314 results about "Range gate" patented technology

Method and system for obtaining information about objects in the environment outside of and around a vehicle and preventing collisions involving the vehicle includes directing a laser beam from the vehicle into the environment, receiving from an object in the path of the laser beam a reflection of the laser beam at a location on the vehicle, and analyzing the received laser beam reflections to obtain information about the object from which the laser beam is being reflected. Analysis of the laser beam reflections preferably entails range gating the received laser beam reflections to limit analysis of the received laser beam reflections to only those received from an object within a defined (distance) range such that objects at distances within the range are isolated from surrounding objects.

Method and system for obtaining information about objects in the environment outside of and around a vehicle and preventing collisions involving the vehicle includes directing a laser beam from the vehicle into the environment, receiving from an object in the path of the laser beam a reflection of the laser beam at a location on the vehicle, and analyzing the received laser beam reflections to obtain information about the object from which the laser beam is being reflected. Analysis of the laser beam reflections preferably entails range gating the received laser beam reflections to limit analysis of the received laser beam reflections to only those received from an object within a defined (distance) range such that objects at distances within the range are isolated from surrounding objects.

A collision avoidance system for a vehicle includes a collision avoidance processor, and an active sensor for obtaining successive range measurements to objects along a path transversed by the vehicle. The active sensor includes a near range gate for obtaining a near range measurement to objects located at a range less than a first predetermined range, and a far range gate for obtaining a far range measurement to objects located at a range greater than a second predetermined range. The near and far range measurements are provided to the collision avoidance processor for maneuvering of the vehicle.

A method of full-field or “ping-based” Doppler ultrasound imaging allows for detection of Doppler signals indicating moving reflectors at any point in an imaging field without the need to pre-define range gates. In various embodiments, such whole-field Doppler imaging methods may include transmitting a Doppler ping from a transmit aperture, receiving echoes of the Doppler ping with one or more separate receive apertures, detecting Doppler signals and determining the speed of moving reflectors. In some embodiments, the system also provides the ability to determine the direction of motion by solving a set of simultaneous equations based on echo data received by multiple receive apertures.

Narrow virtual transmit pulses are synthesized by differencing long-duration, staggered pulse repetition interval (PRI) transmit pulses. PRI is staggered at an intermediate frequency IF. Echoes from virtual pulses form IF-modulated interference patterns with a reference wave. Samples of interference patterns are IF-filtered to produce high spatial resolution holographic data. PRI stagger can be very small, e.g., 1-ns, to produce a 1-ns virtual pulse from very long, staggered transmit pulses. Occupied Bandwidth (OBW) can be less than 10 MHz due to long RF pulses needed for holography, while spatial resolution can be very high, corresponding to ultra-wideband (UWB) operation, due to short virtual pulses. X-Y antenna scanning can produce range-gated surface holograms from quadrature data. Multiple range gates can produce stacked-in-range holograms. Motion and vibration can be detected by changes in interference patterns within a range-gated zone.

An integrated detector and signal processor (31) for ladar focal plane arrays (30) which internally compensates for variations in detector gain, noise, and aerosol backscatter. The invention (31) is comprised of a detector element (42) for receiving an input signal, a circuit (72) for generating a threshold based on the RMS noise level of the input signal, and a circuit (74) determining when the input signal is above that threshold. The detector element (42) is physically located in the interior of the detector array (30), while the signal processing circuitry (50) is located on the periphery of the array (30). In the preferred embodiment, the signal processor (31) also includes a circuit (56) for sampling the input signal and a circuit (58) storing multiple samples, allowing for multiple returns to be detected. In the preferred embodiment, the signal processor (31) can be operated in two modes: self triggered and externally triggered (range-gate mode). In the self triggered mode, the detector continually monitors and samples the incoming signal until a return is detected (by the thresholding circuit). In the range-gate mode, the detector stops sampling when it receives a signal from an external source. Once the data has been acquired, readout electronics (66) output the stored samples along with the stored "stopped" time code to an external computer (26).

The invention discloses an imaging method by a large squint angle airborne SAR spotlight mode based on non-uniform sampling. Based on an analysis of azimuth signals characteristics of targets at different azimuths on the same range gate under the condition of a large squint angle, the method enlarges the azimuth imaging range output by effective focuses by a non-uniform interpolation resampling processing method. In the method, a data acquisition model under the large squint angle is equated with a right side looking data acquisition model of increment motion compensation. The method comprises the following steps: firstly, performing cubic phase compensation in an original data field, then performing range walk correction on a time domain and range migration correction on a 2D frequency domain, completing azimuth compression by the non-uniform interpolation resampling method, and finally, completing autofocus processing by a phase gradient autofocus algorithm. Compared with the prior art, the method can help process a larger squint angle, and has the advantages of small calculation amount and easy real-time processing. The method can be applicable to the conventional radar systems without a function of tracing Dechirp demodulation by a scene center.

The invention provides a laser imaging radar device and a distance measurement method thereof. The laser imaging radar device and the distance measurement method thereof aims at the problem that an existing distance range gate laser imaging radar is low in distance resolution. The laser imaging radar device comprises a laser device, a laser modulation unit, an optical antenna unit, a detecting unit, a data processing unit and an image processing unit, wherein the detecting unit is composed of a counter, a gate controller and an array detector, and the data processing unit is composed of an accumulator and a correlator. According to the distance measurement method, an information loading process is carried out on laser signals with constant amplitude by using a phase code pulse amplitude modulation mode. The laser imaging radar device and the distance measurement method thereof have the advantages that the equipment and the method combine the advantages of long detecting distances of the distance ranging gate layer imaging radar and the advantage of high distance measurement resolution of the pulse phase coding mode, and meanwhile the detect of low distance measurement resolution of the distance ranging gate layer imaging radar and the detect of low imaging speed of the pulse phase coding mode are avoided.

A security system senses intrusions into a shipping container through the opening of doors, cutting an opening, or removing the doors from their hinges. Intrusion information is transmitted to a remote receiver without interrogation, thereby reducing power consumption. Sensing is accomplished by employing a range-gated micro-impulse radar (“RGR”) that generates microwave pulses that bounce around the interior of the container. The RGR includes a range gate that enables measuring reflected signals during the time gate period that is set for the time it takes a pulse to propagate a maximum distance within the container and reflect back. A direct current signal level is produced that represents the average reflected signal level within the container, and a Doppler shift measurement is made that represents motion inside the container. The signals are conveyed to the transmitter for conveyance to the remote receiver.

A radar imaging apparatus includes: (i) a delay code generation unit which repeats, for M scan periods, scan processing of generating, using a transmission code, N delay codes in a scan period for scanning N range gates having mutually different distances from the radar imaging apparatus; (ii) a signal storage unit which stores, in association with a range gate and a scan period, a baseband signal; (iii) a memory control unit which repeatedly writes, in the signal storage unit, for the M scan periods, N demodulated signals corresponding to a single scan period, and reads out a group of M demodulated signals corresponding to mutually different scan periods; (iv) a Doppler frequency discrimination unit which performs frequency analysis on demodulated signals having the same range gate; and (v) a direction of arrival calculation unit which estimates a direction of a target.

A multiple ultrasonic beam is transmitted from an ultrasonic probe, and a velocity of blood flow, azimuth and elevation angle of a sample such as a blood flow are acquired by a three-dimensional information acquisition section, as three-dimensional fluid information in a range gate, based on a Doppler signal output from the ultrasonic probe.

A system for landing or docking a mobile platform is enabled by a flash LADAR sensor having an adaptive controller with Automatic Gain Control (AGC). Range gating in the LADAR sensor penetrates through diffuse reflectors. The LADAR sensor adapted for landing / approach comprises a system controller, pulsed laser transmitter, transmit optics, receive optics, a focal plane array of detectors, a readout integrated circuit, camera support electronics and image processor, an image analysis and bias calculation processor, and a detector array bias control circuit. The system is capable of developing a complete 3-D scene from a single point of view.

A system for scanning light to define a range gated signal includes a pulsed coherent light source that directs light into the atmosphere, a light gathering instrument that receives the light modified by atmospheric backscatter and transfers the light onto an image plane, a scanner that scans collimated light from the image plane to form a range gated signal from the light modified by atmospheric backscatter, a control circuit that coordinates timing of a scan rate of the scanner and a pulse rate of the pulsed coherent light source so that the range gated signal is formed according to a desired range gate, an optical device onto which an image of the range gated signal is scanned, and an interferometer to which the image of the range gated signal is directed by the optical device. The interferometer is configured to modify the image according to a desired analysis.

A security system senses intrusions into a shipping container through the opening of doors, cutting an opening, or removing the doors from their hinges. Intrusion information is transmitted to a remote receiver without interrogation, thereby reducing power consumption. Sensing is accomplished by employing a range-gated micro-impulse radar (“RGR”) that generates microwave pulses that bounce around the interior of the container. The RGR includes a range gate that enables measuring reflected signals during the time gate period that is set for the time it takes a pulse to propagate a maximum distance within the container and reflect back. A direct current signal level is produced that represents the average reflected signal level within the container, and a Doppler shift measurement is made that represents motion inside the container. The signals are conveyed to the transmitter for conveyance to the remote receiver.

The invention discloses a method for controlling microwave vehicle detecting radar, comprising the following steps: microwave detecting radar work parameter is evaluated; pulse compression in the range direction is carried out; sub-echo of each target vehicle is respectively extracted, and whether advancing vehicle exists is judged, speed search is carried out on data of each sub-echo of advancing vehicle, one matched filtering function is obtained after each search, pulse compression in the azimuth direction is carried out, and then the kurtosis value is calculated; if the largest kurtosis value is obtained, the search speed corresponding to the largest kurtosis value is the traveling speed of the vehicle, frequency modulation slope in the azimuth direction is calculated according to the speed and pulse compression in the azimuth direction is carried out, and then signals of each range gates are added and are compared with the set threshold to obtain vehicle length; if the largest kurtosis value is not obtained, then search is kept on by returning to the previous step. The invention has numerous monitoring lanes, wide detection range and more precise detecting speed, can detect vehicle with low speed or even standing vehicle precisely, and can estimate vehicle length, thereby facilitating traffic control.

Equipment and techniques for the accurate estimates of the turbulence profile to improve the performance of adaptive optics systems designed to compensate the degradation effects of turbulence on directed energy systems, in astronomy, and in laser communication systems. The present invention is an optical turbulence profiler. The invention includes a cross-path LIDAR. The cross-path LIDAR technique uses laser guide star technology combined with a cross-path wavefront sensing method. In this method, two Rayleigh, or sodium, laser beacons separated at some angular distance are created by using a pulsed laser and a range-gated receiver. In preferred embodiments a Hartmann wavefront sensor measures the wavefront slopes from two laser guide stars. The cross-correlation coefficients of the wavefront slope are calculated, and the turbulence profile of refractive index structure characteristic Cn2(z) is reconstructed from the measured slope cross-correlations.

A pulsed radar system uses phase noise compensation to reduce phase noise due to drift of the reference oscillator to enable detection of micro movements and particularly human motion such as walking, breathing or heartbeat. The noise level due to A / D sampling must be sufficiently low for the phase noise compensation to be effective. As this is currently beyond state-of-the-art for high bandwidth A / D converters used in traditional receiver design, the receiver is suitably reconfigured to use analog range gates and narrowband A / D sampling having sufficiently low noise level. As technology continues to improve, the phase compensation techniques may be directly applicable to the high bandwidth A / D samples in traditional receiver designs. Whether phase compensation is applied to traditional receiver designs or a receiver configured with analog range gates, the steps are essentially the same: data is processed to position a reference range bin (either an analog range gate or a particular time sample) on a stationary reference and the phase variation of that reference range bin is used to compensate the phase of target data in range bins (either an ensemble of range gates or other time samples) near the stationary reference. This effectively moves the radar system and particularly the reference oscillator to the stationary reference thereby greatly reducing oscillator drift and phase noise and decoupling the stand-off range from the level of phase noise.

A system for scanning light to define a range gated signal includes a pulsed coherent light source that directs light into the atmosphere, a light gathering instrument that receives the light modified by atmospheric backscatter and transfers the light onto an image plane, a scanner that scans collimated light from the image plane to form a range gated signal from the light modified by atmospheric backscatter, a control circuit that coordinates timing of a scan rate of the scanner and a pulse rate of the pulsed coherent light source so that the range gated signal is formed according to a desired range gate, an optical device onto which an image of the range gated signal is scanned, and an interferometer to which the image of the range gated signal is directed by the optical device. The interferometer is configured to modify the image according to a desired analysis.

The invention discloses a flash tracking imaging method for acquiring movement parameters of a moving target. The method utilizes a pulse laser as an illuminated light source and a CCD (Charge Coupled Device) provided with a strobing gate as an imaging device based on a range gating imaging technology and realizes the imaging of a movement trail of the moving target through the working mode of a time delay integral. By adopting the range gating, the range information of the target can be acquired, and the target can be extracted from a complex background, thereby reducing the complexity of post-treatment; and by adopting the time delay integral, the movement trail of the target can be directly acquired. The movement parameters of the target can be inverted through establishing a corresponding relation between a three-dimensional space and a bidimensional image plane of an interested zone of observation, wherein the movement parameters mainly comprise the space position, the speed and the acceleration of the target. The invention has favorable working environment adaptability, can directly acquire the 3D movement trail of the target and realize the non-contact measurement of the movement parameter of the target.

The invention provides a single-photon-counting compression-sampling laser three-dimensional imaging method which is applicable to the fields of topographic mapping, information processing, digital image processing, high-precision topographic reconnaissance and the like. The method is a non-scanning laser three-dimensional imaging method on the basis of single-photon unit-detector compression sampling, a range-gated imaging method is introduced to correct a time-measuring vector obtained on the basis of single-photon-counting compression sampling, and a high-precision three-dimensional image is obtained through reconstruction by adopting a compression perceiving and restoring algorithm. The method has a better practical value and broad application prospects in the technical fields of laser imaging and digital image processing.

The invention brings forward a pulse laser coherent wind measuring radar, for the purpose of providing a pulse laser coherent wind measuring radar which has the advantages of high measuring precision, simple structure and convenient installation and debugging. The pulse laser coherent wind measuring radar is realized through the following technical scheme: a fiber pulse laser emission system is taken as an emission source for generating two beams of laser, one beam of high repetition frequency pulse sequence laser for wind field detection is directly coupled through an optical circulator and enters an optical transmit-receive scanning system to perform collimated emission towards a target spatial domain, the optical circulator utilizes a polarization splitting characteristic to carry out isolation splitting on emission light and air aerosol scattering echo wave light, the air aerosol scattering echo wave light is selected to enter a fiber combiner, the other beam of laser, generated by the fiber pulse laser emission system, is taken as local oscillator light for inputting into a balance amplification photoelectric detector together with the echo wave light in a frequency mixing mode for optical amplification of a frequency mixing signal, through acquisition processing of a signal acquisition processor, the radial speed of each range gate in a current laser emission direction is calculated, and the radial speeds are transmitted to a radar operation display interface.

A method and device for detecting an intruder in a region with increased performance and decreased false alarms. The security device has a microwave sensor and a PIR sensor operatively coupled to a processor. To increase the performance of the security device the device determines distance information of an object in the region with the microwave sensor, processes the distance information to adapt a frequency response of the PIR sensor to provide a frequency adapted PIR signal, and determines if the object is an intruder by using the frequency adapted PIR signal.

A unique hardware architecture that combines short pulse, stepped frequency and centerline processing. The inventive architecture implements a radar system having a transmitter for transmitting short pulses, each pulse being stepped in frequency and a receiver receiving the pulses and providing an output signal in response thereto. In the illustrative embodiment, the transmitter includes a frequency source, an RF switch coupled to the source and a controller for controlling the RF switch. The receiver includes a signal processor implemented with a center line roughing filter. The signal processor has multiple channels each of which has a range gate and a digital filter. The digital filter includes a Fast Fourier Transform adapted to output a range Doppler matrix.

The object detection system includes an object sensor and a controller. The controller is configured to compare a sensed range of an object with a range gate based on the azimuth angle of the object. The range gate for each azimuth angle is programmable and is selected to form a contiguous sensing region closely matching the shape of a desired detection zone. The object sensor is switchable between the plurality of sensing fields, wherein a range gate for each sensing field is programmable to form a contiguous sensing region. The object sensor may be a variety of range sensors including radar, ultrasonic, laser or infrared technologies. The range gate and parameters of the sensing field are each programmable through a controller. Further, the controller may automatically vary the range gate or sensing field based on vehicle parameters.

The invention discloses an average grey-based method for extracting an effective information region of a range gating image. The method comprises the following steps: calculating an initial threshold by utilizing priori knowledge; extracting an effective information region of an original image by utilizing the initial threshold; calculating an average grey value of an edge part of the extracted information region according to the edge part; acquiring a largest eight-connected region of an image background according to a cut result of the initial threshold, wherein the average grey value of the largest eight-connected region is approximate to that of a background region, and the average value of the largest eight-connected region is used as an average grey value of the background region; and comparing the average value of a strip region at the edge of the effective information region with the average grey value of the background region, measuring whether a final cut result cuts information and noise optimally or not by the difference of the average value of the strip region at the edge of the effective information region and the average value of the background region, adjusting the value of the initial threshold if the difference is not in an acceptable range, and performing iterative operation on the adjusted value used as a new initial threshold until the difference is in an acceptable range.

Methods and systems for neurostimulation and / or neurotelemetry of electrically-excitable biological tissue. Embodiments include implanting single or multiple semiconductor diodes and applying a high frequency electrical volume current. Neurostimulation embodiments include local rectification of the volume current by the diode, which can provide a pulsating electrical waveform capable of locally stimulating neural tissue, hi neurotelemetry embodiments, semiconductor diodes can be placed in contact with excitable tissue and a low level electrical carrier wave can be passed through the tissue and implanted diode whereby low level tissue bioelectric events intermodulate with the carrier wave and encode bioelectrical effects. Remote detection and amplitude demodulation of the volume-conducted carrier wave can allow recovery of the bioelectrical waveform and provide a neurotelemetry function, hi other embodiments, implanted diodes are placed in series with a pressure switch or piezoelectric material which enables their function only with the focal application of an acoustic pressure wave. This enables a selectivity amongst multiple diode channels by acoustic wave focusing or alternately by a process of range-gating of a surface applied electrical current to the arrival time of an acoustic wave at a particular device.

A unit is described that is configured to control detonation of a munition such that the munition is detonated at a desired altitude. The unit includes a radar transmitter, a radar receiver that includes a radar range gate, and a sequencer. The sequencer is configured to receive a detonation altitude and set the range gate based on the received detonation altitude. The unit is also configured to output a detonation signal when radar return pulses received by the receiver aligned with gate delay pulses from the range gate.

An ultrasonic flow meter system includes transducers arranged with respect to a conduit to define at least one chordal path through fluid flowing in the conduit, and at least one transmitting transducer and receiving transducer pair on the chordal path for generating a transit time signal. At least one receiving transducer is positioned to receive scattered energy to generate a range gated Doppler signal. The system further includes a processing subsystem for exciting the at least one transmitting transducer. The processing subsystem is responsive to the transit time signal and the range gated Doppler signal and configured to generate a velocity profile and a mean velocity of the fluid in the conduit.

A remote sensor and associated data processor, performs concurrent analysis of backscattered signals from a multi-beam acoustic Doppler emitter / receiver positioned against the inside wall of a conveying pipe or channel. Range-gating of the return signals allows independent analysis of discrete volumes of backscattered signal data corresponding to the distribution, concentration and travel velocity of small individual volumes or bins of water and suspended solids. Velocity is derived from the measured Doppler frequency shift for each bin. Relative solids concentration is estimated as a function of the measured intensity of the backscattered signals. The intensity data are calibrated by inputting site-specific environmental information, such as temperature, salinity, acoustical system constant, backscattered signal interpretation ratio between concentration and particle size, and concurrently measured concentration values obtained from physical sample collection and previous laboratory analysis into the analytical computer program. The program uses iterative routines that adjust calibration parameters using data obtained from the previous measurement on an adjacent layer in a continuous self-correcting process. The apparatus and method provide both historical and real-time measurements of distribution, concentration and velocity of suspended solids in a flow of piped or channeled liquid.

Narrow virtual transmit pulses are synthesized by differencing long-duration, staggered pulse repetition interval (PRI) transmit pulses. PRI is staggered at an intermediate frequency IF. Echoes from virtual pulses form IF-modulated interference patterns with a reference wave. Samples of interference patterns are IF-filtered to produce high spatial resolution holographic data. PRI stagger can be very small, e.g., 1-ns, to produce a 1-ns virtual pulse from very long, staggered transmit pulses. Occupied Bandwidth (OBW) can be less than 10 MHz due to long RF pulses needed for holography, while spatial resolution can be very high, corresponding to ultra-wideband (UWB) operation, due to short virtual pulses. X-Y antenna scanning can produce range-gated surface holograms from quadrature data. Multiple range gates can produce stacked-in-range holograms. Motion and vibration can be detected by changes in interference patterns within a range-gated zone.