy received from the same source a plurality of signals which vary in predetermined manners with variations in the direction from the passive detection and tracking apparatus to said source, gating means operatively connected to said plurality of signal obtaining means, and indicator means operatively connected to said gating means, said gating means being constructed and arranged to pass to the indicator means certain signals only while said plurality of signals have preselected relative characteristics with respect to each other, said indicator means being constructed and arranged to utilize the passed signals to provide an indication of the direction to said source.

Abstract: This detection system of the radar type transmits a sawtooth-shaped frequency-modulated centimeter wave. The wave reflected by an obstacle, if any, is received by two fixed receiving antennas, each of these receiving antennas being connected to a circuit for processing the received signal. The phase shift between the waves is a measure for the angle .theta. formed between the path of flight of the aircraft and the straight line which connects the aircraft with the obstacle. Said phase shift is analyzed in an output circuit of the detection device which also comprises a control loop for controlling the amplitude of the beat-frequency signal between the transmitted signal and the received signal, a synthesizing circuit for a signal fan creating a range window by demodulation of the beat-frequency signal by means of the synthesized signal, a Doppler effect tracking loop and a circuit for analyzing the leading edge of the Doppler effect in the demodulated and filtered signal.

Abstract: A sky wave DF antenna system is disclosed. It is able to respond to an incoming transmitted signal and define the direction of the transmitter. It utilizes six or more simple loops connected and arranged to form a spaced loop antenna system which indicates the incoming direction of the transmitted signal without regard to the polarization or the elevational angle of the sky wave.

Abstract: A navigational-aid apparatus and method involving the use, on a target station or a craft station, of at least two transmitters, separated by a base-line distance, of distinguishable sonic signals and a transmitter of radio or other electromagnetic signals and, on the craft station or the target station respectively, of three receivers for the sonic signals and a receiver for the electromagnetic signals, the receivers for the sonic signals being in two positions separated by a base-line distance, there being two receivers, one for each sonic signal, in one said position and a receiver for one of the said sonic signals in the other position, while the station having the said receivers is provided with timing means for determining the elapsed times between the reception of the electromagnetic signal and the reception of the respective sonic signals.

Abstract: 15. In a secure communication system a transmitter comprising first means to modulate a carrier wave with a sub-carrier wave and a desired signal, a code generator synchronized to said sub-carrier wave, second means to modulate the output of said first modulating means with the output of said code generator, and means to transmit the output of said second modulating means to a distant receiver.

Abstract: Thermoelectric generator assembly accommodating differential thermal expansion between thermoelectric elements by means of a cylindrical split follower forming a slot and having internal spring loaded wedges that permit the split follower to open and close across the slot.

Abstract: An intermediate frequency sidelobe canceller with provision for controlling the saturation level of the cancellation loop. Such control is provided by interposition of limiter means at a particular point in the cancellation loop, and it enables the setting or programming of the loop cancellation time constant as desired. It significantly enhances performance and reduces cost of the canceller loop by reducing substantially the signal power levels within the loop and by making the loop transient response essentially constant over a wide range of input power level.

Abstract: The disclosure relates to radar methods and systems for directionally selective detection of objects and determination of the distances to the objects. A rectangular-wave frequency-shifted radar signal is employed. This radar signal may be generated by inducing a directionally dependent Doppler shift which permits directionally selective detection. Higher and lower frequency portions of the returned radar signal are separately frequency converted and phase compared to determine range. In a preferred embodiment, a collision avoidance system for automobiles is provided.