Abstract: A short range, precision navigation and tracking system and method therefor are disclosed. The navigation and tracking system utilizes a master-repeater configuration with a phase lock loop controlling the modulation frequency of the master FM transmitter.

Abstract: A radar tracking system having a Kalman estimator is disclosed. The estimator is provided with angle and range track error measurements in a coordinate system that is aligned with and normal to the antenna line of sight, commonly referred to as the LOS coordinate system. This estimator implementation uses less computing resources in converting the measurements provided relative to the antenna LOS coordinate system, to predict target position referenced to a stable coordinate system such as geographic, wander azimuth, or inertial.

Abstract: A self-referencing sensing and control apparatus which may be used advantageously in any industrial installation in which an A.C. powered device, such as the down-hole motor in a submersible pumping system or a plunger relay, is remotely located and in which it is desired (i) to monitor certain parameters, such as temperature and pressure, and/or (ii) to control certain operational functions, such as the state of flow valves and latching means, at the remote site. The power cable used to carry A.C. power to the remotely operating device is also used to carry instrumentation and control signals from local control and readout equipment to an instrumentation package installed at the remote site. The present invention comprises switching means to selectively couple and decouple one or more sensors (or control means) in the instrumentation package to and from the A.C. operating device and the power cable, thereby permitting high voltage testing of the A.C. device and cable, or other tests.

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 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: 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: 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: 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.

Abstract: A hydraulic synchronizing system which comprises a double piston power source and a drain valve in fluid communication with the hydraulic lift cylinders of a vehicle mounted vibratory seismic energy source. The double piston power source supplies the hydraulic lift cylinders with substantially equal volumes of hydraulic fluid, and the drain valve adjusts the flow of hydraulic fluid out of the hydraulic lift cylinders. The system synchronizes the operation of the hydraulic lift cylinders and thus coordinates movement of the vibrator guide rods relative to the vehicle upon which the vibrator is mounted.

Abstract: A Doppler radar employing a common antenna for transmitting and receiving. A single sideband modulator (SSBM) is employed in the transmitting circuit to offset the rf reference frequency during transmit time and to discontinue offset during receiver ON time. Through a coupler and isolators an attenuated portion of the rf reference signal is applied to the receiver mixer at gated intervals. The output of the mixer are signals which are free of undesired reflected transmitter signals.

Abstract: An improved high frequency radiometric system features time shared passive and active modes of operation for correlation of active and passive signal returns. The processed, normalized, and stored passive signals are subtracted from similarly treated active signals to suppress the effect of returns from back ground terrain, thus enhancing true target recognition. A second channel provides discrimination against jamming and spurious signals, thus reducing false alarms.

Abstract: A relatively small directional loop antenna adapted for use in an airborne automatic direction finder (ADF) is made to perform like a physically larger loop while being broadly tuned to a mean operating frequency. The total input equivalent noise source is kept low by coupling the loop into an impedance comprised of an active circuit. The active circuit is designed in conjunction with an active feedback circuit into which the ADF sense antenna is fed to maintain a relatively constant phase difference between the ADF loop and sense signals.

Abstract: A method and apparatus for the control of the safety distance of a vehicle with respect to preceding objects wherein various measurements and controls are effected so as to provide control magnitudes for enabling prevention of a collision of the vehicle with an object.

Abstract: A Doppler radar having a single sense Doppler signal from the rf mixer. A single sideband modulator in a common antenna system for transmitting and receiving shifts the fore and aft beams to achieve a single sense Doppler signal. The use of the single sideband modulator results in a differential Doppler shift between fore and aft beams of only a few hundred knots, thereby permitting use of low cost components. A single sense Doppler also reduces the Doppler passband by a 2:1 factor which permits the power supply frequency to operate at a higher frequency than the receiver.

Abstract: This invention discloses pulse radar apparatus for the transmission of radar pulses having a pair of frequencies in each rf pulse. One of the frequencies transmitted in each pulse is repeated in the succeeding pulse while the other frequency is changed to a new frequency. Moreover, the repeated frequency appears in the same relative position in the pulse pair as in its original occurrence.