CN104360329B - Intensity calibrating method of all-digital array phased-array weather radar - Google Patents

Abstract

The invention relates to an intensity calibrating method of all-digital array phased-array weather radar. The intensity calibrating method includes the steps that a radar monitoring terminal controls a correction extension set to send out simulation target signals, and a product terminal calculates an actual pulse pressure gain Gp; the radar monitoring terminal controls the correction extension set to send out a plurality of linear frequency modulation simulation target signals with fixed and sequentially and gradually attenuated echo power values, after the linear frequency modulation simulation target signals are processed by a signal processor, echo signal intensity values and spectrum processing signal intensity values are produced and sent to the product terminal through a network so as to be recorded into an intensity calibrating and testing record list, and an intensity curve yDVIP and a spectrum processing intensity curve yFFT are produced after fitting is conducted on the intensity calibrating and testing record list through the least square method; the product terminal inversely calculates echo power Pr when the radar normally works; the value of the obtained echo power Pr is substituted into an improved radar meteorological equation to obtain the value of a radar reflectivity factor dBZ. By means of the method, the special implementation steps and special testing processes of all-digital array weather radar intensity calibrating are established, and the method is fit for engineering practice and is simple, practical and high in calibrating accuracy.

Description

A kind of intensity calibration method of total word array phased array weather radar

Technical field

The present invention relates to phased array weather radar technical field, especially a kind of total word array phased array weather radar Intensity calibration method.

Background technology

In the various modes that people detect the earth atmosphere oneself depended on for existence, weather radar occupies highly importantly Position, with respect to other detection means, weather radar has high spatial and temporal resolution, can promptly and accurately diastrous weather be entered Row detects, and is highly effective observation work particularly at the aspect such as the monitoring of Small and Medium Sized diastrous weather and short-time weather forecasting Tool.

The China New Generation Weather Radar that China has arranged net at present substantially increases the monitoring to diastrous weather and early warning energy Power, can the information such as quantitative detection rainfall runoff process intensity, radial velocity, speed spectrum width, with its high-spatial and temporal resolution, promptly and accurately Remote sensing ability become diastrous weather, the particularly extremely effective work of the aspect such as mesoscale diastrous weather monitoring and warning Tool.But because the change of convection weather phenomenon is quickly, the development time yardstick of convection cell is sometimes with regard to a few minutes To more than ten minutes, particularly with the strong convection monomer such as storm, a few minutes monomer situation may change a lot.Many at present General Le weather radar need to be improved realization to little yardstick, and the time continues short change and causes the weather phenomenon of larger harm to enter soon Row is effectively observed, and its main cause is that radar detection cycle length, radar detection temporal resolution are low.

The research of China's phased array weather radar relevant at present is still in the starting stage.Scanning due to phased-array radar System and the method with signal processing are different from normal radar, and traditional weather radar calibrating method is no longer applicable to it, anxious The method carrying out intensity calibration for phased array weather radar need to be developed.

Content of the invention

It is an object of the invention to provide a kind of calibration precision is high, simple and practical, laminating actual, easy to spread complete of engineering The intensity calibration method of digital array phased array weather radar.

For achieving the above object, present invention employs technical scheme below: a kind of total word array phased array weather radar Intensity calibration method, the step that the method includes following order:

(1) radar monitoring terminal control correction extension set sends mould mesh signal, the calibrated network of mould mesh signal, digital array mould Block sends to Product Terminal to after signal processor process, and Product Terminal calculates actual pulse pressure Deq g_p；

(2) what radar monitoring terminal control corrected that extension set sends that multiple echo power values fix and progressively decay successively is linear Frequency modulation mould mesh signal, generates echo signal intensity value after calibrated network, digital array module to signal processor process respectively Send to Product Terminal through network with spectrum process signal intensity level, Product Terminal is by each echo power value and its corresponding letter Number intensity level, spectrum process signal intensity level are recorded as intensity calibration test recording table, and by method of least square by this table matching Generate intensity curve y_dvipProcess intensity curve y with spectrum_fft；

(3) in radar normal work, radar antenna receives echo-signal, gives digital array module through feeder network and turns After turning to digital i/q data, send signal processor to process, generate echo signal intensity value, spectrum process signal intensity level to product Terminal, Product Terminal is according to generation echo signal intensity value and intensity curve y_dvipInverse goes out echo power p_r, Product Terminal according to Spectrum process signal intensity level, spectrum process intensity curve y_fftInverse goes out echo power p_r；

(4) by the echo power obtaining p_rValue substitute into improved radar weather equation in, draw radar reflectivity factor The value of dbz.

Described actual pulse pressure Deq g_pComputing formula be: g_p=s_nb-s_nf, wherein, s_nfFor signal to noise ratio before pulse pressure, i.e. numeral I/q signal is through the signal to noise ratio before signal processor pulse compression；s_nbFor signal to noise ratio after pulse pressure, that is, digital i/q signal through signal at After reason machine pulse compression and through the signal to noise ratio before fft conversion, before iir filtering.

Described intensity curve y_dvipLinear relation be: y_dvip=a₁*p_r+b₁, described spectrum process intensity curve y_fftLine Sexual intercourse formula is: y_fft=a₂*p_r+b₂；Determine the coefficient a of above-mentioned two linear relation according to method of least square₁、b₁、a₂With b₂, solution formula is:

$\begin{array}{cc}a=\frac{{\mathrm{n\σx}}_i{y}_i-{\mathrm{\σx}}_i{\mathrm{\σy}}_i}{{\mathrm{n\σx}}_i^2-{\left({\mathrm{\σx}}_i\right)}^2}& b=\frac{1}{n}({\mathrm{\σy}}_i-{\mathrm{a\σx}}_i)\end{array}$

Wherein, x_iRepresent the multiple echo power values in input intensity calibration test log, y_iRepresent multiple with input Echo power value corresponding observed strength value, n is the number of echo power value.

Described improved radar weather equation is:

$dbz=10log\frac{2.69{\mathrm{\λ}}^{2}cos\mathrm{\θ}}{p_t{\mathrm{\τ\θ}}_0{\mathrm{\φ}}_0}+160-g_p-g_t-g_r+l_{\mathrm{\σ}}+p_{\mathrm{\γ}}+20\log r+r\×l_{at}$

In formula, λ is radar operation wavelength, and cos θ sweeps correction, p for vertical beam width phase_tExport its peak work for transmitter Rate, τ is fire pulse width, θ₀For horizontal beam width,For normal direction vertical beam width, g_pObtain for actual pulse pressure Benefit, g_tFor transmitter antenna gain (dBi), g_rFor receiving antenna gain, l_∑For system loss, r is radar range-to-go, l_atFor double Journey atmospheric loss.

The numerical-control attenuator that described radar monitoring terminal control corrects in extension set sends at least two echo power values and fixes And the linear frequency modulation mould mesh signal progressively decayed successively.

As shown from the above technical solution, the present invention is directed to the intensity of the total word array phased array weather radar of brand-new system Scaling Problem, first obtains actual pulse pressure Deq g_p, pass through method of least square further according to multiple measured values and measured value matching generated Intensity curve y_dvipProcess intensity curve y with spectrum_fft, last inverse goes out echo power p_rWith radar reflectivity factor dbz.The present invention According to Practical Project practical experience, improve traditional radar equation, devise acquisition modes and the method for special parameter, and Formulate distinctive implementation steps, the test process of total word array weather radar intensity calibration, the method laminating engineering is actual, Simple and practical, easy to spread and calibration precision is high.

Brief description

Fig. 1 (a) is signal to noise ratio schematic diagram before pulse pressure.

Fig. 1 (b) is signal to noise ratio schematic diagram after pulse pressure.

Fig. 2 is intensity calibration interface schematic diagram.

Fig. 3 arranges terminal interface schematic diagram for radar parameter.

Fig. 4 is the circuit system block diagram of the active phased array Weather radar system of total word array.

Fig. 5 is the circuit block diagram of signal processor.

Specific embodiment

As one of important detection means of modern weather, the accuracy of result of detection is for weather forecast, big for weather radar Gas research all has great importance.Detection accuracy weather radar in order to improve radar all must be calibrated, and passes through work It is exactly radar that journey technological means control the process of error between the theoretical value that actual echo strength and radar weather equation calculate The calibration of system.

Traditional weather radar calibration process is to be -90dbm to -30dbm with signal source in machine (or outside machine) injecting power Signal p_r, it is being 5 to 200km scope, the measured value of inspection echo strength apart from r.Processed by technical method control signal The reflectivity factor actually obtaining and the calculated theory of radar weather equation being given by probert-jones 1962 Error between echo reflection rate is calibrated to radar.

Project cloud when radar beam, on precipitation particles when, cloud, precipitation particles just produce scattering phenomenon.Wherein rearward A part of scattered wave of scattering comes back at radar antenna, and shows various images on radarscope, here it is institute The radar return of meaning.And the intensity of radar return depends not only on the characteristic of each parameter of radar system, and and be observed cloud, The property of precipitation particles is relevant, also relevant with the distance between radar and target being observed and atmospheric condition therebetween.Want Go to infer with, the physical property of precipitation particles it is necessary to exclude the impact of these middle irrelevant factors according to the echo strength measuring. Conventional weather radar, by quoting the radar weather equation that probert-jones derived in 1961, establishes radar and returns Corresponding relation between intensity of wave and meteorological observation target:

Wherein, p_rFor echo power, p_tFor transmission power, h is effective illuminated depth, and g is gain, θ₁Horizontal beam width,Vertical beam width, λ represents wavelength, r observed range, and m is complex refractive index.

Total word array phased array weather radar has higher data time resolution and finer spatial resolution, It is also more accurate to precipitation estimation simultaneously, and it can also undertake multiple-task compared with conventional radar, such as realizes air route prison Survey and follow the trail of etc..Total word array weather radar is undoubtedly the important directions of following weather radar development, but it is seen meteorological The development in survey field is still in the starting stage with applying in China, and many problems need to study further, and the present invention mainly solves The certainly intensity calibration problem of the total word array phased array weather radar of first, China, for total word array phased array weather thunder The radar weather equation reaching probert-jones proposition has following correlative to there occurs change:

Beam angle, its beam angle is no longer definite value, and is as deviateing the change of antenna normal direction orientation angle and becomes Change；

Radar gain, identical with beam angle, its antenna gain is not changeless, is also as deviateing antenna method Change to the angle in direction；

The impact of pulse compression, the operating distance in order to improve radar ensures its resolution, phased array weather thunder simultaneously again Reach and employ pulse compression technique.

In view of above-mentioned Railway Project, as a kind of weather radar of brand-new system, it calibrates phased array weather radar Method is also required to again establish.

As shown in figure 4, the active phased array Weather radar system of total word array, including for launching beam, received wave Bundle and signal processor 1 that echo data is processed, signal processor 1 pass through network respectively with monitor terminal, product Terminal both-way communication, signal processor 1 is connected with the first high-speed high capacity division multiplex fibre-optic communication wave machine by the first optical fiber, the One high-speed high capacity division multiplex fibre-optic communication wave machine passes through the second optical fiber and the second high-speed high capacity division multiplex fibre-optic communication wave machine Be connected, collector ring is set on the second optical fiber, the second high-speed high capacity division multiplex fibre-optic communication wave machine respectively with correction extension set 2, Digital array module 3 both-way communication, digital array module 3 is connected with aerial array 5 by corrective network 4,6 points of frequency source Not do not provide clock signal to digital array module 3, signal processor 1, the outfan of servo drive motor respectively with collector ring, Aerial array 5 is connected.Data processing terminal is made up of monitor terminal and Product Terminal two parts, completes following major function: thunder Reach control, data acquisition, radar data is processed, product generates, product achieves and echo, system monitoring, system has to outer net The ability of network communication, is capable of multi-beam and shows.

As shown in figure 4, described corrective network 4 is made up of main feeder 42 and 128 dual directional couplers 41, main feeder 42 is adopted With waveguide, corrective network 4 is connected by flange as between an entirety and 128 antennas 51 of composition aerial array 5.Described The beam signal that aerial array 5 is transmitted transmits in the form of the traveling wave battle array of rake joist is opened on Narrow Wall of Waveguide side, and aerial array 5 is using splitting Seam waveguide linear array.During transmission signal, pumping signal phase shift, up-conversion, amplification are fed to waveguide battle array by digital transmitting-receiving subassembly 31 Input, radiofrequency signal is radiated the launching beam required for space is formed, during reception, slotted waveguide line by slotted waveguide linear array Battle array will receive target echo signal feeding digital transmitting-receiving subassembly 31 thereafter, the numeral letter of digital transmitting-receiving subassembly 31 output Number sending into Digital Beam Formation Unit 11 forms required reception wave beam.Described correction extension set 2 is received by numerical-control attenuator and correction Send out assembly composition, both-way communication between numerical-control attenuator and correction transmitting-receiving subassembly, numerical-control attenuator is connected with corrective network 4, school Positive transmitting-receiving subassembly and signal processor 1 both-way communication.

As shown in figure 5, described signal processor 1 is by Digital Beam Formation Unit 11 and Doppler's meteorologic signal processor 12 Composition, described Doppler's meteorologic signal processor 12 is by pulse compression unit, fft converter unit, frequency domain filtering unit, iir filter Ripple unit, dvip unit data formatting unit composition, Digital Beam Formation Unit 11 and the communication of the first optical fiber bidirectional, numeral 11 points of two-way outputs of beam forming unit, a road is directly connected with monitor terminal, the input of another road and pulse compression unit It is connected, the outfan of pulse compression unit is connected with the input of fft converter unit, iir filter unit respectively, fft conversion is single Unit is connected with frequency domain filtering unit, and iir filter unit is connected with dvip unit, frequency domain filtering unit, the outfan of dvip unit All it is connected with the input of data form unit, the outfan of data form unit is connected with the input of Product Terminal.

As shown in figure 5, the i/q signal that the digital receiver of dam is sent first carries out dbf digital beam froming, after dbf Data divides two-way, and a road is directly fed to monitor terminal for initial data and is stored, and the advanced horizontal pulse compression of another road, to process The signal of pulse pressure carries out two kinds of process respectively, and the first is fast Fourier transform fft, and time-domain signal is converted to frequency domain letter Number, spectral filter is carried out to frequency-region signal, then spectrum is carried out to spectrum and process intensity, speed and the spectrum width drawing spectrum；Second is straight Connect and iir filtering is carried out to time-domain signal, then carry out dvip video integration process, directly obtain the intensity of signal；At both The result of reason gives Product Terminal through data form through netting twine.

A kind of intensity calibration method of total word array phased array weather radar, comprising: (1) radar monitoring terminal control school Positive extension set sends mould mesh signal, sends to product after the calibrated network of mould mesh signal, digital array module to signal processor process Product terminal, Product Terminal calculates actual pulse pressure Deq g_p；(2) radar monitoring terminal control correction extension set sends multiple echo powers The linear frequency modulation mould mesh signal that value is fixed and progressively decayed successively, at calibrated network, digital array module to signal processor Generate echo signal intensity value and spectrum process signal intensity level after reason respectively to send to Product Terminal through network, Product Terminal will be each Individual echo power value and its corresponding signal strength values, spectrum process signal intensity level are recorded as intensity calibration test recording table, And this table matching is generated by intensity curve y by method of least square_dvipProcess intensity curve y with spectrum_fft；(3) in the normal work of radar When making, radar antenna receives echo-signal, gives digital array module through feeder network and is converted into after digital i/q data, delivers letters Number datatron is processed, and generates echo signal intensity value, spectrum process signal intensity level to Product Terminal, and Product Terminal is according to generating back Ripple signal strength values and intensity curve y_dvipInverse goes out echo power p_r, Product Terminal is according to spectrum process signal intensity level, spectrum process Intensity curve y_fftInverse goes out echo power p_r；(4) by the echo power obtaining p_rValue substitute into improved radar weather equation in, Draw the value of radar reflectivity factor dbz.

Described actual pulse pressure Deq g_pComputing formula be: g_p=s_nb-s_nf, wherein, s_nfFor signal to noise ratio before pulse pressure, i.e. numeral , through the signal to noise ratio before signal processor pulse compression, such as Fig. 1 (a) is shown for i/q signal；s_nbFor signal to noise ratio after pulse pressure, i.e. digital i/q , after signal processor pulse compression and through the signal to noise ratio before fft conversion, before iir filtering, such as Fig. 1 (b) is shown for signal.

The numerical-control attenuator that described radar monitoring terminal control corrects in extension set sends at least two echo power values and fixes And the linear frequency modulation mould mesh signal progressively decayed successively, such as by monitor terminal setting control correction extension set produce power be- The linear FM signal of 24.3dbm, as shown in Fig. 2 the dvip measured value of display and spectrum process intensity measurement value record in intensity On the corresponding position of calibration test log, as shown in table 1:

Table 1

The output signal power changing correction extension set is -34.3dbm, and record dvip measured value and spectrum process intensity measurement Value；Repeat to survey, until until all parameter values of table 1 have been surveyed.The data inputting Product Terminal that table 1 is obtained is corresponding Form in, as shown in Figure 3.

Described intensity curve y_dvipLinear relation be: y_dvip=a₁*p_r+b₁, described spectrum process intensity curve y_fftLine Sexual intercourse formula is: y_fft=a₂*p_r+b₂；Determine the coefficient a of above-mentioned two linear relation according to method of least square₁、b₁、a₂With b₂, solution formula is:

$\begin{array}{cc}a=\frac{{\mathrm{n\σx}}_i{y}_i-{\mathrm{\σx}}_i{\mathrm{\σy}}_i}{{\mathrm{n\σx}}_i^2-{\left({\mathrm{\σx}}_i\right)}^2}& b=\frac{1}{n}({\mathrm{\σy}}_i-{\mathrm{a\σx}}_i)\end{array}$

Wherein, x_iRepresent the multiple echo power values in input intensity calibration test log, y_iRepresent multiple with input Echo power value corresponding observed strength value, n is the number of echo power value.

Described improved radar weather equation is:

$dbz=10log\frac{2.69{\mathrm{\λ}}^{2}cos\mathrm{\θ}}{p_t{\mathrm{\τ\θ}}_0{\mathrm{\φ}}_0}+160-g_p-g_t-g_r+l_{\mathrm{\σ}}+p_{\mathrm{\γ}}+20\log r+r\×l_{at}$

In formula, λ is radar operation wavelength, and cos θ sweeps correction, p for vertical beam width phase_tExport its peak work for transmitter Rate, τ is fire pulse width, θ₀For horizontal beam width,For normal direction vertical beam width, g_pObtain for actual pulse pressure Benefit, g_tFor transmitter antenna gain (dBi), g_rFor receiving antenna gain, l_∑For system loss, r is radar range-to-go, l_atFor double Journey atmospheric loss.

Product Terminal can read and show dvip value and the fft value that signal processor is sent into, can be according to the number of input According to simulating echo power p_rLinear relationship and dvip and fft value between respectively, finally, Product Terminal can be according to antenna The echo signal intensity receiving obtains the value of reflectivity factor dbz.

In sum, the present invention is directed to the intensity calibration problem of the total word array phased array weather radar of brand-new system, First obtain actual pulse pressure Deq g_p, pass through method of least square further according to multiple measured values and measured value matching generated intensity curve y_dvipProcess intensity curve y with spectrum_fft, last inverse goes out echo power p_rWith radar reflectivity factor dbz.The present invention is according to reality Engineering experience, improves traditional radar weather equation, devises acquisition modes and the method for special parameter, and formulates The distinctive implementation steps of total word array weather radar intensity calibration, test process, the method laminating engineering is actual, simple Practical, easy to spread and calibration precision is high.

Claims (4)

1. a kind of intensity calibration method of total word array phased array weather radar it is characterised in that the method include following suitable The step of sequence:

(1) radar monitoring terminal control correction extension set sends mould mesh signal, and the calibrated network of mould mesh signal, digital array module arrive Signal processor sends after processing to Product Terminal, and Product Terminal calculates actual pulse pressure Deq g_p；

(2) radar monitoring terminal control correction extension set sends the linear frequency modulation that multiple echo power values are fixed and progressively decayed successively Mould mesh signal, generates echo signal intensity value and spectrum after calibrated network, digital array module to signal processor process respectively Process signal intensity level sends to Product Terminal through network, and Product Terminal will be strong to each echo power value and its corresponding signal Angle value, spectrum process signal intensity level are recorded as intensity calibration test recording table, and are generated this table matching by method of least square Intensity curve y_dvipProcess intensity curve y with spectrum_fft；

(3) in radar normal work, radar antenna receives echo-signal, gives digital array module through feeder network and is converted into After digital i/q data, send signal processor to process, generate echo signal intensity value, spectrum process signal intensity level to Product Terminal, Product Terminal is according to generation echo signal intensity value and intensity curve y_dvipInverse goes out echo power p_r, Product Terminal according to spectrum at Reason signal strength values, spectrum process intensity curve y_fftInverse goes out echo power p_r；

(4) by the echo power obtaining p_rValue substitute into improved radar weather equation in, draw radar reflectivity factor dbz's Value；Described improved radar weather equation is:

$dbz=10\log \frac{2.69{\mathrm{\λ}}^2\cos \mathrm{\θ}}{p_t{\mathrm{\τ\θ}}_0{\mathrm{\φ}}_0}+160-g_p-g_t-g_r+l_{\σ}+p_r+20\log r+r\×l_{at}$

In formula, λ is radar operation wavelength, and cos θ sweeps correction, p for vertical beam width phase_tExport peak power for transmitter, τ is Fire pulse width, θ₀For horizontal beam width,For normal direction vertical beam width, g_pFor actual pulse pressure Deq, g_tFor sending out Penetrate antenna gain, g_rFor receiving antenna gain, l_∑For system loss, r is radar range-to-go, l_atDamage for round trip air Consumption.

2. total word array phased array weather radar according to claim 1 intensity calibration method it is characterised in that: institute State actual pulse pressure Deq g_pComputing formula be: g_p=s_nb-s_nf, wherein, s_nfFor signal to noise ratio before pulse pressure, i.e. digital i/q signal warp Signal to noise ratio before signal processor pulse compression；s_nbFor signal to noise ratio after pulse pressure, that is, digital i/q signal is through signal processor pulse pressure After contracting and through the signal to noise ratio before fft conversion, before iir filtering.

3. total word array phased array weather radar according to claim 1 intensity calibration method it is characterised in that: institute State intensity curve y_dvipLinear relation be: y_dvip=a₁*p_r+b₁, described spectrum process intensity curve y_fftLinear relation For: y_fft=a₂*p_r+b₂；Determine the coefficient a of above-mentioned two linear relation according to method of least square₁、b₁、a₂And b₂, solve public Formula is:

$\begin{array}{cc}a=\frac{n\σx_i{y}_i-\σx_i\σy_i}{n\σx_i^2-{(\σx_i)}^2}& b=\frac{1}{n}(\σy_i-a\σx_i)\end{array}$

Wherein, x_iRepresent the multiple echo power values in input intensity calibration test log, y_iRepresent the multiple echoes with input Performance number corresponding observed strength value, n is the number of echo power value.

4. total word array phased array weather radar according to claim 1 intensity calibration method it is characterised in that: institute State the numerical-control attenuator that radar monitoring terminal control corrects in extension set and send at least two echo power values and fix and successively progressively The linear frequency modulation mould mesh signal of decay.