CN116482695A - Phased array radar meteorological channel calibration method based on solar radiation power - Google Patents

Phased array radar meteorological channel calibration method based on solar radiation power Download PDF

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Publication number
CN116482695A
CN116482695A CN202310260309.3A CN202310260309A CN116482695A CN 116482695 A CN116482695 A CN 116482695A CN 202310260309 A CN202310260309 A CN 202310260309A CN 116482695 A CN116482695 A CN 116482695A
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radar
solar
phased array
radiation power
solar radiation
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唐滢
陈伟
吴贞宇
熊风
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724 Research Institute Of China Shipbuilding Corp
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724 Research Institute Of China Shipbuilding Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/95—Radar or analogous systems specially adapted for specific applications for meteorological use
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/418—Theoretical aspects
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The invention discloses a phased array radar weather channel calibration method based on solar radiation power, belongs to radar calibration technology, and is used for solving the problem of how to quickly and accurately calibrate a phased array radar weather channel. Comprising the following steps: calculating the position of the sun; measuring solar radiation power actually received by a radar; calculating a solar radiation power theoretical value received by a radar; and (5) calibrating the actual measurement value and the theoretical value. According to the method, the sun is used as a signal source, the meteorological channel of the phased array radar is calibrated by utilizing solar radiation power, calibration can be completed rapidly under a sunny condition, and the detection accuracy of the meteorological channel of the phased array radar can be improved effectively.

Description

Phased array radar meteorological channel calibration method based on solar radiation power
Technical Field
The invention belongs to radar calibration technology.
Background
The phased array radar is a radar adopting a phased array antenna, and has the advantages of capability of space orientation and airspace filtering, space power synthesis, conformal antenna and radar platform, multi-beam formation and the like in the aspects of observing high-speed moving targets, multi-target tracking and remote radar acting distance, anti-interference capability, reliability and the like because the beam direction and the beam shape of the phased array antenna have the capability of rapid change. Therefore, the phased array radar is widely applied to the aspects of reverse guiding early warning, homeland air defense, fleet air defense, fire control guidance, reconnaissance monitoring and the like in the military field. Based on the strong self-adaptive capacity of the phased array radar, after a meteorological channel and meteorological signal processing are added in a matched manner, a military radar can acquire meteorological products simultaneously by utilizing the resource advantages of the military radar, so that a meteorological detection function Duan Shouyuan, shi Yongyi, bow and Yuan 2013 is realized.
The phased array radar is particularly important to accurately detect the intensity value of a meteorological target, calculate the moving speed, the change characteristics and the like of the target and calibrate a meteorological channel. The performance verification of the phased array radar such as searching and tracking can be directly based on GPS to measure the target true value, but the strength true value of cloud and rain cannot be directly obtained for a meteorological channel. The domestic civil weather radar is usually calibrated by adopting an in-machine signal source method, an off-machine instrument testing method, a metal pellet method, a small raindrop method and the like. The method for calibrating the echo intensity by using the built-in signal source method is to transmit a continuous wave test signal within a certain range through a radar built-in signal source, and record the actually measured reflectivity intensity at a signal processor terminal; and then calculating a reflectivity strength expected value based on a radar weather equation by using the known input test signal strength, and correcting the radar equation by comparing the two values of the reflectivity strength expected value and the radar weather equation (Li, li Bai, zhao Kun, etc. 2016. Domestic dual-polarization weather radar differential reflectivity measurement performance analysis, weather science and technology, 44 (6): 855-859. The off-board instrument test method is similar to the on-board signal source method. For a common radar system, radar constants and system constants are determined, but for a multi-channel phased array radar, the radar constants and the system constants of different receiving and transmitting channels are different and need to be calibrated and obtained respectively, the phased array radar usually has hundreds of channels, and channel-by-channel testing can hardly be realized during performance verification, so that the built-in signal element and the off-board instrument testing method are not suitable for calibrating meteorological channels of the phased array radar. The metal pellet method belongs to an external calibration method based on echo intensity, namely, a radar is used for irradiating the metal pellet to obtain an echo signal. The small raindrop method is used for calibrating the reflectivity intensity of the radar based on the characteristic that the small raindrops are approximately spherical, but the radar must be completed under the condition of cloud precipitation with small rain intensity, the condition is severe, and the radar cannot be realized frequently.
In summary, in order to better utilize the phased array radar to perform weather detection and improve the detection accuracy, a calibration method different from a single receiving-transmitting channel radar and suitable for a multi-receiving-transmitting channel phased array radar weather channel needs to be formed.
Disclosure of Invention
The invention provides a phased array radar weather channel calibration method based on solar radiation power, which aims to quickly and accurately calibrate a phased array radar weather channel so as to improve the accuracy of phased array radar weather detection.
The technical scheme adopted by the invention comprises the following steps:
step 1: based on solar declination delta, solar time difference omega and latitude of radarCalculating elevation angle of sun relative to radar>Azimuth angle +>
Step 2: under the sunny condition, after the solar elevation angle and the azimuth angle are obtained through calculation, a radar transmitter is closed, a phased array radar is switched to a meteorological detection mode, a radar area array is adjusted, an area array normal beam is directed to aim at a solar position, and power P received by a meteorological channel is recorded; under the condition of closing the transmitter, aligning the radar to the cold sky with a higher elevation angle far from the solar elevation point, eliminating the influence of ground clutter with a low elevation angle, and measuring the noise power N received by the radar; calculating to obtain the solar radiation power P actually received by the radar S,real =p-N, units dBm;
step 3: according to the wave beam width delta omega of the phased array radar meteorological channel, the effective area A of the antenna eff And a solar energy flow density S of corresponding wavelength 0,ref Computing antenna jointTheoretical value of solar radiation power P S,ref *
Taking into account the influence A of solar radiation power through atmospheric attenuation gas (el)
P S,ref ＝P S,ref * +A gas (el)，
Wherein R is 43 The earth radius is 4/3, a is earth surface single-pass atmospheric attenuation, the unit dB/km is that of the S wave band, the S wave band is 0.0055dB/km, and el is the elevation angle of a radar antenna; z is Z 0 The unit km is the atmospheric thickness of the radar site;
step 4: comparing measured values of solar radiation power P S,real And theoretical value P S,ref If the difference value meets the calibration error specified by the radar specification, the requirement is met, and if the difference value exceeds the error allowable range, the algorithm is adjusted and then recalibrated.
Further, the calculation of the solar declination delta and the solar time difference omega in the step 1 includes that the solar declination is calculated according to the calibration date and time first:
δ＝0.3723+23.2567 sinθ+0.1149 sin2θ-0.1712 sin3θ-0.7580 cosθ+0.3656 cos2θ+0.0201 cos3θ
where θ=2pi× 57.2958 (N-N) 0 ) /365.2422; n is the product of days in order of days, e.g., 1 month and 1 day is 0,2 days is 1, and so on; n (N) 0 ＝79.6764+0.2422(Y-1985)-INT[0.25×(Y-1985)]，INT[X]As a function of taking the largest integer not greater than X;
calculating the solar time difference by taking the first leap year as a period of four years:
where N is the product of days in order of days with the first four leap years starting as a period, e.g. 1 for 1 month 1 for the first year and 1461 for 12 months 31 for the fourth year; a is that k And B k The values are shown in the following table:
TABLE 1A k And B k Value table
Further, the solar energy flow density S corresponding to the radar wavelength in the step 3 0,ref Can be obtained from a solar energy flow density S of 10.7cm 10.7 And (3) calculating:
S 0,ref ＝(αgS 10.7 +β)g(f-2800)+S 10.7
where α and β are constants, α=0.0002, β= -0.01, and f is frequency (MHz);
10.7cm wavelength solar energy flow density S 10.7 Can be obtained by searching Canadian astronomical physical astronomical table official network, S 10.7 Unit is SFU,1 sfu=10 -22 Wm -2 Hz -1 。
The invention designs a convenient and quick phased array radar weather channel calibration method by using the sun as a signal source, and can effectively improve the accuracy of phased array radar weather detection. Compared with the prior method, the method has the following advantages:
1. the sun is used as a signal source, and the calibration can be completed under the sunny condition without depending on other built-in or off-board signal sources or calibrating channel by channel.
2. Taking the sun as a signal source, and measuring solar radiation power actually received by a radar after calculating the position of the sun; calculating the solar energy flow density of the corresponding wavelength, and then combining the radar related parameters to obtain a solar radiation power theoretical value received by the radar; finally, comparing the two to calibrate the reflectivity of the weather channel of the phased array radar; because the daily solar radiation power is stable, and the influence of atmospheric attenuation is fully considered, the calibration error can be controlled within 1dB through test verification.
Drawings
FIG. 1 is a schematic illustration of the present invention;
Detailed Description
When the phased array radar detects weather, the radar is specially used for detecting the weather environment and providing weather detection information. In the weather detection state, there are two modes, namely an intensity mode and a speed mode. The meteorological strength mode is mainly used for meteorological strength detection and obtaining surrounding meteorological strength information. There are two scan modes, PPI scan and body scan. The meteorological speed mode is mainly used for meteorological speed detection and obtaining surrounding meteorological speed information.
The preferred embodiment process includes:
firstly, calculating an elevation angle 29.76 degrees and an azimuth angle 275.65 degrees of the sun relative to the radar according to the calibration time 2022, 9 months, 15 days and 15 hours and combining the latitude of the radar to be about 31.81 degrees N;
secondly, under the sunny condition, closing a radar transmitter, switching a phased array radar into a meteorological detection mode, adjusting a radar area array, aligning the receiving center direction of the area array to the sun position, and recording the power received by a meteorological channel; under the condition of closing the transmitter, the radar is aligned to the cold sky with higher elevation angle to eliminate the influence of ground clutter with low elevation angle, and the noise value received by the radar is measured; calculating to obtain solar radiation power-102.78 dBm actually received by the radar;
thirdly, looking up the solar energy flow density S of the current day to be 114.1SFU through a Canadian astronomical physical astronomical station webpage (https:// www.spaceweather.gc.ca/forecast-precision/solar-solar flux/sx-en.php), and calculating the solar radiation power theoretical value received by an antenna to be-102.52 dBm;
and fourthly, comparing an actual measurement value and a theoretical value of solar radiation power, wherein the error is 0.26dB, and the error range of the radar is met.
According to the embodiment, the phased array radar meteorological channel calibration method based on the solar radiation power can effectively improve the accuracy of phased array radar meteorological detection.

Claims (3)

1.A phased array radar meteorological channel calibration method based on solar radiation power is characterized by comprising the following steps of:
step 1: based on solar declination delta, solar time difference omega and latitude of radarCalculating elevation angle of sun relative to radarAzimuth angle +>
Step 2: under the sunny condition, after the solar elevation angle and the azimuth angle are obtained through calculation, a radar transmitter is closed, a phased array radar is switched to a meteorological detection mode, a radar area array is adjusted, an area array normal beam is directed to aim at a solar position, and power P received by a meteorological channel is recorded; under the condition of closing the transmitter, aligning the radar to the cold sky with a higher elevation angle far from the solar elevation point, eliminating the influence of ground clutter with a low elevation angle, and measuring the noise power N received by the radar; calculating to obtain the solar radiation power P actually received by the radar S,real =p-N, units dBm;
step 3: according to the wave beam width delta omega of the phased array radar meteorological channel, the effective area A of the antenna eff And a solar energy flow density S of corresponding wavelength 0,ref Calculating the theoretical value P of solar radiation power received by the antenna S,ref *
According to the influence A of solar radiation power through atmospheric attenuation gas (el)：
P S,ref ＝P S,ref * +A gas (el)
A gas (el)；
Wherein R is 43 The earth radius is 4/3, a is earth surface single-pass atmospheric attenuation, the unit dB/km is that of the S wave band, the S wave band is 0.0055dB/km, and el is the elevation angle of a radar antenna; z is Z 0 The unit km is the atmospheric thickness of the radar site;
step 4: comparing measured values of solar radiation power P S,real And theoretical value P S,ref If the difference value meets the calibration error specified by the radar specification, the requirement is met, and if the difference value exceeds the error allowable range, the algorithm is adjusted and then recalibrated.
2. The phased array radar weather channel calibration method based on solar radiation power according to claim 1, wherein: the calculation of the solar declination delta and the solar time difference omega comprises the following steps: firstly, calculating solar declination according to the calibration date and time:
δ＝0.3723+23.2567sinθ+0.1149sin2θ-0.1712sin3θ-0.7580cosθ+0.3656cos2θ+0.0201cos3θ
where θ=2pi× 57.2958 (N-N) 0 ) /365.2422; n is the product days arranged according to the sequence of days;
N 0 ＝79.6764+0.2422(Y-1985)-INT[0.25×(Y-1985)]，INT[X]as a function of taking the largest integer not greater than X;
calculating the solar time difference by taking the first leap year as a period of four years:
wherein N is the product days which are arranged according to the sequence of days and take the first leap year to start four years as a period; a is that k And B k Is constant.
3. The phased array radar weather channel calibration method based on solar radiation power according to claim 1, wherein: solar energy flow density S corresponding to radar wavelength 0,ref Can be obtained from a solar energy flow density S of 10.7cm 10.7 And (3) calculating:
S 0,ref ＝(αgS 10.7 +β)g(f-2800)+S 10.7
wherein α and β are constants, α=0.0002, β= -0.01, f is frequency, and the unit is MHz;10.7cm wavelength solar energy flow density S 10.7 Can be obtained by searching Canadian astronomical physical astronomical table official network, S 10.7 Unit is SFU,1 sfu=10 -22 Wm -2 Hz -1 。
CN202310260309.3A 2023-03-17 2023-03-17 Phased array radar meteorological channel calibration method based on solar radiation power Pending CN116482695A (en)

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CN202310260309.3A CN116482695A (en) 2023-03-17 2023-03-17 Phased array radar meteorological channel calibration method based on solar radiation power

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