Abstract: An interpersonal-introduction signalling system includes a receiving and transmitting transceiver having a relatively short range response and of such size as to permit convenient carrying by a person. A code system defines a plurality of categories, each of which has a particularly identifiable characteristic. Each person carrying a similar receiving and transmitting transceiver can select a particular code to send and a particular code to accept, such that designated information is transmitted and/or received. When accepting a signal or information, a different signal is sent by the receiver to indicate the acceptance to the person transmitting. The transceiver includes an indicator to alert the receiving person and indicate the necessity of transmitting a response. Thus, the encoding permits the several persons involved to define the different categories of persons having selected unique characteristics for contact.

Abstract: A system for radar remote sensing of near surface ocean currents in coastal regions. The system employs a pair of low power, transportable high frequency radar units to scatter signals from the shore off to the ocean waves. Underlying surface currents impart a slight change in velocity to the ocean waves which is detected by the radar units. Each radar unit can determine the angular direction of arrival of the radar echo signals by comparing the phase of the signals received at three short antennas on the shore. Signals scattered from the same point on the ocean by each of the two geographically separated radar units are used to construct a complete current vector for that point. The radar pair takes simultaneous measurements over an ocean area with a predetermined grid pattern. Vectors are constructed for each square section of the grid, and a map of the near surface current field is output in real-time by an on-site minicomputer.

Abstract: A circuit for speed measurement of vehicles according to the Doppler-radar principle wherein a Doppler-useful signal is evaluated in a computer to which such signal is infed by means of a threshold value switch. A single sideband modulator is provided, at the input side of which there is supplied the Doppler-useful signal and also a high-frequency signal produced by a high-frequency oscillator. The output side of the single-sideband modulator is connected with the input of a phase-locked loop, the output signal of which is converted into the original frequency band of the Doppler signal by means of a demodulator connected at its output side with the input of the threshold value switch.

Abstract: Multiple interference signals in an electromagnetic wave communication system are individually discriminated against by a beamport sidelobe canceller comprising a multichannel auxiliary system in which spatial filtering of the angular sectors of interest is performed prior to sidelobe cancellation. Each spatial filter of the auxiliary system has its own adaptive control and only those interfering signals appearing in its assigned sector are operated on by that loop. The output of the main communication system receiver is summed with the outputs of the auxiliary system channels to produce a system output and an adaptive control loop feedback signal. The feedback signal initiates the generation of a cancellation signal in any adaptive control loop in which correlation of interference signals occur in both the main communication system received signal and the signal received by the auxiliary system channel to which that loop is connected.

Abstract: Precise azimuthal alignment of troposcatter system antennas is achieved by centering on the great circle, the combined pattern of intercepting beams from two troposcatter antennas. The combined antenna pattern is determined to be centered on and symmetric about the great circle when the Doppler spectrum on a received signal is symmetric about zero Doppler shift. The alignment procedure comprehends antenna manipulation, initially with both beams focussed and subsequently with one beam defocussed, until the desired Doppler spectrum condition is obtained. The requisite Doppler information is derived and processed by novel cross correlation techniques and data processing procedures.

Abstract: 4. A radar disabling means, including:A plurality of individual pieces of radar reflective chaff, each having a tear-drop shape.

Abstract: The present invention relates to a method of cophasing the feed elements of a transmitting or a receiving phased array antenna. To cophase a transmitting antenna, the method entails transmitting a lower sideband and an upper sideband signal from a first and a second one of the feed elements, respectively, while transmitting a carrier signal used to generate the sideband signals on all other feed elements of the array. At each receiver the reference phase angle between the received sideband signals is measured and stored. The above step is sequentially repeated for the first and a third, the first and a fourth, etc., one of the feed elements, and the phase angle measured, subtracted from the reference phase angle, and stored. With the above method, the phase angle between each feed element and the second one of the feed elements is determined and stored and subsequently transmitted back to the transmitter for use in transmitting signals to each receiver.

Abstract: In a Loran Receiver that receives radio frequency (RF) signals from a master beacon and at least two slave beacons (also called secondary transmitters) and converts the received signals into hyperbolic coordinates that locate the position of the receiver with respect to the beacons and a programmed computer controls modes and sequences of operation of the system, these modes being generally the beacon pulse search mode, front edge/zero crossing location mode and the zero crossing track mode, received beacon pulses are searched and identified by the following technique: all received signals are repeatedly sampled at the beacon group repetition interval (GRI) in a regular sampling pattern in which the sampling rate is greater than the beacon pulse rate, each sample interval being only a small portion of a beacon pulse RF excursion; the samples are hard limited and assigned a value of plus or minus, depending upon whether they exceed a threshold, and these plus-minus patterns are accumulated over many GRIs and s

Abstract: A signal proportional to steering angle is produced by a potentiometer controlled by the steering wheel, except for steering angles below about 0.1.degree. that are frequently used for corrections in driving on a straight course. For steering angles above about 0.5.degree., the signal remains constant in magnitude. The signal controls a range gate of the radar system suppressing the effect of echoes beyond a maximum range limit smaller than the intercept of a radar ray at the beam edge on an arc concentric with the curved path of the vehicle having a radius of curvature exceeding that of the vehicle path by a predetermined amount which is chosen so as to preclude reception of echoes from guard rails situated on the outside of highway curves.

Abstract: This invention relates to a focused synthetic array wherein a different signal from a crossed beam antenna is converted to a bipolar video signal and applied as the input to a synthetic array processor. In another embodiment of the invention there is a separate reduction of each beam output from a crossed beam antenna to bipolar video signals with a separate application of asymmetrical amplitude weights to the two bipolar video records and a subsequent subtraction in the course of synthetic array processing.

Abstract: A double loop receiver used in conjunction with a transmitter broadcasting at low frequencies as a vertical magnetic dipole. The two loops are connected with their planes parallel in a resonant circuit, thereby cancelling atmospherics generated by distant thunderstorms and allowing the receiver to receive only the signal produced by the near transmitter. The loops are rotated around a horizontal axis perpendicular to the connecting line between the loops until a maximum signal is obtained. The direction of the connecting line is varied until the maximum signal shows the gradient and the direction to the transmitter. By noting the position of the loops and the loop angles with respect to the horizontal, the position of a transmitter buried in the ground can be determined. This system has particular utility in locating lost miners buried in a cave-in. Additionally, the double loop receiver concept can be used to detect subsurface ore deposits.

Abstract: Eight radiators, disposed along a line, are coupled to a radar via a Butler matrix. In response to a transmitted signal from the radar, inverse transform signals that have amplitudes representative of values of a sinusoid in an angular range of zero radians to .pi. radians is applied to the Butler matrix. The inverse transform signals cause excitation to be applied to two of the radiators that are adjacent to each other. The inverse transform of the sinusoid at the output of the Butler matrix, in addition to allowing the excitation of two adjacent pairs of radiators, also provides a transmitted beam having reduced beamwidth and lower sidelobes. The two adjacent radiators are selected by selecting a phase pattern of the inverse transform signals.

Abstract: An antenna for radio frequency signals including a two flat faced phased arrays and ground plane system therebetween where transmission lines join the antenna planes to electronic control packages such that there is provided proper phase shift, final amplification and timing for retransmission by one of the antenna planes in a preselected direction, and where the signals are space fed to the other antenna plane by a feed system.

Abstract: Seismic waves are detected for a given seismic prospect with an accelerometer and a hydrophone and the outputs of said accelerometer and hydrophone are combined directly to create a signal for seismic analysis. The accelerometer and hydrophone may be combined physically in a single composite unit for recording the seismic waves or an accelerometer and hydrophone may record the seismic survey independently for subsequent combining of the signals from the accelerometer and hydrophone.

Abstract: Distance is measured with a tone modulated AM radio system by making a signal at the ranging tone frequency phase coherent with respect to the modulation on the RF signal at the input to the receiver by means of a product detector located ahead of the receiver of the transponder. In this way, a ranging tone phase is established which is a direct and accurate measure of the modulation phase (delayed by the propagation time) and is independent of any modulation phase shifts experienced in the receiver.

Abstract: A radar attenuator panel incorporating reactive elements is provided comprising a composite of electrically semiconductive or reactive layers separated by relatively non-conductive layers with the entire structure bonded together with compatible thremosetting resins. The electrically reactive attenuator layers have a complex admittance wherein the imaginary portion is substantial compared with the real portion. A sheet having a ratio of the imaginary portion to the real portion of complex admittance in the range of 0.7 to 2.0 throughout the frequency range from S-Band through X-Band is provided by impregnating a glass fabric with a phenolic resin having amorphous carbon and aluminum particles dispersed therein. The carbon is preferably present in the range of 9 to 18 parts by weight and the aluminum is preferably present in the range of 5 to 42 parts by weight per 60 parts by weight of resin.

Abstract: A method and apparatus for use in air-traffic control are described for maintaining substantial registration alignment between radar video signals and associated computer generated data on a television monitor. It is a requirement of the monitor display that the radar video, such as raw radar, map video, etc., be displayed with a long time constant to show the history of the radar trails. Simultaneously, the associated computer generated data, such as vectors, alpha-numerics, etc., must be displayed properly registered with the radar video on the same monitor with a short time constant. This is necessary to avoid smearing, since the latter data moves on the monitor screen as the radar pattern changes. In accordance with the present invention, the radar and computer data are combined into a single cathode ray tube, photographed by a pair of vidicons having different time lag characteristics, and the images of the latter combined on a television monitor.

Abstract: The time-of-arrival of timing signals transmitted by two satellites is measured relative to a crystal clock, and an approximate position fix is computed for the ship or other object being located. Because of clock error the position fixes are displaced along a hyperbolic line of position. A two-way active range measurement through a third satellite or one timing signal satellite enables computation of an independently determined line of position, the true position fix being at its intersection with the hyperbolic line of position. The clock error is corrected and the method of position fixing from two timing satellites is repeated until the clock drift exceeds acceptable limits. A continuous navigation service and also position surveillance are realized.

Abstract: In a multiple antenna array including null steering apparatus of the type utilizing a reference signal generator for preventing a null on a desired signal, weight oscillation eliminating apparatus for shifting the phase of the reference signal to make it generally equal and opposite to the desired signal so that weight oscillation of the system is eliminated.

Abstract: The position of a ship or other object being located is determined at an earth station using an active ranging satellite and a satellite which transmits time signals. One line of position is determined by two-way active ranging through the first satellite. The other line of position is determined by one-way ranging from the second satellite. The time interval between the time of arrival of the timing signal at the ship and reception of the active ranging signal at the ship is measured and sent back to the earth station with the ship's active ranging response. The position fix is then computed at the earth station.