Abstract: A target tracking apparatus to accurately measure the position and dimensions of a target and to adjust the size and position of the tracking gate such that it circumscribes the target. The target dimensions are determined and stored in a dimension memory and are utilized to supplement the incomplete data which occurs when the target is only partially within the tracking gate.

Abstract: A Doppler speed sensor for a ground vehicle wherein errors due to vehicle tilt relative to the ground surface and initial mounting angle error are substantially eliminated by using a first antenna with its radiation pattern directed down and forward and a second antenna with its radiation pattern directed down and rearward, so the principal axes of the radiation patterns are 90.degree. apart. A novel digital technique for processing the signals received from such antennas is also disclosed.

Abstract: A range measuring apparatus of the linear frequency modulation type is disclosed which comprises a measuring control loop for rendering the beat frequency between the transmitted and received frequencies equal to a fixed frequency. The apparatus further includes means for forming a permanent second beat signal between two signals derived from the generator supplying the frequency modulated signal, one of these signals being delayed by means of the delay line. A phase detector receives this second pulsed signal and the signal of a controlled frequency oscillator and supplies a signal which controls the slope of the frequency modulation. The error signal of the measuring control loop controls the frequency of the signal from the oscillator. This arrangement results in an increased precision in the range measurements.

Abstract: A radar system with improved display brightness in high ambient lighting conditions and with simplified deflection and video amplifiers. The incoming radar return signals are digitized and stored in shift registers with the timing to write the data into the shift registers dependent upon the radar range setting. After the digitized radar return signals have been read into the shift registers, they are read out to the display in a constant time period independent of the range setting. The radar system may be used at closer ranges than was previously possible.

Abstract: A vehicle identification system, using microwave, in which every vehicle to be identified has an identification panel attached to its side, containing a very low level power drain tunnel diode transponder and a digital coder plus a small battery and a resonant frequency array. Interrogating transmitter-receivers are placed at designated ground stations. For verification purposes there is a resonant reflective array printed on the identification panel to reflect back a doppler offset signal emitted by the interrogating transmitter, thereby registering that a vehicle with an identification panel has passed, even if the transponder has failed. Unlike optical scanners used for freight car identifications, this system cannot be disrupted by dirt, ice and snow. Vehicles do not have to slow down to be interrogated, and the emitted field strength from this plate is so low that F.C.C. licensing is not required. The code stored in the panel is readily programmable, if desired.

Abstract: A device to be used as a guidance system for sonar or radar or similar transmissions in which a dihedral reflector is used in association with part of the earth's surface (land or sea) whereby a trihedral reflector results for such transmissions in which spurious signals are avoided because the earth forms one of the reflective surfaces to thereby remove spurious signals which could otherwise occur with a normal trihedral reflector.

Abstract: A constant false alarm rate (CFAR) moving target indication (MTI) radar system, operable in various electronic countermeasures (ECM) environments is disclosed. A modified Dicke-Fix circuit is used to drive the MTI. Operation of the invention results in automatic restoration of signal level out of a filter. Thus the invention provides a CFAR-MTI that is not degraded significantly by swept jammers and is not captured by off-frequency jammers.

Abstract: Due to the long dwell time required for doppler processing, most doppler systems are particularly vulnerable to electronic counter measures environments (jamming). Such vulnerability manifests itself by registering numerous false alarms and by receiver saturation. The proposed system will not deviate significantly from an ideal constant false alarm rate (CFAR) device when operated in an electronic countermeasure (ECM) environment nor will its sensitivity degrade as in conventional systems.

Abstract: A television receiver circuit includes a voltage regulator with a feedback circuit for providing a regulated B+ operating voltage, a horizontal deflection circuit including a resonant retrace circuit for generating a scanning current in a deflection winding for producing a raster, a high voltage circuit for providing an ultor voltage for beam current, and a high voltage protection circuit for disabling normal operation of the horizontal deflection circuit when the ultor voltage exceeds a predetermined magnitude. An impedance is included and is capable of being selectively coupled to the feedback circuit. A capacitance is also included and is capable of being selectively coupled to the resonant retrace circuit. Both means combined are selectively capable of decreasing the ultor voltage for preventing unnecessary disabling of the horizontal deflection circuit while maintaining a constant raster width.

Abstract: A signal receiver employing constant false alarm rate (CFAR) circuitry is disclosed. The CFAR circuitry includes a dispersive delay line for stretching received echo signals, means for limiting the stretched echo signals and an inverse dispersive delay line for finally processing the stretched and limited echo signals. With delay lines of proper characteristics, the just-outlined processing of echo signals results in reconstituted signals, the amplitude of each one of such reconstituted signals being indicative of the source of a corresponding echo signal.

Abstract: The apparatus of the invention comprises a radar device for measuring the range of an object and the vehicle speed relative to the object, and a vehicle speed sensor for measuring the vehicle roadway speed. A first computing circuit is provided to set up a first minimum distance allowed for the vehicle when approaching a stationary object and a second computing circuit for setting up a second minimum distance allowed for the vehicle approaching an object moving ahead of the vehicle. An alarm will be given either when the range of the stationary object reaches the first minimum distance or that of the moving object reaches the second minimum distance.

Abstract: In a vertical deflection circuit, a deflection winding is coupled to an output terminal of a deflection amplifier. The amplifier generates a trace current in the winding in response to drive signals coupled to an input terminal of the amplifier. A first voltage source provides an operating voltage for the amplifier. A bidirectional retrace switch couples the output terminal to a second voltage source for providing a greater magnitude voltage for generating a retrace current in the winding. The bidirectional switch has a controlled semiconductor which is responsive to the drive signals for controlling a main conductive path of the switch during a portion of the retrace interval.

Abstract: A convergence correction system is disclosed for digitally controlling the convergence correction signals applied to the convergence correction coils of a color CRT. The convergence correction signals correspond to a plurality of segments defined for the phosphor face of the CRT, so as to produce the convergence of the associated electron beams at the phosphor triads within the individual segments. The system provides for the independent adjustment of the convergence of each electron beam within each of the four quadrants of the phosphor face, independent of the adjustments for the convergence of the other electron beams. The system further provides for the use of only one convergence correction coil for each associated electron beam.

Abstract: A method and apparatus is described for the post processing of return signal data in a single channel medium PRF pulse doppler radar receiver. The disclosure is directed to preventing sidelobe return signals from being displayed as "ghost" or "false" targets. The received signal data is preliminarily processed by a filter bank and a CFAR threshold circuit to remove main beam clutter and area sidelobe clutter returns. The preliminarily processed data is then temporarily stored as two parallel correlations are performed on a range cell by range cell basis to identify range cells which contain discrete sidelobe clutter return signals. One of the parallel correlations is performed on the data after it has passed an STC (Sensitivity Time Control) threshold circuit and the other parallel correlation is performed on the raw data. The outputs of the parallel correlators are compared.

Abstract: Arc-inhibiting means for a television picture tube having an electron gun with a main focus lens section of the extended field type. The lens establishes an extended, axially continuously active focusing field which is substantially shielded from external field disturbances. There exist widely disparate potentials with a potential difference in the range of tens of kilovolts across the gap between a grid means of an electron source means and an initial end electrode of the main focus lens. The potential difference is sufficient to introduce a tendency toward destructive arcing between the grid means and the initial end electrode. The electron gun according to the invention is characterized by having at least one arc-inhibiting electrode disposed between the grid means and the initial end electrode, and having a potential thereon that is intermediate to the disparate potentials to provide an arc-inhibiting voltage gradient between the grid means and the initial end electrode.

Abstract: The present invention relates to a method for eliminating range side lobes of a phase modulated radar pulse when compressing the same in the receiver of a radar equipment. The incoming radar pulse is inverse filtered in the receiver by means of two digital filters. After filtering in the first filter the sequence thus obtained is reversed in time and the reversed sequence is again filtered in the second filter so that it is possible to use only stable filters for the inverse filtering.

Abstract: A method and apparatus for the processing of return signal data in a single channel, medium pulse repetition frequency, pulse doppler radar receiver in which discrete sidelobe return signals are prevented from being recognized as true targets. The return signal data is processed by a clutter cancellation circuit, which in the preferred embodiment is a doppler filter bank, to remove main beam clutter and a constant false alarm rate threshold circuit to remove area sidelobe clutter return signals. The return signal data is temporarily stored as data blocks which are representative of the return data in the interpulse period of each pulse repetition frequency. The data blocks are unfolded over a predetermined range and two parallel correlations are simultaneously performed over the predetermined range to identify discrete sidelobe clutter return signals.

Abstract: The effects of simultaneous platform motion and antenna scanning are compated for in radar systems of the moving-target-indicator type. Signals from auxiliary sub-arrays of the antenna compensate signals from main sub-arrays of the antenna for the effects of antenna scanning. Delayed, scanning-compensated signals from the main sub-arrays are then combined with undelayed, uncompensated signals from the main sub-arrays to provide signals that are compensated for the effects of scanning motion and platform motion. A first embodiment provides a clutter canceller having motion compensation at each stage of cancellation. A second embodiment provides a large number (N) of motion-compensated signals which are synchronized in time and phase for further MTI processing.

Abstract: The effects of platform motion or antenna scanning in radar systems of the oving-target-indicator type are compensated for by arrangements which use difference-channel signals to correct sum-channel signals for the changes in phase and amplitude of the backscattered sum-channel signals due to the platform motion and antenna scanning, respectively. Clutter-canceller arrangements having motion compensation at each stage of cancellation and an arrangement for providing a large number (N) of motion-compensated signals which are synchronized in time and phase are shown.

Abstract: A clutter tracker in which received clutter velocity signal is shifted to zero doppler in order that optimum moving target indicator (MTI) cancellaton can be achieved is disclosed. A frequency controllable voltage controlled crystal oscillator (VCXO) is used as the coherent oscillator (COHO) source. The subject digital system changes the VCXO output bus only once per dwell, thus allowing adequate filtering to achieve desired performance without adversely affecting tracking performance.