Abstract: An antenna system for a flying body for jamming radio/radar signal transmitting and receiving devices. The antenna system includes a receiver with a frequency discriminator, a transmitter with a variable frequency oscillator, a transmit/receive device for conducting signals to the receiver and for conducting the transmitter signal to the antennas, a switch for selectively or cyclically connecting the antennas to the receiver and transmitter, a time which enables the receiver device to receive signals from antennas during one complete cycle of the switch and which enables the transmitter during the subsequent transmit mode to furnish transmitter signals to selected antennas for at least one complete cycle of the switch and a memory in which frequency representations are stored so that each representation corresponds to a particular antenna via which signals were received.

Abstract: A surface acoustic wave (SAW) device in a pseudo-coherent moving target indicator uses a common input transducer to delay both reference and signal inputs to a mixer by varying amounts. The mixer produces a Doppler signal which is processed within a single range cell. The SAW device may contain additional delay paths which drive other range cells. Power splitting and amplification sections of the moving target indicator are minimized through use of the SAW device.

Abstract: The invention relates to a coherent radar comprising a magnetron (10), a modulator (12) for pulsed driving if the magnetron, a stable local oscillator (22) and mixer (20) for producing an intermedicate frequency signal of incoming echoes and an intermediate frequency oscillator (28) and phase sensitive detector (26) for detecting the echo pulses in order to generate a so called bipolar video signal. According to the invention a HF-signal derived from the stable oscillator (22) is fed to the tuning cavities of the magnetron (10), so called priming, at least in the transmission moment, and furthermore the modulator (12) and the intermediate frequency oscillator (28) are mutually time controlled in such manner that the leading edge of the modulator pulse and thereby of the magnetron pulse always appears in a given phase position of the output signal from the intermediate frequency oscillator, for example a zero passage.

Abstract: In a single-frequency precision guidance landing system, the use of a DME interrogator in the aircraft and a DME receiver at the ground installation, each tuned to the same DME channel frequency, to uniquely interrogate a selected ground station and hence identify it by virtue of its replies being synchronous in the aircraft with the interrogations, the interrogations and the replies also being used to obtain range to the ground installation. This technique uses airborne already-installed DME interrogators for selective interrogation of a desired landing installation, thereby to eliminate any need to add additional special purpose equipment to the aircraft to accomplish the desired uniqueness of interrogation and ground installation identification achieved by this invention.

Abstract: A radar receiver having a feed-forward control circuit for adjusting the automatic gain control (AGC) setting in 6 dB increments for each range cell in a next sweep based on the AGC setting of each corresponding range cell in the present sweep, the magnitude of the larger of the in-phase (I) or quadrature (Q) components of the video signals of the present sweep from an A/D converter, the status of present sweep and previous sweep A/D limit conditions, and a selected guardband thereby holding the level of the radar return signal within the dynamic range of the A/D converter. The AGC setting is adjusted using a switchable attenuator which changes the level of the video signal into the A/D converter in 6 dB increments, each increment corresponding to a common I and Q data exponent directly used for floating point signal processing.

Abstract: In a transponder adapted to be attached to an object to be identified, an interrogator for interrogating the transponder utilizes an antenna system including first and second antennae with the first antenna being formed as a loop and the second antenna formed in a figure-8 configuration, and being coplanar with the first antenna. A source of power provides first and second transmission signals to the first and second antennae, respectively. A phase shift is introduced between the first and second transmission signals such that the first and second antennae create an electromagnetic interrogating field in a desired region with the electromagnetic field having a non-zero value at all points within the desired region for activating the transponder regardless of the orientation of the transponder. At least one of the two antennae may be arranged to function as a receiving antenna to receive signals emitted by the transponder.

Abstract: An FM-CW range measuring apparatus (1) to be tested generates a beat signal Fb at the frequency fb between transmitted and received waves. A simulator connected to this apparatus comprises a signal processing link, including a first HF interrupter (6), a circulator (7) and a second HF interrupter (8). A delay line (11) operating in the reflecting mode for producing the delay .tau. is connected to an input-output of the circulator means for controlling the interrupters (26, 28, 29, 33) effect opening thereof at a frequency f.sub.r (f.sub.r >2b), the first interrupter being opened during .delta. (.delta.<<1/f.sub.r), and the second interrupter during .delta.' (.delta.'.perspectiveto..delta.). The phase shift .tau.' between .delta. and .delta.' is such that the durations .delta. and .delta.' are separated from each other and that at least an echo of the order p in the delay line is defined by the equation:p.multidot..tau..perspectiveto.f/f.sub.r +.tau.'where k is a small integer.

Abstract: An aircraft is equipped with a system of the FM-CW type including an on-board radio altimeter which cooperates with a transponder/beacon located at A. The radio altimeter is adapted for the measurement, alternately with the measurement of the altitude H, of the distance D in relation to point A, and of the angle .beta. in relation to a horizontal axis (46) linked to the transponder. The radio altimeter includes two aerials and a supplementary processing chain for the measurement of angle .beta.. The transponder is equipped with a base with two receiving/transmitting aerials (25, 27), switched alternately to sequentially operated circuitry in the transponder. Furthermore, the exact position of the aircraft within the vicinity of point A is determined by at least two measurements of distance D and of the angle .beta. in relation to the aerial base of the transponder.

Abstract: A two-way ranging system in which deviations of transmit times of interrogation signals from a nominal transit time are determined at a transponder. These deviations are dependent upon the propagation conditions for interrogation and reply signals in the medium of propagation. A normally fixed delay is developed in the transponder. This fixed delay occurs between the reception of an interrogation signal and the transmission of a reply signal. This fixed delay is so shortened as to compensate for transit time deviations of the interrogation and reply signals.

Abstract: Microwave communication and radar systems that employ a blazed microwave reflection grating are disclosed in which the grating comprises an array of electrical conducting scattering elements having plane parallel surfaces that face in the same direction. The plane parallel faces are positioned in parallel equally-spaced planes to provide a generally stair-step, or Venetian-blind type structure. Microwave energy beamed onto the plane parallel surfaces of the array exits at a diffraction-mode angle within the reradiation pattern of the individual scattering elements of the array. Frequency steering of the exit beam in one plane of the array is provided by varying the frequency of the illuminating beam.

Abstract: A device for delaying an electric signal comprising means for acquiring the signal, sampling it at a frequency f.sub.e and delivering it in parallel in the form of binary words of M bits, at a frequency f.sub.m such that f.sub.m =(f.sub.e /M); means for storing said binary words for a given period of time and operating at the frequency f.sub.m and means for restoring at frequency f.sub.e the signal from the binary words.

Abstract: An object detecting method and apparatus is disclosed and which operates by transmitting a wave toward an object embedded in a medium having a reflective coefficient at its surface, receiving the resultant reflected wave from the object, applying the received signal to a signal processing unit, and displaying the results of signal processing by the signal processing unit on a display unit.

Abstract: A TEM-mode transmission line such as a microstrip or coplanar line includes a pair of conductors, at least one of which is elongated. A semiconductor junction or junctions are coupled across the conductors. If a single junction is used, the junction may be laterally elongated or distributed. If discrete semiconductor junction devices are used, plural devices may be coupled across the transmission line. The capacitance of the junction(s) controls the phase shift imparted by the transmission lines to AC signals traversing the line. The capacitance of the semiconductor junctions in controlled by light coupled into the junction region. The light is coupled to the junction region by fiber-optic cables or by means of light illuminating the junction.

Abstract: A system for manned or unmanned flying bodies detects covered or hidden targets on the ground by using relatively "longwave" radar radiation for immediately attacking such ground targets, which may be covered by trees for example, but located on a strip of ground extending with a given width below the flight path of the flying body travelling in low altitude flight. Four radar receiver antennas are equally spaced from each other along the wings of the flying body and one transmitter antenna is located between two pairs of receiver antennas. The receiver signals are submitted by a fast Fourier transformation for providing a wavefront reconstruction. The so transformed, received signals are then evaluated in accordance with the known SAR principle directly as the signals are received and transformed by correlation with expected signal functions, so-called reference function, for producing a control signal for the direct or indirect discharge of a weapon.

Abstract: A frequency agile radar system allows tracking of noncooperative targets with high accuracy. The system is particularly useful in an automatic landing system aboard an aircraft carrier. The radar employs an electronically steered planar array antenna system in which a symmetrical pencil beam of 1.degree. beamwidth is steered in 1/2.degree. steps in a raster scan. A space-stabilized acquisition window allows target acquisition, and target scanning modes are chosen as a function of target range. At far range, target scan is effected by those four beam raster positions which bracket the target whereas when the target is at near range where its cross section is larger than a single beamwidth, the raster is "ballooned" to paint or cover the target fully. The computed track of the target provides a continuing update of autopilot command signals radioed to the target to bring it to and hold it on a selected glideslope which effects the automatic landing.

Abstract: A Doppler radar system for a vehicle providing driver warning, vehicle brake application and air bag deployment. The system produces voltage level input directed to the distance and approach rate to an object, vehicle speed and driving monitor inputs, such as steering angles, turning rates, braking, and acceleration/deacceleration. These voltages are properly weighted as to their importance. These weighted instantaneous input voltages are summed. The summed voltage is then compared with a predetermined voltage level dividing safe and danger zones. If the summed level falls within the safe zone, the radar system produces no output signals. If the summed voltage level falls within the danger zone, the radar system produces audio warning signals and if impact with an object is eminent vehicles braking signals are then produced. The invention further includes an air bag deployment feature.

Abstract: A small-size transmitting apparatus for search and rescue operation (SARTR) adapted to be worn by a user for emitting a microwave rescue signal upon a marine accident involving the user. The SARTR includes a power supply, a transmitter unit energizable by the power supply and having a microwave oscillator, a transmitting antenna receiving of a microwave output from the transmitter unit for emitting the microwave rescue signal, a case accommodating the power supply, the transmitter unit, and the transmitting antenna and attachable directly to the user's body, or mountable on clothing or the like worn by the user for being carried thereby, and a switch unit mounted in the case for controlling the emission of the microwave rescue signal.

Abstract: A digital pulse compression filter for use in a radar or sonar transmitting and receiving unit to process sampled and digitized signals. The sampling frequency (f.sub.s) is equal to about four times the center frequency (f.sub.o) and greater than about twice the bandwidth (.DELTA.f) of these signals. The pulse compression filter (5) comprises a time correlation circuit (7) supplied on the one hand with the sampled and digitized signals and on the other hand with signals representing a replica of the radar or sonar transmitter pulse, whereby one of the two types of signals supplied to the correlation circuit (7) is correlated with the orthogonal components of the other type of signals supplied to the correlation circuit (7) to obtain the orthogonal components of the compressed pulse.

Abstract: This radar system can be used as an independent entity or as an addition to n operating radar system for acquiring additional data from a radar target's returned signal that is not currently being utilized. The system is to separate the amplitude modulation and frequency modulation sidebands created by the target's surface motion or vibration into independently useable entities. The system measures near carrier AM and FM noises, together with techniques for integrating these elements into a working radar system.

Abstract: A phase-lock loop system with particular use in radar tracking systems is disclosed. From a number of input signals of varying frequencies such as a carrier frequency and several side band frequencies the system can lock into phase and frequency with the input which has the largest amplitude by sweeping across a predetermined range of frequencies and allowing the phase-lock loop to operate only when a predetermined amplitude is exceeded.