Abstract: An autonomous vehicle (AV) includes a radar sensor system and a computing system that computes velocities of an object in a driving environment of the AV based upon radar data that is representative of radar returns received by the radar sensor system. The AV can be configured to compute a first velocity of the object based upon first radar data that is representative of the radar return from a first time to a second time. The AV can further be configured to compute a second velocity of the object based upon second radar data that includes at least a portion of the first radar data and further includes additional radar data representative of a radar return received subsequent to the second time. The AV can further be configured to control one of a propulsion system, a steering system, or a braking system to effectuate motion of the AV based upon the computed velocities.

Abstract: A method of removing a mobile airborne device from a field of view of a primary camera. A sensor associated with a primary camera detects a mobile airborne device within a field of view of the primary camera, where a three-dimensional physical space is within the field of view of the primary camera. A signal generator generates a signal that, when received by the mobile airborne device, causes the mobile airborne device to exit the three-dimensional physical space. A transmitter transmits the signal to the mobile airborne device to cause the mobile airborne device to exit the three-dimensional physical space that is within the field of view of the primary camera.

Abstract: A method for operating a radar sensor, having the steps: sending out a transmit signal; reception, by a receive unit, of the transmit signal reflected by at least one target object; evaluation of the receive signal; and regulation of a cutoff frequency of a high-pass filter as a function of the evaluated receive signal.

Abstract: Provided are an apparatus and a method for measuring a frequency of a broadband signal by using low-speed ADCs having sub-Nyquist sampling rates. A plurality of channels each including a low-speed ADC having a sub-Nyquist sampling rate (e.g. sampling frequency from several MHz to hundreds of MHz) are provided, and the frequency of an input signal corresponding to a combination of frequencies calculated through the respective channels is estimated. Therefore, as the number of channels increases, the range of measurable frequencies may be extended.

Abstract: A drone detection radar can include a plurality of antenna systems, each antenna system being arranged to transmit a signal into an associated sector, and to receive signals reflected from targets in the sector, the sectors collectively forming a monitored volume, and wherein a sub-set of the antenna systems are active at any one time, with the active sub-set of antenna systems being arranged to monitor their respective volumes for a duration sufficient to measure Doppler signals associated with slow moving drones, with the radar being arranged to switch to a different sub-set of antenna systems after each duration, such that the whole volume is monitored within a predetermined period. Combining a staring array from an antenna system with a plurality of switched antenna system allows drones to be both detected and tracked, with appropriate selection of the predetermined period.

Abstract: A frequency generator includes two voltage controlled oscillators, which have a plurality of switchable sub-bands, each, and which are designed to produce respective frequency signals, wherein a switching from one sub-band to a neighboring sub-band occurs at predetermined switching locations. The sub-bands of the second oscillator are arranged offset in frequency relative to the sub-bands of the first oscillator. The frequency generator includes an electronic switch element, which is designed to switch either the first or the second frequency signal through to the output of the electronic switch element, and to switch the switch element such that during the producing of the frequency ramp alternately either the first or the second frequency signal is switched through to the output. When at one of the oscillators the switching between two neighboring sub-bands is occurring, the frequency signal produced by the other oscillator is switched through to the output.

Abstract: A method and device for vehicle-supported object detection. A pulse is emitted into the surroundings using a transducer situated in a vehicle, and the pulse, which is reflected back by an object in the surroundings, is recorded using the transducer. The transducer and the object move relative to each other. The emission and/or the recording are carried out according to a directional characteristic of the transducer, which has at least two directional lobes. Signal components of the reflected pulse, which have different frequency shifts, are separated from one another on the basis of the frequency shift or are assigned to respectively one of the directional lobes. An object detection is carried out in each case for the different signal components and the assigned directional lobes.

Abstract: Method and apparatus for leakage signal cancellation in a simultaneous transmit and receive RF system includes: generating a digital transmit signal for transmission from the system; receiving a receive signal produced by reflection of the transmit signal from an object or generated by a second RF system; adaptively filtering the transmit signal by an adaptive finite input response (FIR) filter; calculating filter coefficients for the adaptive FIR filter in real-time at a different sampling rate; adaptively inputting the calculated filter coefficients to the adaptive FIR filter to generate a cancellation signal in real-time; and applying the cancellation signal to the receive signal to cancel leakage in the receive signal to generate an optimum receive signal.

Abstract: A system for determining a spatial disposition or a characteristic of a target external to a terrestrial vehicle is provided. The system may comprise a radar antenna array comprising a transmitting antenna and a receiving antenna, a vehicle position sensor configured to obtain a spatial disposition of the terrestrial vehicle, and a controller operatively coupled to the radar antenna array and the vehicle position sensor. The controller can be configured to synchronize successive radar pulses transmitted by the transmitting antenna and a plurality of signals received by the receiving antenna, with the spatial disposition of the terrestrial vehicle obtained by the vehicle position sensor substantially in real time as the terrestrial vehicle is in motion, to generate a set of synchronized measurements, and use the set of synchronized measurements to determine (i) the spatial disposition of the target relative to the terrestrial vehicle or (ii) the characteristic of the target.

Abstract: An apparatus for a low-power radar detection (LPRD) receiver is proposed in this disclosure. The LPRD receiver comprises an analog-to-digital converter (ADC) circuit configured to receive an analog dynamic frequency selection (DFS) signal associated with a DFS channel in a DFS frequency band to generate a digital DFS signal. The ADC circuit comprises a finite impulse response (FIR) filter circuit configured to sample the analog DFS signal at an FIR sampling rate determined based on a predetermined frequency plan associated with the DFS frequency band to generate a sampled DFS signal; and an ADC conversion circuit configured to convert the sampled DFS signal to the digital DFS signal at an ADC conversion rate that is lower than the FIR sampling rate.

Abstract: A method is provided for correcting radar signal transient variation induced by power amplification in a pulse radar transmitter. The method includes establishing a first plurality of characteristics of a first pulse sequence having a digital pulse; establishing a second plurality of characteristics of a second pulse sequence having a plurality of digital pulses; comparing the first and second pluralities of characteristics to determine a sequence difference; providing pre-distortion coefficients for the plurality of digital pulses corresponding to the signal transient variation in response to the sequence difference; and applying the coefficients to the plurality of digital pulses prior to the power amplification.

Abstract: This relates to methods and apparatus for mitigating effects of the presence of RF communication signals. In some examples, non-linearity and rectification of the RF communication signals can become rectified in sensor circuitry such that spectral components of a frame or sub-frame timing of the RF communication signals can be aliased into the sensor circuitry output within a bandwidth of interest. In some examples, a notch filter can be employed to remove the aliased RF communication signals from the sensor output. In some examples, a sampling rate used for sampling the user's physiological signals can be generated such that the sampling of the sensor is synchronous with the RF communication signals. In some examples, the sampling rate for the sensor can be generated as an integer multiple or integer submultiple of the frame or sub-frame timing of the RF communication signals.

Abstract: A method and system for managing data from an aircraft radio-altimeter. The data management system includes a monitoring unit for checking, automatically and repetitively, when the radio-altimeter is outside of its operational range, from data generated by the radio-altimeter for a predetermined duration, whether the trend of the data corresponds to an aircraft approaching the ground, and a data transmission unit configured to automatically transmit the data generated by the radio-altimeter to a user system, only if the monitoring unit considers that the trend of the data corresponds to an aircraft approaching the ground.

Abstract: Various technologies for isolating a signal of interest from signals received contemporaneously by an antenna are described herein. A time period for which a signal of interest is present in a second signal can be identified based upon ratios of values of the second signal to the mean value of the second signal. When the ratio of the value of the second signal at a particular time to the mean of the second signal exceeds a threshold value, the signal of interest is considered to be present in the second signal.

Abstract: A sparse multichannel array includes a plurality of array elements, a receiver behind each array element, and a Doppler filter bank behind each receiver, whereby within each Doppler bin is placed spatial nulls at selected angles of undesired interference. The invention enables Doppler processing to be performed on sparse arrays, such as nested or coprime arrays, used in nonlinear adaptive beamforming to mitigate the impact of unintentional interference and hostile jamming on the received signal.

Abstract: A radio frequency (RF) noise reduction system is disclosed to include a first antenna for receiving a RF signal, a phase shifter coupled to the first antenna for generating a phase shifted RF signal, and an amplitude detector coupled to the first antenna for outputting a signal representative of an amplitude of the RF signal. Additionally, the RF noise reduction system includes a microcontroller coupled to the amplitude detector for controlling the phase shifter. Still yet, the RF noise reduction system includes a second antenna coupled to the phase shifter and being configured to transmit the phase shifted RF signal.

Abstract: A method for computing a cross-correlation between a first sequence and a second sequence includes: generating a first index vector based on the first sequence, the first index vector including a plurality of first elements, the first index vector excluding indices of zero valued elements of the first sequence; generating a second index vector based on the second sequence, the second index vector including a plurality of second elements, the second index vector excluding indices of zero valued elements of the second sequence; computing, on a processor, a plurality of pairwise differences between each of first elements of the first index vector and each of the second elements of the second index vector; and binning, on the processor, the plurality of pairwise differences to generate the cross-correlation of the first sequence and the second sequence.

Abstract: A radar system has different modes of operation. In one mode the radar operates as a single-input, multiple-output (SIMO) radar system utilizing one transmitted signal from one antenna at a time. Codes with known excellent autocorrelation properties are utilized in this mode. At each receiver the response after correlating with various possible transmitted signals is measured in order to estimate the interference that each transmitter will represent at each receiver. The estimated effect of the interference from one transmitter on a receiver that correlates with a different code is used to mitigate the interference. In another mode, the radar operates as a MIMO radar system utilizing all the antennas at a time. Interference cancellation of the non-ideal cross correlation sidelobes when transmitting in the MIMO mode are employed to remove ghost targets due to unwanted sidelobes.

Abstract: A vertical alignment method for a radar of a vehicle includes the steps of radiating radio wave to a forward ground by a radar which is installed on the vehicle; receiving reflected wave which is reflected from the ground; and determining whether or not a vertical misalignment of the radar occurs, based on the reflected wave.

Abstract: In accordance with an embodiment, a method includes producing a baseband variable frequency signal and producing a substantially fixed frequency signal by phase-locking an oscillator to a substantially fixed reference frequency. The method further includes upconverting the baseband variable frequency signal by mixing the variable frequency signal with the substantially fixed frequency signal to produce an RF variable frequency signal.

Abstract: The present invention is directed to a ground moving target (GMTI) radar that can detect targets, including dismounts, with very small minimum detectable velocities by combining signals from antennas on different spatially separated platforms in a main beam clutter-suppressing spatially adaptive process without requiring that the relative positions of the antenna phase centers be accurately tracked. The clutter nulling is in addition to that provided by the Doppler filters. The spatial displacement provides a narrow mainbeam clutter null reducing undesired target suppression. The clutter-suppressing spatially adaptive structure is used in both the sum and delta channels of the monopulse processor so that the beam distortion caused by the spatial nulling is compensated for, and the monopulse look-up process is preserved to maintain angle accuracy. Noncoherent integration is employed to recover signal to noise loss resulting from the uncertain relative locations of the platforms.

Abstract: Disclosed herein are a radar apparatus and a method of operating the same. The radar apparatus includes a clutter analysis unit, a screen change detection unit, a representative value acquisition unit, and a target detection unit. The clutter analysis unit analyzes the clutter value of a signal that is received by a reception unit. The screen change detection unit calculates the screen change time up to the time at which a screen has been changed from an image captured by an imaging apparatus. The representative value acquisition unit acquires a representative value based on a plurality of clutter values analyzed for the screen change time by the clutter analysis unit. The target detection unit determines the signal to be a target signal if the size of the signal is larger than both the clutter value and representative value of the signal.

Abstract: According to one embodiment, a radar equipment includes a radio transmitter, a pulse compressor, a Doppler filter, and an integration processor. The radio transmitter receives pulse signals and digitizes the received pulse signals by oversampling with a frequency higher than that for generation of a pulse compression coefficient to generate digital data. The pulse compressor performs pulse compression on the digital data using the pulse compression coefficient to generate range bin data for each of the pulse signals. The Doppler filter processor performs Doppler filter processing on the range bin data. The integration processor integrates the range bin data subjected to the Doppler filter processing for each range bin.

Abstract: Various aspects of the present invention are shown and described, each of which has stand alone utility in a navigated medical environment. A receiver position calibration system and method facilitates calibration of a reference frame prior to each navigated procedure. A concept and application of confidence weights is introduced. Confidence weights can be applied to distance calculations to mitigate the effects of interference and increase the tolerance of the navigated medical system. Multi-path interference is minimized through the transmission of a signal having a pattern of unique frequencies and filtering of the distance calculations for each frequency to identify the ‘best’ distance in the presence of multi-path interference. A position determination method and system that transmits a signal having multiple frequency components permits positions to be identified with high resolution over a large area.

Abstract: A method and apparatus is disclosed to recover at least one information payload from a frame and/or to configure one or more reception parameters to receive a future frame to support RIFS. A physical layer device (PHY) receives at least a training sequence embedded in the frame of a transmitted communication signal using a receiver filter bandwidth corresponding to a variable filter training sequence bandwidth. The PHY determines an amount of gain necessary to recover an information payload embedded in the frame based on the recovery of the training sequence. The PHY determines an amount of gain necessary to recover an information payload embedded in the frame based on the recovery of the preamble. A previous communications receiver gain is adjusted by the difference between the amount of gain necessary to recover the information payload and the previous communications receiver gain.

Abstract: A computer-implemented method for probabilistically classifying an occurrence of an event, a change in the state of a target, includes measuring feature data of the target simultaneously processing the measured feature data through first and second filters. The first filter is suited for a situation in which the target is in a first state and generates a first residual and a first residual covariance for the measured feature data. The second filter is suited for a situation in which the target is in a second state and generates a second residual and a second residual covariance for the feature data. By determining a probability of the occurrence of the event and the probability of the non-occurrence of the event and comparing the two probabilities with at least one threshold value the occurrence or non-occurrence of the event is determined.

Abstract: Electronically steered radar systems such as frequency scanning radars are particularly suitable for detecting and monitoring slow moving, ground-based targets. So-called crawler radar systems are intended for detection of targets that deliberately attempt to avoid detection by keeping low and by moving slowly. Disclosed is a radar system which includes an electronically steered antenna and a receiver arranged to process signals received from a target located at a distance from the radar system so as to identify a Doppler frequency associated with the target. The antenna stares at, rather than glides past, the target surrounding clutter. This means that the spectral spreading of static ground clutter associated with mechanical radar systems can be eliminated, overcoming one of the shortcomings of mechanical radar systems that would otherwise render a crawler radar system unsuitable for Doppler processing.

Abstract: The present solution provides methods and systems for realizing hardware efficient mismatched filters for pulse compression codes. For pulse compression codes with sufficiently small sidelobe structures, such as in the cases of odd length Barker codes, the proposed filters require a small number of adders and multipliers per output. This translates to significantly reduced chip-area and lower power consumption when implemented on a chip. In one aspect, the present application features a method for suppressing an undesired part of a waveform. The method includes filtering a signal via a filter. In one embodiment, the signal includes an expected waveform that can be represented as a sum of the desired part and the undesired part. The impulse response of the filter can be represented a sum of the desired part and a negative of the undesired part.

Abstract: A light source device includes: a light source which emits light; an optical member through which light emitted from the light source enters; a base on which the light source is mounted; a first holding member which fixes the optical member; and a second holding member which holds the first holding member and stands on the base in the emission direction of the light emitted from the light source.

Abstract: Various embodiments are described herein for a moving target detector that processes input data to perform detection for a current range cell. The moving target detector includes a Doppler filter bank module for processing the input data to provide several Doppler outputs for the current range cell, a no-land-clutter path for processing several input data sets related to the several Doppler outputs to provide detection data by performing peak selection on each of the several input data sets and performing detection on the results of the peak selection, a land-clutter path for processing the several input data sets to provide detection data by performing Constant False Ala?n Rate (CFAR) detection on each of the several input data sets and merging the detection results; and a switching logic module for selecting one of the land-clutter path and the no-land-clutter path based on clutter information.

Abstract: An interface system of the present invention interconnects with a collision avoidance system and a radar detector. The interface system monitors and determines when sensors, from the collision avoidance system, are not required and selectively turns them off, thereby eliminating interference from the sensor and allowing the radar detector to work properly. The interface system also acts as a filter which enables and disables the audible and visual alerts of the radar detector and selects when to turn these filters on and off.

Abstract: A high resolution Doppler analysis of a radiofrequency signal is exemplified by the analysis of air mass movement using meteorological radar. A high resolution spectral analysis method for a remotely sampled periodic radiofrequency signal, based on the application of a trellis autoregressive filtering Burg algorithm, is used to determine the natural frequencies of the received signal for each distance cell based on the determination of an optimum set of reflection coefficients of the signal. Reflection coefficients are the object of a regularization operation aiming to limit the numerical instabilities of the calculations. These regularized reflection coefficients are used to estimate the effective order of the identification model of the trellis filter, and to determine the natural frequencies of the signal by determining the arguments of the complex roots of the polynomial representing the transfer function of the trellis filter.

Abstract: Various embodiments are described herein for a moving target detector that processes input data to perform detection for a current range cell. The moving target detector includes a Doppler filter bank module for processing the input data to provide several Doppler outputs for the current range cell, a no-land-clutter path for processing several input data sets related to the several Doppler outputs to provide detection data by performing peak selection on each of the several input data sets and performing detection on the results of the peak selection, a land-clutter path for processing the several input data sets to provide detection data by performing Constant False Ala?n Rate (CFAR) detection on each of the several input data sets and merging the detection results; and a switching logic module for selecting one of the land-clutter path and the no-land-clutter path based on clutter information.

Abstract: Digital beamforming is provided for use with electronically scanned radar. In an aspect, the present invention provides enhanced sensitivity, wide angle or field of view (FOV) coverage with narrow beams, minimized number of receivers, reduced sidelobes, eliminated grating lobes and beam compensation for target motion. In an aspect, the present invention employs a uniform overlapped subarray feed network, a time multiplexed switch matrix, and a restructured digital signal processor. Antenna channels share a receiver, rather than maintain a dedicated receiver for each antenna element, as in conventional systems. In an aspect, Doppler/frequency filtering is performed on each antenna element or subarray output prior to digital beamforming. Further, Doppler compensation is employed following Doppler/frequency filtering, followed by digital beamforming.

Abstract: A sensor suite determines location and velocity information relating to a missile threat, which is converted to missile or rocket state estimates. The state estimates are transformed into time-invariant dynamic parameters, unique for each missile type. Estimated rocket dynamic parameters are computed for each target type being considered, and compared with a reference set of rocket parameters representing different target types. The estimated rocket parameters are compared with the reference parameters in a maximum-likelihood sense, and combined using fuzzy logic to identify the rocket type and the likelihood. The identified rocket type and likelihood is used to aid in determining the future location of the missile so countermeasure can be applied.

Abstract: A radar system in which a beat signal is generated by transmitting a transmission signal that is subjected to frequency modulation into a triangular wave and receiving a reflection signal from a target, the beat signal is sampled, and a window function is applied to yield a discrete frequency spectrum. When the window function is applied, a first window function having an amplitude that is gently attenuated from the center of the sampling period toward both sides thereof is applied in a lower frequency band in the frequency spectrum (at close range), and a second window function having an amplitude that is sharply attenuated from the center of the sampling period toward both sides thereof is applied in a higher frequency band in the frequency spectrum (at far range).

Abstract: A test device for a frequency modulated continuous wave (FMCW) radar is provided. The test device has a central control unit for monitoring the FMCW radar. When the FMCW radar transmits a frequency modulated continuous signal to search for a target, the central control unit of the test device in present invention will simulate the motion of the target according to a plurality of setting parameters and generate an echo signal to the FMCW radar. The present invention also includes a first digital signal synthesizer and a transmitting unit. The first digital signal synthesizer is coupled to the central control unit for generating and transmitting an intermediate-frequency signal to the transmitting unit according to the settings in the central control unit and a reference clock. The transmitting unit generates the echo signal according to the intermediate-frequency signal.

Abstract: A radar tracking system for an anti-aircraft, missile, including angle tracking, doppler tracking and range tracking feedback loops operating on sum and difference channels. Fast fourier transform digital filters are used to provide a frequency spectrum of the sum and difference I.F. channels and detection and confirmation algorithms are employed for selecting the F.F.T. target ‘bin’. Adjacent F.F.T. bins are used to simulate a bin centered on the target frequency, shifts of the latter with target/missile acceleration causing frequency errors which are detected by a discriminator and used to control the target I.F. Confirmation of target acquisition is achieved by successive summations of the target bin power the totals being accumulated and compared with upper and lower thresholds. Confirmation and rejection results from total levels outside the thresholds while further accumulation and comparison follow the intermediate condition.

Abstract: Sensors determine the kinematic measurements of a boosting missile, and the information is applied to a plurality of pairs or sets of filters, one of which is matched to the characteristics of a particular target type, and the other of which is general, and not matched to a particular target, for producing from each filter of the set missile position, velocity, acceleration, and specific mass flow rate states, and covariances of those states. From the filtered information, the estimates are made of at least missile mass flow rate, thrust, velocity at stage burnout, and remaining burn time. The likelihood is computed that the states and covariances from the filter sets represent the same target. The largest likelihood is selected as representing the target. In one mode, the estimated parameters are weighted and summed for a composite likelihood.

Abstract: A signal separating system 1 comprises a frequency conversion element 3, a dynamic filter component 4 with associated coherent stop slot and non-coherent passband, optionally a signal wave enhancer 7 with bypass, and a frequency reconversion element 8. In operation of the system, mixed incoming signals 12 (CW or pulse signals) having known interference and unknown emission components can be effectively separated, permitting a virtually instantaneous separation of the known interference from the unknown emissions and permitting an unobscured monitoring and/or characterization of the extracted unknown emissions 21, if desired. The arrangement bears definite advantage over known arrangements and retains utility for various frequency/agile or multiple or non-agile unknown signal applications.

Abstract: Resolution of a radar operating within a bandwidth is improved by defining a quantity of substantially rectangular sub-band filters to subdivide the bandwidth in the frequency domain into the quantity of sequential sub-bands having a sub-bandwidth. Each signal sent by the radar is associated with a transmission temporal moment. Each of the quantity of return signals received is routed in one to one correspondence to the sub-band filters, each signal being received at a corresponding sub-band filter. The return signals received are summed by synchronizing the associated transmission temporal moment to produce a reconstructed return signal.

Abstract: A calibration module and methods for a time-of-flight ranging system. The calibration module may be built into the circuitry of the time-of-flight ranging system and allows various operating parameters to be measured and evaluated. The calibration modes include amplitude calibration, frequency calibration, and time delay calibration. The calibration mode also includes an electronic noise measurement mode. The calibration modes may be initiated on power-up or reset, or in response to user input or time-based trigger.

Abstract: A method of printing an ink jet ink on a print medium is provided, wherein a printed image is formed that is both waterfast and smearfast. The method employs a water-insoluble colorant and comprises: (a) providing an aqueous-based ink containing at least one disperse, sublimation dye and at least one dispersant for dispersing the dye; (b) jetting the ink onto the print medium to form an intermediate printed image; and (c) subjecting the print medium to a combination of heat and pressure for a period of time to convert the intermediate printed image to the waterfast and smearfast printed image. The temperature is high enough to cause the disperse, sublimation dye to disintegrate and diffuse into the print medium, thereby diffusing the coloring agents out of the dispersant “shell” around the dye particulate and recondensing in the same place as solvent dyes, free of the dispersant. Solvent dyes are insoluble in water.

Abstract: A vehicle (160) such as a motor road vehicle is fitted with an electromagnetic sensor system comprising transmitting means (e.g. 4, 1) for transmitting a radio frequency signal, receiving means (e.g. 2, 6) for receiving reflections of said signal from remote objects, sampling means (20, 28) operable to sample the received reflected signal (or a signal derived therefrom), and processing means (e.g. 36) for processing the sampled signal, and operable to detect said reflections in the sampled signal, and to determine information on the presence, position and/or range of said object. The system includes filter means (e.g. 34) for preventing radio signals transmitted by other sources or noise spikes from causing interference which results in spurious detections or indications of range by the processing means.

Abstract: A method and apparatus for equalizing a signal to accurately deconvolute the channel includes deriving a functional relationship between Doppler frequency and variance between the instantaneous energy of the received signal and the mean energy of the received signal. Theoretical values of Doppler frequency for a range of values of variance are mapped based on the derived functional relationship. The variance of a received signal is determined and the corresponding Doppler frequency estimate selected from the map. Optimal equalization learning parameters are then selected based on the corresponding Doppler frequency estimate so that the received signal may be deconvoluted independent of the impact of Doppler frequency.

Abstract: An electronic counter-measure receiver can be colocated with a threat simulator radar, which transmits a radar signal. As a pulsed-Doppler signal, this transmitted radar signal is sampled as a reference signal by the receiver to determine quadrature, coherent matched filter coefficients. A return signal is received and processed with the reference signal as quadrature signal components with the quadrature, coherent matched filter coefficients within a matched filter. The return signal is processed as a first intermediate frequency via a mixer and local oscillator and a second quadrature intermediate frequency via a digital local oscillator and mixer. A fast Fourier transform is performed to determine Doppler information. In a continuous wave transmission for sampling arbitrary but unevenly spaced in time pulses are generated from a pulse generator source internal to the receiver.

Abstract: In a radar system having a transmitter that produces pulses to be radiated by an antenna and a receiver that detects target information, complex demodulation is performed on an attenuated and limited waveform of the transmitter produced pulse. A matched filter is generated responsive to the complex demodulated waveform that is a time reversed conjugate image of the waveform corresponding to the produced pulse. Complex demodulation is performed on the return signal received by the receiver corresponding the produced pulse and the complex demodulated return signal is correlated with the matched filter that corresponds to the time reversed conjugate image of the waveform of the produced pulse.

Abstract: In order to produce relative velocity signals in accordance with the relative velocity between a following and a preceding vehicle, a Doppler signal transmitter, which targets the preceding vehicle, is attached to the following vehicle. The thus obtained Doppler signals impinge on a signal processor which analyzes the frequency spectrum of the Doppler signal. Velocity signals are formed from the frequencies within this frequency spectrum, which frequencies lie outside the range of those frequencies caused by the velocity of the following vehicle moving relative to the surface.

Abstract: A method for separating a desired signal from an interfering signal, which is particularly useful when the desired signal is substantially weaker than the interfering signal, includes the steps of providing a combined signal which contains both a desired signal and an interfering signal; performing a Fourier transform upon the combined signal; providing a reference function which is a function of the amplitude, frequency and phase of the interfering signal; performing a Fourier transform upon the referenced function; multiplying the real components of the Fourier transform of the combined signal by the real components of the Fourier transform of the reference signal to form a product; and subtracting the product from the Fourier transform of the combined signal to form transformed data less interference, i.e., the desired signal.

Abstract: A process and a system for selecting a pulse repetition frequency that causes clutter pulse repetition frequency lines from the negative carrier frequency and from the clutter harmonic frequencies to lay on top of clutter pulse repetition frequency lines from the positive carrier frequency. A pulsed Doppler radar receiver of the system has one or more channels each comprising of a radio frequency input section for receiving a radio frequency carrier. Following the radio frequency input section are one or more serially arranged intermediate frequency sections that terminate in a last intermediate frequency section. The last intermediate frequency section is followed by analog-to-digital conversion and down-conversion to baseband in-phase and quadrature channels. In-phase and quadrature data from the in-phase and quadrature channels is processible by a computational system to detect and track a target in the presence of clutter.