System design method of multi-wavelength dual-polarization ground-based microwave radiometer

Abstract

The invention discloses a system design method of a multi-wavelength dual-polarization ground-based microwave radiometer, relates to the technical field of microwave radiation detection, and solves the technical problem that during rainfall, brightness temperature information of meteorological target radiation is coupled with the scale of particles, inversion blur is brought, and the measurement accuracy is affected. According to the invention, wavelengths of three wave bands of the multi-wavelength dual-polarization ground-based microwave radiometer are set, and brightness temperature radiation signals of the atmosphere are detected according to the wavelengths of the three wave bands; when the tail end of the antenna receives a brightness temperature radiation signal, the brightness temperature radiation signal is transmitted to the integrated receiving channel after passing through the orthogonal coupler; the receiving channel outputs the brightness temperature radiation signal as an electric signal, and then inputs the electric signal into an AD acquisition module to be converted into a digital signal; the monitoring processing system packs the digital signals into Ethernet frames and outputs the Ethernet frames to the terminal system; communication and control are carried out on the servo system and various peripherals, and working data are sent to the terminal system; and the measurement accuracy can be improved.

Description

Technical Field

[0001] The invention belongs to the field of microwave radiation detection, and in particular is a system design method for a multi-wavelength dual-polarization ground-based microwave radiometer. Background Art

[0002] The microwave radiometer is a passive atmospheric microwave remote sensing device that can realize continuous and automatic observation of the atmosphere. It has an unmanned, nearly all-weather observation mode. Its applications include inversion of atmospheric temperature profiles, water vapor density profiles and refractive index profiles, as well as integrated total water vapor and integrated total liquid water.

[0003] At present, ground-based microwave radiometers are the most suitable equipment for estimating the ground-integrated liquid water path (LWP). Ground-based microwave radiometers can remotely sense the atmospheric integrated water vapor and liquid water path under almost all weather conditions; however, the LWP inversion method given by the current ground-based microwave radiometers is limited to measuring the microwave radiation brightness temperature of clouds in the absence of precipitation, and inverting LWP through the microwave radiation brightness temperature of clouds; in the case of rainfall, the brightness temperature information radiated by the meteorological target is coupled with the scale of the particles, resulting in inversion ambiguity, which in turn affects the measurement accuracy.

[0004] The present invention provides a system design method for a multi-wavelength dual-polarization ground-based microwave radiometer to solve the above technical problems. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a system design method for a multi-wavelength dual-polarization ground-based microwave radiometer, which is used to solve the technical problem that when rainfall occurs, the brightness temperature information radiated by the meteorological target is coupled with the scale of the particles, causing inversion ambiguity and thus affecting the measurement accuracy.

[0006] To achieve the above object, a first aspect of the present invention provides a system design method for a multi-wavelength dual-polarization ground-based microwave radiometer, comprising:

[0007] The wavelengths of the three bands of the multi-wavelength dual-polarization ground-based microwave radiometer are set to detect the horizontal and vertical brightness temperature radiation signals of the atmosphere according to the wavelengths of the three bands;

[0008] When the antenna end receives the brightness temperature radiation signal, the brightness temperature radiation signal is transmitted to the integrated receiving channel after passing through the orthogonal coupler; wherein each wavelength corresponds to two receiving channels, which are the vertical polarization receiving channel and the horizontal polarization receiving channel respectively;

[0009] After the receiving channel outputs the brightness temperature radiation signal as an electrical signal, the electrical signal is input into the AD acquisition module and converted into a digital signal;

[0010] The monitoring and processing system integrates and smoothes the collected 6-channel AD digital signals, packages them into Ethernet frames and outputs them to the terminal system; receives control instructions from the terminal through the network, communicates and controls the servo system and various peripherals, and sends the working data of the servo system and various peripherals to the terminal system; the working data includes working status, parameters and BITE information.

[0011] Preferably, the multi-wavelength dual-polarization ground-based microwave radiometer also includes a constant temperature system and a terminal display system. The constant temperature system adopts an intelligent fuzzy PID adaptive algorithm. The terminal display system displays the voltages of the vertical and horizontal channels of the three bands, the detected atmospheric horizontal and vertical brightness temperature radiation signals through a human-computer interaction interface. The multi-wavelength dual-polarization ground-based microwave radiometer monitors data and stores information in real time.

[0012] The constant temperature system of the present invention adopts an intelligent fuzzy PID adaptive algorithm to achieve high-stability and high-precision constant temperature control of the channel, thereby solving the problem of amplitude and phase consistency of the receiving channel working in a wide temperature range to a certain extent; thereby ensuring that internal components work in a temperature environment and increasing the stability of signal processing.

[0013] Preferably, the servo system transmission architecture of the multi-wavelength dual-polarization ground-based microwave radiometer adopts a radar servo architecture, which can perform 0-360° rotation control in the azimuth direction and 0-180° rotation control in the elevation direction.

[0014] The servo system transmission architecture of the present invention adopts a radar servo architecture, which can perform 360-degree rotation control in the azimuth direction and 180-degree rotation control in the pitch direction. It can collect signals in all directions, lay the foundation for subsequent analysis, and is conducive to ensuring the comprehensiveness of signal collection.

[0015] Preferably, the wavelengths of the three bands of the multi-wavelength dual-polarization ground-based microwave radiometer are respectively X-band 10.65 GHz, K-band 18.7 GHz and Ka-band 36.5 GHz; the 10.65 GHz band uses a bias-fed reflector and a corrugated horn, and the 18.7 GHz and 36.5 GHz band use a corrugated horn + dielectric lens.

[0016] It should be noted that the antenna's indicator data are: 3dB beam less than or equal to 6.5°±0.5°; gain greater than or equal to 28dB; first sidelobe level less than or equal to -25dB; X-band cross-polarization less than or equal to -25dB; K-band cross-polarization less than or equal to -28dB; Ka-band cross-polarization less than or equal to -28dB.

[0017] The present invention selects wavelengths of three bands, the K band 18.7 GHz is mainly used for water vapor detection, the Ka band 36.5 GHz is used as an atmospheric window area to mainly detect liquid water, and the X band 10.65 GHz is mainly used for attenuation compensation correction. At the same time, the X band data can be corrected when the K and Ka band detections are saturated; it has the singleness of absorption, which is conducive to processing the observation results.

[0018] Preferably, the receiving channel is an integrated module, including an input end and an output end, the input end is provided with three interfaces, namely a signal access interface, a load access interface and a noise source interface; the output has an interface, which outputs the electrical signal processed by the receiving channel; each receiving channel is provided with a switch control, and the monitoring and processing system is used to control the echo signal or the load signal to enter the receiving channel, and the noise source interface is controlled by a three-throw switch to control whether the noise source signal enters the receiving channel.

[0019] It should be noted that the gain of the receiving channel is greater than 60dB; the gain change is less than or equal to 0.5dB within 2 hours; the channel noise coefficient is less than or equal to 4.5dB; the channel gain consistency is less than or equal to 0.5dB; the channel gain flatness is less than or equal to 1.5dB; the channel phase consistency is less than or equal to 10°; the isolation is 30dB; the input and output standing waves of the receiving channel are less than or equal to 1.5; and the bandwidth is 400MHz.

[0020] Preferably, the monitoring and processing system is composed of a signal processing board and a signal acquisition board; the signal acquisition board is used to collect digital signals from the Ka receiver, the K receiver and the X receiver; the signal processing board is used to process the collected digital signals and then send control signals to the servo system and various peripherals.

[0021] Preferably, the constant temperature system is used to collect temperature information and fan speed information of the three receivers, generate control signals based on the temperature information and fan speed information of the three receivers, adjust the fan speeds of the three receivers, and simultaneously generate control currents to control the semiconductor refrigeration plates of the three receivers; and the constant temperature system transmits system data to the monitoring and control system, and the monitoring and control system forwards the system data of the constant temperature system.

[0022] The constant temperature system of the present invention uses an intelligent fuzzy PID adaptive algorithm semiconductor refrigeration plate and a fan for constant temperature control, achieving high-stability and high-precision constant temperature control of the channel, thereby ensuring that internal components work in a temperature environment.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention selects wavelengths of three bands, K band 18.7 GHz is mainly used for water vapor detection, Ka band 36.5 GHz is used as the atmospheric window area to mainly detect liquid water, and X band 10.65 GHz is mainly used for attenuation compensation correction. At the same time, X band data can be corrected when the K and Ka band detections are saturated; it has the singleness of absorption, which is conducive to processing the observation results; the constant temperature system adopts an intelligent fuzzy PID adaptive algorithm to achieve high stability and high precision constant temperature control of the channel, thereby solving the problem of amplitude and phase consistency of the receiving channel working in a wide temperature range to a certain extent; thereby ensuring that the internal components work in a temperature environment and increasing the stability of signal processing; the servo system transmission architecture adopts a radar servo architecture, which can be rotated 360 degrees in the azimuth direction and 180 degrees in the pitch direction, and can collect signals in all directions, laying a foundation for subsequent analysis and ensuring the comprehensiveness of signal collection.

[0025] 2. The ground-based dual-polarization microwave radiometer of the present invention can independently estimate the liquid water paths of clouds and rain by utilizing the polarization difference of the downward radiation brightness temperature radiation of clouds and rain, and can provide more accurate liquid water path information; it can not only promote the study of cloud-liquid radiation transmission, but also provide additional constraints for the model parameterization of cloud microphysics in climate models, thereby improving the accuracy of climate model calculations; the use of multi-wavelength simultaneous observation can further reduce the detection impact caused by the uncertainty of particle scale spectrum, and adapt to the dynamic range of brightness temperature under different weather conditions; multi-wavelength observation will help to overcome the uncertainty that may be caused by unknown droplet size distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 is a schematic diagram of the external structure of the antenna device of the present invention;

[0028] Figure 2 A schematic diagram of the steps of the design method of the present invention;

[0029] Figure 3 It is a schematic diagram of the internal structure of the receiving channel of the present invention;

[0030] Figure 4 It is a schematic diagram of the structure of the monitoring and processing system of the present invention;

[0031] Figure 5It is a schematic diagram of the structure of the constant temperature system of the present invention;

[0032] Figure 6 It is a schematic diagram of the software interface of the terminal display system of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figure 1-Figure 2 The first aspect of the present invention provides a system design method for a multi-wavelength dual-polarization ground-based microwave radiometer, comprising:

[0035] The wavelengths of the three bands of the multi-wavelength dual-polarization ground-based microwave radiometer are set to detect the brightness temperature radiation signal of the atmosphere according to the wavelengths of the three bands;

[0036] When the antenna end receives the brightness temperature radiation signal, the brightness temperature radiation signal is transmitted to the integrated receiving channel after passing through the orthogonal coupler; wherein each wavelength corresponds to two receiving channels, which are the vertical polarization receiving channel and the horizontal polarization receiving channel respectively;

[0037] After the receiving channel outputs the brightness temperature radiation signal as an electrical signal, the electrical signal is input into the AD acquisition module and converted into a digital signal;

[0038] The monitoring and processing system integrates and smoothes the collected 6-channel AD digital signals, packages them into Ethernet frames and outputs them to the terminal system; receives control instructions from the terminal through the network, communicates and controls the servo system and various peripherals, and sends the working data of the servo system and various peripherals to the terminal system; the working data includes working status, parameters and BITE information.

[0039] The multi-wavelength dual-polarization ground-based microwave radiometer also includes a constant temperature system and a terminal display system. The constant temperature system adopts an intelligent fuzzy PID adaptive algorithm. The terminal display system displays the voltages of the vertical and horizontal channels of the three bands, the detected atmospheric vertical and horizontal brightness temperature radiation signals, and the real-time monitoring data and information storage of the multi-wavelength dual-polarization ground-based microwave radiometer through a human-computer interaction interface. The servo system transmission architecture of the multi-wavelength dual-polarization ground-based microwave radiometer adopts a radar servo architecture, which can be rotated 0-360° in the azimuth direction and 0-180° in the elevation direction. The wavelengths of the three bands of the multi-wavelength dual-polarization ground-based microwave radiometer are 10.65GHz for the X band, 18.7GHz for the K band, and 36.5GHz for the Ka band. The 10.65GHz band uses a bias-fed reflector and a corrugated horn, and the 18.7GHz and 36.5GHz bands use a corrugated horn + dielectric lens.

[0040] It should be noted that there are two principles to consider when selecting the band:

[0041] 1) The mixing ratio of a certain gas concentration that produces radiation in the atmosphere should be constant, that is, this gas component will appear at all altitudes (thus generating radiation of a certain band), and their proportion in the unit volume is constant, so that the temperature factor can be highlighted and the intensity of the radiation measured in this band is only related to the temperature of the gas, and has nothing to do with the absolute content change of the gas at different altitudes or the synchronous change of the absolute content of various gases at the same altitude. In this way, the temperature at each altitude can be measured.

[0042] 2) The selected waveband should have strong absorption and single absorption for a certain gas. According to Kirchhoff's law, if the gas has strong absorption for a certain waveband, it must also have strong radioactivity for this waveband. Single absorption means that the gas has strong absorption for this waveband, and other types of gases do not absorb radiation in this waveband.

[0043] Combining the above factors and the atmospheric absorption spectrum, X-band 10.65 GHz, K-band 18.7 GHz and Ka-band 36.5 GHz are selected for detection. K-band 18.7 GHz is mainly used for water vapor detection, Ka-band 36.5 GHz is mainly used for liquid water detection as the atmospheric window area, and X-band 10.65 GHz is mainly used for attenuation compensation correction. At the same time, X-band data can be corrected when K and Ka-band detections are saturated.

[0044] Actual experiments on antennas with three wavelength bands can obtain a summary table of antenna measured index data

[0045]

[0046] The measured index data of the antenna are compared with the set antenna index data, and it is found that the measured antenna index data are all within the set antenna index data range, so the antennas of the three band wavelengths meet the requirements.

[0047] It should be noted that the set antenna index data are: 3dB beam less than or equal to 6.5°±0.5°; gain greater than or equal to 28dB; first sidelobe level less than or equal to -25dB; X-band cross-polarization less than or equal to -25dB; K-band cross-polarization less than or equal to -28dB; Ka-band cross-polarization less than or equal to -28dB; polarization mode is vertical polarization and horizontal polarization.

[0048] See also Figure 3 The receiving channel is an integrated module, including an input end and an output end. The input end is provided with three interfaces, namely, a signal access interface, a load access interface and a noise source interface; the output has an interface, which outputs the electrical signal processed by the receiving channel; each receiving channel is provided with a switch control, and the monitoring and processing system is used to control the echo signal or the load signal to enter the receiving channel. The noise source interface is controlled by a three-throw switch to control whether the noise source signal enters the receiving channel.

[0049] The signal in the receiving channel enters the coupler through a single-pole double-throw switch. The coupled signal enters the low-noise amplifier and bandpass filter after passing through the isolator, and then passes through the second-stage low-noise amplifier and bandpass filter to output the signal.

[0050] See also Figure 4-Figure 5 The monitoring and processing system consists of a signal processing board and a signal acquisition board; the signal acquisition board is used to collect digital signals from Ka receiver, K receiver and X receiver; the signal processing board is used to process the collected digital signals and send control signals to the servo system and various peripherals;

[0051] It should be noted that the various peripherals include automatic heating systems, ground meteorological element sensors, etc.

[0052] The constant temperature system is used to collect temperature information and fan speed information of the three receivers, generate control signals according to the temperature information and fan speed information of the three receivers, adjust the fan speeds of the three receivers, and generate control currents to control the semiconductor refrigeration plates of the three receivers; and the constant temperature system transmits system data to the monitoring and control system, and the monitoring and processing system forwards the system data of the constant temperature system.

[0053] See also Figure 6The terminal displays the software interface of the system. The data of the monitoring and processing system is transmitted to the computer through the IP / TCP network protocol. The terminal software parses the IP data packet and obtains the data packet sent by the monitoring and processing system; and obtains the voltage data of different bands analyzed. The voltage data is converted into the brightness temperature radiation data of the atmosphere after calibration; and the terminal software detects the working status of the entire system in real time, including the temperature information of the three receivers, the fan speed information, the network connection status, the servo status, the switching of different states of the receiver and the storage of the collected data.

[0054] like Figure 1 As shown, in the second aspect, the system design method of a multi-wavelength dual-polarization ground-based microwave radiometer also includes: an antenna device, which includes a turntable bracket, a turntable is arranged above the turntable bracket, a left box and a right box are respectively installed on both sides of the turntable, a Ka receiver, an X receiver and a K receiver are installed on the top of the turntable through a mounting frame, and an X receiving antenna is arranged above the X receiver.

[0055] The working principle of the present invention is as follows: the present invention sets three wavelength bands of the multi-wavelength dual-polarization ground-based microwave radiometer, and detects the brightness temperature radiation signal of the atmosphere according to the wavelengths of the three wavelength bands; when the brightness temperature radiation signal is received at the antenna end, the brightness temperature radiation signal is transmitted to the integrated receiving channel after passing through an orthogonal coupler; after the receiving channel outputs the brightness temperature radiation signal as an electrical signal, the electrical signal is input into an AD acquisition module to be converted into a digital signal; the monitoring and processing system integrates and smoothes the collected 6-channel AD digital signals, packages them into Ethernet frames and outputs them to the terminal system; the control instructions of the terminal are received through the network, the servo system and various peripherals are communicated and controlled, and the working data of the servo system and various peripherals are sent to the terminal system.

[0056] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A system design method for a multi-wavelength dual-polarization ground-based microwave radiometer, characterized in that: The wavelengths of the three bands of the multi-wavelength dual-polarization ground-based microwave radiometer are set to detect the polarized brightness temperature radiation signals in the vertical and horizontal directions of the atmosphere according to the wavelengths of the three bands; When the antenna end receives the brightness temperature radiation signal, the brightness temperature radiation signal is transmitted to the integrated receiving channel after passing through the orthogonal coupler; wherein each wavelength corresponds to two receiving channels, which are the vertical polarization receiving channel and the horizontal polarization receiving channel respectively; After the receiving channel outputs the brightness temperature radiation signal as an electrical signal, the electrical signal is input into the AD acquisition module and converted into a digital signal; The monitoring and processing system integrates and smoothes the collected 6-channel AD digital signals, packages them into Ethernet frames and outputs them to the terminal system; receives control instructions from the terminal through the network, communicates and controls the servo system and various peripherals, and sends the working data of the servo system and various peripherals to the terminal system; the working data includes working status, parameters and BITE information.

2. The system design method of a multi-wavelength dual-polarization ground-based microwave radiometer according to claim 1, characterized in that: The multi-wavelength dual-polarization ground-based microwave radiometer also includes a constant temperature system and a terminal display system. The constant temperature system adopts an intelligent fuzzy PID adaptive algorithm. The terminal display system displays the voltages of the vertical and horizontal channels of the three bands and the detected atmospheric vertical and horizontal polarization brightness temperature radiation signals through a human-computer interaction interface. The multi-wavelength dual-polarization ground-based microwave radiometer system monitors real-time data and information storage.

3. The system design method of a multi-wavelength dual-polarization ground-based microwave radiometer according to claim 1, characterized in that: The servo system transmission architecture of the multi-wavelength dual-polarization ground-based microwave radiometer adopts a radar servo architecture, which can perform 0-360° rotation control in the azimuth direction and 0-180° rotation control in the elevation direction.

4. The system design method of a multi-wavelength dual-polarization ground-based microwave radiometer according to claim 1, characterized in that: The wavelengths of the three bands of the multi-wavelength dual-polarization ground-based microwave radiometer are respectively X-band 10.65 GHz, K-band 18.7 GHz and Ka-band 36.5 GHz; the 10.65 GHz band adopts a bias-fed reflector and a corrugated horn, and the 18.7 GHz and 36.5 GHz band adopt a corrugated horn + dielectric lens.

5. The system design method of a multi-wavelength dual-polarization ground-based microwave radiometer according to claim 1, characterized in that: The receiving channel is an integrated module, including an input end and an output end. The input end is provided with three interfaces, namely a signal access interface, a load access interface and a noise source interface; the output has an interface, which outputs the electrical signal processed by the receiving channel; each receiving channel is provided with a switch control, and the monitoring and processing system is used to control the echo signal or the load signal to enter the receiving channel. The noise source interface is controlled by a three-throw switch to control whether the noise source signal enters the receiving channel.

6. The system design method of a multi-wavelength dual-polarization ground-based microwave radiometer according to claim 1, characterized in that: The monitoring and processing system is composed of a signal processing board and a signal acquisition board; the signal acquisition board is used to collect digital signals from Ka receiver, K receiver and X receiver; the signal processing board is used to process the collected digital signals and then send control signals to the servo system and various peripherals.

7. The system design method of a multi-wavelength dual-polarization ground-based microwave radiometer according to claim 2, characterized in that: The constant temperature system is used to collect temperature information and fan speed information of the three receivers, generate control signals according to the temperature information and fan speed information of the three receivers, adjust the fan speeds of the three receivers, and generate control currents to control semiconductor cooling sheets of the three receivers; And the constant temperature system transmits the system data to the monitoring control system, and the monitoring control system forwards the system data of the constant temperature system.

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