Dual polarization radar calibration method and system

Abstract

The embodiment of the present application discloses a dual-polarization radar calibration method and system. At the end of each plane scan of the dual-polarization radar, the calibration signal source is controlled to generate a radio frequency signal, the frequency of the radio frequency signal is the same as the operating frequency of the dual-polarization radar; the radio frequency signal is divided into two identical target signals; the two target signals are respectively injected into the two receiving channels of the dual-polarization radar; the first difference of the signals output by the two receiving channels is obtained; at the end of each volume scan of the dual-polarization radar, based on the multiple first differences obtained during the volume scan and the preset reference differences, it is determined whether the dual-polarization radar is abnormal. The solution provided by the embodiment of the present application performs a calibration between each two adjacent plane scans, and then uses the multiple first differences determined during a volume scan to determine whether the dual-polarization radar is abnormal, thereby ensuring the accuracy and timeliness of the dual-polarization radar calibration without affecting the operation of the radar service.

Description

Technical Field

[0001] The present application relates to the field of radar technology, and more specifically, to a dual-polarization radar calibration method and system. Background Art

[0002] At present, my country's dual-polarization radar has been transformed from trial operation to operational operation, and the number of dual-polarization radars in the new generation weather radar network is increasing year by year. Dual-polarization radars can transmit and receive both horizontally polarized waves and vertically polarized waves. Based on the difference between horizontally polarized waves and vertically polarized waves, technicians can conduct operational research such as precipitation estimation.

[0003] In practical applications, horizontal polarization waves are received through the horizontal receiving channel in the dual polarization radar, while vertical polarization waves are received through the vertical receiving channel in the dual polarization radar. Under normal circumstances, due to the differences between the two transmission channels (i.e., the horizontal receiving channel and the vertical receiving channel), there is a certain deviation between the difference between the polarization waves output by the two receiving channels and the difference between the polarization waves input to the two transmission channels, which is allowed. However, when an abnormality occurs in the dual polarization radar system, the deviation between the difference between the polarization waves output by the two receiving channels and the difference between the polarization waves input to the two transmission channels will also increase, affecting the accuracy of the business research results. Therefore, it is necessary to calibrate the dual polarization radar to monitor whether the dual polarization radar system has abnormalities. Summary of the invention

[0004] The purpose of this application is to provide a dual-polarization radar calibration method and system, including the following technical solutions:

[0005] A dual-polarization radar calibration method, comprising:

[0006] At the end of each plane scan of the dual polarization radar, controlling the calibration signal source to output a radio frequency signal, wherein the frequency of the radio frequency signal is the same as the central frequency of the dual polarization radar;

[0007] Splitting the radio frequency signal into two identical target signals;

[0008] Injecting the two target signals into two receiving channels of the dual-polarization radar respectively;

[0009] Obtaining a first difference between signals output by the two receiving channels;

[0010] At the end of each volume scan of the dual polarization radar, it is determined whether the dual polarization radar is abnormal according to a plurality of first differences obtained during the volume scan and a preset reference difference.

[0011] In the above method, preferably, the step of controlling the calibration signal source to output a radio frequency signal comprises:

[0012] A control instruction is sent to a high-speed switch in the calibration signal source, so that the high-speed switch supplies power to the output path switch of the radio frequency signal, so as to open the output path of the radio frequency signal.

[0013] The above method preferably further comprises:

[0014] Before the next plane scanning of the dual polarization radar starts, the control instruction is stopped from being sent to the high-speed switch of the calibration signal source to shut off the output path of the calibration signal source.

[0015] In the above method, preferably, the injecting the two target signals into the two receiving channels of the dual-polarization radar respectively comprises:

[0016] Input each channel of target signal to a corresponding directional coupler through an amplitude-stabilized and phase-stabilized cable;

[0017] Each directional coupler inputs a target signal into a corresponding receiving channel.

[0018] In the above method, preferably, the first difference between the signals output by the two receiving channels is a difference in amplitude and / or a difference in phase between the signals output by the two receiving channels.

[0019] In the above method, preferably, determining whether the dual polarization radar is abnormal based on the multiple first differences obtained during the volume scanning process and the preset reference difference includes:

[0020] Calculating the difference between each first difference and the reference difference to obtain a calculation result;

[0021] If the calculation result indicates that each of the first differences is consistent with the reference difference, it is determined that the dual polarization radar is normal; otherwise, it is determined that the dual polarization radar is abnormal.

[0022] The above method preferably further comprises:

[0023] If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is within a preset range, a deviation value is determined according to the difference between each first difference and the reference difference; and the difference in polarization waves output by the two receiving channels during the next volume scanning process is corrected according to the deviation value;

[0024] If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is not within a preset range, an alarm message is output.

[0025] A dual-polarization radar calibration system includes: a calibration signal source, a control terminal, and a dual-polarization radar receiving system; wherein:

[0026] The control terminal is used to control the calibration signal source to output a radio frequency signal at the end of each plane scan of the dual polarization radar, wherein the frequency of the radio frequency signal is the same as the central frequency of the dual polarization radar;

[0027] The calibration signal source is also used to divide the radio frequency signal into two identical target signals; and inject the two target signals into two receiving channels of the dual-polarization radar receiving system respectively;

[0028] The dual-polarization radar receiving system is used to obtain the first difference of the signals output by the two receiving channels; at the end of each volume scan of the dual-polarization radar, it is determined whether the dual-polarization radar is abnormal based on multiple first differences obtained during the volume scan and a preset benchmark difference.

[0029] In the above system, preferably, when the control terminal controls the calibration signal source to output the radio frequency signal, it is specifically used to:

[0030] A control instruction is sent to a high-speed switch in the calibration signal source, so that the high-speed switch supplies power to the output path switch of the radio frequency signal, so as to open the output path of the radio frequency signal.

[0031] The above system preferably further comprises: two directional couplers connected to the calibration signal source via amplitude- and phase-stabilized cables, each directional coupler being connected to a receiving channel of the dual-polarization radar receiving system;

[0032] Each target signal is injected into two receiving channels of the dual-polarization radar receiving system through a one-to-one corresponding directional coupler.

[0033] In the above system, preferably, when the dual polarization radar receiving system determines whether the dual polarization radar is abnormal based on the multiple first differences obtained during the volume scanning process and the preset reference difference, it is specifically used to:

[0034] Calculating the difference between each first difference and the reference difference to obtain a calculation result;

[0035] If the calculation result indicates that each of the first differences is consistent with the reference difference, it is determined that the dual polarization radar is normal; otherwise, it is determined that the dual polarization radar is abnormal.

[0036] In the above system, preferably, the dual polarization radar receiving system is also used for:

[0037] If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is within a preset range, a deviation value is determined according to the difference between each first difference and the reference difference; and the difference in polarization waves output by the two receiving channels during the next volume scanning process is corrected according to the deviation value;

[0038] If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is not within a preset range, an alarm message is outputted through the control terminal.

[0039] Through the above scheme, it can be known that the present application provides a dual-polarization radar calibration method and system. At the end of each plane scan of the dual-polarization radar, the calibration signal source is controlled to generate a radio frequency signal, and the frequency of the radio frequency signal is the same as the operating frequency of the dual-polarization radar; the radio frequency signal is divided into two identical target signals; the two target signals are respectively injected into the two receiving channels of the dual-polarization radar; the first difference of the signals output by the two receiving channels is obtained; at the end of each volume scan of the dual-polarization radar, based on the multiple first differences obtained during the volume scan and the preset reference differences, it is determined whether the dual-polarization radar is abnormal. The scheme provided in the embodiment of the present application performs a calibration between each two adjacent plane scans, and then uses the multiple first differences determined during a volume scan to determine whether the dual-polarization radar is abnormal, thereby ensuring the accuracy and timeliness of the dual-polarization radar calibration without affecting the operation of the radar business. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 A flowchart for implementing the dual-polarization radar calibration method provided in an embodiment of the present application;

[0042] Figure 2 An example diagram of the connection relationship between the high-speed switch of the calibration signal source and the output path switch of the radio frequency signal provided in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of a dual polarization radar provided in an embodiment of the present application after correction using the calibration technology provided in an embodiment of the present application;

[0044] Figure 4 An exemplary diagram in which the differences between each first difference and the reference difference provided in the embodiment of the present application are all outside the preset range;

[0045] Figure 5 An example diagram of a design interface for a reference difference corresponding to an amplitude difference provided in an embodiment of the present application;

[0046] Figure 6 An example diagram of the configuration interface for turning on and off the calibration signal source function provided in an embodiment of the present application;

[0047] Figure 7 An example diagram of a configuration interface for different working logic modes of a calibration signal source provided in an embodiment of the present application;

[0048] Figure 8 A schematic diagram of the structure of a dual-polarization radar calibration system provided in an embodiment of the present application;

[0049] Fig. 9 A schematic diagram of the internal structure of a calibration signal source provided in an embodiment of the present application;

[0050] Fig.10 A schematic diagram of the housing structure of a calibration signal source provided in an embodiment of the present application.

[0051] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims and the above drawings are used to distinguish similar parts, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated herein. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] The signals received by the radar can be divided into two types according to their functions: "test signals" and "echo signals". The test signal is used to check or calibrate the radar system, and the echo signal is the radar's working signal, which is used to check the target's amplitude, direction, speed and other information. However, only one of the test signal and the echo signal can exist at the same time, and they cannot appear at the same time, otherwise confusion will occur. Therefore, the dual-polarization radar calibration method provided in the embodiment of the present application uses the time period when the radar system neither transmits nor receives (i.e., the moment of raising the elevation angle, and the time period after one volume scan ends and before the next volume scan begins) for calibration.

[0054] like Figure 1As shown, a flowchart of an implementation of the dual-polarization radar calibration method provided in an embodiment of the present application may include:

[0055] Step 101: At the end of each plane scan of the dual polarization radar, the calibration signal source is controlled to output a radio frequency signal, and the frequency of the radio frequency signal is the same as the central frequency of the dual polarization radar.

[0056] When dual-polarization radar is scanning, it performs volume scans in a cycle, that is, after one volume scan is completed, the next volume scan is performed. Each volume scan consists of multiple plane scans, and each plane scan is performed at a specific elevation angle. Different plane scans have different elevation angles. After each plane scan is completed, the elevation angle is adjusted, and the next plane scan is performed after the elevation angle is adjusted until a volume scan is completed. Usually, it takes 6 minutes to perform a volume scan, and 30 seconds to perform a plane scan.

[0057] Therefore, in the embodiment of the present application, the time of raising the elevation angle of the radar (i.e. adjusting the elevation angle) is used for calibration, which is equivalent to calibrating the two receiving channels of the dual-polarization radar once every 30 seconds.

[0058] In an embodiment of the present application, the opening and closing of the calibration signal source is controlled by a control terminal installed in the radar equipment room, and the control command is issued by the control software. The control signal is converted by the interface and transmitted by optical fiber and finally sent to the calibration signal source installed in the antenna cover. Among them, when the calibration signal source is turned on, a radio frequency signal will be output, and when the calibration signal source is turned off, no radio frequency signal will be output. Optical fiber transmission can reduce the interference caused by transmission and ensure the reliability of control command transmission. Optionally, in order to reduce environmental electromagnetic interference, the control command can be transmitted in the form of two differential signals. In order to avoid the signal source generating interference signals during radar operation and affecting the data quality of the radar, in an embodiment of the present application, the calibration signal source is installed in the antenna cover.

[0059] In addition, in order to improve the ambient temperature adaptability of the calibration signal source, for example, the calibration signal source can work stably in the ambient temperature range of -20℃~+50℃, a temperature compensation circuit can be designed in the calibration signal source to cope with low temperature environment, and a cooling fan can be installed to cope with high temperature environment.

[0060] Optionally, the calibration signal source may be a signal source whose output frequency can be programmed, so that through programming, the calibration signal source can generate radio frequency signals of different frequencies so as to be suitable for radar systems at different frequency points.

[0061] Step 102: Split the radio frequency signal into two identical signals (referred to as target signals for ease of description).

[0062] Optionally, a two-way power splitter may be used to split the RF signal into two identical target signals.

[0063] Optionally, a multi-channel power splitter may be used to split the radio frequency signal into multiple identical signals, and two of the signals are taken as target signals.

[0064] Optionally, in order to prevent the high-power RF signal during radar operation from affecting or damaging the calibration signal source, an isolator can be set inside the calibration signal source, and the RF signal is first input to the isolator, and then the isolator inputs the RF signal to the power divider. In order to further improve the isolation of the calibration signal source from the high-power RF signal during radar operation, an electromagnetic shielding design can also be made on the outer shell of the calibration signal source.

[0065] The frequency of the target signal is the same as the center frequency of the dual-polarization radar.

[0066] Step 103: Inject the two target signals into two receiving channels of the dual polarization radar respectively. The two receiving channels are generally called a horizontal channel and a vertical channel.

[0067] Step 104: Obtain a first difference between signals output by the two receiving channels. The first difference may be a difference in amplitude of the signals output by the two receiving channels, or may be a difference in phase of the signals output by the two receiving channels, or may include both a difference in amplitude of the signals output by the two receiving channels and a difference in phase of the signals output by the two receiving channels.

[0068] Step 105: At the end of each volume scan of the dual polarization radar, determine whether the dual polarization radar is abnormal according to a plurality of first differences obtained during the volume scan and a preset reference difference.

[0069] The reference difference is the difference in the signals output by the two receiving channels after the calibration signal source is controlled to generate a radio frequency signal in a normal state of the dual polarization radar, the radio frequency signal is divided into two identical target signals, and the two target signals are respectively injected into the two receiving channels of the dual polarization radar. The working state of the dual polarization radar after it is installed and tested and can be put into use is usually normal. Therefore, when the dual polarization radar is just installed and tested and can be put into use, the calibration signal source is controlled to generate a radio frequency signal, the radio frequency signal is divided into two identical target signals, and the two target signals are respectively injected into the two receiving channels of the dual polarization radar. The difference in the signals output by the two receiving channels is used as the reference difference.

[0070] As can be seen from the above content, it usually takes 6 minutes for the radar to perform a volume scan, and 30 seconds for a plane scan. Therefore, 12 first differences will be obtained during a submitted scan. In some cases, the radar system will change its working mode. At this time, the volume scan method will change. After the volume scan method is changed, the time required for a volume scan and the number of plane scans will also be adjusted accordingly.

[0071] The dual polarization radar calibration method provided in the embodiment of the present application, at the end of each plane scan of the dual polarization radar, controls the calibration signal source to generate a radio frequency signal, the frequency of the radio frequency signal is the same as the working frequency of the dual polarization radar; divides the radio frequency signal into two identical target signals; injects the two target signals into the two receiving channels of the dual polarization radar respectively; obtains the first difference of the signals output by the two receiving channels; at the end of each volume scan of the dual polarization radar, determines whether the dual polarization radar is abnormal according to the multiple first differences obtained during the volume scan and the preset reference difference. The scheme provided in the embodiment of the present application performs a calibration between each two adjacent plane scans, and then determines whether the dual polarization radar is abnormal using the multiple first differences determined during a volume scan, and ensures the accuracy and timeliness of the dual polarization radar calibration without affecting the radar business operation. It realizes the automatic online calibration of the amplitude and phase consistency of the dual polarization radar receiving channel without affecting the business operation to improve the calibration accuracy and timeliness of the dual polarization radar, improve the data quality of the dual polarization radar, and better play the role of the dual polarization radar.

[0072] The inventor of the present application found in the process of implementing the present application that when controlling the calibration signal source to output the radio frequency signal, if it is implemented in the following manner:

[0073] The power source of the calibration signal source is controlled to supply power to the calibration signal source to turn on the calibration signal source, so that the calibration signal source generates a radio frequency signal. Before the next plane scanning of the dual-polarization radar starts, the power source of the calibration signal source is controlled to stop supplying power to the calibration signal source to turn off the calibration signal source, so that the calibration signal source no longer generates a radio frequency signal.

[0074] Although this control method can make the isolation of the calibration signal source (that is, the power difference of the calibration signal source when the RF switch is turned on and off) reach more than 80dB, it still cannot meet the use requirements and will affect the radar noise floor.

[0075] In order to improve the isolation of the calibration signal source, in an optional embodiment, an implementation method of controlling the calibration signal source to output a radio frequency signal provided in the embodiment of the present application may be:

[0076] A control instruction is sent to the high-speed switch in the calibration signal source, so that the high-speed switch supplies power to the output path switch of the radio frequency signal in the radio frequency signal source, so as to open the output path of the radio frequency signal.

[0077] Optionally, the high-speed switch may be implemented based on a transistor, for example, the high-speed switch may include an NPN transistor and a PNP transistor. Figure 2 , which is an example diagram of the connection relationship between the high-speed switch of the calibration signal source (not shown in the figure) and the output path switch of the radio frequency signal provided in the embodiment of the present application. In this example,

[0078] The main components of the high-speed switch include NPN transistor V1, PNP transistor V2 and +5v DC power supply, and other components of the high-speed switch are used to cooperate with NPN transistor V1 and PNP transistor V2 to enable the high-speed switch to generate the voltage required for the output path switch U6 of the RF signal to work. Therefore, the structure of the high-speed switch in the embodiment of the present application is not limited to Figure 2 The structure shown can also have other structures, as long as the high-speed switch generates the voltage required for the output path switch U6 of the RF signal to work. The RF signal generated by the calibration signal source is output through U6, that is, the output path of the RF signal generated by the calibration signal source is the branch where U6 is located. Among them, the input end of U6 is pin No. 2 V-TUNE, which is connected to the output of the calibration signal source, and the output end of U6 is pin No. 10 RF-OUT. After pin No. 14 VCC is connected to the power supply, U6 is turned on, and the RF signal generated by the calibration signal source is input into U6 through pin No. 2 V-TUNE of U6, and then output through pin No. 10 RF-OUT of U6. The output path switch U6 can be a voltage-controlled oscillator.

[0079] In the embodiment of the present application, the control instruction sent to the high-speed switch can be an analog signal that makes the level of the high-speed switch tube conduction be a predetermined level. After receiving the control instruction, the high-speed switch will be turned on, so that the high-speed switch supplies power to U6, that is, the output of the high-speed switch, that is, the output of the collector of the transistor V2 is connected to the pin 14 VCC of U6, so that U6 is turned on, so that the RF signal output by the calibration signal source is output through U6.

[0080] The time for raising the elevation angle during radar operation is usually relatively short, and the time left for calibration is within 1 second. In the embodiment of the present application, in order to ensure the timeliness of calibration, the calibration signal source is always powered and generates RF signals. The output path of the calibration signal source is turned on and off by controlling the high-speed switch to ensure that the calibration signal source outputs RF signals stably when powered on, and outputs quickly when powered off. The isolation of the calibration signal source is also improved, with an isolation of more than 100dB, so that the noise of the calibration signal source itself is much lower than the sensitivity of the radar system.

[0081] In an optional embodiment, before the next plane scan of the dual polarization radar starts, the control instruction is stopped from being sent to the high-speed switch of the calibration signal source to shut down the output path of the radio frequency signal generated by the calibration signal source. At this time, the calibration signal source still generates a radio frequency signal, but because the output path is closed, the radio frequency signal cannot be output through the output path.

[0082] In an optional embodiment, an implementation method of respectively injecting the two target signals into the two receiving channels of the dual-polarization radar may be:

[0083] Input each channel of target signal to a corresponding directional coupler through an amplitude-stabilized and phase-stabilized cable;

[0084] Each directional coupler inputs a target signal into a corresponding receiving channel.

[0085] That is to say, in the embodiment of the present application, the calibration signal source has two signal output interfaces, each output interface is connected to a directional coupler, and each directional coupler is connected to a receiving channel of the dual-polarization radar.

[0086] In an optional embodiment, an implementation method of determining whether the dual-polarization radar is abnormal based on the multiple first differences obtained during the volume scanning process and the preset reference difference may be:

[0087] The difference between each first difference and the reference difference is calculated to obtain a calculation result.

[0088] If the calculation result indicates that each first difference is consistent with the reference difference, it is determined that the dual polarization radar is normal; otherwise, it is determined that the dual polarization radar is abnormal.

[0089] In the embodiment of the present application, for each first difference, if the absolute value of the difference between the first difference and the reference difference is less than the first threshold, it means that the first difference is consistent with the reference difference, otherwise, it means that the first difference is inconsistent with the reference difference. As an example, for the amplitude difference, the first threshold may be 0.01 dB; for the phase difference, the first threshold may be 0.1°.

[0090] Further, if the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is within a preset range, for example, the absolute value of the difference between each first difference and the reference difference is between the first threshold and the second threshold, then the deviation value is determined according to the difference between each first difference and the reference difference; and the difference in polarization waves output by the two receiving channels during the next volume scan is corrected according to the deviation value. The second threshold is greater than the first threshold. As an example, corresponding to the amplitude difference, the second threshold can be 0.2dB; corresponding to the phase difference, the second threshold can be 0.6°.

[0091] In the embodiment of the present application, if the difference between each first difference and the reference difference is within the preset range, it means that the radar system has changed and needs to be revised. Optionally, the mean or median of the difference between each first difference and the reference difference can be used as the deviation value, and the difference in polarization waves output by the two receiving channels during the next volume scan can be adjusted in the opposite direction according to the deviation value. For example,

[0092] Take the difference between the signals output by the two receiving channels as the amplitude difference between the signals output by the horizontal channel and the signals output by the vertical channel as an example. Assume that the reference difference between the signals output by the horizontal channel and the signals output by the vertical channel is 0.5dB, and the calculated deviation value is 0.15dB. That is to say, during the actual scanning process, the difference between the signals output by the horizontal channel and the signals output by the vertical channel is 0.15dB higher than the reference difference. In the next volume scanning process, the difference between the polarization waves output by the two receiving channels should be lowered by 0.15dB, and the difference between the signals output by the horizontal channel and the signals output by the vertical channel after being lowered by 0.15dB should be output to the user. If the calculated deviation value is -0.15dB, that is, during the actual scanning process, the difference between the signals output by the horizontal channel and the signals output by the vertical channel is 0.15dB lower than the reference difference, in the next volume scanning process, the difference between the polarization waves output by the two receiving channels should be increased by 0.15dB, and the difference between the signals output by the horizontal channel and the signals output by the vertical channel after being increased by 0.15dB should be output to the user. Figure 3 As shown, this is a schematic diagram of the dual-polarization radar provided in the embodiment of the present application after being corrected using the calibration technology provided in the embodiment of the present application. Obviously, after using the calibration technology provided in the embodiment of the present application, the maximum variation range of the amplitude difference between the two channels is 0.07dB, which meets the technical indicator requirement of not more than 0.2dB. The radar difference at the corresponding moment is normal, which meets the needs of business observation.

[0093] If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is not within the preset range, for example, the absolute value of the difference between each first difference and the reference difference is greater than the second threshold, then an alarm message is output to remind the radar operator that the radar needs maintenance or repair. Figure 4As shown, the difference between each first difference and the reference difference provided by the embodiment of the present application is not within the preset range. In this example, the maximum range of the amplitude difference between the two channels is 6.5dB, which exceeds the set threshold range. Therefore, no revision is made, but an alarm message is generated to prompt the radar operator that the radar system needs maintenance or repair to prevent abnormal data from entering the business radar network and affecting the forecaster's judgment. The fault is fed back to the radar operator in a timely manner through the alarm information. After replacing the faulty spare parts, the radar calibration result is normal and it is put into business operation again.

[0094] Further, in the embodiment of the present application, the reference difference can be set by the user, such as Figure 5 FIG. 1 is an example diagram of a design interface for a reference difference corresponding to an amplitude difference provided in an embodiment of the present application. In this interface, a user can enter a reference difference in an input box after “SP14 TSZDR reference value”.

[0095] Furthermore, the embodiment of the present application also adds a configuration function for the calibration signal source, which can be specifically: the configuration file can be used to facilitate the user to control the calibration signal source function to be turned on and off, or to implement different control logics. Figure 6 As shown, it is an example diagram of the calibration signal source function on and off configuration interface provided in the embodiment of the present application. In this interface, by assigning different values ​​to ts_enable, the calibration signal source function can be controlled to be on or off, for example, ts_enable = 1, indicating that the calibration signal source function is to be controlled to be on, and ts_enable = 0, indicating that the calibration signal source function is to be controlled to be off. Only when the calibration signal source function is turned on can the dual polarization radar calibration method provided in the embodiment of the present application be executed.

[0096] like Figure 7 As shown, it is an example diagram of the configuration interface of the working logic of the calibration signal source in different modes provided in the embodiment of the present application. The control logic of the calibration signal source is divided into two types: continuous wave control mode and pulse control mode; wherein, the continuous wave control mode refers to controlling the calibration signal source to output a continuous wave RF signal at a specified time point, which is used for calibration of the amplitude and phase consistency of the two receiving channels. The pulse control mode refers to controlling the output width and output timing position of the pulse, which can realize calibration under each radar transmit pulse. The radar system currently in operation uses the continuous wave control mode for calibration by default. Figure 7 In the example, tswlTrgPos=64, tswlTrgLen=0, indicating that the calibration signal source works in continuous wave control mode.

[0097] In summary, dual-polarization radars account for an increasingly high proportion in China's new generation weather radar network, and the data quality requirements for dual-polarization radars are significantly higher than those for single-polarization radars. In order to meet the automatic online inspection and online correction of the core technical indicators of dual-polarization radars and ensure the precision and accuracy of dual-polarization radar data, the calibration signal source and calibration technology of this application are proposed to achieve online calibration of the amplitude and phase consistency of the receiving channel of the dual-polarization radar, and ensure that the dual-polarization radar operates within the technical indicator range of an amplitude difference of no more than 0.2 dB and a phase difference of no more than 3°. The calibration system will automatically correct data with small calibration deviations to avoid unqualified dual-polarization radar products being used in business systems. At the same time, for situations where the calibration results seriously exceed the standards and are in urgent need of maintenance, an alarm signal is generated to promptly notify the radar operating technicians to avoid forecasters making correct forecasts due to radar system data quality issues, and decision-making departments such as flood control and disaster relief making wrong decisions.

[0098] The invention and business application of calibration signal sources and calibration technologies can better leverage the technical advantages of dual-polarization radar in quantitative precipitation estimation and precipitation type classification, and better leverage the important role of dual-polarization radar in disaster prevention and mitigation.

[0099] Corresponding to the method embodiment, the embodiment of the present application further provides a dual polarization radar calibration system. A structural schematic diagram of the dual polarization radar calibration system provided by the embodiment of the present application is shown in FIG. Figure 8 As shown, it may include:

[0100] Calibration signal source 801, control terminal 802, dual polarization radar receiving system 803; wherein,

[0101] The control terminal 802 is used to control the calibration signal source 801 to output a radio frequency signal at the end of each plane scan of the dual polarization radar, and the frequency of the radio frequency signal is the same as the center frequency of the dual polarization radar. The control terminal 802 can send a control instruction to the calibration signal source through the signal processor of the dual polarization radar receiving system 803 to control the calibration signal source 801 to output a radio frequency signal. That is, the control signal generated by the control terminal 802 is transferred to the calibration signal source 801 through the signal processor. During the normal working time of the radar system, the dual polarization radar receiving system is used for the transmission or reception of the normal working signal of the radar system and related processing.

[0102] Optionally, the control terminal 802 may be a host computer, or may be a mobile communication terminal, such as a smart phone.

[0103] The calibration signal source 801 is also used to divide the radio frequency signal into two identical target signals; the two target signals are respectively injected into two receiving channels of the dual-polarization radar receiving system 803; these two receiving channels are generally called horizontal channel and vertical channel.

[0104] The dual-polarization radar receiving system 803 is used to obtain a first difference between signals output by two receiving channels through a signal processor; the first difference may be a difference in amplitude of the signals output by the two receiving channels, or may be a difference in phase of the signals output by the two receiving channels, or may include both a difference in amplitude of the signals output by the two receiving channels and a difference in phase of the signals output by the two receiving channels. At the end of each volume scan of the dual-polarization radar, the signal processor determines whether the dual-polarization radar is abnormal based on multiple first differences obtained during the volume scan and a preset reference difference.

[0105] The dual-polarization radar calibration system provided in the embodiment of the present application, at the end of each plane scan of the dual-polarization radar, controls the calibration signal source to generate a radio frequency signal, the frequency of the radio frequency signal is the same as the working frequency of the dual-polarization radar; divides the radio frequency signal into two identical target signals; injects the two target signals into the two receiving channels of the dual-polarization radar respectively; obtains the first difference of the signals output by the two receiving channels; at the end of each volume scan of the dual-polarization radar, determines whether the dual-polarization radar is abnormal according to the multiple first differences obtained during the volume scan and the preset reference difference. The scheme provided in the embodiment of the present application performs a calibration between each two adjacent plane scans, and then determines whether the dual-polarization radar is abnormal using the multiple first differences determined during a volume scan, and ensures the accuracy and timeliness of the dual-polarization radar calibration without affecting the radar business operation. It realizes the automatic online calibration of the amplitude and phase consistency of the dual-polarization radar receiving channel without affecting the business operation to improve the calibration accuracy and timeliness of the dual-polarization radar, improve the data quality of the dual-polarization radar, and better play the role of the dual-polarization radar.

[0106] In an optional embodiment, of the two target signals output by the calibration signal source 801, one target signal is input into the horizontal channel through a directional coupler, and the other target signal is input into the vertical channel through another directional coupler. The calibration signal source 801 is connected to the coupler through an amplitude-stabilizing and phase-stabilizing cable. The amplitude-stabilizing and phase-stabilizing cables connecting the two directional couplers are of equal length.

[0107] In an optional embodiment, a schematic diagram of an internal structure of a calibration signal source provided in an embodiment of the present application is as follows: Fig. 9 As shown, it may include:

[0108] Programmable signal source 901 and power divider 902; wherein,

[0109] The programmable signal source 901 is used to generate a radio frequency signal. Its output frequency can be compiled, so that the programmable signal source 901 can generate radio frequency signals of different frequencies through compilation, which is suitable for radar systems with different frequency points.

[0110] The power splitter 902 may be a two-way power splitter or a multi-way power splitter.

[0111] Preferably, in order to prevent the high-power radio frequency signal from affecting or damaging the calibration signal source during radar operation, the calibration signal source may further include an isolator 903 .

[0112] In an optional embodiment, in order to further improve the isolation of the calibration signal source from the high-power radio frequency signal during radar operation, an electromagnetic shielding design may be made on the housing of the calibration signal source. Fig.10 As shown, it is a schematic diagram of the shell structure of the calibration signal source provided in an embodiment of the present application. In this example diagram, the two output interfaces J1 and J2 are used to output two target signals, and the XS3 interface is used to receive the control instructions sent by the control terminal 802.

[0113] In an optional embodiment, the control terminal 802 may send a control instruction to the high-speed switch in the programmable signal source 901 through the signal processor of the dual-polarization radar receiving system 803, so that the high-speed switch supplies power to the output path switch of the RF signal, so as to open the output path of the RF signal generated by the programmable signal source 901, and the output path is used to output the RF signal generated by the programmable signal source 901.

[0114] In an optional embodiment, before the next plane scan of the dual-polarization radar starts, the control terminal 802 stops sending control instructions to the high-speed switch of the calibration signal source 801 to shut down the output path of the radio frequency signal generated by the calibration signal source 801.

[0115] In an optional embodiment, when the dual polarization radar receiving system 803 (mainly a signal processor) determines whether the dual polarization radar is abnormal according to the multiple first differences obtained during the volume scanning process and the preset reference difference, it is specifically used to:

[0116] The difference between each first difference and the reference difference is calculated to obtain a calculation result.

[0117] If the calculation result indicates that each of the first differences is consistent with the reference difference, it is determined that the dual polarization radar is normal; otherwise, it is determined that the dual polarization radar is abnormal.

[0118] In an optional embodiment, the dual polarization radar receiving system 803 (mainly a signal processor) is also used for:

[0119] If the calculation result indicates that each first difference is inconsistent with the benchmark difference, and the difference between each first difference and the benchmark difference is within a preset range, a deviation value is determined according to the difference between each first difference and the benchmark difference; and the difference in polarization waves output by the two receiving channels during the next volume scanning process is corrected according to the deviation value.

[0120] If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is not within a preset range, an alarm message is outputted through the control terminal 802 .

[0121] In an optional embodiment, the dual-polarization radar receiving system 803 (mainly a signal processor) can also be used for:

[0122] The control terminal 802 outputs a configuration interface, for example, a design interface for outputting a reference difference so that the user can set the reference difference, or an output configuration interface for turning the calibration signal source function on and off, or an output configuration interface for outputting the working logic of different modes of the calibration signal source, etc.

[0123] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0124] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0125] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0126] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0127] It should be understood that in the embodiments of the present application, the various embodiments and features can be combined with each other to solve the aforementioned technical problems.

[0128] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0129] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual polarization radar calibration method, characterized in that: include: At the end of each plane scan of the dual polarization radar, controlling the calibration signal source to output a radio frequency signal, wherein the frequency of the radio frequency signal is the same as the central frequency of the dual polarization radar; Splitting the radio frequency signal into two identical target signals; Injecting the two target signals into two receiving channels of the dual-polarization radar respectively; Obtaining a first difference between signals output by the two receiving channels; At the end of each volume scan of the dual polarization radar, determining whether the dual polarization radar is abnormal according to a plurality of first differences obtained during the volume scan and a preset reference difference; The control calibration signal source outputs a radio frequency signal, comprising: A control instruction is sent to a high-speed switch in the calibration signal source, so that the high-speed switch supplies power to the output path switch of the radio frequency signal, so as to open the output path of the radio frequency signal.

2. The method according to claim 1, characterized in that Also includes: Before the next plane scanning of the dual polarization radar starts, the control instruction is stopped from being sent to the high-speed switch of the calibration signal source to shut off the output path of the calibration signal source.

3. The method according to claim 1, characterized in that The step of injecting the two target signals into two receiving channels of the dual-polarization radar respectively comprises: Input each channel of target signal to a corresponding directional coupler through an amplitude-stabilized and phase-stabilized cable; Each directional coupler inputs a target signal into a corresponding receiving channel.

4. The method according to claim 1, characterized in that: The first difference between the signals output by the two receiving channels is a difference in amplitude and / or a difference in phase between the signals output by the two receiving channels.

5. The method according to any one of claims 1 to 4, characterized in that: The determining whether the dual-polarization radar is abnormal according to the multiple first differences obtained during the volume scanning process and the preset reference difference includes: Calculating the difference between each first difference and the reference difference to obtain a calculation result; If the calculation result indicates that each of the first differences is consistent with the reference difference, it is determined that the dual polarization radar is normal; otherwise, it is determined that the dual polarization radar is abnormal.

6. The method according to claim 5, characterized in that Also includes: If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is within a preset range, a deviation value is determined according to the difference between each first difference and the reference difference; and the difference in polarization waves output by the two receiving channels during the next volume scanning process is corrected according to the deviation value; If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is not within a preset range, an alarm message is output.

7. A dual polarization radar calibration system, characterized in that: include: Calibration signal source, control terminal, dual polarization radar receiving system; Among them, The control terminal is used to control the calibration signal source to output a radio frequency signal at the end of each plane scan of the dual polarization radar, wherein the frequency of the radio frequency signal is the same as the central frequency of the dual polarization radar; The calibration signal source is also used to divide the radio frequency signal into two identical target signals; and inject the two target signals into two receiving channels of the dual-polarization radar receiving system respectively; The dual-polarization radar receiving system is used to obtain a first difference in the signals output by the two receiving channels; at the end of each volume scan of the dual-polarization radar, it is determined whether the dual-polarization radar is abnormal according to a plurality of first differences obtained during the volume scan and a preset reference difference; When the control terminal controls the calibration signal source to output the radio frequency signal, it is specifically used to: A control instruction is sent to a high-speed switch in the calibration signal source, so that the high-speed switch supplies power to the output path switch of the radio frequency signal, so as to open the output path of the radio frequency signal.

8. The system according to claim 7, characterized in that Also includes: Two directional couplers connected to the calibration signal source via amplitude- and phase-stabilized cables, each directional coupler being connected to a receiving channel of the dual-polarization radar receiving system; Each target signal is injected into two receiving channels of the dual-polarization radar receiving system through a one-to-one corresponding directional coupler.

9. The system according to claim 7 or 8, characterized in that: When the dual polarization radar receiving system determines whether the dual polarization radar is abnormal according to the multiple first differences obtained during the volume scanning process and the preset reference difference, it is specifically used to: Calculating the difference between each first difference and the reference difference to obtain a calculation result; If the calculation result indicates that each first difference is consistent with the reference difference, it is determined that the dual polarization radar is normal; Otherwise, it is determined that the dual polarization radar is abnormal.

10. The system according to claim 9, characterized in that The dual polarization radar receiving system is also used for: If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is within a preset range, a deviation value is determined according to the difference between each first difference and the reference difference; and the difference in polarization waves output by the two receiving channels during the next volume scanning process is corrected according to the deviation value; If the calculation result indicates that each first difference is inconsistent with the reference difference, and the difference between each first difference and the reference difference is not within a preset range, an alarm message is outputted through the control terminal.

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