A design method for in-machine online real-time calibration system of dual polarization radar

Abstract

The invention belongs to the technical field of meteorological detection, and discloses a design method for an in-machine online real-time calibration system of a dual-polarization radar. The in-machine calibration of the invention can realize the in-machine calibration function of parameters such as noise, intensity, speed, spectrum width, differential reflectivity, differential propagation phase shift, etc. through a built-in calibration source, a digitally controlled attenuator, a noise source, etc., which is equivalent to a built-in signal source. The calibration source signal switch and frequency are controlled by a host computer software, and the attenuation value of the digitally controlled attenuator is controlled by the host computer software to control the intensity of the calibration signal. After the in-machine source and the external instrument are calibrated with each other, the in-machine source can be used to replace the external instrument for testing, thereby avoiding other faults or errors that may be caused by periodic shutdown testing and maintenance and frequent disassembly, reducing maintenance costs, and improving maintenance efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of meteorological detection, and in particular relates to a design method for an in-machine online real-time calibration system of a dual-polarization radar. Background Art

[0002] In the meteorological detection system of disastrous weather, weather radar is an important pillar and a key detection means for my country's meteorological, water conservancy, agriculture and other departments. Due to its unique dual polarization function, dual polarization weather radar can more accurately observe the internal three-dimensional dynamics and microphysical structure of disastrous weather systems compared to conventional single polarization weather radars. It plays a key role in the formation and evolution of severe weather (such as tornadoes, hail, and strong winds) and in capturing fine-scale physical and dynamic processes, effectively improving the monitoring capabilities of disastrous weather such as rainstorms. Dual polarization weather radar can improve the accuracy of precipitation estimation and hydrometeor classification, as well as identify the characteristics of severe convective weather, but the premise is that the various parameters of dual polarization weather radar must be accurate, especially the amplitude and phase consistency of the dual channels, which greatly affects the data quality and detection capability of dual polarization radar. For dual polarization weather, the basic data types mainly include intensity (Z), velocity (V), spectral width (W), differential reflectivity (ZDR), differential propagation phase shift (PHIDP), differential propagation phase shift ratio (KDP), correlation coefficient (CC), etc. In actual operation, dual-polarization weather radar is easily affected by changes in surrounding environmental conditions and its own system status. For example, changes in temperature will affect the noise floor and the consistency of dual-channel amplitude and phase. These parameter changes will directly affect the quality of radar observation data, thereby affecting radar performance. If you want to keep the dual-polarization radar system stable, one way is to control changes in the radar working environment so that the radar can continue to work in a relatively stable environment. Another way is to design an in-machine online real-time calibration link to calibrate the radar parameters in real time, obtain radar parameter status changes in a timely manner, and eliminate errors in time to ensure radar data quality.

[0003] At present, the calibration system designs of most manufacturers are relatively simple, but there are certain problems: the calibration channel is not the entire radar transceiver link, and only a section of the change can be obtained, which cannot characterize the real changes in the system; only some parameters are calibrated, not all parameters can be calibrated; the radar is still out of service, components are disassembled, and high-precision instruments are used for testing and calibration, which is time-consuming and costly. Repeated disassembly will also cause other faults or errors, and automatic and efficient radar full-link calibration technology has not been achieved; the calibration method is relatively simple. For example, in the calibration process of the receiver's dual-channel consistency, the temperature factor is crucial. The temperature drift of active devices in the receiver, such as low-noise amplifiers, due to temperature changes will directly affect the consistency of the receiving channel. Some manufacturers directly use finished air conditioners to control the receiver temperature, which cannot accurately control the temperature and eliminate the consistency impact caused by temperature drift.

[0004] Through the above analysis, the problems and defects of the prior art are as follows:

[0005] (1) The calibration channel is not the entire radar transceiver link, and can only obtain a portion of the change, which cannot represent the real changes produced by the system;

[0006] (2) Only some parameters are calibrated, not all parameters can be calibrated;

[0007] (3) The radar is still out of service, components are disassembled, and high-precision instruments are used for testing and calibration, which is time-consuming and costly. Repeated disassembly will also lead to other faults or errors. Automatic and efficient radar full-link calibration technology has not been realized.

[0008] (4) The calibration method is relatively simple. For example, in the process of calibrating the consistency of the receiver's dual channels, the temperature factor is crucial. The temperature drift of active devices in the receiver, such as low-noise amplifiers, will directly affect the consistency of the receiving channel due to temperature changes. Some manufacturers directly use finished air conditioners to control the receiver temperature, which cannot accurately control the temperature and eliminate the consistency impact caused by temperature drift. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a design method for an in-machine online real-time calibration system of a dual-polarization radar.

[0010] The present invention is implemented in this way: a design method for an in-machine online real-time calibration system of a dual-polarization radar comprises:

[0011] Step 1: The function of sending and receiving at the same time is compatible with the function of sending and receiving at the same time;

[0012] The transmitter uses a three-state polarization switch to select or distribute the transmission output. The transmitter also has temperature and humidity detection, power coupling detection, and power linear detection functions;

[0013] The receiver contains two independent receiver modules, and adopts constant temperature technology to ensure the amplitude and phase consistency and stability of the two receivers. Each receiver module is divided into two channels of high and low gain to meet the dynamic range requirements. It also has temperature detection, standing wave detection, and power resistance protection functions; the frequency source module can generate a local oscillation frequency hopping signal and a frequency signal and a continuously adjustable point frequency signal of the intermediate frequency required for calibration; the calibration module contains a digitally controlled attenuator, a function selection switch, a power divider, and a solid-state noise source device;

[0014] Step 2, normal working mode;

[0015] Including receiving state, transmitter horizontal channel coupling down-conversion detection, transmitter vertical coupling down-conversion detection mode, horizontal channel reflection signal detection mode, vertical channel reflection signal detection mode;

[0016] Step 3, noise test mode;

[0017] Step 4, calibration source calibration mode;

[0018] Step 5, up-conversion coupling calibration mode;

[0019] Step 6: Power amplifier coupling calibration mode.

[0020] Furthermore, the normal working mode:

[0021] The calibration link is closed, the attenuator is at full attenuation, the noise source is turned off, the calibration source is turned off, the receiver is in normal receiving state, and the signal comes from the outside.

[0022] Furthermore, in the noise test mode, the attenuator is fully attenuated to prevent internal signal interference, and then the noise source is powered on. The signal generated by the noise source is input to the front end of the receiver limiter, and the signal is down-converted through the receiver. The upper computer software obtains the value of the noise power under different states by turning the noise source on and off, and calculates the noise coefficient through the formula and sends it to the signal processing algorithm for parameter estimation.

[0023] Furthermore, the calibration source calibration mode: the calibration source generates a continuous wave signal which is sent to the front end of the receiver limiter after up-conversion, and is given to the signal processor after down-conversion by the receiver; in this mode, the host computer software can control the DDS signal frequency, and complete the control of the input signal amplitude of the front end of the receiver limiter by controlling the numerically controlled attenuator on the link. The host computer software obtains the change of the numerical value in real time and compares it with the theoretical calculated value, and counts and corrects the difference. This calibration link realizes the calibration of parameters such as intensity, speed, spectral width, differential reflectivity, and differential propagation phase shift.

[0024] Furthermore, in the up-conversion coupling calibration mode, after the intermediate frequency signal is up-converted, it is coupled and output from the front end of the power divider to the front end of the receiver limiter, and down-conversion is realized inside the receiver. This calibration link realizes the calibration of strength, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters.

[0025] Furthermore, the power amplifier coupling calibration mode: after the intermediate frequency signal is up-converted and amplified, it is coupled and output from the front end of the power divider to the front end of the receiver limiter, down-converted inside the receiver, and the whole machine coherence test and positioning test are completed in conjunction with the optical fiber delay line.

[0026] Another object of the present invention is to provide an in-machine online real-time calibration system for a dual-polarization radar, comprising:

[0027] Compatible module, used for the function of simultaneous transmission and reception, which is compatible with the single transmission and dual reception function;

[0028] Normal module, used to calibrate link closure, attenuator full attenuation, noise source closure, calibration source closure, receiver in normal receiving state, signal source external;

[0029] The noise test module is used to fully attenuate the attenuator to prevent internal signal interference. Then the noise source is powered on, and the signal generated by the noise source is input to the front end of the receiver limiter. The signal is down-converted through the receiver. The upper computer software turns on and off the noise source to obtain the value of the noise power under different states, and calculates the noise coefficient through the formula and sends it to the signal processing algorithm for parameter estimation;

[0030] The calibration source calibration module is used to calibrate the source to generate a continuous wave signal, which is then sent to the receiver limiter front end after up-conversion, and then sent to the signal processor after down-conversion by the receiver. In this mode, the host computer software can control the DDS signal frequency, and control the amplitude of the input signal at the receiver limiter front end by controlling the digitally controlled attenuator on the link. The host computer software obtains the change of the value in real time and compares it with the theoretical calculated value, and then counts and corrects the difference. This calibration link realizes the calibration of parameters such as intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift.

[0031] The frequency conversion coupling calibration module is used to couple the intermediate frequency signal from the front end of the power divider to the front end of the receiver limiter after the intermediate frequency signal is up-converted, and down-convert it inside the receiver. This calibration link realizes the calibration of intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters;

[0032] The power amplifier coupling calibration module is used to couple the intermediate frequency signal from the front end of the power divider to the front end of the receiver limiter after up-conversion and power amplification, realize down-conversion inside the receiver, and cooperate with the optical fiber delay line to complete the coherence test and positioning test of the whole machine.

[0033] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for designing an in-machine online real-time calibration system for the dual-polarization radar.

[0034] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the method for designing an in-machine online real-time calibration system for the dual-polarization radar.

[0035] Another object of the present invention is to provide an information data processing terminal, which is used to implement an in-machine online real-time calibration system of the dual-polarization radar.

[0036] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0037] 1. In-machine calibration: Through the built-in calibration source, CNC attenuator, noise source, etc., the in-machine calibration function of parameters such as noise, intensity, speed, spectral width, differential reflectivity, differential propagation phase shift, etc. can be realized. It is equivalent to a built-in signal source. The calibration source signal switch and frequency are controlled by the host computer software. The attenuation value of the CNC attenuator is controlled by the host computer software to control the strength of the calibration signal. After the in-machine source and the external instrument are calibrated with each other, the in-machine source can be used instead of the external instrument for testing, avoiding periodic shutdown testing and maintenance and other faults or errors that may be caused by frequent disassembly, reducing maintenance costs and improving maintenance efficiency.

[0038] 2. Full-link calibration: Through the above calibration link design, full-link calibration of the dual-polarization weather radar transmission channel and receiving channel can be achieved. The calibration source is located at the front end. In the calibration mode, the flow of the calibration signal generated by the calibration source covers the entire link and each channel is adequately protected and isolated. The noise source and the digital attenuator are not designed on the main channel and do not affect normal reception. The noise source signal is input between the receiver low noise and limiter, covering the entire receiving link and avoiding external signal interference. Full-link calibration is conducive to the real feedback of changes in the system, and realizes the monitoring and calibration correction of all parameters of the full link.

[0039] 3. Online real-time calibration: The system is designed with different working modes to realize the calibration of different parameters. The host computer software can realize the online calibration of the radar by switching the working mode online. The dual-polarization weather radar usually adopts the volume scanning method. In different volume scanning interval time periods, the host computer software can combine different working modes to realize the calibration mode of each parameter combination, thus completing the real-time calibration function of the radar. The calibration results are stored in a fixed format and uploaded statistically. Users can consult the calibration file to learn the changes of various parameters of the radar system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The present invention provides a flow chart of a method for designing an in-machine online real-time calibration system for a dual-polarization radar.

[0041] Figure 2 The present invention provides a structural block diagram of an in-machine online real-time calibration system for a dual-polarization radar.

[0042] Figure 3 is a diagram of a dual-channel solid-state TR component provided in an embodiment of the present invention.

[0043] Figure 4 It is a circuit signal flow diagram of a normal working mode provided by an embodiment of the present invention.

[0044] Figure 5 It is a circuit signal flow diagram of a transmit-coupled down-conversion detection mode provided by an embodiment of the present invention.

[0045] Figure 6 It is a circuit signal flow diagram of a transmission reflection signal detection mode provided by an embodiment of the present invention.

[0046] Figure 7 It is a circuit signal flow diagram of the noise test mode provided by an embodiment of the present invention.

[0047] Figure 8 It is a circuit signal flow diagram of the calibration source calibration mode provided by an embodiment of the present invention.

[0048] Fig. 9 It is a circuit signal flow diagram of the up-conversion coupling calibration mode provided by an embodiment of the present invention.

[0049] Fig.10 It is a circuit signal flow diagram of a power amplifier coupling calibration mode provided by an embodiment of the present invention.

[0050] Fig.11 It is a volume scan data diagram at a certain moment provided by an embodiment of the present invention.

[0051] Fig.12 It is a ZDR distribution diagram of all data at a moment provided by an embodiment of the present invention.

[0052] Fig.13 10 zenith data ZDR average deviations provided by the embodiment of the present invention vary with time.

[0053] Fig.14 10 zenith data ZDRs are shown in FIG. 1 according to an embodiment of the present invention.

[0054] Fig.15 These are 10 zenith data PHIDP diagrams provided by an embodiment of the present invention.

[0055] Fig.16 3 is a graph showing the change of PHIDP with respect to orientation provided by an embodiment of the present invention.

[0056] Fig.17 4 is a graph showing the change of the average initial PHDP of 10 zenith data over time provided by an embodiment of the present invention.

[0057] Fig.18 It is a strength comparison diagram before and after the calibration function provided by an embodiment of the present invention is enabled.

[0058] Fig.19 It is a comparison diagram of PHIDP before and after the calibration function provided by the embodiment of the present invention is enabled. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0060] like Figure 1 As shown, a method for designing an in-machine online real-time calibration system of a dual-polarization radar provided by an embodiment of the present invention comprises the following steps:

[0061] S101, simultaneous transmission and reception is compatible with single transmission and dual reception functions;

[0062] The transmitter uses a three-state polarization switch to select or distribute the transmission output. The transmitter also has temperature and humidity detection, power coupling detection, and power linear detection functions;

[0063] The receiver contains two independent receiver modules, and adopts constant temperature technology to ensure the amplitude and phase consistency and stability of the two receivers. Each receiver module is divided into two channels of high and low gain to meet the dynamic range requirements. It also has temperature detection, standing wave detection, and power resistance protection functions; the frequency source module can generate a local oscillation frequency hopping signal and a frequency signal and a continuously adjustable point frequency signal of the intermediate frequency required for calibration; the calibration module contains a digitally controlled attenuator, a function selection switch, a power divider, and a solid-state noise source device;

[0064] S102, normal working mode;

[0065] Including receiving state, transmitter horizontal channel coupling down-conversion detection, transmitter vertical coupling down-conversion detection mode, horizontal channel reflection signal detection mode, vertical channel reflection signal detection mode;

[0066] S103, noise test mode;

[0067] S104, calibration source calibration mode;

[0068] S105, up-conversion coupling calibration mode;

[0069] S106, power amplifier coupling calibration mode.

[0070] This system is designed to be compatible with both simultaneous transmission and reception and single transmission and dual reception working modes to meet different radar working requirements. The transmitter adopts a three-state polarization switch, and realizes the transmission control of horizontal polarization and vertical polarization through flexible signal distribution. It is also equipped with temperature and humidity detection, power coupling detection and power linear detection functions to ensure the stability and high precision of the transmitted signal. The receiver module is designed as two independent channels, and the constant temperature technology is used to ensure the amplitude and phase consistency of the receiver module, and the power distribution of high gain and low gain channels meets the wide dynamic range requirements. In addition, the receiver also has temperature detection, standing wave detection and power resistance protection functions to further improve the reliability of the system. The frequency source module can generate frequency hopping signals, baseband signals and adjustable point frequency signals to provide accurate frequency support for the calibration module.

[0071] In normal working mode, the system includes multiple sub-modes: receiving state, horizontal channel coupled down-conversion detection, vertical channel coupled down-conversion detection, horizontal channel reflected signal detection and vertical channel reflected signal detection mode.

[0072] Receiving state: The receiving module receives radar echo signals through high and low gain channels to achieve high dynamic range imaging of the target;

[0073] Transmitting state: Using a three-state polarization switch, the transmitting signal is corrected by power detection in horizontal or vertical polarization transmission to ensure the linear distribution and stability of the transmitting power;

[0074] Reflected signal detection: The horizontal or vertical polarized signal returned from the target is received by the receiving module to perform signal amplitude and phase calibration.

[0075] In the noise test mode, the system uses the solid-state noise source device of the receiver module to generate a set of standard noise signals to calibrate the noise parameters of the receiving channel. By measuring the noise power, the gain consistency and dynamic range of the receiving module are calibrated to ensure the working stability of the receiver under different ambient temperature conditions. This mode further optimizes the noise performance of the receiver through constant temperature control to adapt it to complex working environments.

[0076] The calibration source calibration mode controls the signal source strength through the digitally controlled attenuator and power divider to generate accurate calibration signals for calibrating the system's transmit and receive channels. The function selection switch in the system can select the horizontal polarization or vertical polarization calibration channel, input the calibration signal to the receiving module, measure and record the signal power and phase information, and achieve full-link amplitude and phase consistency calibration. The calibration process can provide higher frequency resolution by regulating the power divider and point frequency signal.

[0077] In the up-conversion coupling calibration mode, the frequency source module provides a continuously adjustable point frequency signal, which is input to the up-conversion module to test the frequency response and power stability of the transmission channel. By analyzing the power attenuation and spectrum characteristics of the up-conversion signal, the nonlinear distortion of the transmission signal is detected and the nonlinear error of the transmission link is corrected. This mode can effectively improve the accuracy of the radar system at the transmitting end.

[0078] In the PA coupling calibration mode, the calibration module provides a controlled input signal to the power amplifier (PA) and uses the power coupling detection function of the transmitted signal to detect the gain characteristics and output power of the PA in real time. By comparing the input and output signals of the PA, its gain linearity and frequency characteristics are evaluated. At the same time, combined with the temperature and humidity detection function, the stability of the PA under different environmental conditions is evaluated. This mode can ensure the accuracy and consistency of the PA output power.

[0079] The design method of the system combines high-precision signal detection and control mechanisms, and uses multiple working modes (including noise testing, calibration source calibration, up-conversion calibration, and power amplifier calibration) to achieve comprehensive calibration of dual-polarization radar transmission and reception links. Through modular design and real-time online calibration functions, the system's working stability and detection accuracy in complex environments are ensured.

[0080] The normal working mode provided by the embodiment of the present invention is:

[0081] The calibration link is closed, the attenuator is at full attenuation, the noise source is turned off, the calibration source is turned off, the receiver is in normal receiving state, and the signal comes from the outside.

[0082] The noise test mode provided by the embodiment of the present invention is as follows: the attenuator is fully attenuated to prevent internal signal interference, and then the noise source is powered on. The signal generated by the noise source is input to the front end of the receiver limiter, and the signal is down-converted by the receiver. The upper computer software obtains the value of the noise power in different states by turning the noise source on and off, and obtains the noise coefficient through the formula and sends it to the signal processing algorithm for parameter estimation.

[0083] The calibration source calibration mode provided by the embodiment of the present invention is as follows: the calibration source generates a continuous wave signal which is sent to the front end of the receiver limiter after up-conversion, and is given to the signal processor after down-conversion by the receiver; in this mode, the host computer software can control the DDS signal frequency, and complete the control of the input signal amplitude of the front end of the receiver limiter by controlling the numerically controlled attenuator on the link. The host computer software obtains the change of the numerical value in real time and compares it with the theoretical calculated value, and counts and corrects the difference. This calibration link realizes the calibration of parameters such as intensity, speed, spectral width, differential reflectivity, and differential propagation phase shift.

[0084] The up-conversion coupling calibration mode provided by the embodiment of the present invention: after the intermediate frequency signal is up-converted, it is coupled and output from the front end of the power divider to the front end of the receiver limiter, and down-conversion is realized inside the receiver. This calibration link realizes the calibration of strength, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters.

[0085] The power amplifier coupling calibration mode provided in the embodiment of the present invention: after the intermediate frequency signal is up-converted and amplified, it is coupled and output from the front end of the power divider to the front end of the receiver limiter, down-converted inside the receiver, and the whole machine coherence test and positioning test are completed in conjunction with the optical fiber delay line.

[0086] like Figure 2 As shown, an in-machine online real-time calibration system for a dual-polarization radar provided by an embodiment of the present invention includes:

[0087] Compatible module, used for the function of simultaneous transmission and reception, which is compatible with the single transmission and dual reception function;

[0088] Normal module, used to calibrate link closure, attenuator full attenuation, noise source closure, calibration source closure, receiver in normal receiving state, signal source external;

[0089] The noise test module is used to fully attenuate the attenuator to prevent internal signal interference. Then the noise source is powered on, and the signal generated by the noise source is input to the front end of the receiver limiter. The signal is down-converted through the receiver. The upper computer software turns on and off the noise source to obtain the value of the noise power under different states, and calculates the noise coefficient through the formula and sends it to the signal processing algorithm for parameter estimation;

[0090] The calibration source calibration module is used to calibrate the source to generate a continuous wave signal, which is then sent to the receiver limiter front end after up-conversion, and then sent to the signal processor after down-conversion by the receiver. In this mode, the host computer software can control the DDS signal frequency, and control the amplitude of the input signal at the receiver limiter front end by controlling the digitally controlled attenuator on the link. The host computer software obtains the change of the value in real time and compares it with the theoretical calculated value, and then counts and corrects the difference. This calibration link realizes the calibration of parameters such as intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift.

[0091] The frequency conversion coupling calibration module is used to couple the intermediate frequency signal from the front end of the power divider to the front end of the receiver limiter after the intermediate frequency signal is up-converted, and down-convert it inside the receiver. This calibration link realizes the calibration of intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters;

[0092] The power amplifier coupling calibration module is used to couple the intermediate frequency signal from the front end of the power divider to the front end of the receiver limiter after up-conversion and power amplification, realize down-conversion inside the receiver, and cooperate with the optical fiber delay line to complete the coherence test and positioning test of the whole machine.

[0093] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for designing an in-machine online real-time calibration system for the dual-polarization radar.

[0094] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the method for designing an in-machine online real-time calibration system for the dual-polarization radar.

[0095] Another object of the present invention is to provide an information data processing terminal, which is used to implement an in-machine online real-time calibration system of the dual-polarization radar.

[0096] The present invention is specifically implemented:

[0097] The working principle of dual-polarization weather radar is to up-convert and power-amplify the intermediate frequency signal generated by the digital intermediate frequency receiver to form a frequency within the X-band, and transmit the radio frequency signal in two channels at the same time, which is fed to the antenna through the circulator; the antenna echo signal received by the circulator is low-noise-amplified and down-converted to the intermediate frequency signal, and transmitted to the digital intermediate frequency receiver; it also has the calibration function of the uplink channel and the downlink channel (including amplitude, phase, noise coefficient), module fault detection and protection functions, etc. This design has strict requirements on the amplitude and phase difference and stability of the two transmitting channels and the two receiver modules, so the transmitter is required to distribute and select power through a three-state polarization switch, and the receiver adopts constant temperature receiving technology.

[0098] Figure 3 The dual-channel solid-state TR component includes a frequency source module, an up-conversion module, a calibration module, a dual-receiver module, a main power amplifier module, etc. Among them, in order to ensure the function of simultaneous transmission and reception compatible with single transmission and dual reception, the transmitter uses a three-state polarization switch to select or distribute the transmission output. The transmitter also has functions such as temperature and humidity detection, power coupling detection, and power linear detection; the receiver contains two independent receiver modules, and uses constant temperature technology to ensure the amplitude and phase consistency and stability of the two receivers. Each receiver module is divided into two channels of high and low gain (that is, the receiver has four-channel output) to meet the dynamic range requirements. At the same time, it has functions such as temperature detection, standing wave detection, and power resistance protection; the frequency source module is required to generate a local oscillation frequency hopping signal and a frequency signal and a point frequency signal with continuously adjustable intermediate frequency required for calibration; the calibration module contains devices such as a digitally controlled attenuator, a function selection switch, a power divider, and a solid-state noise source.

[0099] The dual-polarization weather radar is designed with 8 working modes, namely normal working mode (including receiving state, transmitter horizontal channel coupling down-conversion detection, transmitter vertical coupling down-conversion detection mode, horizontal channel reflection signal detection mode, vertical channel reflection signal detection mode), noise test mode, calibration source calibration mode, up-conversion coupling calibration mode, power amplifier coupling calibration mode. Through different control signals C1~C7, C15, T, RH, RV to control the on and off of various signals such as reception, transmission, calibration, etc., a variety of working modes can be realized.

[0100] The circuit signal flow in normal working mode is shown in Figure 4 As shown, the calibration link is closed, the attenuator is fully attenuated, the noise source is closed, the calibration source is closed, the receiver is in a normal receiving state, and the signal comes from the outside.

[0101] The circuit signal flow of the transmit coupled down-conversion detection mode is shown in Figure 5 As shown, the circuit signal flow of the transmission reflection signal detection mode is shown in Figure 6 As shown, through these two working modes, the transmitter power can be detected and the status of the transmitter and the front-end antenna can be judged. In actual operation, one of the four transmission coupling / transmission reflection signals of the horizontal / vertical path can be selected to work.

[0102] The circuit signal flow of the noise test mode is shown in Figure 7 As shown, the attenuator is fully attenuated to prevent internal signal interference, and then the noise source is powered on. The signal generated by the noise source is input to the front end of the receiver limiter, and the signal is down-converted through the receiver. The upper computer software turns on and off the noise source to obtain the value of the noise power under different states, and calculates the noise coefficient through the formula and sends it to the signal processing algorithm for parameter estimation.

[0103] The circuit signal flow of the calibration source calibration mode is shown in Figure 8 As shown in the figure, the calibration source generates a continuous wave signal which is sent to the receiver limiter front end after up-conversion, and then sent to the signal processor after down-conversion by the receiver. In this mode, the host computer software can control the DDS signal frequency, and can complete the control of the input signal amplitude of the receiver limiter front end by controlling the digitally controlled attenuator on the link. The host computer software can obtain the change of the value in real time and compare it with the theoretical calculated value, count and correct the difference. This calibration link can realize the calibration of parameters such as intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift.

[0104] The signal flow of the up-conversion coupling calibration mode circuit is shown in Fig. 9 As shown, after the intermediate frequency signal is up-converted, it is coupled from the front end of the power divider to the front end of the receiver limiter, and down-conversion is realized inside the receiver. This calibration link can realize the calibration of parameters such as intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift.

[0105] The signal flow of the power amplifier coupling calibration mode circuit is shown in Fig.10 As shown, after up-conversion and power amplification, the intermediate frequency signal is coupled from the front end of the power divider to the front end of the receiver limiter, and down-conversion is realized inside the receiver. In conjunction with the optical fiber delay line, the whole machine coherence test, positioning test, etc. can be completed.

[0106] The design method of the in-machine online real-time calibration system of the dual-polarization radar ensures the accuracy and stability of the system in different working modes by being compatible with the functions of single-transmit dual-receive and simultaneous transmission and simultaneous reception. At the transmitting end, the transmitter uses a three-state polarization switch to select or distribute polarization signals. The transmitter also has temperature and humidity detection, power coupling detection, and power linear detection functions to ensure the reliability and stability of the transmitted signal. The receiving end consists of two independent receiver modules. The stability of the two receiver modules in amplitude and phase consistency is guaranteed by constant temperature control technology, and the dynamic range requirements of the radar signal are met by high and low gain channel design. The system is also equipped with temperature detection and standing wave detection functions, as well as a power protection mechanism to ensure the normal operation of the receiver under different working conditions.

[0107] The normal working mode of the system includes multiple working states. Through the receiving state, the coupling detection of the horizontal channel and the vertical channel of the transmitter, the consistency of the horizontal polarization and vertical polarization signal processing in the system is further ensured. The up-down frequency conversion coupling detection is performed between the transmitter and the receiver through the coupler, the signal changes are monitored in real time, and necessary feedback adjustments are made to ensure the frequency consistency and signal quality reliability of the system during operation.

[0108] In the noise test mode, the system uses a solid-state noise source to generate a specific noise signal to test the noise characteristics and sensitivity of the receiving channel. The noise signal is adjusted through a digitally controlled attenuator and power divider to simulate different noise levels in the receiving environment, ensuring that the receiver can maintain consistent receiving performance in different noise environments. Through this mode, the performance of the receiving end can be calibrated in real time to ensure that the system has high sensitivity and anti-interference capabilities.

[0109] The calibration mode is the core of the system. It uses the point frequency signal generated by the frequency source module in conjunction with internal digitally controlled attenuators, solid-state noise sources and other equipment to achieve self-calibration of the system by controlling switches and power dividers. The calibration source calibration mode and the up-conversion coupling calibration mode respectively ensure the accuracy and consistency of different frequency bands and different gain paths in the system. At the same time, the power amplifier coupling calibration mode can calibrate the power output of the power amplifier in real time to ensure the reliable operation of the entire system in different working environments. Through these calibration modes, the system can adaptively calibrate the power, frequency and phase differences between the transmit and receive paths, thereby ensuring the real-time calibration capability of the system and the accuracy and reliability of the radar data.

[0110] 2. Relevant evidence of the technical effects obtained by the embodiments of the present invention.

[0111] Select a precipitation weather process for analysis. The volume scan data at a certain moment is as follows: Fig.11 As shown:

[0112] The radar elevation angle was adjusted to 90°, the automatic online real-time calibration function was turned on, and the data of the radial 30-60 library, about 1.8-3.6 km, were selected. The data with Z greater than 20 dBz or Z less than 10 dBz or CC less than 0.95° were excluded for analysis.

[0113] Fig.12 The distribution of all data at a moment. The ZDR distribution is relatively concentrated, with a variance of 0.0016, and the data quality is good.

[0114] Fig.13 This is the change of the ZDR average deviation of 10 zenith data over time. It can be seen that the ZDR system deviation is basically stable between 1 and 1.08, and the system is relatively stable.

[0115] Fig.14 The figure shows the change of ZDR with azimuth for 10 zenith data. It can be seen that ZDR basically does not change with azimuth. A fixed deviation can be added to the signal processing software or in subsequent quality control.

[0116] Fig.15 The distribution of all data at a moment is relatively concentrated, with a mean of 0.103 and a variance of 0.0417.

[0117] Fig.16 The change of PHIDP with the direction is basically stable.

[0118] Fig.17 This is the change of the average initial PHIDP of 10 zenith data over time. It can be seen that the PHIDP system deviation is basically stable between 0 and 0.2, and the system is relatively stable.

[0119] After turning on or off the automatic online real-time calibration function of the radar, the precipitation process was observed, and the light rain area in the data was selected for evaluation. The data with CC < 0.95 of low elevation angle data were eliminated, and then the tangential average was performed to obtain the radial variation of the variable. Fig.18 The left picture shows the intensity before the calibration function is turned on, and the right picture shows the intensity after the calibration function is turned on. The red straight line is the connection between the long and short pulses. Before the automatic online real-time calibration function is turned on, the echo intensity Z has a step change due to the different detection capabilities of the long and short pulses. It can be seen that there is a sudden change at the connection of the long and short pulse echo intensity Z. After calibration, there is no sudden change at the long and short pulses. The calibration system can accurately obtain the difference between different pulse intensities and automatically compensate for it.

[0120] Fig.19The left picture shows the radial change of PHIDP after tangential averaging, and the right picture shows it after the calibration function is turned on. Before the automatic online real-time calibration function is turned on, the echo differential propagation phase shift PHIDP shows a step change due to the inconsistent starting phases of the long and short pulses. It can be seen that there is a mutation at the connection of the long and short pulse differential propagation phase shift PHIDP, and the difference between the before and after average values ​​is large. After calibration, the connection between the long and short pulses is relatively continuous, and the calibration system can accurately obtain the difference between different pulse phases and automatically compensate for it.

[0121] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0122] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A design method for an in-machine online real-time calibration system of a dual-polarization radar, characterized in that: The following steps are involved: (1) The transmitter uses a three-state polarization switch to select the simultaneous transmission and reception mode or the single transmission and dual reception mode to control the transmitter to output polarization signals. At the same time, temperature and humidity detection, power coupling detection, and power linear detection are performed to ensure the accuracy and stability of the transmitted signal. (2) The receiver uses constant temperature control technology to maintain the amplitude and phase consistency of the two independent receiving modules, uses high and low gain channels to meet the dynamic range of the radar signal, and performs temperature detection, standing wave detection, and power protection to ensure the stability of the received signal; (3) The frequency source module generates frequency hopping signals and intermediate frequency point frequency signals for calibration. The calibration module performs real-time calibration and calibration through a digitally controlled attenuator and a solid-state noise source. (4) In normal working mode, the system sequentially performs receiving state, transmitter horizontal channel coupling detection, transmitter vertical channel coupling detection, horizontal channel and vertical channel reflection signal detection to ensure the accuracy of the signal path; (5) In the noise test mode, the system uses a solid-state noise source to test the noise performance of the receiving channel; (6) In the calibration source calibration mode, up-conversion coupling calibration mode and power amplifier coupling calibration mode, the system calibrates the power, frequency and phase difference of the transmit and receive paths respectively to ensure real-time calibration and synchronization of each channel of the system; The normal working mode: the calibration link is closed, the attenuator is fully attenuated, the noise source is closed, the calibration source is closed, the receiver is in a normal receiving state, and the signal comes from the outside; The noise test mode: the attenuator is fully attenuated to prevent internal signal interference, and then the noise source is powered on. The signal generated by the noise source is input to the front end of the receiver limiter, and the signal is down-converted by the receiver. The upper computer software obtains the value of the noise power under different states by turning on and off the noise source, and calculates the noise coefficient through the formula and sends it to the signal processing algorithm for parameter estimation; The calibration source calibration mode: the calibration source generates a continuous wave signal which is sent to the front end of the receiver limiter after up-conversion, and is sent to the signal processor after down-conversion by the receiver; in this mode, the host computer software can control the DDS signal frequency, and complete the control of the input signal amplitude of the front end of the receiver limiter by controlling the digitally controlled attenuator on the link. The host computer software obtains the change of the value in real time and compares it with the theoretical calculated value, and counts and corrects the difference. This calibration link realizes the calibration of intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters; The up-conversion coupling calibration mode: after the intermediate frequency signal is up-converted, it is coupled and output from the front end of the power divider to the front end of the receiver limiter, and down-conversion is realized inside the receiver. This calibration link realizes the calibration of strength, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters; The power amplifier coupling calibration mode: after the intermediate frequency signal is up-converted and amplified, it is coupled and output from the front end of the power divider to the front end of the receiver limiter, down-converted inside the receiver, and the whole machine coherence test and positioning test are completed in conjunction with the optical fiber delay line.

2. An in-machine online real-time calibration system for a dual polarization radar implementing the in-machine online real-time calibration system design method for a dual polarization radar as claimed in claim 1, characterized in that: The in-machine online real-time calibration system of the dual polarization radar includes: Compatible module, used for the function of simultaneous transmission and reception, which is compatible with the single transmission and dual reception function; Normal module, used to calibrate link closure, attenuator full attenuation, noise source closure, calibration source closure, receiver in normal receiving state, signal source external; The noise test module is used to fully attenuate the attenuator to prevent internal signal interference. Then the noise source is powered on, and the signal generated by the noise source is input to the front end of the receiver limiter. The signal is down-converted through the receiver. The upper computer software turns on and off the noise source to obtain the value of the noise power under different states, and calculates the noise coefficient through the formula and sends it to the signal processing algorithm for parameter estimation; The calibration source calibration module is used to calibrate the source to generate a continuous wave signal, which is then sent to the receiver limiter front end after up-conversion, and then sent to the signal processor after down-conversion by the receiver. In this mode, the host computer software can control the DDS signal frequency, and control the amplitude of the input signal at the receiver limiter front end by controlling the digitally controlled attenuator on the link. The host computer software obtains the change of the value in real time and compares it with the theoretical calculated value, and counts and corrects the difference. This calibration link realizes the calibration of intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters. The frequency conversion coupling calibration module is used to couple the intermediate frequency signal from the front end of the power divider to the front end of the receiver limiter after the intermediate frequency signal is up-converted, and down-convert it inside the receiver. This calibration link realizes the calibration of intensity, speed, spectrum width, differential reflectivity, and differential propagation phase shift parameters; The power amplifier coupling calibration module is used to couple the intermediate frequency signal from the front end of the power divider to the front end of the receiver limiter after up-conversion and power amplification, realize down-conversion inside the receiver, and cooperate with the optical fiber delay line to complete the coherence test and positioning test of the whole machine.

3. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for designing an in-machine online real-time calibration system for a dual-polarization radar as claimed in claim 1.

4. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the method for designing an in-machine online real-time calibration system for a dual-polarization radar as claimed in claim 1.

5. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the in-machine online real-time calibration system of the dual-polarization radar as claimed in claim 2.

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