CN205015473U - Online calibration device of dual -polarization weather radar ZDR - Google Patents
Online calibration device of dual -polarization weather radar ZDR Download PDFInfo
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- CN205015473U CN205015473U CN201520773068.3U CN201520773068U CN205015473U CN 205015473 U CN205015473 U CN 205015473U CN 201520773068 U CN201520773068 U CN 201520773068U CN 205015473 U CN205015473 U CN 205015473U
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Abstract
The utility model discloses an online calibration device of dual -polarization weather radar ZDR. The utility model discloses the online calibration device of ZDR includes network communication module, GPS module, the main control panel, horizontal inclination module and memory, the main control panel links to each other with waiting the signal processor who marks dual -polarization weather radar through network communication module, the main control panel links to each other with GPS module, horizontal inclination module and memory respectively. Adopt the utility model discloses can effectively carry out real -time on -line proving, need not artificial intervention, the normal observation of radar need not suspend to automatic the completion.
Description
Technical field
The utility model relates to a kind of ZDR(Analysis of Differential Reflectivity Factor Measured of dual-polarization weather radar) demarcate, be specifically related to a kind of on-line proving device.
Background technology
Polarization weather radar (hereinafter referred to as dual polarization radar) simultaneously or alternate emission horizontal and vertical polarized electromagnetic wave, obtains the observation information such as size, shape, quantity, phase (solid-state, liquid, mixed state), spatial orientation of sexual intercourse particle.These observation datas are widely used in closing on multiple fields such as weather forecast, diastrous weather early warning, weather modification, hydrology Runoff Forecast in short-term.
Analysis of Differential Reflectivity Factor Measured (ZDR) is one of dominant polarization amount of dual polarization radar observation, and being calculated by the difference of horizontal and vertical passage echo power, is small-signal amount.It is not only relevant with the feature of sexual intercourse particle, also relevant with binary channels difference (antenna, waveguide, receiver horizontal vertical difference).Owing to affecting by hardware machining precision, component parameter drift, thermonoise fluctuating etc., the horizontal vertical channel parameters of dual polarization radar can not be completely the same, so need often to demarcate the hardware deviation revising ZDR in observation process.
Patent of invention CN201310202199.1 describes and adopts binary channels complete trails transmitting-receiving calibration technology, reduces binary channels receive-transmit system error, namely revises ZDR hardware deviation.The shortcoming of this technology be cannot real-time calibration antenna, feeder line (waveguide) horizontal vertical difference, there is the problem of calibration signal errors simultaneously.Therefore, the scaling method based on natural source signal is widely used in weather radar.One of conventional scaling method is with radar observation sun signal, is called as sun method.Sun method has been widely used in weather radar and has demarcated, and conventional Weather utilizes sun method to demarcate antenna pointing error, and dual-polarization weather radar also utilizes sun method to carry out ZDR demarcation, corrects the inconsistent ZDR deviation caused of binary channels.Because solar radiation electromagnetic wave is random/non-uniform polar (polarization), the emittance in horizontal and vertical direction is identical, and ZDR theory/actual value is 0.So, be exactly the twin-channel difference of radar by the theoretical value of radar observation sun signal and the difference of measured value.
It is off-line type that traditional sun method is demarcated, there is following step: at specific time period, stop weather echo observation (closedown radar transmitter), run demarcation/testing software, calculate the angle of the sun, control radar is searched for up and down near sun current angular, find maximum echo power (main beam center is just to the sun) position, calculate ZDR mean deviation (simultaneously calculating radar angular deviation), amendment signal processor parameter, terminates to demarcate.See (Du Muyun etc., 2013; Quick depending on reaching radar test software user's mannual, chapter 10 P54) document description.Off-line type demarcates the shortcoming of mode:
1, radar normal observation is interrupted.Can not weather echo be observed in calibration process, cause the discontinuous of observation data.
2, whole process wants manual control.Timing signal, artificial weather echo of closing observes software, during to accurate pair of computing machine, starts demarcation/testing software.
3, calibrating parameters arranges more complicated, needs the personnel through specific training to come.
4, sun angle is constantly change, is difficult to radar antenna accurately to point to sun central authorities, so require repeated multiple times carrying out.
Summary of the invention
The purpose of this utility model is the defect existed to solve prior art, provides one can carry out dual-polarization weather radar ZDR on-line proving device.
In order to achieve the above object, the utility model provides a kind of ZDR on-line proving device of dual-polarization weather radar, comprises network communication module, GPS module, master control board, level inclination module and storer; Master control board is connected by the signal processor of network communication module with dual-polarization weather radar to be calibrated; Master control board is connected with GPS module, level inclination module and storer respectively.
Wherein, network communication module adopts OAHEW5500 Ethernet chip; GPS module adopts the GPS module of HOLUXM-87 superhigh precision; Level inclination module adopts Wuxi intelligent LIS326 double-shaft tilt angle sensor module.
The utility model has the following advantages compared to existing technology: the utility model effectively carries out real-time online demarcation, without the need to manual intervention, automatically complete, do not need the normal observation of interrupting radar, weather echo can be observed simultaneously in calibration process, ensure that the continuity of observation data.The utility model is applicable to all dual-polarization weather radars, can improve dual polarization radar data precision, have broad application prospects.
Accompanying drawing explanation
Fig. 1 is the process flow diagram adopting the utility model to carry out on-line proving;
Fig. 2 is the structured flowchart of the utility model on-line proving device;
Fig. 3 is the sun echo adopting dual-polarization weather radar to observe in effect example;
Fig. 4 is the surface chart that in effect example, matching obtains.
Embodiment
Below in conjunction with specific embodiment, the utility model is described in detail.
Device embodiment
As shown in Figure 2, the utility model dual-polarization weather radar ZDR on-line proving device comprises network communication module, master control board, GPS module, level inclination module and storer.
1, network communication module adopts OAHEW5500 Ethernet chip, and based on ICP/IP protocol, (communications protocol: radial data temporal frequency is high, data volume large, receive and adopt UDP multicast protocol, transfer rate is high, and real-time is good.Revise deviation amount instruction data little, adopt Transmission Control Protocol, good reliability), with the signal processor communication of dual-polarization weather radar, the radial data that real-time reception signal processor exports also sends master control board to; The correction deviation instruction that master control board generates is sent to signal processor.
2, GPS module adopts GPS module (the GPS module positioning precision <=10 rice of HOLUXM-87 superhigh precision, output frequency >1HZ), with master control borad by RS-232TTL port communication, communications protocol adopts NMEA0183, for master control board provides high-frequency gps time, latitude and longitude information.
3, level inclination module adopts Wuxi intelligent LIS326 double-shaft tilt angle sensor module (measurement range >10 degree, precision <=0.1 degree, frequency response >100Hz), serial communication is passed through with master control board, communications protocol adopts NMEA0183, for master control board provides high-frequency antenna XY axle level inclination information.
4, memory module adopts ArduinoMicroSD card module and SanDiskSDHC card (capacity >=32G, read or write speed >=10M/s), be connected by SPI interface with master control borad, for storing the information such as gps time, antenna bearingt reading, antenna pitching reading, level inclination reading automatically identifying sun signal data and the correspondence thereof come.
5, master control board: master control borad adopts ARM11 tetra-core, 256 MB of memory, runs linux system.Method core code is realized by C Plus Plus, comprises sun angle calculating, radial data process, sun Signal analysis, Quadratic Surface Fitting, binary channels variance analysis etc.5 modules are under master control board is coordinated, and real-time reception radial data, On-line testing sun echo, analyzes ZDR deviation, sends and revises deviation instruction to radar, coordinated whole real-time online calibration process.
Embodiment of the method
The concrete grammar of the utility model dual-polarization weather radar ZDR on-line proving is as follows:
1) by the radial data of network communication module network reception signal processor output.
Radial data refers to the data of a radar observed ray, comprises the reflectivity factor (Z) on position angle, the elevation angle, time and each range bin, radial velocity (V), spectrum width (SW), Analysis of Differential Reflectivity Factor Measured (ZDR), related coefficient (CC) etc.Real-time network transmission supported by the signal processor of dual-polarization weather radar main flow.
2) automatically sun echoed signal is identified
2.1) utilize antenna level inclination data, revise the platform deviation of radial data.
In general radar antenna is installed after adjustment is all level, but some horizontal adjustment error, radar high tower naturally swing or movable radar feet unreal, all may produce inclination deviation.These deviations can make on-line proving result more accurate after level inclination data correction.
2.2) method for feature analysis identification sun echoed signal is utilized.
The sun echo of dual polarization radar observation has space, form, physical quantity distribution characteristics.Spatially, the angle of sun echo appearance is close with true sun angle.If antenna direction is talked about accurately in theory, two angles are strict conformances.But in fact because antenna direction exists slight error, so two angles are very close.In echo form, sun echo concentrates in some or several adjacent radial, and reflectivity factor and Different reflectivity factor Z_DR are full of all range bins of whole radial direction, and the Z(in different distance storehouse ignores distance corrects) or ZDR numerical value suitable, rise and fall little.In physical quantity, sun echo only exists in Z and ZDR.Sun electromagnetic wave phase place random variation, so the physical quantity relevant with phase place, as radial velocity, spectrum width, related coefficient etc., sun echo place is null value or invalid data.Based on These characteristics, devise 6 sun echo character conditions for identification, if a certain radial data meets all conditions, then think sun echoed signal, otherwise be not.
Concrete grammar is as follows:
A) angle judges
Judge current radial data angle whether near true sun angle.After GPS module obtains time and longitude and latitude accurately, astronomical algorithm is utilized to calculate sun true bearing angle and the elevation angle in current time place.If it is 3.0 degree that the position angle of current radial data and sun true bearing angular difference value are less than threshold value THRES_AZ(default value), and it is 1.0 degree that the elevation angle of current radial data and the sun true elevation angle difference are less than threshold value THRES_EL(default value), then satisfy condition; Otherwise do not meet.This condition can reduce the interference of most of electromagnetism clutter and Stratiform Cloud Precipitation echo, improves the accuracy rate of sun reflection pickup.
B) reflectivity factor (Z) effectively storehouse number judgement
Calculate the ratio shared by the number of reflectivity factor effective storehouse of current radial data, judge whether to meet threshold value.In radial direction, the data of each range bin are filled by effective value or null value (invalid value), and effective value is echo values in the reasonable scope; Null value (invalid value) is special mark value (as-32768), represents that this range bin is without echoed signal.Add up the ratio of Shuo Zhanzong storehouse, the effective storehouse number of current radial Z, if ratio is greater than threshold value THRES_Z_BINS(be defaulted as 0.8), then satisfy condition, otherwise do not meet.
C) Analysis of Differential Reflectivity Factor Measured (ZDR) effectively storehouse number judgement
Similar with condition (2), calculate the ratio shared by the number of current radial ZDR effective storehouse.If be greater than threshold value THRES_ZDR_BINS(to be defaulted as 0.8), then satisfy condition, otherwise do not meet.
D) radial velocity (V) effectively storehouse number judgement
Calculate the ratio shared by the number of radial velocity effective storehouse in current radial direction.If be less than threshold value THRES_V_BINS(to be defaulted as 0.2), then satisfy condition, otherwise do not meet.Because the radial velocity that sun echo is corresponding is null value, if so a radial data is sun echo, so in radial velocity, null value is necessarily in the great majority.
E) the average reflectance factor (Z) judges
With precipitation signal ratio, sun signal is more weak, and reflectivity factor value is very little.Calculate current radial reflectivity factor average.If average is less than threshold value THRES_Z_MEAN(be defaulted as 10.0dB), then satisfy condition, otherwise do not meet.
F) reflectivity factor (Z) standard variance judges
Ignore after distance corrects, the Z value of sun echo is relatively more uniform diametrically, changes very little, so standard variance is little between storehouse.Calculate current radial reflectivity factor standard variance.If standard variance is less than threshold value THRES_Z_STD(be defaulted as 1.0dB), then satisfy condition, otherwise do not meet.
If a radial data meets above-mentioned 6 conditions, then be judged as sun signal, the position angle of the position angle of radial direction and the elevation angle, gps time and longitude and latitude, the sun and the elevation angle, reflectivity factor average and variance, Analysis of Differential Reflectivity Factor Measured average and variance are recorded, forms a sample.
3) Quadratic Surface Fitting calculates ZDR deviation
If sample number is greater than threshold value THRES_SAMPLE_NUM(be defaulted as 50), then think that sample number is enough, start to calculate ZDR deviation.Be different from conventional offline method, the sun signal that this method is extracted is in antenna main beam width range, and beam center accurately may not point to the sun.In theory, if antenna main beam horizontal width and vertical width completely the same, namely horizontal vertical antenna gain is identical, and so in any position of main beam, the ZDR of sun signal is 0, and like this direct ZDR mean value with all samples is exactly ZDR deviation.But in fact by the restriction of antenna processing technology, antenna horizontal vertical cannot be reached completely the same, therefore can not carry out calculation deviation by sample ZDR average.When antenna horizontal vertical is inconsistent, according to the feature that ZDR value distributes in main beam, the closer to main beam center, ZDR value is less, and more away from main beam center, ZDR value is larger, and presents the feature of Gaussian distribution.Thus, adopt the paraboloidal method of fitted ellipse, X-axis gets the difference at solar azimuth and radial orientation angle; Y-axis gets the difference at the sun elevation angle and the radial elevation angle; Z axis gets the ZDR value of the sun.By elliptic paraboloid equation, calculating the ZDR value on curved surface summit, is exactly ZDR deviation.By orientation and elevation angle error that the X at summit place and Y value are exactly antenna.
Each threshold value can adjust according to concrete dual-polarization weather radar parameter above, as shown in the table.
Table 1 method threshold list and best realization explanation
| method threshold value name | symbol | default value | best realization explanation |
| the position angle of current radial data and solar azimuth difference limen value | tHRES_AZ | 3.0 degree | according to servo accuracy and main beam width adjustment.Servo accuracy is lower, main beam is wider, should arrange larger.Threshold value is not less than 2 times of the maximum error in pointing of antenna and main beam width. |
| the elevation angle of current radial data and the true elevation difference threshold value of the sun | tHRES_EL | 1.0 degree | the same |
| reflectivity factor effective storehouse proportion threshold value | tHRES_Z_BINS | 0.8 | default value |
| analysis of Differential Reflectivity Factor Measured effective storehouse proportion threshold value | tHRES_ZDR_BINS | 0.8 | default value |
| radial velocity effective storehouse proportion threshold value threshold value | tHRES_V_BINS | 0.2 | default value |
| average reflectance factor threshold | tHRES_Z_MEAN | 10.0 dB | according to receiver sensitivity, antenna gain adjustment.Receiver sensitivity is higher, antenna gain is larger, and threshold value is larger.Threshold value is added up by the sun echo samples of some and is drawn. |
| reflectivity factor standard variance threshold value | tHRES_Z_STD | 1.0 | added up by the sun echo samples of some and draw. |
| sample number threshold value | tHRES_SAMPLE_NUM | 50 | according to antenna main beam width, receiver sensitivity adjustment.Main beam is wider, receiver sensitivity is lower, and threshold value should arrange larger. |
Effect example
In order to check the validity of the utility model method, Nanjing Information engineering Univ's C-band Dual-Polarized Doppler Weather Radar (NUIST-CDP) data are adopted to carry out comparison test, the sun echo observed under normal weather pattern as shown in Figure 3, in figure, a left side is reflectivity factor, and the right side is the differential transmission rate factor).Shown in the sun echo samples drafting pattern 4 of >50 On-line testing, in figure, three coordinates are respectively dEL and represent the sun elevation angle and radial data elevation difference; DAZ is for representing the sun elevation angle and the radial data angle of cut; ZDR is the Analysis of Differential Reflectivity Factor Measured value of sun signal.After Quadratic Surface Fitting, obtaining radar ZDR deviation is 0.066dB.The deviation that off-line calibration obtains is 0.05dB.Using off-line calibration result as true value, so higher 0.016dB of on-line proving, much smaller than the accuracy requirement of 0.1dB, therefore on-line proving result is same with off-line calibration result effective.
Claims (2)
1. a dual-polarization weather radar ZDR on-line proving device, is characterized in that: comprise network communication module, GPS module, master control board, level inclination module and storer; Described master control board is connected by the signal processor of network communication module with dual-polarization weather radar to be calibrated; Described master control board is connected with GPS module, level inclination module and storer respectively.
2. dual-polarization weather radar ZDR on-line proving device according to claim 1, is characterized in that: described network communication module adopts OAHEW5500 Ethernet chip; Described GPS module adopts the GPS module of HOLUXM-87 superhigh precision; Described level inclination module adopts Wuxi intelligent LIS326 double-shaft tilt angle sensor module.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106970365A (en) * | 2017-05-12 | 2017-07-21 | 西安华腾微波有限责任公司 | Active calibration facility and scaling method outside a kind of weather radar machine |
| CN109521406A (en) * | 2018-12-17 | 2019-03-26 | 北京敏视达雷达有限公司 | A kind of reflectance difference rate ZDR scaling method and device |
| CN111044983A (en) * | 2019-12-26 | 2020-04-21 | 清华大学 | Method and device for verifying external calibration of dual-band meteorological radar and computer equipment |
| CN114485731A (en) * | 2022-01-28 | 2022-05-13 | 中国人民解放军63921部队 | Spacecraft double-shaft parabolic antenna in-orbit pointing calibration method and device |
| CN115356696A (en) * | 2022-07-30 | 2022-11-18 | 中国气象局气象探测中心 | Weather radar signal processing system algorithm calibration method and device |
| CN115656947A (en) * | 2022-12-15 | 2023-01-31 | 南京信大气象科学技术研究院有限公司 | Real-time correction method and device for ZDR deviation of dual-polarization weather radar |
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2015
- 2015-10-08 CN CN201520773068.3U patent/CN205015473U/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106970365A (en) * | 2017-05-12 | 2017-07-21 | 西安华腾微波有限责任公司 | Active calibration facility and scaling method outside a kind of weather radar machine |
| CN106970365B (en) * | 2017-05-12 | 2019-08-02 | 西安华腾微波有限责任公司 | Active calibration facility and scaling method outside a kind of weather radar machine |
| CN109521406A (en) * | 2018-12-17 | 2019-03-26 | 北京敏视达雷达有限公司 | A kind of reflectance difference rate ZDR scaling method and device |
| CN109521406B (en) * | 2018-12-17 | 2021-03-23 | 北京敏视达雷达有限公司 | Differential reflectivity ZDR calibration method and device |
| CN111044983A (en) * | 2019-12-26 | 2020-04-21 | 清华大学 | Method and device for verifying external calibration of dual-band meteorological radar and computer equipment |
| CN111044983B (en) * | 2019-12-26 | 2022-02-18 | 清华大学 | Method and device for verifying external calibration of dual-band meteorological radar and computer equipment |
| CN114485731A (en) * | 2022-01-28 | 2022-05-13 | 中国人民解放军63921部队 | Spacecraft double-shaft parabolic antenna in-orbit pointing calibration method and device |
| CN115356696A (en) * | 2022-07-30 | 2022-11-18 | 中国气象局气象探测中心 | Weather radar signal processing system algorithm calibration method and device |
| CN115356696B (en) * | 2022-07-30 | 2023-07-04 | 中国气象局气象探测中心 | Weather radar signal processing system algorithm calibration method and device |
| CN115656947A (en) * | 2022-12-15 | 2023-01-31 | 南京信大气象科学技术研究院有限公司 | Real-time correction method and device for ZDR deviation of dual-polarization weather radar |
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