116results about How to "Reduce ranging error" patented technology

The invention discloses a method of single end distance measurement of power transmission line malfunction based on traveling wave inherent frequency extraction. The method comprises the following steps of: after extracting to analyze a principal component of the inherent frequency of a current traveling wave signal of the power transmission line malfunction, selecting a corresponding modulus and a failure type according to the principal component frequency and the malfunction type; obtaining a circuit characteristic impedance matrix, a reflection coefficient matrix, a reflection angle matrix and a modulus wave velocity under the principle component frequency; finally calculating out distance of the malfunction according to the traveling wave inherent frequency, the modulus wave velocity, and the reflection angle, and providing a distance measurement result of the power transmission line malfunction. The method can effectively extract the principal component frequency of the current traveling wave of the power transmission line malfunction, and has the accurate and reliable distance measurement result and convenient implementation without special requirements on equipment.

The invention provides a positioning method and device, belonging to the field of wireless communication application. The method comprises the following steps: acquiring a wireless signal in an unknown position; acquiring the signal intensity of the wireless signal and an identification code ID of a preset beacon node to which the wireless signal belongs; processing the beacon node ID and the signal intensity to obtain the characteristics of the unknown position; acquiring a coordinate of a last position of the unknown position; removing the grids divided in a positioning region in advance according to the coordinates of the last position; sorting the grids in the positioning region by utilizing a support vector machine; acquiring barycentric coordinates of the designated grids which are sorted at the top; and obtaining the coordinates of the unknown position by calculation. The positioning method and device provided by the invention do not need to measure the distance, thus the distance measuring error can not be generated, the precision in positioning is high, the influence degree by the signal is low, and the correlation between the last position and the current position in the dynamic positioning process can be reflected, thus decreasing the positioning error.

The invention relates to a method for hybrid electric power circuit fault distance measurement of a power distribution network, in particular to a method for hybrid circuit combined distance measurement of the power distribution network based on single-ended fault information. The method for hybrid circuit combined distance measurement comprises the steps that firstly, high-frequency traveling wave components of a fault current signal and a fault voltage signal of a hybrid circuit are decomposed; secondly, the wave velocity of traveling waves transmitted in an overhead line and a cable is measured offline; thirdly, preliminary fault distance measurement is conducted according to a correlation coefficient analytical method; fourthly, final fault distance measurement is conducted according to a wave tip combining method; fifthly, a fault distance measurement result is verified. According to the method, only the fault information measured at one end of the circuit is used, initial wave tips and various reflecting wave tips of the traveling waves can be effectively extracted when a fault occurs, the method can be applied to the occasions without the double-ended traveling wave distance measurement function, accurate fault distance measurement is achieved, and the defects of fault distance measurement in the hybrid circuit of an existing power distribution network are overcome. According to the method, on the basis that fault distance measurement is achieved through the current traveling waves, a voltage traveling wave distance measurement result is comprehensively considered, and the reliability and the accuracy of distance measurement judgment are improved.

The invention discloses an indoor range finding positioning method based on improved traceless Kalman filtering, and the method comprises the steps: selecting the Kalman filtering to carry out the processing of a received RSSI value, and obtaining the optimal estimation of a state vector; carrying out the numerical fitting of the RSSI value, processed through the Kalman filtering, through the least square method, and obtaining two environment parameters A and m in a current test environment; carrying out the secondary processing of the RSSI value through the improved traceless Kalman filtering, and obtaining the value of the distance between an anchor node and a target node; and estimating the position coordinates of an unknown node through the solved distance value between the anchor node and the target node and a three-side measurement method. The method corrects the noise estimation value in the traceless Kalman filtering in real time through a robust target function, reduces the weight of an estimation value with the in accurate noise, and improves the state variable estimation precision.

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.

A ranging system is disclosed which measures a distance between terminals operating on a multi-carrier transmission system. The ranging system includes a frequency domain data processing device that acquires impulse responses by subjecting data from transmitted and / or received packets to fast discrete Fourier transform for conversion into frequency domain data subject to a predetermined process and by applying a spectrum estimation algorithm to the processed frequency domain data.

The invention belongs to the field of mapping and navigation, and discloses a pseudolite system and a method based on GNSS(Global Navigation Satellite System) precision time service. The method comprises the following steps: driving a GNSS receiver and a pseudolite signal transmitter by utilizing a homologous crystal oscillator, and solving a clock difference of a local clock of a receiver in realtime by utilizing a precision single point positioning model with coordinate constraint; eliminating a hardware delay between the signal transmitter and the GNSS receiver through a method of calibrating the hardware delay; and broadcasting an obtained clock difference of the local clock to a user in a form of electric files to realize a mathematical synchronization of the local clock and the GNSSsystem time. According to the pseudolite system and the method based on GNSS precision time service, the precision time synchronization of a single pseudolite system and a GNSS system can be realized, and a wired or wireless time synchronization link does not need to be constructed, so that the laying cost and hardware complexity are reduced; and the pseudolite system facilitates the joint positioning calculation with GNSS signals, so that the usability and the reliability of navigation positioning are improved.

The invention relates to a network node positioning method of a wireless sensor. The network node positioning method is characterized in that a mechanism is selected by aid of the ranging techniques, different ranging techniques are selected according to difference in the number of hops away from anchor nodes, the distance border-crossing phenomenon appearing when the number of the hops is two is analyzed, errors are reduced by using the border crossing and returning method, five anchor nodes nearest to a node to be positioned are selected and participate in final positioning after the information of distance between the node to be positioned and all anchor nodes, the five anchor nodes are divided with three anchor nodes forming a group, the anchor node groups having three-point collineation are filtered, the other groups are subjected to trilateral positioning, and finally a final coordinate is obtained after averaging.

The invention provides an indoor positioning method for RSSI ranging based on iBeacons nodes. The method comprises the following steps: S1, carrying out continuous and multiple collections of RSSI values of anchor nodes in different positions through mobile equipment in a fixed position, and establishing a corresponding relationship between the RSSI values and distances between the mobile equipment and the anchor nodes; S2, preprocessing the RSSI values, and selecting normal values from the RSSI values and establishing a corresponding relationship between the normal values and the distances to establish a ranging model; S3, collecting the RSSI values of the anchor nodes through the mobile equipment in unknown positions, and calculating the distances between the mobile equipment and all the anchor nodes through the ranging model; S4, selecting the four anchor nodes which are the nearest to the mobile equipment, and reading coordinate information of the four anchor nodes; S5, calculating the actual coordinates of the mobile equipment through the re-weighted centroid algorithm; and S6, optimizing the positioning coordinates according to map restrictions of an actual environment. The invention further provides an indoor positioning system for RSSI ranging based on the iBeacons nodes.

The invention relates to a laser ceilometer dynamic threshold selecting method based on pulse echo forms, and belongs to the field of laser remote sensing. The laser ceilometer dynamic threshold selecting method based on the pulse echo forms solves the problems that in an existing threshold selecting method, only extreme point positions or fifty-percent peak point positions or dual-threshold positions of pulse echoes are adopted to confirm transition time of laser pulses, the selected thresholds can be only suitable for specific measurement conditions or plane targets of small slopes. According to the laser ceilometer dynamic threshold selecting method based on the pulse echo forms, a mathematic model of the laser ceilometer pulse echo forms, noise standard deviation and threshold rising edge moment variance is regarded as a theoretical basis, the range error minimization of a laser ceilometer serves as a basis, and the optimization selection of the threshold coefficient of the laser ceilometer is achieved through a parameter iterative search method. The influences of noise and pulse widening introduced by gap title effects of the plane targets are fully considered in the threshold value selection method, range errors caused by threshold setting can be reduced, and the satellite-borne laser ceilometer can complete high-precision laser ranging of the plane targets of different slopes under different measurement conditions.

The invention discloses an underwater positioning method based on ranging and a neural network algorithm. The method comprises the steps that K anchor nodes and N to-be-positioned nodes are arranged in positioning water; the distance between each to-be-positioned node and K anchor nodes is measured; and positioning is carried out for two stages of offline training and online positioning. The stage of offline training comprises the steps that the distance between the n-th to-be-positioned node and all anchor nodes is measured to form a distance vector, and the distance vector is input into a three-layer nerve network which comprises a neural network input layer, a neural network hidden layer and a neural network output layer; prediction model parameters are updated through algorithm iteration; and neural network model parameters are output. The stage of online positioning comprises the steps that the current distance between the n-th to-be-positioned node and all anchor nodes is measured to form a distance vector; the distance vector is input to the neural network model parameters acquired in the stage of offline training; and the position coordinates of the to-be-positioned nodes are output to reduce ranging errors.

The invention discloses a power distribution grid fault positioning method with high precision and low cost. According to the fault positioning method, a small amount of traveling wave detection devices with GPS time comparison functions are mounted at two ends of different overhead lines and cable lines of a power distribution grid; when the power distribution grid has faults, the wave speeds of traveling wave line mode component and floor mold component in different lines are calculated by using detection devices of a non-fault line, subsequently the distance of a fault point to one detection device is calculated according to the time difference of the traveling wave line mode component and the floor mold component reaching the detection device, and finally the position of the fault point is confirmed according to the ranging result of a plurality of detection devices. The power distribution grid fault positioning method can achieve accurate fault positioning, shortens the time for troubleshooting, improves the power supply reliability, is small in mounting equipment quantity and good in economy, and has very good practicability.

The invention discloses a small-error positioning method for a wireless sensor network, and provides two improved DV-Hop positioning algorithms, a mandist weighted least square method and a dist weighted least square method. According to the two algorithms, minimum hop mandist weighted processing and minimum hop dist weighted processing are carried out on the average hop distance with a large error in a classical DV-Hop algorithm, and therefore the average hop distance can be estimated more effectively through the improved DV-Hop algorithms. As is shown in a simulation result, compared with the classical DV-Hop algorithm, the average positioning error of the two improved algorithms is reduced, and the positioning accuracy of the two improved algorithms is more stable.

The earth fault ranging method for automatic on / off circuit in railway belongs to the field of single phase earth fault locating method for small current earth system of electric power network. On-line detectors are installed on two ends of the line, and voltage traveling wave signal the small current earth system in failure generates is transmitted in the voltage signal transformers in the line. The on-line detectors detect the absolute time for the initial failure traveling wave to reach the voltage signal transformers on two ends, determine the time difference, and calculate the precise position in certain equation with the total line length and the traveling wave transmission speed. The present invention has the advantages of being fast and accurate, no influence of unstable electric arc and uneven load, etc.

The invention relates to a ranging method and a ranging system for tracking a laser point. The system comprises an image acquisition unit, a laser ranging unit, a high-precision cradle head, a transparent debugging plate, a signal processing unit, a central management platform and a remote control unit. The placement position of the laser ranging unit on the high-precision cradle head is adjustedthrough the transparent debugging plate, so that laser rays are parallel to the rays of an image acquisition center, meanwhile, the laser ranging unit is fixed, and the distance between the laser rays and the rays of the image acquisition center is determined. The accurate position of the laser point can be tracked, positioned and displayed according to the ranging data, and the laser emitting direction is adjusted by adjusting the rotating direction of the high-precision cradle head, so that the laser point is accurately dotted on a target point, ranging errors when the position of the laserpoint cannot be viewed clearly or viewed due to the factors such as long distance or strong rays and the like are reduced, and accuracy and reliability of the laser ranging data are realized.

The invention provides a vehicle braking system combined control method and system. The method includes the steps of consecutively collecting a first vehicle spacing, a second vehicle spacing and a third vehicle spacing at a preset time interval, wherein the preset time interval is not longer than 0.1s; when the second vehicle spacing is smaller than the first vehicle spacing and the third vehiclespacing is smaller than the second vehicle spacing, determining the vehicle spacing variation; determining the driving distance of vehicles within the preset time interval for collecting the second vehicle spacing and the third vehicle spacing and judging whether or not the difference between the driving distance and the vehicle spacing variation is smaller than a preset threshold value; if yes,comparing the third vehicle spacing with data in a braking database to determine whether or not automatic emergency braking needs to be carried out. By means of the method, a high-precision vehicle spacing can be selected out, and the precision of distance measurement of each kind of sensors is greatly improved, so that the precision of prewarning and the accuracy of initiative emergency braking are effectively improved, and the FCWS / AEBS comprehensive performance can be improved.

The invention relates to a WSN node positioning method based on combination of PSO and UKF. The PSO is utilized to carry out preliminary positioning, and the acquired coordinate figure is taken as an initial value of the UKF; a state equation and a measurement equation of the positioning system are established, an RSSI value is taken as observed quantity, a coordinate estimate of an unknown node is acquired, and multitime iteration is carried out; a mass center algorithm principle is utilized, and a polygon mass center coordinate is taken as the final estimate coordinate of the unknown node. Compared with a traditional positioning algorithm, the WSN node positioning method has advantages of higher positioning precision, stronger reliability and relatively strong practical value.

The invention, which belongs to the technical field of wireless sensor networks, discloses a UWB positioning method based on combination of an SVM and barycentric coordinates under an NLOS condition.The method comprises: step one, identifying whether a collected measurement value is under an NLOS or LOS propagation condition by using an SVM algorithm and reducing a measurement error caused by theNLOS; step two, with the measurement value under the LOS condition and the measurement value after NLOS reduction, constructing a distance squared matrix and acquiring a relative position of each UWBnode based on an MDS algorithm; step three, calculating a generalized barycentric coordinate related to an unknown node according to therelative positions obtained by the MDS algorithm; and step four, calculating an actual coordinate of the unknown node by combining the generalized barycentric coordinate and the known coordinates of all anchor nodes. Therefore, the NLOS in a complex environmentcan be identified effectively; and the positioning accuracy of the UWB is improved effectively.

The invention discloses a synchronization method of ultra wide band communication technology and relates to an ultra wide band synchronization method. The method comprises the following steps. Firstly, peak noise serves as a threshold, and long sliding step length is used for performing cross-correlation. When a ratio of the peak noise exceeds the preset threshold, a received signal is regarded to be captured correctly. Secondly, a small peak signal is output through a correlator, a smooth envelope curve output by the correlator is generated by secondary enveloping. Thirdly, the highest point of the envelope curve output by the correlator is taken as a center so as to confirm a thin synchronization interval. Fourthly, small sliding step length undergoes correlation again on the thin synchronization interval which is confirmed, and a peak value output by correlation is obtained and corresponding time shifting of a pilot frequency sequence is calculated. The problem of accuracy in confirming the thin synchronization interval by performing cross-correlation of the small sliding step length and obtaining the peak value, and precision in time delay estimation is improved.

The invention provides a light airplane comprehensive obstacle avoiding system. The light airplane comprehensive obstacle avoiding system comprises data acquisition equipment including aviation bus conversion equipment, GPS (Global Position System) equipment and two high-definition cameras and the like, data processing equipment including two sets of video processing equipment, an embedded type computer, a server and the like, and man-machine interaction equipment including a control panel, sound equipment, a liquid crystal display and the like. The two high-definition cameras are integrated and designed into a nacelle and the optical axes are parallel; and an image plane is parallel or overlapped so that a distance measuring error is reduced. The video processing adopts an FPGA+FIFO+DSP (Field Programmable Gate Array+First-In First-Out-Digital Signal Processor) framework, and a DSP is connected by a high-speed interface. The GPS is fused with a digital map and the like so that known obstacles are avoided. The unknown obstacles are realized by real-time video processing. The server is operated by adopting a website form. The light airplane comprehensive obstacle avoiding system has the advantages that an avionics comprehensive technology, a vision identification technology and a digital map technology are adopted so that a light airplane comprehensive obstacle avoiding function is realized; and the video processing speed is rapid, and the system is economical and intelligent.

The invention discloses a TDOA-based CSS (chirp spread spectrum) precise positioning method. According to the method, a base station model with different mobile station-co-base station virtual receivers is adopted; all the virtual receivers, namely, base station antennas, adopt the same clock, and therefore, requirements for clock synchronization can be eliminated from the source; when distance measurement is performed on a node to be positioned, namely, a mobile terminal, obtained distance measuring values between the node to be positioned and reference nodes are processed through adopting a voting and average combined filtering algorithm, and errors caused by environment are removed, and dynamic correction is performed on left distance measuring values through using a dynamic error correction algorithm, and therefore, distance measuring errors can be decreased to the greatest extent; the corrected distance measuring values are averaged, so that an average value can be obtained; the obtained average value is processed through using a TDOA three-dimensional localization algorithm, so that the position coordinates of the node to be positioned can be obtained, and therefore, final precise positioning can be realized.

The invention relates to a non-whole-course double-circuit parallel power transmission line non-synchronous data fault distance detection principle. The non-whole-course double-circuit parallel powertransmission line non-synchronous data fault distance detection principle is characterized in that utilizing an electric transformer at a protection mounting position to acquire the electrical data ofeach end of a system, respectively decoupling a double-circuit coupling line section and a single-circuit line section, calculating the positive sequence voltage of each end, and the whole power andthe fault component of the current of the line; according to the magnitude, of the positive sequence voltage fault component of the connection point, calculated at two ends of the same line, determining the fault branch circuit; and on the fault branch circuit, according to the double end non-synchronous fault distance detection principle to position the fault so as to eliminate invalid false rootand determine the fault position.

The invention relates to a distance measuring method for adjusting a femtosecond laser resonator cavity to realize optical sampling. A reflector is placed at a reference position, and a computer collects cross-correlation fringes and repetition frequency changes at the same time, and Hilbert transforms the cross-correlation fringes. , find the instantaneous repetition frequency of the femtosecond laser corresponding to the highest point of the cross-correlation fringe envelope, the change of the repetition frequency is realized by adjusting the resonator of the femtosecond laser, at this time, the optical pulse of the signal source optical path and the local oscillator source optical path The light pulses are completely coincident, and the absolute distance of the reflector at the reference position is calculated. Then, the absolute distance of the second reflector at the position to be measured is calculated by the same method, and the measured distance is finally obtained. The invention utilizes a stable long optical fiber as a delay line, combines the pulse time-domain cross-correlation of a femtosecond laser, and realizes a ranging method and a ranging system for optical sampling by adjusting a resonant cavity, thereby effectively improving measurement accuracy.

The invention discloses a DC earth electrode line fault location method. The method comprises the following steps: S10) injecting a pulse signal to a line from a neutral bus end to an earth electrode end at a preset time interval, and receiving a reverse pulse signal and a fault transient traveling wave signal at the neutral bus end; S20) calculating the distance between a fault point and the neutral bus end under the pulse signal; S30) according to the section, where the fault point locates, under the pulse signal and the propagation path of the fault transient traveling wave, calculating the stroke of the fault transient traveling wave received twice, and calculating the distance between the fault point and the neutral bus end under the fault transient traveling wave; and S40) for the distance between the fault point and the neutral bus end under the pulse signal and the distance between the fault point and the neutral bus end under the fault transient traveling wave, obtaining the arithmetic mean value of the two as an approximate position of an actual fault point. The fault location method can locate the fault point quickly and accurately, reduce fault line repair time and is of great significance to reducing outage rate of the whole DC transmission system.

The invention belongs to the technical field of wireless internet, internet of things and mobile communication, and discloses a ranging and position localization method based on the radio wave field strength RSSI; the data value of RSSI is optimized and filtered by using a Gaussian model to reduce the randomness fluctuation of the data itself, and abnormal data samples are eliminated; a RSSI fieldstrength-distance path conversion model used in the distance conversion phase and a dynamic parameter estimation method for the RSSI field strength-distance path conversion model are given; a weighted parameter estimation method is used for performing real-time calibration on the model parameters. The method estimates the dynamic model parameters in the current environment and reduces ranging errors by mutual cooperation between the anchor nodes with known positions before the positioning starts, and has the advantages of simple calculation and easy dynamic correction in the positioning process; the accuracy and stability of wireless ranging and geometric positioning are effectively improved.

The invention provides an indoor positioning method based on range finding error correction and relates to the wireless positioning field. A wireless signal transceiver is used to measure the actual data of a positioning environment, and the function model of an error compensation value and a real distance is established. According to a prior error model, an initial error compensation value is given to a range finding value, a positioning equation is established, and the relative positional relationship between any two positioning circles is determined. If each two of the positioning circles are intersected, there is no need to adjust the range finding value again. If the two positioning circles are not intersected, a pre-corrected range finding value is optimized again according to an established error compensation value adjustment function. Finally, the positioning equation is established and a final positioning result is acquired. In the invention, the range finding error is reduced, the accurate positioning result is acquired, positioning cost is saved, the construction of a range finding error prior model is simple and fast, applicability is wide and portability is high.

The invention relates to a wireless positioning system and method based on multiple mobile terminals. The positioning system comprises a server, a positioning algorithm processing module, a database module and a plurality of mobile terminals provided with communication modules; the plurality of mobile terminals provided with the communication modules form a network, and each mobile terminal sendsthe own information and information of other mobile terminal nodes around to the server at a specific time interval; after receiving the information, the server analyzes the information into a standard format and stores the information in a database module, and then calls the positioning algorithm processing module to process the information, further calculates the position of a target mobile terminal, and returns the position to a user. According to the positioning system disclosed by the invention, when a target communication system is abnormal, the remote positioning of a target can still be realized through the system; and the positioning method uses the revised positioning weight coefficient to calculate the position, so that the adaptability of the positioning algorithm can be realized, the positioning error can be reduced, and the positioning accuracy can be improved.

The embodiment of the disclosure discloses a calibration and ranging method and device, an electronic device, and a computer-readable storage medium. The ranging method includes: acquiring calibrationdata of an image collection device; carrying out calculation based on the calibration data to obtain a calibration distance between a to-be-measured target and the image collection device, and carrying out estimation based on the calibration data to obtain an estimated distance between the to-be-measured target and the image collection device; and calculating a distance between the distance between the to-be-measured target and the image collection device based on the calibration distance and the estimated distance. Therefore, the calibration and ranging accuracy is improved while the viewingangle is extended and the calibration and ranging errors are reduced; and the hardware resources are saved and the application range is wide.