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923results about How to "Improve ranging accuracy" patented technology

Generation system for high-precision road map

The invention relates to a generation system for a high-precision road map and belongs to the technical field of high-precision maps. The purpose is to solve the problems that the workload of producing or updating an existing high-precision map is large, and cost is high. High-precision positioning and high-precision matching are achieved relative to the existing map, existing information of the existing map is fully utilized, and the workload and cost for producing / updating of the high-precision map are lowered. The generation system is characterized in that road elements recognized through deep learning, computer vision and other methods and obtained accurate relative position information form a ground one-dimension thick and space three-dimensional sparse map similar to Mobileye, and the map can be matched and fused with an existing traffic information system GIS-T. Based on an existing low-precision electronic map, a positioning system and a vehicle-mounted camera, producing / updating of the high-precision map are achieved at a low cost. The generation system is used for producing or updating the existing high-precision road map.
Owner:陈曦

Ladar sensor for landing, docking and approach

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.
Owner:CONTINENTAL AUTONOMOUS MOBILITY US LLC

Optical Detection and Ranging Sensor System For Sense and Avoid, and Related Methods

An apparatus carried by an unmanned vehicle to provide passive sensing and facilitate avoiding airborne aerial obstacles is provided. The apparatus can include at least one, but typically multiple optical systems installed, for example, in the nose of the aerial vehicle to passively sense and determine a range, direction, and velocity of the airborne obstacles to allow the aerial vehicle to avoid the airborne obstacles. The typical optical system includes at least one focal plane array or other imaging device configured to receive a wide field of view and at least one focal plane array or other imaging device configured to receive a steerable narrow field of view within the wide field of view to allow concentrated determination of the range, direction, and / or velocity of obstacles detected by the wide field of view imaging devices.
Owner:LOCKHEED MARTIN CORP

Dual-wavelength dipulse non-fuzzy laser ranging device

ActiveCN103885065AOvercoming distance ambiguityNo modulation misalignmentElectromagnetic wave reradiationLaser rangingBeam splitting
The invention discloses a dual-wavelength dipulse non-fuzzy laser ranging device. According to the basic principle, two laser pulses with two wavelengths are emitted, time intervals of the two laser pulses are sequentially encoded, a receiving channel receives laser back waves with two wavelengths with a wavelength beam splitting method and transmits the laser back waves to two detectors respectively, and time measurement is conducted on the laser back waves; back wave time difference between the pulses with the two wavelengths is calculated, the time difference of the starting pulse corresponding to the current laser back wave is accurately decoded, and the distance of a target is calculated. The dual-wavelength dipulse non-fuzzy laser ranging device has the advantages that the two pulses with the two wavelengths and encoded time intervals are adopted for ranging, and remote high-repetition-frequency non-fuzzy laser ranging can be achieved.
Owner:SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI

Vehicle-mounted millimeter-wave radar moving target recognizer and recognition method

The invention discloses a vehicle-mounted millimeter-wave radar moving target recognizer. The vehicle-mounted millimeter-wave radar moving target recognizer is characterized in that the recognizer is a frequency synthesizer; a frequency agility continuous signal is modulated into a pulse signal and then is processed into a millimeter-wave signal by up-conversion; after being amplified by a power amplifier, the millimeter-wave signal is transmitted out; an antenna receives a radar echo signal back to a circulator and then the signal is transmitted into a frequency mixer; a high-frequency echo pulse and constant-amplitude high-frequency voltage generated by a high-stability local oscillator are mixed and the signal is reduced to a middle frequency and then is processed by a middle-frequency amplifier; the middle-frequency signal is directly sampled by an A / D (Analogue / Digital) conversion module; after being sampled, echo signals of a whole pulse string are stored into a storage unit; and information of targets, such as quantity, speed and direction, is measured by a signal processing unit and then is transmitted to an alarm executing unit. With the adoption of the structure, the vehicle-mounted millimeter-wave radar moving target recognizer has the advantages that 1 the distance measuring precision and the angle measuring precision of a moving target are improved; and 2 excessive hardware does not need to be added and the production cost is lower.
Owner:ANHUI NORMAL UNIV

Digital vertical level indicator for improving the aim of projectile launching devices

An electronic vertical angle sensing and indicating device for use on aiming systems is provided for bow sights and for other aiming sights for projectile launchers. Improved vertical level measurement and display minimizes the left-right drift of a projectile by sensing and indicating to the user when the projectile launcher is tilted slightly prior to release of the projectile. The vertical level indicator is easily viewed within the field of direct or near direct vision and focus of the eye in a reduced profile that does not distract the operator from the task of accurately aiming the projectile is provided. One embodiment of the present invention positions the signal indicators in the far-field of view of the eye, so that all of the signal indicators, the sighting means and the distant target being viewed are simultaneously in focus or near-focus.
Owner:MURPHY PATRICK J +2

Wireless sensor network node positioning method based on received signal strength indicator (RSSI)

The invention relates to a wireless sensor network node positioning method based on a received signal strength indicator (RSSI). The precision of the traditional method is not high, and the traditional method is easily disturbed by environment. In the method, an effective RSSI value is selected by using a Gaussian distribution function model in the aspect of reading RSSI value, so that small probability events during RSSI measurement are removed to a certain extent, and the precision of RSSI value between nodes is improved; and the coordinates of an unknown node are obtained by a triangular positioning method, and the unknown node is circularly refined via the distribution probability model of the unknown node, so that a point with the maximum distribution probability is found and is used as the final positioning coordinate. In the method, the signal intensity and distance information between anchor nodes are introduced and are used as the reference; the unknown node coordinate is found out via the distribution probability model of the unknown node; the distance measurement precision and the positioning precision between the unknown node and the anchor node are improved; and the method is not easily disturbed by environment.
Owner:HANGZHOU DIANZI UNIV

Wavelet difference algorithm-based cable fault localization method

The invention discloses a wavelet difference algorithm-based cable fault localization method. The method comprises the following steps of: 1, detecting a signal in real time and synchronously uploading the signal; 2, performing signal acquisition; 3, performing cable fault localization by steps of performing signal pre-treatment which comprises normalization treatment, de-noising treatment and fault signal modulus transformation, judging a wavelet packet entropy fault region, determining the fault point by selecting a one-dimensional signal, performing wavelet transformation, solving a wavelet coefficient, detecting a modulus maximum point, sorting singular points after the maximum point, performing first-order difference operation and difference comparison, and performing localization operation on the cable fault position by using a single-end fault localization method free from influence of the wave velocity; and 4, synchronously outputting the treatment result. The method has the advantages of reasonable design, simple operation, convenient implementation and high localization precision, and effectively solves the practical problems that the fault region cannot be identified and the localization precision is relatively low and easily influenced by various factors in the conventional cable fault detection method.
Owner:XIAN UNIV OF SCI & TECH

Ladar sensor for landing, docking and approach

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.
Owner:CONTINENTAL AUTONOMOUS MOBILITY US LLC

Wireless and ultrasonic composite location system and location method for wireless and ultrasonic composite location system

The invention provides a wireless and ultrasonic composite location system and a location method for the wireless and ultrasonic composite location system, wherein the wireless and ultrasonic composite location system comprises a plurality of beacon modules with fixed positions, at least one mobile location module and an electronic location platform; each of the beacon modules comprises a first wireless receiving and sending module, an ultrasonic transmitting module and a first intelligent processing module; the mobile location module is arranged on a mobile object, and comprises a second wireless receiving and sending module, an ultrasonic receiving array, an array processing module and a central processer; the electronic location platform is used for building an electronic map and sending the electronic map to the mobile location module, and is also used for coordinating the synchronization of the beacon modules and the mobile location module. The invention also comprises the location method for the wireless and ultrasonic composite location system. By adopting the system and the method, the problems of multipath effect and none-line-of-sight are solved, the measurement precision is improved, and the theoretical precision of less than 0.1mm can be reached.
Owner:长沙开山斧智能科技有限公司

Bidirectional ranging and time comparision process terminal

The invention relates to a two-way ranging and time comparison processing terminal which is characterized in that: the processing terminal comprises a frequency benchmark, a radio frequency front end, a noise source, a frequency synthesis, a transmitting channel, a receiving channel, a medium frequency signal processor, a machine case, a display and control system, a power source distributor and a LAN switching module, wherein the configuration of the entire processing terminal is a 4U machine case postnotal plate joint interconnecting structure fastened by a standard machine cabinet; the frequency benchmark, the transmitting channel, the receiving channel, the medium frequency signal processor and the power source distributor are arranged inside a standard 4U machine case; the display and control system, which is realized through the configuration of an external notebook computer and display and control software, is in interaction with the outside through the LAN switching module. The entire processing terminal has simple equipment and high integration level; communication, ranging and time comparison are completed inside a unified channel, thereby saving frequency band resource; a pseudo code ranging system is adopted to ensure high ranging precision; moreover, the processing terminal, which has the functions of simulating dynamic state and time delay inside the transmitting channel, is used to realize the quantitative detection of the performance of a receiving terminal.
Owner:BEIHANG UNIV

Indoor localization method based on clustering algorithm analytical data optimization

The invention relates to an indoor localization method based on clustering algorithm analytical data optimization, which is used for carrying out accurate localization on an unknown node in a complex index environment. The indoor localization method comprises the steps of: executing an RSSI (Received Signal Strength Indicator) signal processing optimization strategy, i.e., optimizing an RSSI value by using a clustering analysis Gaussian hybrid filtering model so as to eliminate the problems of dispersed intersection and serious jitter of the RSSI value, which exist due to factors of a multipath effect, a barrier and the like, and obtain one more reliable and reasonable RSSI value; adopting a fitting RSSI distance measurement model, i.e., according to an RSSI-distance conversion curve, carrying out fitting of the curve by adopting a least square method so as to obtain a logarithm path loss model suitable for a current environment; and then estimating out position information of the unknown node by using a weighted centroid localization algorithm. According to the indoor localization method disclosed by the invention, by an optimal RSSI distance measurement algorithm, accuracy of localization and distance measurement is improved, so that adaptability and localization accuracy of the localization algorithm are improved; and the indoor localization method is suitable to apply and popularize in the complex indoor environment.
Owner:TIANJIN UNIV

RSSI and TOA distance measurement based WIFI indoor positioning method

The invention discloses an RSSI and TOA distance measurement based WIFI indoor positioning method. The RSSI and TOA distance measurement based WIFI indoor positioning method comprises the steps of acquiring an RSSI signal and establishing a database, adopting a positioning matching algorithm to perform data processing, adopting arrival time or colored noise elimination to perform distance measurement, establishing and rotating a planar rotating frame and performing searching, positioning and judgment. The RSSI and TOA distance measurement based WIFI indoor positioning method adopts united RSSI and TOA distance measurement to perform positioning, overcomes the defects existing when an RSSI and TOA are independently positioned and improves positioning precision and accuracy. Especially, a measurement error adapts to change of distance measurement data by establishing a target state equation and a colored noise measurement equation, and large-deviation data filtering-out effect is good. In addition, the planar rotating frame diagram established by means of the method enables the positioning process to be accurate and enables a positioning result to be high in accuracy and approximate to an actual result, and the RSSI and TOA distance measurement based WIFI indoor positioning method can be widely applied to WIFI based indoor positioning.
Owner:HEFEI UNIV OF TECH

Range finding method of pulsed laser rangefinder

The invention discloses a range finding method of a pulsed laser rangefinder. The pulsed laser rangefinder comprises a pulsed laser, a photoelectric detector, an amplifier, a double-channel comparator, a time digital converter TDC and a measurement control module, wherein the photoelectric detector is connected with the amplifier; an output end of the amplifier is connected with two positive input ends of the double-channel comparator; two different discriminating threshold levels are respectively input to two positive input ends of the double-channel comparator; an output end of the double-channel comparator is connected with the time digital converter TDC; and the measurement control module is respectively connected with the time digital converter TDC and the pulsed laser; and by using the range finding method disclosed by the invention, the drift error can be reduced and the range finding accuracy can be improved.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Optical axis nonlinear binocular range finding method

The invention provides an optical axis nonlinear binocular range finding method. The method comprises the following steps: at first, establishing a binocular range finding device, establishing a range finding formula, which is matched with the binocular range finding device, when the optical axes of a left camera and a right camera are non-ideally parallel to each other; and calibrating the parameters of the range finding formula to obtain a rang finding formula that only comprises unknown quantities namely the imaging positions of a scene object to be measured in the left camera and right camera of the binocular range finding device. In actual application, the data of imaging positions of a scene object to be measured in the left camera and right camera of the binocular range finding device can be directly read; and then the data can be substituted into the calibrated range finding formula to calculate the distance between the scene object and a reference camera in the binocular range finding device. The provided method is suitable for the binocular stereoscopic vision device, reduces the distance measurement error caused by unparallel optical axes, and improves the ranging accuracy in actual projects.
Owner:NANJING UNIV OF SCI & TECH

Laser radar device for measuring mine gas concentration distribution and working method thereof

The invention relates to a laser radar device for measuring mine gas concentration distribution, comprising a DFB (Distributed Feed Back) laser (101), a signal generating circuit (102), a laser driving and temperature control circuit (103), a frequency doubling circuit (104), an optical machine transmitting / receiving unit (105), a low-noise preamplifier and filter circuit (106), an orthogonal phase locking demodulation circuit (107), a micro-controller (108), a key module (109), a liquid crystal display module (110), an audible and visual alarm module (111), a data storage module (112), a data communication module (113) and a low-power consumption power management module (114). The laser radar device for measuring mine gas concentration distribution provided in the invention is also capable of measuring the distance between a gas leakage point and a measurement point while measuring the gas concentration, and further capable of finding out the source of gas outburst in a mine conveniently and quickly.
Owner:山东华辰泰尔信息科技股份有限公司

Marine obstacle recognition method and system based on binocular vision and radar

InactiveCN111856448AMake up for the disadvantage of not being able to detect target classesMake up for the shortcomings of low ranging accuracyRadio wave reradiation/reflectionPattern recognitionData matching
The invention provides a marine obstacle recognition method and system based on binocular vision and radar. The method comprises the steps of obtaining a target object classification label according to a trained deep learning network model and a binocular vision image after time fusion, and carrying out three-dimensional reconstruction on the target object to obtain target object information of the target object under a binocular vision coordinate system; obtaining target object information under a radar coordinate system according to the radar data after time fusion; respectively carrying outspace fusion on the target object information under the binocular vision coordinate system and the radar coordinate system, and carrying out data matching on the target object information after spacefusion to obtain an optimal matching pair of the target object; and marking a classification label on the target object detected by the radar according to the optimal matching pair to obtain a finaltarget object recognition result. The defects of a single sensor are overcome, and the method is more suitable for being implemented in a severe marine environment on the premise that the positioningprecision and the recognition accuracy are ensured.
Owner:OCEANOGRAPHIC INSTR RES INST SHANDONG ACAD OF SCI

Combined traveling wave fault location method of high-voltage overhead line and cable hybrid line

The invention provides a combined traveling wave fault location method of a high-voltage overhead line and cable hybrid line. The method comprises the following steps of: firstly, carrying out fault section selection by using a double-ended principle according to time difference generated when a fault initial traveling wave of the hybrid line arrives at two ends, then carrying out initial fault location by using a single-ended principle, and finally working out an accurate result via the single-ended principle by combining with the time difference generated when the fault initial traveling wave arrives at two sides of the line. The method has the advantages that: the obtained fault location result is the result of the single-ended fault location principle, and the effects of hybrid line length error and accurate time synchronization problem of two sides of the line to the fault location accuracy are eliminated in the fault location by using the double-ended principle so that the accuracy and reliability of the fault location are improved. Therefore, the traveling wave fault location of the high-voltage overhead line and cable hybrid line is realized by using the method, the problem on how to accurately search a fault point position after the hybrid line is in the fault can be reliably solved and the traveling wave fault location method has a good application prospect.
Owner:SHANDONG UNIV OF TECH

Method of locating object using phase differences among multiple frequency beacons transmitted from spaced apart transmitter sites

A technique for geolocating (mobile) objects within an environment where other locating systems, such as GPS-based systems, may not be expected to operate successfully, uses at least three transmitter sites whose geolocations are fixed and known, and which transmit dual frequency beacons that are readily received by a mobile receiver within the environment of interest. The object's receiver processes the three sets of received signals by measuring the phase differences among respective pairs of the beacons, and then processes these phase differences to perform time difference of arrival-based or time of arrival-based distance information to locate the object relative to the beacons sites. Phase errors or offsets are readily calibrated out, to realize geolocation information at the mobile receiver.
Owner:HARRIS CORP

Fault positioning method for common-tower double-circuit line

A fault positioning method for a common-tower double-circuit line comprises the following steps: firstly, carrying out six-sequence decomposition for electrical quantity at two ends of the double-circuit line; next, calculating the fault distance by a long line equation of a transmission line of a same positive-sequence fault component of the six-sequence components, and obtaining six-sequence current of a fault point according to the electrical quantity at two ends of the double-circuit line, the fault distance and the long line equation; then converting the six-sequence current into six-phase current; and finally, judging a fault phase according to the amplitude value characteristic of the phase current of the fault point. According to the method provided by the invention, when fault phase-selection of the double-circuit line is carried out, the fault distance detection can be performed at the same time, and the advantages of clear principle, high distance detection accuracy, simple and reliable phase-selection logic and the like are provided. The method provided by the invention is free of the influence of fault point transitional resistance, circuit distributed capacitor current and load current, can automatically adapt to and regulate a definite value of the phase-selection criterion with the change of a system operation manner, and can provide effective phase-selection logic for distance protection of the common-tower double-circuit line.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Vision navigating method for movement carrier based on laser plane assistance

The invention discloses a vision navigating method for a movement carrier based on the laser plane assistance. The method comprises the following steps: building a distance measurement and environment system, determining the position of a rectangular bright spot to be detected in an image, determining the center coordinate of the rectangular bright spot, obtaining a geometric distance measurement model, correcting the distance measurement model, segmenting the visual image, determining a local vectorization environmental space with distance information, positioning the position of the carrier per se, and building a global environmental space. Through the adoption of the method different from the traditional movement carrier autonomous navigation middle distance obtaining method, a laser plane is introduced as an auxiliary means, a single or a plurality of vision sensors are combined, the threadlike bright spot formed by the reflection of the laser plane on an object to be irradiated is fully utilized and taken as an cooperated distance measurement target, and the geometric relationship between the vision sensor and a laser light source is effectively utilized, so that the requirements for the precision, yield ratio and real-time performance of the distance calculating can be met. Therefore, the method is a reliable navigation method, and can be applied to a movement carrier autonomous navigation system.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Transmission line single-phase grounding fault single-end ranging method

A transmission line single-phase grounding fault single-end ranging method belongs to the field of power system protection and control. According to the method of the invention, positive, negative and zero sequence voltage and current phasors of a line during the time section between the occurrence of a single phase grounding fault and single phase tripping and the time section between single phase tripping and reclosing are measured at a substation protection installation site and are used as input. The initial value of fault distance is set from 0 to the overall length of the line with delta1 as the step length, and the initial value of transition resistance starts from 1 ohm and increases to 1000 ohms with 1 ohm as the step length. For each combination of the values of fault distance and transition resistance, the equivalent electromotive force values of a system at the opposite end of the line during the time section between the occurrence of the single phase grounding fault and single phase tripping and the time section after single phase tripping are respectively calculated, the sum of absolute errors of the equivalent electromotive force values is calculated, and the fault distance value corresponding to the minimum value of the sum of absolute errors is selected as the fault ranging distance. The method is high in precision, is not affected by distributed capacitive current, transition resistance, load and system impedance and has very high practical values.
Owner:TSINGHUA UNIV

Emulational USB intermediate frequency responser used for satellite test and control

The invention discloses an emulational USB intermediate frequency responser used for satellite test and control. The emulational USB intermediate frequency responser used for the satellite test and control consists of a front-end analog-to-digital converter, a digital down-conversion module, a carrier synchronization module, a demodulation filter module, a forwarding modulation module and an output analog-to-digital converter; the connecting relations and the signal flow paths are that: an output signal of the front-end analog-to-digital converter enters the digital down-conversion module for processing; the output of the digital down-conversion module is processed in the carrier synchronization module; an output signal of the carrier synchronization module enters the demodulation filter module for processing; one output signal obtained by the demodulation filter module is remote subcarrier output of a demodulator; the other signal is a ranging signal; the ranging signal enters the forwarding modulation module for processing; and the output signal of the forwarding modulation module enters a digital-to-analog converter; and the output of the digital-to-analog converter is an intermediate frequency output signal of the responser. The emulational USB intermediate frequency responser has high stability, low design complexity, high compatibility, a practical value and an application prospect.
Owner:BEIHANG UNIV

Distance image acquisition apparatus and distance image acquisition method

Disclosed are a distance image acquisition apparatus and a distance image acquisition method capable of achieving high distance measurement accuracy and omitting wasteful imaging or calculation. The distance image acquisition apparatus (10) includes a distance image sensor (14), a drive mode setting unit (20A), a distance image generation unit (20B), a pulse light emission unit (22), and an exposure control unit (24). The exposure control unit (24) controls emission and non-emission of pulse light emitted from the pulse light emission unit (22) according to a drive mode set by the drive mode setting unit (20A), and controls exposure in the distance image sensor (14). The distance image generation unit (20B) performs calculation processing of a sensor output acquired from the distance image sensor (14) according to the drive mode set by the drive mode setting unit (20A) to generate a distance image corresponding to a distance of a subject.
Owner:FUJIFILM CORP

Robot location navigation system and navigation method

The invention relates to a robot location navigation system and navigation method. The robot location navigation system comprises a plurality of beacon modules, at least one robot location terminal and an electronic navigation platform; each beacon module comprises a first wireless receiving-transmitting module, an ultrasonic transmitting module and a first intelligent processing module; each robot location terminal comprises a second wireless receiving-transmitting module, an ultrasonic receiving array, an array processing module and a central processor; the electronic navigation platform is used for storing codes of all robots, establishing an electronic map, planning and calculating a motion target or path of the robot as well a position of the beacon module and dispatching the robot to avoid a barrier and also used for coordinating the synchronism of the beacon module and the robot location terminal and receiving position coordinate data uploaded by each robot location terminal. The invention also relates to a navigation method of the robot location navigation system. By adopting the robot location navigation system and navigation method, the multi-path effect and non-line-of-sight propagation problem can be solved, the measurement precision can be improved, and automatic location is implemented.
Owner:长沙开山斧智能科技有限公司

Ranging method and ranging system of femtosecond laser frequency comb synthesis wave interference

ActiveCN103197322AAchieve ultra-high precision distance measurementHigh measurement accuracyElectromagnetic wave reradiationPhotovoltaic detectorsLength wave
The invention relates to a ranging method and a ranging system of femtosecond laser frequency comb synthesis wave interference. The ranging method and the ranging system of the femtosecond laser frequency comb synthesis wave interference comprises a femtosecond laser frequency comb, a Michelson interference system and the like. The light emitted by the femtosecond laser frequency comb enters a first spectroscope, transmission light through the first spectroscope is emitted to a first reflecting mirror, and reflected light returns to the first spectroscope through the first reflecting mirror. The emitted light is emitted to a second spectroscope through the first spectroscope, reflected light through the second spectroscope is emitted to a second reflecting mirror through a first single wavelength generating and frequency shifting light path, and the reflected light through the second reflecting mirror and the first single wavelength generating and frequency shifting light path returns to the second spectroscope. The emitted light through the second reflecting mirror is emitted to a third reflecting mirror through a second single wavelength generating and frequency shifting light path, and reflected light through the third reflecting mirror returns to the second spectroscope through the second single wavelength generating and frequency shifting light path. The reflected light through the second reflecting mirror and the reflected light through the third reflecting mirror are combined on the position of the second spectroscope, and are combined with light pulses of a gage beam, the interference signals of two wavelengths are divided through a diffraction grating and are respectively detected and received by two photoelectric detectors, and range measurement is completed.
Owner:TSINGHUA UNIV

Ranging device based on laser phase method

The invention discloses a ranging device based on a laser phase method, and the ranging device provided by the invention comprises a laser emitting and electro-optical modulating module, an internal-external optical path module, and a photoelectric detecting and data processing module, wherein the laser emitting and electro-optical modulating module is used for emitting an infrared laser subjected to high frequency modulation, the internal-external optical path module comprises an internal optical path and an external optical path; the infrared laser is transmitted to the photoelectric detecting and signal processing module respectively through the internal optical path and the external optical path; the photoelectric detecting and signal processing module is used for respectively performing the conversion and frequency-conversion process on the two transmitted optical signals to obtain a phase difference between two optical signals so as to obtain a to-be-measured distance value. Thedevice directly transmits the light emitted by the laser to an integrated electro-optical modulator through an optical fiber; an exit beam is transmitted to the focus point of a range finder emittinglens through the optical fiber so as to greatly simplify the optical path structure; and meanwhile, the modulation frequency of the integrated electro-optical modulator is much higher than the directmodulation frequency of the laser, thereby achieving higher measurement precision.
Owner:HUAZHONG UNIV OF SCI & TECH

Coupling double line down distance measuring method using six-phase system new phase mode transformation

Disclosed is a fault distance measurement method for a coupled double loop line through mode transformation of a six-phase system, belonging to the technical field of relay protection for an electric power system. In the method, a mode transformation matrix suitable for the loop lines is deduced from the fact that a single module is capable of reflecting the new mode transformation matrix of a common three-phase system according to the relationship between the impedance matrix of the common three-phrase system and the impedance matrix of the system of the double loop lines within the same tower. The invention provides a time domain fault locating method for double loop line based on new mode transformation. The method fabricates the criterion for distance measurement by making use of the transfer characteristics of the arc voltage and current under certain module. The method is characterized in that the measurement is carried out in time domain, the needed time window is short and the method avoids wave filtration; with the method of least square, the distance measurement precision is improved and the distance measurement precision is free from the influences from transition resistance, fault type and impedance change of the opposite system. A large number of electromagnetic transient simulation results show that the method is highly precise.
Owner:KUNMING UNIV OF SCI & TECH

Method for measuring fault location of HVDC (High Voltage Direct Current) transmission line under consideration of measured wave velocity

The invention relates to a method for measuring fault location of a HVDC transmission line under consideration of measured wave velocity; the method is characterized by comprising the following steps: considering the variation characteristic of the wave velocity on the basis of the traditional dual-end location measuring method, and performing the calibration of a wave tip and the determination of the wave velocity in the same process; respectively acquiring the positive and negative data of the voltage of the HVDC transmission line by means of devices at two ends of the line; after the data is subjected to filtering processing and line-mode conversion, analyzing the obtained line-mode traveling wave, obtaining a time-frequency oscillogram of signals and determining the arrival time of the fault traveling wave to two ends of the line as well as a corresponding instantaneous frequency value; obtaining the corresponding line-mode wave velocity by using frequency-wave velocity curves; and finally, obtaining the fault distance by means of a dual-end distance measurement formula.
Owner:XIAN UNIV OF TECH

Panoramic photoelectric radar and scanning method utilizing ground object image positioning

The invention provides a panoramic photoelectric radar which comprises a rotary table which employs a light backflow ring and is capable of rotating 360 degrees continuously, two cameras and a computer matched with the two cameras. A horizontal camera is installed at a horizontal direction of the rotary table, a pitching support of the rotary table is provided with a pitching camera, and the computer is connected with the rotary table and the cameras. The horizontal camera rotates with rotation of the rotary table, and a pitch angle of the horizontal camera is unchanged and is always aimed ata ground object. The pitching camera scans different air areas with change of a pitch angle of the rotary table, and a pitching scanning amplitude is 0 to 90 degrees. The horizontal camera is coaxialwith to a vertical direction of the pitching camera. According to the panoramic photoelectric radar, by utilizing a ground object, employing a double site scanning method, omnidirectional scanning with a 0-360 degrees horizontal angle and a 0-90 degrees pitching angle is realized. By utilizing a method of image processing, an air object is identified automatically, by utilizing a method of image coupling, an accurate azimuth angle and distance of a known ground object reference point are notified, accurate positioning and range finding are carried out on an air object, and an image, a motion parameter and a locus of the air object are accurately displayed.
Owner:银河港(北京)技术有限公司
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