A fully automatic calibration method for weather radar

Abstract

The present application discloses a fully automatic calibration method for a meteorological radar, and relates to the technical field of meteorological radars. The method sequentially injects multiple groups of calibration differential signals into a receiver of a meteorological radar to be calibrated, wherein at least two groups of calibration differential signals have different injection powers, at least two groups of calibration differential signals have different frequency deviations, and at least two groups of calibration differential signals have different spectral widths. Then, according to the injection powers, frequency deviations, and spectral widths of the calibration differential signals of each group, combined with the measured values ​​of the intensity, velocity, and spectral width under the corresponding calibration differential signals, the calibration of the intensity, velocity, spectral width, differential reflectivity factor, and differential propagation phase shift can be uniformly completed. On the basis of ensuring comprehensive calibration of various radar parameters, the method innovatively unifies these radar parameters into the same calibration process, greatly reducing the calibration time and projects, optimizing the calibration process, and improving the calibration efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of meteorological radars, and in particular to a fully automatic calibration method for meteorological radars. Background Art

[0002] Meteorological radar can complete real-time monitoring of the occurrence, development, intensity and position of meteorological targets within the range around the station, so as to timely obtain the distance, azimuth, intensity, speed, spectral width, differential reflectivity factor, differential propagation phase shift, differential propagation phase shift rate, correlation coefficient and other echoes and inversion products of weather targets such as clouds and rain relative to the radar. Based on these inversion products, automatic identification, tracking and analysis of meteorological targets can be realized, and dangerous weather can be effectively monitored and warned, providing meteorological forecasters with rich and comprehensive analysis data and effectively improving meteorological support capabilities.

[0003] At present, meteorological radar systems are gradually adopting dual polarization systems, and the dual polarization parameters measured by meteorological radars are affected by the fluctuations of the weather radar's own hardware, which reduces the data quality and is not conducive to the analysis and forecast of weather processes. Therefore, it is necessary to calibrate the meteorological radar, which can effectively reduce the errors in the meteorological radar system and ensure that it can accurately measure precipitation or other meteorological targets in the atmosphere. However, the current calibration process of meteorological radars is either incomplete or too cumbersome, and the calibration effect is not ideal. Summary of the invention

[0004] In view of the above problems and technical requirements, this application proposes a fully automatic calibration method for weather radar. The technical solution of this application is as follows:

[0005] A fully automatic calibration method for a weather radar, the fully automatic calibration method comprising:

[0006] Injecting multiple groups of calibration differential signals into the receiver of the meteorological radar to be calibrated in sequence, at least two groups of calibration differential signals have different injection powers, at least two groups of calibration differential signals have different frequency deviations, and at least two groups of calibration differential signals have different spectrum widths;

[0007] Obtain the measured values ​​of intensity, velocity, spectrum width, differential reflectivity factor and differential propagation phase shift of the meteorological radar to be calibrated under each set of calibration differential signals;

[0008] The calibration error of intensity is obtained according to the injected power of each group of calibration differential signals and the actual measured value of intensity of the meteorological radar to be calibrated under the corresponding calibration differential signals; the calibration error of speed is obtained according to the frequency deviation of each group of calibration differential signals and the actual measured value of speed of the meteorological radar to be calibrated under the corresponding calibration differential signals; the calibration error of spectrum width is obtained according to the spectral width of each group of calibration differential signals and the actual measured value of spectrum width of the meteorological radar to be calibrated under the corresponding calibration differential signals; the calibration error of differential reflectivity factor and the calibration error of differential propagation phase shift are obtained according to the actual measured value of differential reflectivity factor and the actual measured value of differential propagation phase shift of the meteorological radar to be calibrated under the corresponding calibration differential signals.

[0009] A further technical solution is to sequentially inject multiple sets of calibration differential signals into the receiver of the meteorological radar to be calibrated, including:

[0010] An external signal source is used to output several different output signals. Each output signal outputs two equal calibration signals through a power divider to form a set of calibration differential signals that are injected into the receiver of the meteorological radar to be calibrated, and the corresponding external calibration errors of various radar parameters are obtained.

[0011] Its further technical solution is that the fully automatic calibration method also includes:

[0012] The transmitter of the weather radar to be calibrated is controlled to transmit at several different target powers, and a power meter is used to measure the actual power value of the power coupling port of the weather radar to be calibrated at each target power as the internal calibration benchmark under the working pulse width.

[0013] A further technical solution is to sequentially inject multiple sets of calibration differential signals into the receiver of the meteorological radar to be calibrated, including:

[0014] The internal calibration source built into the weather radar to be calibrated is controlled to generate several groups of calibration differential signals and injected into the receiver of the weather radar to be calibrated, thereby obtaining the internal calibration errors of various radar parameters.

[0015] Its further technical solution is that the fully automatic calibration method also includes:

[0016] The transmitter of the meteorological radar to be calibrated is controlled to transmit according to several groups of working pulse widths, and the internal power measurement value calculated by the meteorological radar to be calibrated under each group of working pulse widths is determined, the power error between the internal power measurement value under each working pulse width and the internal calibration reference under the working pulse width is calculated, and the root mean square error of the power error under all working pulse widths is calculated to obtain the internal and external calibration error of the power.

[0017] Its further technical solution is that the fully automatic calibration method also includes:

[0018] During the detection interval of the weather radar to be calibrated, the internal calibration source is used to perform internal calibration operation on the weather radar to be calibrated, and the internal calibration errors of various radar parameters are obtained;

[0019] When the deviation between the internal calibration error of each radar parameter and the external calibration error of the corresponding radar parameter exceeds the deviation threshold, the internal calibration source of the meteorological radar to be calibrated is corrected until the deviation between the internal calibration error of the radar parameter and the corresponding external calibration error is within the deviation threshold.

[0020] A further technical solution is to obtain the calibration errors of various radar parameters including:

[0021] Calculate the theoretical value of intensity corresponding to the injection power of each group of calibration differential signals, and calculate the error between the measured intensity value of the meteorological radar to be calibrated under the corresponding calibration differential signal and the theoretical value of intensity to obtain the intensity error corresponding to a group of calibration differential signals, and calculate the root mean square error of the intensity error corresponding to each group of calibration differential signals to obtain the calibration error of the intensity;

[0022] Calculate the theoretical speed value corresponding to the frequency deviation of each set of calibration differential signals, and calculate the error between the actual speed value of the meteorological radar to be calibrated under the corresponding calibration differential signal and the theoretical speed value to obtain a set of speed errors corresponding to the calibration differential signals, and calculate the root mean square error of the speed errors corresponding to each set of calibration differential signals to obtain the calibration error of the speed;

[0023] The error between the measured value of the spectrum width of the meteorological radar to be calibrated under the corresponding calibration differential signal and the corresponding theoretical value of the spectrum width is calculated to obtain a set of spectrum width errors corresponding to the calibration differential signals, and the root mean square error of the spectrum width errors corresponding to each set of calibration differential signals is calculated to obtain the calibration error of the spectrum width;

[0024] The root mean square error of the measured value of the differential reflectivity factor of the meteorological radar to be calibrated under each group of calibration differential signals is calculated to obtain the calibration error of the differential reflectivity factor;

[0025] The root mean square error of the measured value of the differential propagation phase shift of the meteorological radar to be calibrated under each group of calibration differential signals is calculated to obtain the calibration error of the differential propagation phase shift.

[0026] A further technical solution is that a variation range of the injection power of the calibration differential signal injected into the receiver of the meteorological radar to be calibrated meets a fluctuation range requirement.

[0027] The beneficial technical effects of this application are:

[0028] The present application discloses a fully automatic calibration method for a meteorological radar. The fully automatic calibration method can automatically calibrate the meteorological radar for several parameters such as intensity, speed, spectral width, differential reflectivity factor and differential propagation phase shift, and innovatively unifies the intensity, speed, differential reflectivity factor and differential propagation phase shift into the same calibration process. On the basis of ensuring comprehensive calibration of various radar parameters, the calibration time and projects are greatly reduced, the calibration process is optimized, and the calibration efficiency is improved.

[0029] This fully automatic calibration method can be used for both fully automatic external calibration and fully automatic internal calibration of the weather radar to be calibrated, and can meet the requirements of internal and external joint calibration of the weather radar to be calibrated in actual application scenarios. In addition, this method can automatically compare and correct the external calibration error and the internal calibration error, further improving the calibration efficiency and avoiding errors introduced by human operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of a method for using the fully automatic calibration method to perform external calibration on a weather radar to be calibrated in one embodiment of the present application.

[0031] Figure 2 This is a flow chart of a method for performing internal calibration on a weather radar to be calibrated using the fully automatic calibration method in one embodiment of the present application.

[0032] Figure 3 It is a hardware structure diagram for implementing a fully automatic calibration method in one embodiment of the present application. DETAILED DESCRIPTION

[0033] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0034] This application discloses a fully automatic calibration method for a weather radar, which includes the following steps: Figure 1 and Figure 2 The flowchart shown:

[0035] Step 1: inject multiple sets of calibration differential signals into the receiver of the meteorological radar to be calibrated in sequence.

[0036] There are at least two groups of calibration differential signals with different injection powers, there are at least two groups of calibration differential signals with different frequency deviations, and there are at least two groups of calibration differential signals with different spectrum widths.

[0037] In addition, the variation range of the injection power of the calibration differential signal injected into the receiver of the meteorological radar to be calibrated meets the fluctuation range requirement. For example, the variation range of the injection power of the calibration differential signal should actually be greater than 100 dB.

[0038] Step 2: Obtain the measured values ​​of intensity, velocity, spectrum width, differential reflectivity factor and differential propagation phase shift of the meteorological radar to be calibrated under each set of calibration differential signals.

[0039] Step 3: obtain the calibration error of intensity according to the injected power of each group of calibration differential signals and the actual measured value of the intensity of the meteorological radar to be calibrated under the corresponding calibration differential signal; obtain the calibration error of speed according to the frequency deviation of each group of calibration differential signals and the actual measured value of the speed of the meteorological radar to be calibrated under the corresponding calibration differential signal; obtain the calibration error of spectrum width according to the spectral width of each group of calibration differential signals and the actual measured value of the spectrum width of the meteorological radar to be calibrated under the corresponding calibration differential signal; obtain the calibration error of differential reflectivity factor and the calibration error of differential propagation phase shift according to the actual measured value of differential reflectivity factor and the actual measured value of differential propagation phase shift of the meteorological radar to be calibrated under the corresponding calibration differential signal.

[0040] In the conventional calibration test process, when it is necessary to calibrate the intensity, speed, spectrum width, differential reflectivity factor and differential propagation phase shift, it is necessary to build a system to calibrate these different radar parameters separately. For example, it is necessary to first inject several groups of single-channel signals with different injection powers into the receiver of the meteorological radar to be calibrated for intensity calibration. After the intensity calibration is completed, several groups of single-channel signals with different frequency deviations are injected into the receiver of the meteorological radar to be calibrated for speed calibration. After the speed calibration is completed, several groups of single-channel signals with different spectrum widths are injected into the receiver of the meteorological radar to be calibrated for spectrum width calibration. Then, differential signals are injected into the receiver of the meteorological radar to be calibrated for differential reflectivity factor and differential propagation phase shift calibration. That is, the traditional calibration process requires the intensity, speed, spectrum width, differential reflectivity factor and differential propagation phase shift to be calibrated in sequence, which means that when all these radar parameters need to be fully calibrated, it takes a long calibration time. At present, it takes one or even multiple days of testing to complete the calibration of all the above radar parameters for the radar to be calibrated.

[0041] The present application performs a unified calibration of intensity, speed, spectral width, differential reflectivity factor and differential propagation phase shift. Based on the calibration test of differential reflectivity factor and differential propagation phase shift, the injection power change required for intensity calibration is included in the calibration differential signal to synchronously complete the intensity calibration, the frequency offset change required for speed calibration is included in the calibration differential signal to synchronously complete the speed calibration, and the spectral width change required for spectral width calibration is included in the calibration differential signal to synchronously complete the speed calibration. Since the injection power and frequency offset are independent of each other, the above calibration process will not cause mutual interference between intensity, speed, spectral width, differential reflectivity factor and differential propagation phase shift.

[0042] Based on this, the calibration errors of various radar parameters are obtained uniformly, including:

[0043] (1) Calculate the theoretical value of the intensity corresponding to the injection power of each set of calibration differential signals, and calculate the error between the measured intensity value of the meteorological radar to be calibrated under the corresponding calibration differential signal and the theoretical value of the intensity to obtain the intensity error corresponding to a set of calibration differential signals. Since there are at least two sets of calibration differential signals with different injection powers, and the actual implementation includes more different injection powers, it is equivalent to achieving the effect of intensity testing under different injection powers. Therefore, the root mean square error of the intensity error corresponding to each set of calibration differential signals can be calculated to obtain the calibration error of the intensity.

[0044] (2) Calculate the theoretical speed value corresponding to the frequency deviation of each set of calibration differential signals, and calculate the error between the actual speed value of the meteorological radar to be calibrated under the corresponding calibration differential signal and the theoretical speed value to obtain a set of speed errors corresponding to the calibration differential signals. Since there are at least two sets of calibration differential signals with different frequency deviations, and more different frequency deviations are included in the actual implementation, it is equivalent to achieving the effect of speed testing under different frequency deviations. Therefore, the root mean square error of the speed errors corresponding to each set of calibration differential signals is calculated to obtain the calibration error of the speed.

[0045] (3) Calculate the error between the measured value of the spectrum width of the meteorological radar to be calibrated under the corresponding internal calibration differential signal and the corresponding theoretical value of the spectrum width to obtain a set of spectrum width errors corresponding to the internal calibration differential signal, and calculate the root mean square error of the spectrum width errors corresponding to each set of internal calibration differential signals to obtain the internal calibration error of the spectrum width.

[0046] (4) Calculate the root mean square error of the measured value of the differential reflectivity factor of the meteorological radar to be calibrated under each set of calibration differential signals to obtain the calibration error of the differential reflectivity factor.

[0047] (5) Calculate the root mean square error of the measured value of the differential propagation phase shift of the meteorological radar to be calibrated under each group of calibration differential signals to obtain the calibration error of the differential propagation phase shift.

[0048] The above-mentioned fully automatic calibration method provided in the present application can be used for external calibration of the meteorological radar to be calibrated, and can also be used for internal calibration of the meteorological radar to be calibrated. In actual implementation, it is necessary to perform external calibration on the meteorological radar to be calibrated according to the fully automatic calibration method of the present application, and it is also necessary to perform internal calibration on the meteorological radar to be calibrated according to the fully automatic calibration method of the present application. The application scenarios of the two parts are slightly different:

[0049] 1. Use this fully automatic calibration method to realize external calibration of the weather radar to be calibrated

[0050] The fully automatic calibration method is based on Figure 3The hardware system shown is implemented. This fully automatic calibration method requires the use of a calibration host, an external signal source and a power divider as well as necessary connecting cables. The calibration host is connected to the external signal source, the output end of the external signal source is connected to the input end of the power divider, the two output ends of the power divider are connected to the relevant test ports of the meteorological radar to be calibrated to connect to the receiver inside the meteorological radar to be calibrated, and the calibration host is also connected to the meteorological radar to be calibrated for information exchange.

[0051] based on Figure 3 Hardware architecture, after completing the cable connection between the devices, the calibration host can perform fully automatic external calibration operations on the meteorological radar to be calibrated according to the fully automatic calibration method of this application, then the above step 1 is specifically implemented as follows: using an external signal source to output a number of different output signals respectively, each output signal outputs two equal calibration signals through a power divider to form a set of calibration differential signals injected into the receiver of the meteorological radar to be calibrated, thereby obtaining the corresponding calibration error of each radar parameter and recording it as the external calibration error to distinguish it from the internal calibration. Then the calibration host can realize fully automatic external calibration according to the actual measured values ​​of the meteorological radar to be calibrated. Figure 1 The figure is a flow chart of the method for external calibration using the fully automatic calibration method.

[0052] In addition, the fully automatic calibration method of the present application can also calibrate the coupling power. Figure 3 As shown, the hardware system also includes a power meter, the input end of the power meter is connected to the power coupling port of the weather radar to be calibrated, and the output end of the power meter is connected to the calibration host. The fully automatic calibration method performed by the calibration host also includes:

[0053] The transmitter of the weather radar to be calibrated is controlled to transmit according to several different working pulse widths, and the power meter is used to measure the actual power value of the power coupling port of the weather radar to be calibrated under each working pulse width as the internal calibration benchmark of the working pulse width.

[0054] 2. Use this fully automatic calibration method to realize internal calibration of the weather radar to be calibrated

[0055] This method also uses Figure 3 The calibration host in the present invention performs fully automatic internal calibration on the weather radar to be calibrated according to the fully automatic calibration method of the present invention, including controlling the internal calibration source built into the weather radar to be calibrated to generate several groups of calibration differential signals and injecting them into the receiver of the weather radar to be calibrated, thereby obtaining the calibration errors of various radar parameters and recording them as internal calibration errors to distinguish them from external calibration. Figure 2 The figure is a flow chart of the method for external calibration using the fully automatic calibration method.

[0056] In addition, in the internal calibration scenario, the internal calibration reference obtained in the external calibration scenario can be used as a reference to calculate the error between the internal calibration and the external calibration. The fully automatic calibration method executed by the calibration host also includes: controlling the transmitter of the meteorological radar to be calibrated to transmit according to several groups of working pulse widths, and determining the internal power measurement value calculated for the meteorological radar to be calibrated under each group of working pulse widths, calculating the power error between the internal power measurement value under each working pulse width and the internal calibration reference under the said working pulse width, and calculating the root mean square error of the power errors under all working pulse widths to obtain the internal and external calibration errors of the power.

[0057] In actual application, the weather radar to be calibrated is subjected to external calibration operation according to a predetermined period according to the fully automatic calibration method of the present application, and the external calibration errors of various radar parameters are obtained. In the working process of the weather radar to be calibrated, the weather radar to be calibrated is subjected to internal calibration operation according to the fully automatic calibration method of the present application in the detection gap (in each volume scanning interval) of the weather radar to be calibrated using the internal calibration source, and the internal calibration errors of various radar parameters are obtained.

[0058] The calibration host will also automatically compare the external calibration error with the internal calibration error. When the deviation between the internal calibration error of each radar parameter and the external calibration error of the corresponding radar parameter exceeds the deviation threshold, the internal calibration source of the meteorological radar to be calibrated will be corrected until the deviation between the internal calibration error of the radar parameter and the corresponding external calibration error is within the deviation threshold, thereby realizing automatic correction of internal and external calibration errors, improving correction efficiency and avoiding operational errors introduced by manual correction.

[0059] The above is only a preferred embodiment of the present application, and the present application is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the protection scope of the present application.

Claims

1. A fully automatic calibration method for a weather radar, characterized in that: The fully automatic calibration method comprises: Injecting multiple groups of calibration differential signals into the receiver of the meteorological radar to be calibrated in sequence, at least two groups of calibration differential signals have different injection powers, at least two groups of calibration differential signals have different frequency deviations, and at least two groups of calibration differential signals have different spectrum widths; Obtaining the measured value of the intensity, the measured value of the velocity, the measured value of the spectrum width, the measured value of the differential reflectivity factor and the measured value of the differential propagation phase shift of the meteorological radar to be calibrated under each set of calibration differential signals; The calibration error of intensity is obtained according to the injection power of each group of calibration differential signals and the actual measured value of the intensity of the meteorological radar to be calibrated under the corresponding calibration differential signals; the calibration error of speed is obtained according to the frequency deviation of each group of calibration differential signals and the actual measured value of the speed of the meteorological radar to be calibrated under the corresponding calibration differential signals; the calibration error of spectrum width is obtained according to the spectral width of each group of calibration differential signals and the actual measured value of the spectrum width of the meteorological radar to be calibrated under the corresponding calibration differential signals; the calibration error of differential reflectivity factor and the calibration error of differential propagation phase shift are obtained according to the actual measured value of differential reflectivity factor and the actual measured value of differential propagation phase shift of the meteorological radar to be calibrated under the corresponding calibration differential signals.

2. The fully automatic calibration method according to claim 1, characterized in that: Injecting multiple sets of calibration differential signals into the receiver of the weather radar to be calibrated in sequence includes: An external signal source is used to output several different output signals. Each output signal outputs two equal calibration signals through a power divider to form a set of calibration differential signals that are injected into the receiver of the meteorological radar to be calibrated, and the corresponding external calibration errors of various radar parameters are obtained.

3. The fully automatic calibration method according to claim 2, characterized in that: The fully automatic calibration method further comprises: The transmitter of the meteorological radar to be calibrated is controlled to transmit according to several different working pulse widths, and a power meter is used to measure the actual power measured value of the power coupling port of the meteorological radar to be calibrated under each working pulse width as the internal calibration benchmark under the working pulse width.

4. The fully automatic calibration method according to claim 3, characterized in that: Injecting multiple sets of calibration differential signals into the receiver of the weather radar to be calibrated in sequence includes: The internal calibration source built into the weather radar to be calibrated is controlled to generate several groups of calibration differential signals and injected into the receiver of the weather radar to be calibrated, so as to obtain the internal calibration errors of various radar parameters.

5. The fully automatic calibration method according to claim 4, characterized in that: The fully automatic calibration method further comprises: The transmitter of the meteorological radar to be calibrated is controlled to transmit according to several groups of working pulse widths, and the internal power measurement value calculated by the meteorological radar to be calibrated under each group of working pulse widths is determined, the power error between the internal power measurement value under each working pulse width and the internal calibration reference under the working pulse width is calculated, and the root mean square error of the power error under all working pulse widths is calculated to obtain the internal and external calibration error of the power.

6. The fully automatic calibration method according to claim 4, characterized in that: The fully automatic calibration method further comprises: During the detection interval of the weather radar to be calibrated, an internal calibration operation is performed on the weather radar to be calibrated using an internal calibration source, and internal calibration errors of various radar parameters are obtained; When the deviation between the internal calibration error of each radar parameter and the external calibration error of the corresponding radar parameter exceeds the deviation threshold, the internal calibration source of the meteorological radar to be calibrated is corrected until the deviation between the internal calibration error of the radar parameter and the corresponding external calibration error is within the deviation threshold.

7. The fully automatic calibration method according to claim 1, characterized in that: The calibration errors of various radar parameters include: Calculate the theoretical value of the intensity corresponding to the injection power of each group of calibration differential signals, and calculate the error between the measured intensity value of the meteorological radar to be calibrated under the corresponding calibration differential signal and the theoretical value of the intensity to obtain the intensity error corresponding to the calibration differential signal, and calculate the root mean square error of the intensity error corresponding to each group of calibration differential signals to obtain the calibration error of the intensity; Calculate the theoretical speed value corresponding to the frequency deviation of each group of calibration differential signals, and calculate the error between the actual speed value of the meteorological radar to be calibrated under the corresponding calibration differential signal and the theoretical speed value to obtain the speed error corresponding to the calibration differential signal, and calculate the root mean square error of the speed error corresponding to each group of calibration differential signals to obtain the calibration error of the speed; Calculate the error between the measured value of the spectrum width of the meteorological radar to be calibrated under the corresponding calibration differential signal and the corresponding theoretical value of the spectrum width to obtain the spectrum width error corresponding to the calibration differential signal, and calculate the root mean square error of the spectrum width errors corresponding to each group of calibration differential signals to obtain the calibration error of the spectrum width; Calculating the root mean square error of the measured value of the differential reflectivity factor of the meteorological radar to be calibrated under each group of calibration differential signals to obtain the calibration error of the differential reflectivity factor; The root mean square error of the measured value of the differential propagation phase shift of the meteorological radar to be calibrated under each group of calibration differential signals is calculated to obtain the calibration error of the differential propagation phase shift.

8. The fully automatic calibration method according to claim 1, characterized in that: The variation range of the injection power of the calibration differential signal injected into the receiver of the meteorological radar to be calibrated meets the fluctuation range requirement.

Images