Abstract: A car security system has a proximity sensor such as a radar sensor with variable sensitivity and capable of producing a detection signal upon detecting motion of a person in a monitoring area. A control circuit is provided controls the sensitivity of said proximity sensor. The system also has a monitoring/alarming control circuit for control of predetermined monitoring and alarming control on the basis of the output from the proximity sensor, and alarming devices such as a headlight flash circuit, buzzer and siren for performing a predetermined alarming operation under the control of the monitoring/alarming control circuit. The sensitivity control circuit operates in response to a predetermined operation such as an arming start operation to vary the sensitivity of the proximity sensor so as to automatically set the sensitivity to a first sensitivity level which is the highest level within a range which does not cause the sensor to produce the detection output.

Abstract: The signal that controls the gain of a sensitivity timing control (STC) circuit is slimmed with a gain correction signal to compensate for gain variations introduced by items such as variations in the parameters of electronic components. A known test signal is injected into the STC circuit and the resulting output signal is measured. The amplitude of the gain correction signal is determined based on the difference between the desired output signal amplitude and the measured output signal amplitude.

Abstract: An automatic thresholding target detection system operable in high clutter, noisy environments provides target recognition through the generation of automatic signal thresholds. Infrared and radar detectors scanning an environment detect radiant energy from manmade and natural sources. The energy received is converted to electrical signals representative of the varying energy intensities which are filtered and compared with a computed target signal threshold. Signal spikes having amplitudes greater than the automatically generated threshold are then evaluated using a shape parameter test. Finally, an automatic region clutter recognition processor confirms that the spike is a true target, clutter or noise.

Abstract: A video signal processor for a radar system includes A/D converters for receiving radar signals to digitize the signals at a predetermined speed, direct averagers for writing signals included in the predetermined size of azimuth among the digitized radar signals into different memories according to the azimuths and for averaging signals corresponding to the same range gates, cell average processors having a microcomputer and a RAM for cell-averaging the output of the direct averagers with the processing program down-loaded from a main controller, an extractor for extracting only target data from the output of one of the cell average processors, a radar video processor controller for generating various control signals, and a communication processor for performing the data transmission and reception between the main controller and the radar video processor controller of the radar system.

Abstract: A tracking radar system comprising an aerial arrangement having a plurality of outputs, means for deriving from the aerial outputs a sum signal representative of the sum of the aerial outputs and a difference signal representative of the direction of a target relative to the aerial, a receiver for processing said sum and difference signals to produce corresponding intermediate frequency sum and difference signals, means for comparing the intermediate frequency sum signal with the output of an oscillator in a first phase-locked loop and using the resulting signal to control the oscillator frequency so as to cause the oscillator to lock on to the frequency of the intermediate frequency sum signal, a phase-sensitive detector for comparing the intermediate frequency difference signal with the output of the oscillator to produce an output signal representative of the phase difference between the sum and difference signals, and bandwidth alteration means responsive to the sum signal to alter the bandwidth of the fi

Abstract: The disclosure relates to guidance devices on board autonomous vehicles or robots which have to move about notably in environments that are inaccessible or dangerous to human beings. Disclosed is a device for the detection of the environment, and the positioning and/or the guidance of a mobile vehicle on the ground, of the type comprising, firstly, means for the generation and transmission of a signal that can be reflected by a fixed obstacle and, secondly, means for the reception and processing of the signal reflected by said fixed obstacle, said processing means enabling the recognition of the environment and/or the guidance of said autonomous mobile vehicle, said transmitted signal being a millimetric wave radar signal and said transmission and reception means cooperating with a rotary antenna having a 360.degree. rotation in azimuth.

Abstract: A method and apparatus that uses iteration to achieve a better prediction of the values of the commands needed to balance the gains of .SIGMA.+.DELTA. and .SIGMA.-.DELTA. channels of a radar guidance system, when an imbalance occurs due to a change caused by the AGC circuitry. An improved method of measuring channel-to-channel gain imbalance versus AGC measurements is provided, which produces modified input values that are used as commands that correct the mismatch during missile flight so that residual error is minimized and more accurate guidance is achieved. The present method is implemented by measuring the gain imbalance at predetermined AGC points during system calibration, and iterating these measurements to produce a relatively small channel-to-channel gain imbalance at the .DELTA.AGC amplifiers. The measured imbalance is then converted to .DELTA.AGC commands and applied to the .DELTA.AGC amplifiers. The resulting gain imbalance is measured and this value is added to the originally measured value.

Abstract: An object detection system and method for detecting the presence of objects in the path of a vehicle, and in which includes a self test operation. The system includes a transmitter which transmits object detection signals and a receiver which receives reflections of the transmitted object detection signals. A controller is provided for adjusting the gain and signal threshold of the receiver so that the receiver initially is able to detect reflections from irregularities in the ground surface. Once the receiver receives a signal reflected from the ground surface, an indication is provided that the system is in a ready or operable state. Thereafter, the controller adjusts the receiver gain and signal detection threshold so that signals reflected from the ground surface are effectively ignored and only signals reflected from significant objects in the path of the vehicle are detected. An alarm signal is generated in response to the receiver receiving signals reflected from the object.

Abstract: An apparatus comprises a signal input and a sampler and analog-to-digital (A/D) converter coupled to the signal input. The sampler and A/D converter forms a digital pre-look signal from an input signal. The apparatus further comprises a digital memory coupled to the sampler and A/D converter. The digital memory stores sensitivity time control (STC) data and provides specific STC data in response to the digital pre-look signal. The apparatus further comprises a digital-to-analog converter coupled to the digital memory. The digital-to-analog converter converts the specific digital STC data to a first analog STC signal. The apparatus also includes a first comparator coupled to the signal input and to the digital-to-analog converter. The first comparator has an input for receiving the first analog STC signal. The first comparator compares a present input signal to the first analog STC signal to provide a detection signal.

Abstract: The present invention is a radar system that corrects for changes in apparent reflectivity and two-way precipitation attenuation using a correction curve that includes a segment for low rain rates, a segment for high rain rates and, if desired, a transition segment for medium rain rates. The signal to noise ratio is further improved by using a sliding azimuth window during post detection integration processing.

Abstract: A system for detecting phase and gain imbalance errors in a synchronous detector. The synchronous detector (10) is assumed to have a fist circuit (16) for providing a first signal representing a first sinusoidal term (e.g., a cosine term) and for providing a second signal representing a second sinusoidal term (e.g., a sine term) complementary to the first sinusoidal term, circuitry (12) for mixing an input signal with the first signal and circuitry (14) for mixing the input signal with the second signal. The system (16) for detecting phase and gain imbalance errors of the invention includes an amplitude compensation circuit (24) for detecting and correcting amplitude errors in the first and second signals and a phase compensation circuit (26) for detecting and correcting phase errors in the first and second signals. For amplitude compensation, the outputs of the amplitude and phase compensation circuits are input to first and second amplitude detector circuits (28) and (30).

Abstract: A method and apparatus are used in the acquisition of data by ground-penetrating radar, wherein the signals thus obtained are input to a pre-amplifier which contains filtering component such as an anti-aliasing filter. The base gain of the system is switch selectable and electronically adjusted to bring the input signal to between one half and full scale on an analog to digital converter input. The converted digital value has a resolution of fifteen bits for processing.

Abstract: A gain control network having a phase splitter circuit responsive to an RF input signal for providing first and second RF signals that are out of phase relative to each other, a first series of switched gain control elements, and a second series of switched gain control elements substantially identical to the first series and commonly controlled therewith. The first series of gain control elements is responsive to the first RF signal for providing a first gain controlled signal, and the second series of switched gain control elements is responsive to the second RF signal for providing a second gain controlled signal. A phase combining circuit combines the first and second gain controlled signals to provide a gain controlled RF output. By performing gain control with two gain control channels having substantially identical circuits and common switching control, transient glitches in each of the channels are substantially identical and are substantially cancelled via the phase combiner.

Abstract: In a sensitivity time control device for an imaging radar system with an automatic gain control attenuator, a sensitivity time control attenuator and an analog-digital converter, output signals of the analog-digital converter are applied, via a device (20) generating an average value and a comparator device, to a control device, which has a ideal on-off relay connected with a device for determining its control parameter, an integrating member, switched downstream, and a device for calculating the operating point of the automatic gain control attenuator device. Furthermore, an n-bit digital analog converter is switched downstream of the control device, by means of the analog output voltage of which the sensitivity time control attenuator is controlled. It is possible, with the aid of the sensitivity time control device, to evaluate continuously the backscatter signal of an imaging radar system in real time, so that it is continuously possible in this way to determine an optimal sensitivity time control curve.

Abstract: An apparatus for detecting bodies in motion on the ground of a protected area, particularly for military use and the like, wherein, by means of an antenna buried and shielded from the air, an electromagnetic signal in the range of radio frequency is radiated into the ground. Receiver means comprising means for detecting variations of the signal intensity are placed at a known distance from the receiving antenna. The intensity variation is dependent on the presence of bodies in motion within the range of action of the apparatus.

Abstract: A vehicle-mounted ultrasonic velocity sensor includes an ultrasonic transmitter and receiver coupled to transmit and receive horns. In one embodiment, a phase-locked-loop signal processing circuit converts the transmitted and reflected frequencies into a signal indicative of the vehicle velocity. In another embodiment, velocity data is obtained by measuring the period of a certain number of cycles of the reflected signal using a pair of counters, one counting at a rate equal to the reflected frequency, the other counting at a fixed rate. In both embodiments, the variable magnitude reflected signal is applied to an input of a drop-out detection circuit whose output is then connected to an input or inputs of the velocity determining circuits to prevent velocity detection during dropout periods.The velocity sensor may be implemented utilizing radar components.

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: 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 pulse doppler radar system which provides dynamic correction to variable radar echo return signals from clutter end targets using a block adaptive signal regulator (BASR) and a fast Fourier transform (FFT), a gain restoration circuit is used to optimize the gain corrected amplitudes over a plurality of time samples so that the tendancy of larger targets to obscure the return signals of smaller targets is minimized. The BASR conventionally evaluates the amplitude of echo returns in each time sample before it enters the FFT, by determining if they exceed the radar receiver's dynamic range, and dividing all samples by 2.sup.N when a sample exceeds the dynamic range (where N equals a shift number which signifies a shift by the BASR). The gain restoration circuit feeds information which indicates the number of BASR shifts to the output of the FFT as a function of range gate.

Abstract: A technique for correcting the non-uniform illumination and return echo strength from a mapped area resulting from antenna beam shape and range loss effects in a batch high resolution synthetic aperture radar. The technique involves changing the radar receiver gain in a precisely defined compensating manner and eliminates amplitude roll off at the edges of the display map so that equal target returns are displayed at equal amplitudes at any point of the map. The compensation arrangement requires minimal memory and computational overhead and thereby achieves minimal impact on frame time of the displayed map. The disclosure includes a computer simulation of the radar system performnce and comparison of the simulated before and after compensation radar maps.