Close-range search method for secondary wind sounding radar

Abstract

The present invention relates to the field of radar, and in particular to a close-range search method for a secondary wind sounding radar. In this method, a ground radar includes a broadband antenna and multiple narrowband antennas; during close-range search, the broadband antenna transmits a signal, and a phase angle measurement method is used to measure the phase difference between the multiple narrowband antennas, and multiple measurement angles containing fuzzy values ​​are calculated; the measurement angles containing fuzzy values ​​are brought into the directional diagrams of the narrowband antenna and the broadband antenna, and the theoretical power ratios of the received signals of the multiple narrowband antennas and the broadband antenna are calculated, and compared with the actual power ratios of the received signals, the true angle of the sounding balloon is determined, and the actual power ratios of the received signals of the narrowband antenna and the broadband antenna corresponding to the true angle are compared with a threshold to determine whether the sounding balloon is within the main lobe range of the narrowband antenna. Compared with the prior art, the present invention improves the close-range search performance and reduces the complexity of the ground radar antenna.

Description

Technical Field

[0001] The invention relates to the field of radars, and in particular to a close-range search method for a secondary wind sounding radar. Background Art

[0002] Meteorological instruments are special instruments serving atmospheric science. They mainly use sensitive components, sensors, encoders and other devices in the instruments to measure weather conditions or changes at specific times and places, such as temperature, humidity, air pressure, wind direction and speed, sunshine, radiation, etc. The secondary wind sounding system is a meteorological instrument that uses radio means to achieve meteorological measurements. It consists of ground radar and a sounding meteorological instrument carrying a sounding instrument. The ground radar is used in conjunction with the sounding instrument installed on the sounding balloon to obtain meteorological parameters such as wind direction, wind speed, temperature, air pressure, and temperature at all levels from the ground to 30km in the air. The ground radar can quickly search and track the sounding balloon, which is an important guarantee for the transmission of meteorological parameters. Especially when the sounding meteorological instrument is just released on the ground, it is difficult for the ground radar to search and track the sounding balloon.

[0003] In the prior art, ground radar searches for sounding balloons mainly using the amplitude method and the phase method. Among them, the amplitude method has low measurement accuracy, and the ground radar needs to perform a large-scale spatial scan before it can capture the target; the phase method has high measurement accuracy, but due to factors such as the radar baseline and wavelength, this method has measurement angle ambiguity values, resulting in multiple false targets in the search and tracking target. Furthermore, in the prior art, when the ground radar conducts close-range search, it usually uses multiple broadband antennas to complete it, and when it conducts long-range search, it is composed of multiple narrowband antennas. The broadband antenna and the narrowband antenna are used in different distance modes, resulting in a complex ground radar antenna system, reduced reliability, and poor wind resistance; further, in the prior art, the multiple broadband antennas used for close-range search have small fluctuations in the antenna gain of the broadband antenna, resulting in reduced search angle resolution and susceptibility to interference, which makes the close-range search time long.

[0004] How to improve the close-range search performance of secondary wind sounding radar, shorten the search time, and reduce the complexity of the antenna system is a difficult problem that technical personnel in this field need to solve. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the present invention provides a close-range search method for a secondary wind sounding radar to improve the close-range search performance, shorten the search time, and reduce the complexity of the antenna system.

[0006] To achieve the above object, the present invention discloses a secondary wind sounding radar close-range search method, comprising the following steps:

[0007] (S1) using a broadband antenna to transmit a signal, using a phase angle measurement method to measure the phase difference between multiple narrowband antennas, and calculating multiple measurement angles containing ambiguity values;

[0008] (S2) Substituting the multiple measurement angles containing ambiguity values ​​obtained in step (S1) into the directional diagrams of the narrowband antenna and the broadband antenna, and calculating the theoretical power ratio of the received signals of the multiple narrowband antennas and the broadband antenna under the multiple measurement angles containing ambiguity values;

[0009] (S3) measuring and calculating the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna;

[0010] (S4) comparing the multiple received signal theoretical power ratios with the received signal actual power ratio α to obtain the theoretical power ratio that is closest to the actual power ratio α, and determining the measured angle at this time as the true angle of the sounding balloon;

[0011] (S5) Substitute the actual angle of the sounding balloon into the broadband antenna pattern to obtain the broadband antenna gain G U , the maximum antenna gain G of the sidelobe of the narrowband antenna pattern N With broadband antenna gain G U In comparison, the ratio β is set as the threshold;

[0012] (S6) Compare the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna with the threshold β. If:

[0013] α>β, then the sounding balloon is considered to be within the main lobe of the narrowband antenna;

[0014] If α≤β, the sounding balloon is considered to be within the sidelobe range of the narrowband antenna, and step 7 is executed;

[0015] (S7) On the premise that the rotation direction is consistent with the search direction, the motor is driven to rotate and the real angle of the sounding balloon is updated, and (S5) and (S6) are repeatedly executed until the sounding balloon enters the main lobe range of the narrowband antenna.

[0016] Preferably, in step (S7), the method for determining whether the rotation direction is consistent with the search direction is:

[0017] After the driving motor rotates, the signal power received by the broadband antenna is compared with that before the rotation. If the signal power increases, the rotation direction is consistent with the search direction. If the signal power decreases, the rotation direction is opposite to the search direction.

[0018] Preferably, in step (S7), the driving motor rotates at an angle of:

[0019] Determine whether the sounding balloon is within the first sidelobe of the narrowband antenna:

[0020] If it is within the first-stage side lobe, the angle at which the drive motor rotates is the main lobe beam width of the narrowband antenna;

[0021] If it is not within the first-stage side lobe, the angle at which the driving motor rotates is half the beam width of the main lobe of the narrowband antenna.

[0022] Preferably, the method for determining whether the sounding balloon is within the first-order side lobe of the narrowband antenna is:

[0023] The maximum antenna gain of the first sidelobe of the narrowband antenna pattern is equal to the broadband antenna gain G U The ratio β1 is set as the first sidelobe threshold; the maximum antenna gain of the second sidelobe of the narrowband antenna pattern is divided by the broadband antenna gain G U In comparison, the ratio β2 is set as the second sidelobe threshold;

[0024] Compare the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna with the first sidelobe threshold β1 and the second sidelobe threshold β2 respectively, if:

[0025] α>β1, the sounding balloon is considered to be within the main lobe of the narrowband antenna;

[0026] β2<α≤β1, the sounding balloon is considered to be within the first sidelobe range of the narrowband antenna;

[0027] If α≤β2, the sounding balloon is considered to be out of the first sidelobe range of the narrowband antenna.

[0028] Preferably, the narrowband antenna main lobe beamwidth is 12°.

[0029] The present invention has the following technical effects:

[0030] 1. Improved close-range search performance

[0031] In the technical solution disclosed in the present invention, a broadband antenna and a narrowband antenna are used in combination for close-range search, a wide-beam antenna is used to transmit a signal, and a phase method direction finding is performed based on a narrow-beam antenna to obtain the measurement angle of the sounding balloon deviating from the normal direction and containing an ambiguous value; a narrow-beam antenna is used to receive a signal, and based on the characteristics of a small gain change of a wide-beam antenna and a large gain change of a narrow-beam antenna, the measurement angle is deblurred by comparing the received signal power ratio of the wide-beam antenna and the narrow-beam antenna; based on the difference in the main lobe and side lobe gain of the narrow-band antenna radiation pattern, by comparing the main lobe and side lobe gain and the threshold setting, it is determined whether the sounding balloon is within the main lobe beam range, and the close-range search for the sounding balloon is completed. This method overcomes the problem of long ground radar target search time caused by the low measurement accuracy of the traditional amplitude method, and also overcomes the problem of multiple false targets caused by the ambiguity of the angle measurement of the traditional phase method. Therefore, compared with the prior art, the present invention greatly improves the close-range search performance and shortens the search and tracking time.

[0032] 2. Reduce the complexity of ground radar antenna system

[0033] In the technical solution disclosed in the present invention, the ground radar antenna system is composed of a broadband antenna and multiple narrowband antennas. The broadband antenna and the narrowband antenna jointly participate in the close-range search. Based on the characteristics of small gain change of the wide-beam antenna and large gain change of the narrow-beam antenna, the phase method angle measurement is combined with the amplitude method angle measurement to complete the close-range search. In the prior art, multiple broadband antennas are used to complete the close-range search, and multiple narrowband antennas are used to complete the long-range search. The broadband antenna and the narrowband antenna are used for different distance modes, respectively, which leads to the complexity of the ground radar antenna system, reduced reliability, and poor wind resistance. Therefore, compared with the prior art, the present invention greatly reduces the complexity of the ground radar antenna system, is conducive to reducing economic costs, and improves wind resistance. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below in conjunction with embodiments; the examples given are only used to explain the present invention; they are not used to limit the scope of the present invention.

[0035] In the prior art, the ground radar antenna system is complex and consists of multiple broadband antennas and narrowband antennas. Multiple broadband antennas complete short-range searches, and multiple narrowband antennas complete long-range searches. When searching at short range, when the amplitude method is used to measure the angle to search for a sounding balloon, the angle measurement accuracy is low, and the ground radar needs to perform a large-scale spatial scan to capture the target, and the search time is long; when the phase method is used to measure the angle to search for a sounding balloon, due to factors such as the radar baseline and wavelength, this method has fuzzy values ​​in measuring the angle, resulting in multiple false targets in the search and tracking target, making it difficult to achieve a rapid search for a sounding balloon.

[0036] In order to solve the problems existing in the prior art, an embodiment of the present invention discloses a close-range search method for a secondary wind sounding radar. In this method, a ground radar antenna includes a broadband antenna and multiple narrowband antennas, and completing a close-range search for a sounding balloon includes the following steps:

[0037] (S1) using a broadband antenna to transmit a signal, using a phase angle measurement method to measure the phase difference between multiple narrowband antennas, and calculating multiple measurement angles containing ambiguity values;

[0038] (S2) Substituting the multiple measurement angles containing ambiguity values ​​obtained in step (S1) into the directional diagrams of the narrowband antenna and the broadband antenna, and calculating the theoretical power ratio of the received signals of the multiple narrowband antennas and the broadband antenna under the multiple measurement angles containing ambiguity values;

[0039] (S3) measuring and calculating the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna;

[0040] (S4) comparing the multiple received signal theoretical power ratios with the received signal actual power ratio α to obtain the theoretical power ratio that is closest to the actual power ratio α, and determining the measured angle at this time as the true angle of the sounding balloon;

[0041] (S5) Substitute the actual angle of the sounding balloon into the broadband antenna pattern to obtain the broadband antenna gain G U , the maximum antenna gain G of the sidelobe of the narrowband antenna pattern N With broadband antenna gain G U In comparison, the ratio β is set as the threshold;

[0042] (S6) Compare the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna with the threshold β. If:

[0043] α>β, then the sounding balloon is considered to be within the main lobe of the narrowband antenna;

[0044] If α≤β, the sounding balloon is considered to be within the sidelobe range of the narrowband antenna, and step 7 is executed;

[0045] (S7) On the premise that the rotation direction is consistent with the search direction, the motor is driven to rotate and the real angle of the sounding balloon is updated, and (S5) and (S6) are repeatedly executed until the sounding balloon enters the main lobe range of the narrowband antenna.

[0046] In the prior art, the ground radar antenna system is complex. The essential reason is that the broadband antenna and the narrowband antenna are used independently when exploring the sounding balloon. In the short-range search, only the broadband antenna is used, and in the long-range search, only the narrowband antenna is used. This leads to a complex antenna system, high economic cost, poor wind resistance, and low system reliability. Further, in the prior art, when the broadband antenna uses the amplitude method to measure the angle of the sounding balloon, although the measured angle has a single-value characteristic, the angle measurement accuracy is low, and the wide beam gain change of the broadband antenna is small, which easily leads to the ground radar to capture the target after a large-scale spatial scan, and the search time is long; when the broadband antenna uses the phase method to measure the angle of the sounding balloon, although the measurement angle has a high accuracy, it does not have a single-value characteristic, so that there are multiple false targets in the search and tracking target, and it is difficult to achieve rapid search and capture of the sounding balloon.

[0047] In order to solve the problems existing in the prior art, in the technical solution disclosed in the implementation of the present invention, during close-range search, a broadband antenna and a narrowband antenna are used in combination for search. Based on the advantages of small gain change of the wide beam of the broadband antenna and large gain change of the narrow beam of the narrowband antenna, the phase method angle measurement is combined with the amplitude method angle measurement, and the advantages of high accuracy of the phase method angle measurement and single value of the amplitude method angle measurement are fully utilized to achieve close-range rapid search of the sounding balloon. Further, in the technical solution disclosed in the implementation of the present invention, a wide beam antenna is used to transmit a signal, and multiple narrowband antennas receive signals. Phase method direction finding is performed based on the narrow beam antenna. Each narrowband antenna can obtain a phase value based on the I-path and Q-path information, and then the phase difference between the multiple narrowband antennas is obtained. Substituting the phase difference into the phase method angle measurement formula, multiple measurement angles containing fuzzy values ​​can be calculated. As for how to use the phase method to measure angles, it is existing knowledge and conventional technical means for those skilled in the art, and will not be repeated here. Furthermore, the measurement angle containing the ambiguous value is respectively brought into the directional diagram of the narrowband antenna and the broadband antenna, and the theoretical power ratios of the received signals of the multiple narrowband antennas and the broadband antenna are calculated under the multiple measurement angles containing the ambiguous value. In order to remove the ambiguous value of the measurement angle, the theoretical power ratio of the received signal is compared with the actual power ratio of the received signal of the narrowband antenna and the broadband antenna. The measurement angle corresponding to the theoretical power ratio of the received signal that is closest to the actual power ratio of the received signal is the true angle of the sounding balloon, thereby achieving the uniqueness of the measurement angle. After removing the multi-value ambiguity of the measurement angle, it is also necessary to determine whether the current sounding balloon is within the main lobe range of the antenna beam according to the true angle of the sounding balloon. If it is not within the main lobe, the motor is driven to rotate so that the sounding balloon falls into the main lobe beam of the antenna to achieve close-range search. In the technical solution disclosed in the implementation of the present invention, full use is made of the large variation in the gain of the narrowband antenna beam, and the maximum antenna gain G of the side lobe of the narrowband antenna directional diagram is set. N Broadband antenna gain G corresponding to the true angle of the sounding balloon UBy comparison, the ratio β is set as the threshold, and by comparing it with the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna, it is determined whether the sounding balloon falls into the main lobe beam of the antenna. If it is not in the main lobe, the motor is driven to rotate a certain angle under the premise that the rotation direction is consistent with the search direction, and the real angle of the sounding balloon is updated, and the received signal power value is repeatedly measured and compared and judged with the threshold until the sounding balloon enters the main lobe range of the narrowband antenna.

[0048] Through the above analysis, it can be known that in the technical solution disclosed in the implementation of the present invention, the advantages of broadband antennas and narrowband antennas are fully utilized, and the shortcomings of angle measurement by phase method and amplitude method are reasonably avoided. The characteristics of fast change of narrowband antenna beam gain and small change of broadband antenna gain are combined, which not only overcomes the multi-value of the measured angle, but also improves the accuracy of the measured angle, and realizes the close-range rapid search of the sounding balloon. In the prior art, multiple broadband antennas are used to complete the close-range search, and multiple narrowband antennas are used to complete the long-range search. The broadband antenna and the narrowband antenna are used independently of each other and are used for different distance modes, respectively, which leads to the complexity of the ground radar antenna system, reduced reliability, and poor wind resistance. Therefore, compared with the prior art, the present invention greatly reduces the complexity of the ground radar antenna system, is conducive to reducing economic costs, and improves wind resistance.

[0049] Furthermore, in the technical solution disclosed in the implementation of the present invention, if the sounding balloon is not in the main lobe, one measurement cannot determine whether the current sounding balloon is on the left or right side of the main lobe. In order to determine whether the rotation direction is consistent with the search direction, the characteristic of the broadband antenna beam gain change is small. After the motor is driven to rotate a certain angle, the signal power received by the broadband antenna is compared with that before the rotation. If the signal power is enhanced, the rotation direction is consistent with the search direction. If the signal power is weakened, the rotation direction is opposite to the search direction.

[0050] In the prior art, when the driving motor rotates to make the sounding balloon enter the main lobe range of the antenna beam, it is easy for the driving motor to rotate too much, causing the sounding balloon to exceed the main lobe range, or because the driving motor rotates too little, it takes a long time for the sounding balloon to enter the main lobe range of the antenna beam. This is mainly due to the unreasonable size of the driving motor rotation angle. The size of the driving motor rotation angle is related to the antenna beam position where the sounding balloon is located.

[0051] In order to solve this problem, the rotation angle of the driving motor is reasonably set. In the technical solution disclosed in the implementation of the present invention, if the sounding balloon is not in the main lobe, the angle of rotation of the driving motor is related to whether the current sounding balloon is in the first-level side lobe of the narrowband antenna. If it is in the first-level side lobe, the angle of rotation of the driving motor is the main lobe beam width of the narrowband antenna; if it is not in the first-level side lobe, the angle of rotation of the driving motor is half of the main lobe beam width of the narrowband antenna. The method for judging whether the sounding balloon is in the first-level side lobe is:

[0052] The maximum antenna gain of the first sidelobe of the narrowband antenna pattern is equal to the broadband antenna gain G U The ratio β1 is set as the first sidelobe threshold; the maximum antenna gain of the second sidelobe of the narrowband antenna pattern is divided by the broadband antenna gain G U In comparison, the ratio β2 is set as the second sidelobe threshold;

[0053] Compare the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna with the first sidelobe threshold β1 and the second sidelobe threshold β2 respectively, if:

[0054] α>β1, the sounding balloon is considered to be within the main lobe of the narrowband antenna;

[0055] β2<α≤β1, the sounding balloon is considered to be within the first sidelobe range of the narrowband antenna;

[0056] If α≤β2, the sounding balloon is considered to be out of the first sidelobe range of the narrowband antenna.

[0057] Typically, in the technical solution disclosed in the implementation of the present invention, the narrowband antenna of the ground radar is equipped with a large parabola, with a narrow beam direction and a main lobe beam of about 12°; the wide beam antenna has a small gain, a wide beam range, and a main lobe beam width of about 60°.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A secondary wind sounding radar close-range search method, characterized in that: The following steps are involved: (S1) using a broadband antenna to transmit a signal, using a phase angle measurement method to measure the phase difference between multiple narrowband antennas, and calculating multiple measurement angles containing ambiguity values; (S2) Substituting the multiple measurement angles containing ambiguity values ​​obtained in step (S1) into the directional diagrams of the narrowband antenna and the broadband antenna, and calculating the theoretical power ratio of the received signals of the multiple narrowband antennas and the broadband antenna under the multiple measurement angles containing ambiguity values; (S3) measuring and calculating the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna; (S4) comparing the multiple received signal theoretical power ratios with the received signal actual power ratio α to obtain the theoretical power ratio that is closest to the actual power ratio α, and determining the measured angle at this time as the true angle of the sounding balloon; (S5) Substitute the actual angle of the sounding balloon into the broadband antenna pattern to obtain the broadband antenna gain G U , the maximum antenna gain G of the sidelobe of the narrowband antenna pattern N With broadband antenna gain G U In comparison, the ratio β is set as the threshold; (S6) Compare the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna with the threshold β. If: α>β, then the sounding balloon is considered to be within the main lobe of the narrowband antenna; If α≤β, the sounding balloon is considered to be within the sidelobe range of the narrowband antenna, and step 7 is executed; (S7) On the premise that the rotation direction is consistent with the search direction, the motor is driven to rotate and the real angle of the sounding balloon is updated, and (S5) and (S6) are repeatedly executed until the sounding balloon enters the main lobe range of the narrowband antenna.

2. The secondary wind sounding radar close-range search method according to claim 1, characterized in that: In step (S7), the method for determining whether the rotation direction is consistent with the search direction is: After the driving motor rotates, the signal power received by the broadband antenna is compared with that before the rotation. If the signal power increases, the rotation direction is consistent with the search direction. If the signal power decreases, the rotation direction is opposite to the search direction.

3. The secondary wind sounding radar close-range search method according to claim 1, characterized in that: In step (S7), the driving motor rotates at an angle of: Determine whether the sounding balloon is within the first sidelobe of the narrowband antenna: If it is within the first-stage side lobe, the angle at which the drive motor rotates is the main lobe beam width of the narrowband antenna; If it is not within the first-stage side lobe, the angle at which the driving motor rotates is half the beam width of the main lobe of the narrowband antenna.

4. The secondary wind sounding radar close-range search method according to claim 3, characterized in that: The method to determine whether the sounding balloon is within the first sidelobe of the narrowband antenna is: The maximum antenna gain of the first sidelobe of the narrowband antenna pattern is equal to the broadband antenna gain G U In comparison, its ratio β1 is set as the first sidelobe threshold; The maximum antenna gain of the second sidelobe of the narrowband antenna pattern and the broadband antenna gain G U In comparison, the ratio β2 is set as the second sidelobe threshold; Compare the actual power ratio α of the received signal of the narrowband antenna and the broadband antenna with the first sidelobe threshold β1 and the second sidelobe threshold β2 respectively. If: α>β1, the sounding balloon is considered to be within the main lobe of the narrowband antenna; β2<α≤β1, the sounding balloon is considered to be within the first sidelobe range of the narrowband antenna; If α≤β2, the sounding balloon is considered to be out of the first sidelobe range of the narrowband antenna.

5. The secondary wind sounding radar close-range search method according to claim 3, characterized in that: The narrowband antenna main lobe beamwidth is 12°.