Abstract: The present invention relates to a device for simulating the locating signals of an I L S beacon, said device comprising on the one hand two chains in parallel respectively intended for generating sinusoidal modulation I L S signals, each comprising a digital generator for one of said signals and a digital analog converter provided with an input for controlling the reference amplitude of its output voltage and, on the other hand, an at least partially digital arrangement for producing reference voltages for said inputs for controlling the digital/analog converters. The invention is applicable for testing apparatus on board an aircraft.

Abstract: A method for locatingweak targets such as power lines and tree tops in the presence of terrain clutter by separating the weak target from the clutter in the elevation plane.

Abstract: A system for providing aircraft guidance at elevation angles less than the transmitting antenna beamwidth.

Abstract: Passive frequency measuring circuit comprising a number of frequency discriminators to obtain a digital code representing the frequency of an applied r.f. signal. Each discriminator is tuned to different frequency ranges, and provided with a plurality of similar frequency analysers for the phase detection of the applied r.f. signal passed through different delay lines. As each discriminator delivers an ambiguous code at the boundaries of its characteristic, a digital filter is incorporated to resolve the ambiguity. If such an ambiguity is established, an adjoining discriminator is activated to deliver information for obtaining a digital code representing an unambiguous frequency value.

Abstract: A system in which the characteristics of a microwave power transmission beam are controlled in accordance with power distribution profiles altered due to the detected presence or entrance of an object into the beam which causes changes that are perceived in various received, reflected and scattered power distribution profiles resulting over various receiving elements of the system. An analysis of these changes is made, the results of which are used to reshape, dim or douse the power beam in accordance with predetermined criteria. Additionally, a "FAIL SAFE" condition is obtained by employing a beam penetration tester, whose function is to repeatedly test the correct performance of the beam intrusion detecting scheme by presenting a minimal threshold scattering or absorbing cross section while crossing the power beam. If the beam penetration tester is undetected by the beam safety system, then the beam control is preconditioned to turn off the power beam.

Abstract: The invention relates to a system for the reception, storage and subsequent ransmission of information. The system utilizes a main memory and an auxiliary memory. The information received by the auxiliary memory updates and corrects the information in the main memory. A timing generator controls the timing of the memory scan periods and a time normalizer is utilized to correct frequency deviations of the timing generator. A detector monitors the operation of the system.

Abstract: Complex modulation--that is, amplitude and phase modulation--is used to provide smaller beamwidth and better angular resolution of a scanning radio beam generated by a commutatively switched aerial. The way in which the modulation pattern may be determined is detailed, and examples are given of the application of complex modulation techniques to different types of commutative aerials.

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: In an information receiving apparatus having a time-shared mode of operation for simultaneously receiving a plurality of information carrying signals, at least one signal of which includes an identification tone superimposed thereupon, a tone reconstitution scheme for providing a continuous tone from a received tone signal which contains absences of tone signal due to the time-shared partial duty dedication of the receiver to that signal and its superimposed tone.

Abstract: A general aviation navigational receiver is provided with a digital channel selection wherein a channel selection knob on the aircraft control board may be operated to control the functioning of a digitally implemented frequency synthesizer which in turn controls the operation of a voltage controlled oscillator for providing frequency signals to an RF mixer of the unit, the frequency synthesizer being programmed for both possible VOR/LOC and GS channel frequencies wherein switching between frequencies is accomplished in synchronism with the basic clock within the synthesizer greatly reducing transient changeover time.

Abstract: The invention provides a side-looking coherent pulse radar for use on a moving platform and for exploring space laterally with respect to the displacement of the platform. The receiver includes a detector which coherently detects echo signals having a Doppler component and applies these to a correlation processor which samples the detector output signals and performs a correlation process with a reference correlation waveform having a center frequency which is chosen to bear a predetermined relationship with the Doppler frequency component of the received echo pulses. Sensors derive the accelerations of the platform in three mutually orthogonal planes (one of which is in the platform displacement direction) and the parameters derived by the sensors are utilized to maintain the aforementioned predetermined relationship as the Doppler frequency component of the echo pulses vary with movement of the platform from the required displacement direction.

Abstract: The present invention relates to a target location method, and more particularly to such a system using passive listening devices to determine the range, course and speed of one or more targets simultaneously. The invention may be used effectively against targets which emit either continuous or pulsed electromagnetic energy signals.

Abstract: An AFC system for a radar comprising means for changing in one sense a control voltage fed to a voltage controlled local oscillator forming part of the radar receiver when a predetermined number of cycles of a difference frequency between a local oscillator and a transmitted radar frequency obtain during a predetermined period until less than the predetermined number of cycles obtain whereupon the voltage is changed in the opposite sense whereby the frequency of the local oscillator is automatically controlled.

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 antenna for the short-range reception of an emitted signal comprises at least two independent sectors for the coarse location of an emission-beam source in two predetermined directions. Each sector is constituted by a waveguide having a single open face oriented in the intended direction of surveillance. A microwave diode is placed within each sector at right angles to, and at the geometrical center of, the supporting wall of the waveguide which is associated with the diode. The frequencies detected by the antenna are within the range of 10.sup.9 Hz to 30.times.10.sup.9 Hz.

Abstract: A system is disclosed for locating missing vehicles. Each vehicle broadcasts a locator signal when queried from a central station by an encoded call signal having a code characteristic of the vehicle. Indicators responsive to the locator signal are provided to determine the location of the missing vehicle.

Abstract: A near-range personnel beacon locator apparatus utilizing a tuned tank circuit to receive the emitted signal from an activated personnel beacon. The detected signal is applied to a D.C. amplifier to provide a D.C. level which drives a controlled variable duty cycle timer for driving a light emitting diode indicator.

Abstract: A sidelobe canceller in which the undesired signals in the main antenna channel are cancelled at RF using signals from multiple auxiliary antennas, where each auxiliary antenna signal has been weighted in a vector modulator while at RF. The weighting is determined in a single wideband IF loop by multiplexing the multiple auxiliary antenna signals through the same auxiliary receiver, correlator and demodulator. The demodulated output signal from each auxiliary antenna is sampled and retained as a weighting to adjust the vector modulator for the corresponding auxiliary antenna. A timing and control circuit coordinates the multiplexing and sampling functions.

Abstract: The present invention provides a method and apparatus for effecting, in a ssive manner, the acquisitioning of a broadband barrage jammer type radar target, by detecting the differential delay between the barrage signal as received at a predetermined location over direct and indirect paths and producing a signal distinctly identifying the location of the jammer target relative to the receiving station. More specifically, the present invention includes means for generating reference pulses of varying frequency which are utilized in determining the phase relationship which exists between each of these reference pulses and the corresponding frequency component of the jammer signal as received over the direct path to the target.