Short-wave antenna performance test system

Abstract

The invention relates to the technical field of mobile communication base stations, and particularly discloses a short-wave antenna performance test system, which is used for testing the short-wave antenna performance of a mobile communication base station, and comprises a transmitter connected with a tested short-wave antenna and used for transmitting a single-frequency-point signal with a specified short-wave frequency and monitoring output forward power and backward power; the unmanned aerial vehicle is used for providing longitude, latitude and elevation of the center point of the short-wave antenna; the field intensity meter is carried by the unmanned aerial vehicle and is used for receiving the signal transmitted by the measured antenna and carrying out spectrum analysis and field intensity measurement operation, and the monitoring frequency setting of the field intensity meter comprises the transmitter frequency; and the ground monitoring terminal is used for collecting monitoring and measuring information of the unmanned aerial vehicle and the transmitter, calculating and drawing an antenna pattern by combining the antenna transmitting frequency and the field intensity acquired by the field intensity meter, and calculating gain. The problems that a short-wave antenna space directional diagram and gain are difficult to measure, and environment interference is caused are solved, and high-precision and full-space coverage short-wave antenna performance testing is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile communication base stations, and particularly relates to a performance test system for short-wave antennas used in mobile communication base stations. Background Art

[0002] Existing short-wave antennas are mostly fixedly erected at antenna sites due to their large size and cannot be measured in a laboratory. Existing large short-wave antennas can measure ground antennas on the ground using an antenna and a spectrum analyzer (or receiver). However, since the main radiation direction of the short-wave antenna is towards the air, ground monitoring can only understand the antenna performance at the ground, so the antenna pattern and gain in space cannot be understood.

[0003] Therefore, for the antenna pattern and gain of existing large short-wave antennas, a drone is further used to carry a broadband field strength probe. By utilizing the characteristics of the drone such as accurate positioning and path planning for cruising, the spatial electric field distribution and antenna field pattern of the short-wave antenna are measured and obtained through theoretical calculation or simulation. For example, in the prior art, a method for measuring the gain of a short-wave antenna based on a drone with the application number 202410385145.1. However, in the actual use process, this method still has the following deficiencies:

[0004] (1) Conventionally, a drone is used to carry a broadband field strength probe to measure a short-wave antenna, and the frequency cannot be measured, so it is impossible to confirm that the measured field strength is only emitted by the antenna under test, which is applicable to the scenario where there is only the signal emitted by the antenna under test in the environment and the field strength is greater than the detection lower limit of the probe.

[0005] (2) The conventional detection lower limit of the probe is usually 0.2 V / m, which is too high a field strength requirement for most short-wave antennas. Only those large short-wave transmitting antennas or in the near field can generate such a large field strength, so it is not applicable to many scenarios of short-wave antennas.

[0006] (3) The conventional measurement of the antenna field pattern only reflects the field pattern distribution of the antenna in the near field, which is different from the antenna pattern. The antenna pattern needs to be tested under far-field conditions, and the antenna gain cannot be obtained from the antenna field pattern diagram.

[0007] (4) In the prior art, the measurement of gain often relies on a preset flight path or manual measurement, cannot be dynamically corrected, and can only calculate the gain in the preset maximum radiation direction, and cannot ensure that the gain calculation is based on the actual maximum radiation direction. Therefore, key parameters such as sidelobe level and beam width cannot be obtained, and only the gain in the main lobe direction can be reflected in the actual use process, and the actual coverage ability of the antenna cannot be comprehensively evaluated. Therefore, it is not applicable to the performance test of short-wave antennas in complex environments.

[0008] Therefore, this application specifically proposes a short-wave antenna performance test system to solve the above technical problems. Summary of the Invention

[0009] The main object of the present invention is to provide a short-wave antenna performance testing system to solve the technical problems raised in the background art.

[0010] The present invention adopts the following technical solutions to solve the above technical problems:

[0011] A short-wave antenna performance testing system includes:

[0012] A transmitter, as a ground transmitting device, is connected to the short-wave antenna under test at the output end. This antenna can be a receiving antenna or a transmitting antenna, and is used to transmit a single-frequency signal of a specified short-wave frequency, and at the same time monitor the forward power and backward power of the output;

[0013] An unmanned aerial vehicle (UAV), as a monitoring point, is used to provide the longitude, latitude, and altitude of the center point of the short-wave antenna;

[0014] An electric field strength meter, carried by the UAV, consists of a three-axis orthogonal loop magnetic field antenna and a spectrum analysis module, and has the capabilities of spectrum analysis and field strength measurement. It is used to receive the signal emitted by the antenna under test and perform spectrum analysis and field strength measurement operations. The monitoring frequency setting of the electric field strength meter includes the transmitter frequency;

[0015] Information such as the monitoring frequency, monitoring field strength, longitude, latitude, and altitude of the UAV is transmitted wirelessly to the ground monitoring terminal in real time;

[0016] The ground monitoring terminal is used to collect the monitoring and measurement information of the UAV and the transmitter, combine the antenna emission frequency and field strength obtained by the analysis and measurement of the electric field strength meter, calculate and draw the antenna pattern, and calculate the gain in decibel form based on the azimuth and elevation components of the actual distance and the electric field strength. The ground monitoring terminal is time-synchronized with the transmitter and the UAV.

[0017] Preferably, during the operation of the short-wave antenna performance testing system, the monitoring point is set in the far field area. When monitoring in the far field area, the distance S between the monitoring point and the antenna should satisfy the larger value between 5 times the wavelength of the operating frequency and 5 times the maximum antenna size. At this time, it can be considered that the monitoring point is in the far field area. For a short-wave antenna, considering the ground mirror of the maximum antenna size, the determination condition for the monitoring point to be in the far field area is:

[0018] S≥max(5λ + 5D max )

[0019]

[0020] where S is the distance between the monitoring point and the short-wave antenna under test, and D max$D$ is the maximum antenna size of the short-wave antenna under test, $H$ is the erection height of the short-wave antenna under test, $L$ is the length of the short-wave antenna under test, and $W$ is the width of the short-wave antenna under test.

[0021] Preferably, during the performance test operation of the short-wave antenna, the flight trajectory of the unmanned aerial vehicle is set as a circle or a semi-circle centered on the short-wave antenna under test (longitude, latitude, altitude) for performing the operation of drawing the antenna pattern. Specifically, the flight trajectory of the unmanned aerial vehicle includes:

[0022] When the drawing of the antenna pattern is set as the horizontal antenna pattern, the flight trajectory of the unmanned aerial vehicle is correspondingly set as a horizontal circle with a height from the ground of $h = r\times\sin\theta + H$ and a radius of $r = R\times\cos\theta$, where $R$ is the flight monitoring sphere radius of the horizontal antenna pattern and $\theta$ is the elevation angle of the horizontal antenna pattern.

[0023] When the drawing of the antenna pattern is set as the vertical antenna pattern, the flight trajectory of the unmanned aerial vehicle is correspondingly set as a vertical semi-circle crossing the center point of the antenna. The radius of the semi-circle is the same as the flight monitoring sphere radius, which is $R$.

[0024] Preferably, the short-wave antenna under test is set as a wire antenna. The main radiation direction is usually perpendicular to the antenna element, and for some antennas, the main radiation direction is along the antenna element.

[0025] Preferably, the operation process of drawing the antenna pattern includes:

[0026] Measure and analyze the vertical antenna pattern data to obtain the main radiation elevation angle;

[0027] Measure the horizontal antenna pattern data at the main radiation elevation angle;

[0028] Obtain the azimuth angle of the monitoring point through the vertical antenna pattern data and the horizontal antenna pattern data, and calculate the gain of the short-wave antenna under test by combining the monitoring data of the unmanned aerial vehicle and the field strength meter;

[0029] Draw the gain change curve of the short-wave antenna under test to obtain the vertical antenna pattern and the horizontal antenna pattern.

[0030] Preferably, the measurement process of the vertical antenna pattern data includes:

[0031] At azimuth angles of and centered on the short-wave antenna under test, use the vertical semi-circle perpendicular to the antenna element of the short-wave antenna under test as the flight monitoring trajectory, set a number of waypoints, set the flight trajectory between waypoints as a vertical arc, and change the pitch angle attitude of the unmanned aerial vehicle during the flight along the flight monitoring trajectory for monitoring. At this time, the elevation angle $\alpha$ corresponding to the maximum field strength is set as the main radiation elevation angle.

[0032] Preferably, the measurement process of the horizontal antenna pattern data includes:

[0033] If the main radiation elevation angle α ≤ 70°, then change the azimuth angle. With the short-wave antenna under test as the center, with a radius of R, and a horizontal circle with an elevation angle of α as the flight monitoring trajectory, set a series of flight points on the horizontal circle, and set horizontal arcs for the flight trajectories between the flight points. During the process of using the UAV to fly along the flight monitoring trajectory, keep the pitch angle unchanged for monitoring, and finally obtain the horizontal antenna pattern at the main radiation elevation angle.

[0034] If the main radiation elevation angle α > 70°, it indicates that the antenna has a high elevation angle. At this time, for the horizontal antenna pattern, the main radiation elevation angle α is set to 70° in the measurement process.

[0035] Preferably, the gain calculation process of the short-wave antenna under test includes:

[0036] Integrate the UAV monitoring data and the transmitter monitoring data into a data record according to the data acquisition time;

[0037] Calculate the actual distance r between the monitoring point and the antenna center point from the longitude, latitude, and altitude of the monitoring point, as well as the longitude, latitude, and altitude of the antenna center point;

[0038] Subtract the backward power from the forward power of the transmitter and consider the insertion loss brought by the antenna feeder to calculate the net input power P at the antenna port in ;

[0039] Calculate and obtain the gain at the azimuth angle and elevation angle θ and take the maximum value of the gain as the gain of the antenna. The formula for the gain is:

[0040]

[0041] where the azimuth angle is the azimuth angle of the monitoring point relative to the antenna center point, is the field strength measured by the field strength meter.

[0042] Preferably, the drawing process of the vertical antenna pattern and the horizontal antenna pattern includes:

[0043] Draw a curve of the gain varying with the pitch angle θ for the measured azimuth angle and use polar coordinates to obtain the vertical antenna pattern;

[0044] Draw a curve of the gain varying with the azimuth angle at the measured elevation angle θ0 and use polar coordinates to obtain the horizontal antenna pattern.

[0045] Preferably, the external structure of the three-axis orthogonal circular magnetic field antenna is vertically downward from the fuselage, and the overall isotropic index of the UAV and the field strength meter is optimized to be less than 1.5 dB.

[0046] Preferably, the frequency range measured by the system is set to cover the short-wave frequency band of 2 MHz - 30 MHz, the electric field measurement sensitivity is set to 1 mV / m, the data acquisition rate is set to more than 5 times per second, and the transmitter output power is set to 10 W to support the overall monitoring operation of the UAV and the field strength meter during flight.

[0047] As can be seen from the above technical solutions, the present invention provides a short-wave antenna performance test system. Compared with the prior art, the present invention has the following advantages:

[0048] 1. The present invention solves the problems of difficult measurement of the spatial pattern and gain of short-wave antennas and environmental interference by using a UAV to carry a field strength meter with a three-axis orthogonal circular magnetic field antenna and a spectrum analysis module, and combines far-field area monitoring and synchronous calculation. Through gain calculation evaluation and high-precision and high-efficiency drawing of the spatial pattern, high-precision and full-space coverage short-wave antenna performance testing is realized.

[0049] 2. The present invention comprehensively considers the antenna size, height, and mirror effect to determine the monitoring points in the far-field area for monitoring, which can ensure that the monitoring points meet the radiation field distribution law, thereby ensuring the validity of the measurement data, solving the problem of large measurement errors in the near-field area, and improving the accuracy of antenna gain calculation.

[0050] 3. The present invention can realize continuous layout of monitoring points, improve data acquisition efficiency, and facilitate rapid drawing of high-resolution antenna patterns by setting the UAV to fly along continuous flight trajectories of horizontal circles and vertical semi-circles and using non-hovering measurement.

[0051] 4. The present invention dynamically correlates the forward power and backward power of the transmitter and calculates the gain in combination with the field strength and distance, which can convert environmental factors into quantitative parameters, facilitate the analysis of simplified complex field strengths, solve the defect that traditional gain calculation depends on empirical models, and realize automated and standardized gain evaluation.

[0052] 5. The present invention calculates the gain in decibel form based on the azimuth and elevation components of the actual distance and the electric field strength, which can improve the accuracy and applicability scenario flexibility of gain calculation, and combines multi-angle data when drawing vertical and horizontal patterns to comprehensively display the radiation characteristics of the antenna, and is applicable to short-wave antenna performance testing and optimization in complex environments.

[0053] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. Of course, any product implementing the present invention does not necessarily need to achieve all of the above-described advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0055] Figure 1 is a schematic diagram of the overall system framework structure of the present invention;

[0056] Figure 2 is a schematic diagram of the system data acquisition structure of the present invention;

[0057] Figure 3 is a schematic diagram of the flight trajectory of the unmanned aerial vehicle in the state of measuring the antenna pattern of the present invention;

[0058] Figure 4 is a three-dimensional sectional view of the pressure plate limiting assembly of the present invention;

[0059] Figure 5 is an example of an antenna pattern in the prior art, where: the left figure is an example of a three-dimensional antenna pattern, the upper right figure is an example of a horizontal plane antenna pattern, and the lower right figure is an example of a vertical plane antenna pattern. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0060] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Without conflict, the embodiments and features in this application can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0061] In the embodiment, refer in detail to Figures 1 to 5 .

[0062] As Figure 1 and Figure 2 shown, a short-wave antenna performance test system proposed in an embodiment of the present invention includes an unmanned aerial vehicle, an unmanned aerial vehicle carrying a three-axis omnidirectional frequency-selective field strength meter (including a spectrum analyzer and an antenna), a ground receiving and monitoring terminal, a ground transmitting device, an unmanned aerial vehicle ground station, and a short-wave vertically polarized receiving standard antenna, where:

[0063] A ground-based transmitting device (transmitter) with its output connected to the short-wave antenna under test for transmission. It can work independently or be controlled by a ground receiving and monitoring terminal. The antenna can be a receiving antenna or a transmitting antenna, transmitting a certain short-wave frequency, a single-frequency signal, and monitoring the forward power and backward power output by the transmitter.

[0064] A drone is equipped with a three-axis omnidirectional frequency-selective field strength meter (including a spectrum analyzer and an antenna). The field strength meter consists of three orthogonal antennas and a spectrum analysis module, and has the capabilities of spectrum analysis and field strength measurement. The monitoring frequency setting of the field strength meter includes the transmitter frequency and, in a specific embodiment, can also be the same as the transmitter frequency to effectively filter out environmental interference signals and facilitate accurate identification of the field strength emitted by the antenna under test.

[0065] The drone provides the longitude, latitude, and elevation of the antenna center point, and the drone uses RTK positioning to improve the positioning accuracy. The drone communicates wirelessly with the drone ground station, and the ground receiving and monitoring terminal receives real-time field strength, frequency, longitude, latitude, elevation, waypoint, and time and other information relayed by the drone ground station.

[0066] The drone, the ground monitoring terminal, and the transmitter are time-synchronized, capable of accurately correlating field strength, power, and position data, eliminating time-delay errors, thereby ensuring the reliability of data collection and the accuracy of antenna pattern calculation, drawing, and finally gain calculation.

[0067] It should be explained that the most important role of the drone is to serve as a carrying platform for the field strength meter to reach the predetermined monitoring points in space. It is the carrier for realizing flight monitoring, providing monitoring time, point information (including longitude, latitude, and altitude), as well as flight state information such as waypoints, flight speed, and heading angle for the entire monitoring. And it timestamp each of these information and the field strength monitoring data of the field strength meter and send them back to the ground monitoring terminal. During operation, the drone flies horizontally or vertically around the short-wave antenna under test in a certain radius according to the flight monitoring plan. The drone equipped with the field strength meter measures the electric field strength E(r, θ, φ) generated at the spatial points with distance r, elevation angle θ, and azimuth angle φ in the far field of the transmitting antenna, and calculates the antenna directivity coefficient corresponding to each monitoring point (azimuth angle φ, elevation angle θ) centered on the short-wave antenna under test through information such as field strength, distance, and transmission power.

[0068] In addition, it should be supplemented that during actual use, a vertically polarized receiving antenna is used to calibrate the measurement data of the field strength meter on the drone. The antenna carried by the drone is optimized as follows Figure 4The shown three-axis orthogonal loop magnetic field antenna consists of three orthogonal loop coils as the magnetic field antenna. The external structure of the antenna is perpendicular to the fuselage downward, ensuring the isotropy of the whole UAV. The isotropy index of the whole antenna (including the UAV) is set to be less than 1.5 dB, which can ensure the isotropy of measurement from the physical structure, and ensure the consistency of field strength measurement under different orientations of the UAV during the measurement process, playing a role in avoiding the interference of antenna directivity. Compared with the traditional use of electric field antennas, the magnetic field measured by the magnetic field antenna used in this system is relatively less affected by the distortion of the UAV fuselage. Therefore, it can ensure that the field strength measurement is not affected by the UAV attitude, guaranteeing the reliability of data acquisition in a complex electromagnetic environment.

[0069] In summary, by mounting a field strength meter composed of a three-axis orthogonal loop magnetic field antenna on the UAV, it can effectively eliminate the distortion effect of the UAV fuselage on the electromagnetic field, improve the measurement accuracy, thus solving the problem that it is difficult to measure the radiation pattern and gain of traditional short-wave antennas, and realizing the high-precision performance test of large short-wave antennas and antenna arrays.

[0070] Furthermore, the frequency range measured by the system is set to cover the 2 MHz - 30 MHz short-wave band, the electric field measurement sensitivity is set to 1 mV / m, the data acquisition rate is set to more than 5 times per second, and the transmitter output power is set to 10 W to support the monitoring operation during flight without the need for hovering monitoring. It is convenient to fly horizontally in a circle or vertically in a semicircle around the antenna at the center in the far field of the short-wave antenna to be measured. At this time, the frequency and field strength of the antenna emission can be combined with the collected longitude, latitude, and altitude information to draw the antenna radiation pattern and gain.

[0071] Therefore, by designing the continuous flight trajectory (non-hovering measurement) of the UAV along a horizontal circle and a vertical semicircle, it can realize the continuous layout of monitoring points, thereby improving the data acquisition efficiency, solving the problem of insufficient layout density in traditional fixed-point measurement, and facilitating the rapid drawing of a high-resolution antenna radiation pattern.

[0072] In the specific implementation process, the system ensures the measurement accuracy through the following experiments:

[0073] In the electromagnetic field, metal media cause distortion to the electric field (the electric field lines are perpendicular to the metal surface). Therefore, magnetic media will cause distortion to the magnetic field distribution around them. Therefore, the UAV used in this system usually has components such as metal and carbon fiber, and basically no magnetic media.

[0074] At this time, using a magnetic field antenna is less affected by the field distortion of the UAV fuselage compared to using an electric field antenna. Its specific tests include:

[0075] (1) Precision debugging:

[0076] Under the transmitting state of the short-wave antenna under test, at the same point in the far field area of the antenna, an active loop antenna is connected to a spectrum analyzer, adjusted to the maximum receiving direction, the signal level emitted by the short-wave antenna under test is measured, and the antenna coefficient is multiplied to obtain the electric field strength of the signal;

[0077] Use the UAV test system for short-wave antenna performance to measure the electric field strength of the signal emitted by the short-wave antenna under test at the same point and height;

[0078] Compare the electric field strengths measured by the above two measuring devices. If the difference is within 2 dB, it meets the requirements of measurement accuracy.

[0079] (2) Measurement records:

[0080] During the measurement process, adjust the direction of the loop antenna in the horizontal and pitch directions, find the direction with the maximum measured level, and record the measured level;

[0081] Monitor the level value (dBμV), multiply it by the electric field antenna coefficient to obtain the electric field strength in dBμV / m, and then convert it to the electric field strength in V / m.

[0082] The test data is as follows:

[0083] The output of the ground transmitting equipment (transmitter) is connected to a dipole antenna. The dipole antenna is the transmitting antenna. Measure the frequency, forward power, and backward power of the transmitted signal. Subtract the backward power from the forward power to obtain the power radiated from the antenna. First, use an active loop antenna to connect to the ground receiving and monitoring equipment at a certain distance from the above dipole antenna to receive and measure the level of the electromagnetic field signal emitted by the dipole antenna, and then convert it to the electric field strength in V / m. The calculation formula: Electric field strength (V / m) = 10^((level (dBm) + antenna coefficient (dB1 / m) + 107) / 20) * 0.000001. Take the field strength measured by this loop antenna as the reference electric field strength. Then let the UAV (equipped with receiving and monitoring equipment) measure at the same point and height as the loop antenna to obtain the electric field strength, and then compare it with the reference electric field strength measured by the loop antenna to verify the accuracy of the UAV measurement. The precision measurement data is as follows:

[0084]

[0085] (3) Conclusion description:

[0086] It can be seen that when the above-mentioned dipole antenna operates at frequencies of 5 MHz and 14 MHz, at the same point, the electric field intensity measured by the UAV test system for the short-wave antenna performance is basically the same as that measured by the loop antenna (including ground receiving and monitoring equipment). The measured values of the electric field intensity of the UAV test system at 5 MHz and 14 MHz deviate from the measured values of the loop antenna by -0.2 dB and 0.48 dB respectively, indicating that the measurement accuracy of the UAV test system for the short-wave antenna performance meets the requirement of 2 dB, that is, the measurement error achieved by this system is very small.

[0087] In the specific implementation process, the operation process of this short-wave antenna performance test system includes:

[0088] The first step: Determine the position of the monitoring point.

[0089] It should be noted that according to conventional theory, the antenna pattern and gain measurement of a short-wave antenna need to be measured in the far field area, and the farther the test distance, the better. However, from the perspective of actual engineering practice, there cannot be an infinitely far distance for testing, and if the distance is too close, the problem of inaccurate measurement of the pattern will also occur. Therefore, based on the actual short-wave antenna performance test requirements, this system determines the monitoring point position that is most suitable for the system test application to meet the actual engineering test application requirements. The specific operation is as follows:

[0090] During the operation process of the system for performing short-wave antenna performance tests, the monitoring point is set in the far field area. When monitoring in the far field area, the distance S between the monitoring point and the antenna should satisfy the larger value between being greater than or equal to 5 times the wavelength of the operating frequency and 5 times the maximum antenna size. At this time, it can be considered that the monitoring point is located in the far field area. For a short-wave antenna, considering the ground mirror image for the maximum antenna size, the determination condition for the monitoring point to be located in the far field area is:

[0091] S≥max(5λ + 5D max )

[0092]

[0093] Among them, S is the distance between the monitoring point and the short-wave antenna under test, D max is the maximum antenna size of the short-wave antenna under test, H is the erection height of the short-wave antenna under test, L is the length of the short-wave antenna under test, and W is the width of the short-wave antenna under test.

[0094] In summary, by using the far field area distance calculation formula (comprehensively considering the antenna size, height, and mirror image effect), it is possible to determine that the monitoring point is monitored in the far field area, ensure that the monitoring point meets the radiation field distribution law, thereby guaranteeing the validity of the measurement data, solving the problem of large measurement errors in the near field area, and improving the accuracy of antenna gain calculation.

[0095] The second step is to set the flight trajectory of the UAV.

[0096] During the operation of the system for performing short-wave antenna performance tests, the flight trajectory of the unmanned aerial vehicle (UAV) is set as a circle or semi-circle centered at the short-wave antenna under test (longitude, latitude, altitude) for performing the operation of drawing the antenna pattern, where the flight trajectory of the UAV refers to Figure 3 , specifically including:

[0097] When the drawing of the antenna pattern is set as the horizontal antenna pattern, the flight trajectory of the UAV is correspondingly set as a horizontal circle with a height from the ground of h = r×sinθ + H and a radius of r = R×cosθ, where R is the radius of the flight monitoring sphere of the horizontal antenna pattern and θ is the elevation angle of the horizontal antenna pattern;

[0098] When the drawing of the antenna pattern is set as the vertical antenna pattern, the flight trajectory of the UAV is correspondingly set as a vertical semi-circle spanning the center point of the antenna, and the radius of the semi-circle is the same as the radius of the flight monitoring sphere, which is R.

[0099] At this time, the short-wave antenna under test is set as a wire antenna, and the main radiation direction is usually perpendicular to the antenna element. For some antennas, the main radiation direction is along the direction of the antenna element.

[0100] In summary, the present application dynamically generates a flight path through geometric formulas, which is directly related to the elevation angle of the antenna.

[0101] In the third step, calculate and evaluate the gain of the short-wave antenna under test, and perform the operation of drawing the antenna pattern.

[0102] The specific process includes:

[0103] (1) Measure and analyze the vertical antenna pattern data to obtain the main radiation elevation angle;

[0104] At this time, the measurement process of the vertical antenna pattern data includes:

[0105] At azimuth angles of and , with the short-wave antenna under test as the center, use the vertical semi-circle along the antenna element perpendicular to the short-wave antenna under test as the flight monitoring trajectory, set a number of waypoints, and set the flight trajectory between waypoints as a vertical arc. During the process of using the UAV to fly along the flight monitoring trajectory, change the pitch angle attitude of the UAV for monitoring. At this time, the elevation angle α corresponding to the maximum field strength obtained is set as the main radiation elevation angle, that is: in the vertical pattern measurement, the UAV continuously scans by dynamically changing the pitch angle attitude, so as to obtain the main radiation elevation angle corresponding to the maximum field strength in real time. During the horizontal pattern measurement, keep the elevation angle fixed. Therefore, the solution of the present application supports dynamic elevation angle adjustment and can achieve continuous measurement.

[0106] At this time, by dynamically adjusting the attitude of the UAV, a wider elevation angle range is covered, and the main radiation elevation angle of the antenna is accurately captured. The main radiation elevation angle (α) is determined based on the actual measurement data instead of relying on a preset value, ensuring that the gain calculation is consistent with the true radiation characteristics of the antenna.

[0107] (2) Measure the horizontal antenna pattern data at the main radiation elevation angle;

[0108] At this time, the measurement process of the horizontal antenna pattern data includes:

[0109] If the main radiation elevation angle α ≤ 70°, then change the azimuth angle. With the measured short-wave antenna as the center, with a radius of R, and a horizontal circle with an elevation angle of α as the flight monitoring trajectory, set a series of waypoints on the horizontal circle, and set horizontal arcs for the flight trajectories between waypoints. During the flight of the UAV along the flight monitoring trajectory, keep the pitch angle unchanged for monitoring, and finally obtain the horizontal antenna pattern at the main radiation elevation angle;

[0110] If the main radiation elevation angle α > 70°, it indicates that the antenna is at a high elevation angle. At this time, for the horizontal antenna pattern, the main radiation elevation angle α is set to 70° in the measurement process.

[0111] At this time, the flight trajectories for measuring the vertical antenna pattern, analyzing the vertical antenna pattern, etc. Figure 3 , the antenna is installed at the Zp position, with the ground plane below. The circle of the blue line segment is the flight trajectory for horizontal monitoring and circumferential flight, and the semi-circle of the green line is the flight trajectory during vertical monitoring, that is, the semi-circle perpendicular to the ground plane passing directly above the antenna.

[0112] (3) Obtain the azimuth angle of the monitoring point through the vertical antenna pattern data and the horizontal antenna pattern data, and calculate the gain of the measured short-wave antenna by combining the monitoring data of the UAV and the field strength meter;

[0113] At this time, the gain calculation process of the measured short-wave antenna includes:

[0114] Integrate the UAV monitoring data and the transmitter monitoring data into a data record according to the data acquisition time;

[0115] Calculate the actual distance r between the monitoring point and the antenna center point from the longitude, latitude, and altitude of the monitoring point, as well as the longitude, latitude, and altitude of the antenna center point;

[0116] Subtract the backward power from the forward power of the transmitter and consider the insertion loss caused by the antenna feeder to calculate the net input power P at the antenna port in ;

[0117] Calculate and obtain the gain at the azimuth angle and the elevation angle θ The maximum gain is taken as the gain of the antenna. At this time, based on the azimuth and elevation components of the actual distance and electric field strength, the calculated gain is expressed in decibels. The calculation formula is:

[0118]

[0119] Among them, the azimuth is the azimuth of the monitoring point relative to the center point of the antenna, and is the electric field strength measured by the field strength meter.

[0120] In summary, dynamically correlating the forward power and backward power of the transmitter and combining the electric field strength and distance to calculate the gain can convert environmental factors into quantitative parameters, facilitating the analysis of complex electric field strength by simplification, solving the defect that traditional gain calculation relies on empirical models, and realizing automated and standardized gain evaluation. In addition, by setting a co-frequency monitoring mechanism in the transmitter and the field strength meter, it can also solve the problem of field strength attribution in a multi-signal environment in the prior art, achieving accurate measurement of only the target antenna signal in a complex electromagnetic environment.

[0121] In addition, it should be further noted that at this time, compared with the conventional gain calculation of the prior art (a method for measuring the gain of a short-wave antenna based on an unmanned aerial vehicle with the application number 202410385145.1 in the prior art), although the overall calculation direction is the same, in practical applications, the prior art cannot match the engineering standards (such as dBd / dBi), and the operation is cumbersome. However, this application is superior in that it can directly output the gain value in decibels, seamlessly connect with the antenna gain standards (such as dBd / dBi) in engineering practice, so no additional conversion is required, thus simplifying the data processing process. At the same time, this application can also ensure that the gain calculation is based on the actual maximum radiation direction rather than a preset assumption through the dynamic optimization of the main radiation elevation angle, thereby improving the accuracy. Moreover, the solution of this application can adapt to the position changes during the dynamic flight of the unmanned aerial vehicle, avoid distance errors caused by flight deviations, and realize dynamic adjustment of the gain result during the flight of the unmanned aerial vehicle. In summary, compared with the static formula and simplified model proposed in the prior art, this application can significantly improve the accuracy and applicability scenario flexibility of gain calculation through multi-dimensional parameter integration and dynamic optimization, and comprehensively display the antenna radiation characteristics by combining multi-angle data when drawing the vertical and horizontal direction diagrams subsequently, and is applicable to the performance test and optimization of short-wave antennas in complex environments.

[0122] (4) Draw the gain change curve of the measured short-wave antenna, and obtain the vertical antenna pattern and the horizontal antenna pattern. At this time, the vertical antenna pattern and the horizontal antenna pattern can refer to the antenna pattern format adopted by the prior art, such as Figure 5 shown. The left figure is an example of a three-dimensional antenna pattern, the upper right figure is an example of a horizontal plane antenna pattern, and the lower right figure is an example of a vertical plane antenna pattern;

[0123] The drawing process of the vertical antenna pattern and the horizontal antenna pattern at this time includes:

[0124] Draw the measured azimuth angle The curve of the gain varying with the elevation angle θ is drawn, and polar coordinates are used to obtain the vertical antenna pattern;

[0125] Draw the curve of the gain varying with the azimuth angle at the measured elevation angle θ0, and polar coordinates are used to obtain the horizontal antenna pattern.

[0126] In summary, the operation process of the short-wave antenna performance test system can solve the problems of difficult measurement of the spatial pattern and gain of short-wave antennas and environmental interference in the prior art by using a field intensity meter carried by a drone with a three-axis orthogonal loop magnetic field antenna and a spectrum analysis module, combined with far-field area monitoring and synchronous calculation. Through gain calculation evaluation and efficient and high-precision drawing of the spatial pattern, high-precision and full-space coverage short-wave antenna performance testing is achieved.

[0127] In addition, it can be further proposed that the measurement scheme adopted by this system can be applied not only to short-wave antennas, especially short-wave receiving antennas, but also to performance testing of large antenna arrays. The measurement flight of the pattern can be carried out at different flight monitoring sphere radii, and the larger the radius, the better the effect. In actual use, it is not necessarily required to be determined according to 5 times the wavelength or 5 times the maximum size of the antenna.

[0128] In addition, the vertically polarized receiving standard antenna adopted by this system is selected and used according to the actual test application requirements, and it is not a necessary structure of the device.

[0129] On the other hand, a computer-readable storage medium is provided inside the ground monitoring terminal adopted by the present invention, storing a computer program. When the computer program is executed by a processor, the processor performs corresponding calculation operation steps based on the above system.

[0130] On yet another hand, the ground monitoring terminal adopted by the present invention includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs corresponding calculation operation steps based on the above system.

[0131] In another embodiment provided by this application, a computer program product containing instructions is also provided. When it runs on a computer, the computer performs any calculation operation step based on the above short-wave antenna performance test system.

[0132] It is understandable that the system provided by the embodiments of the present invention corresponds to the method provided by the embodiments of the present invention. For the explanations, examples and beneficial effects of the relevant content, reference can be made to the corresponding parts in the above method.

[0133] An embodiment of the present application further provides an electronic device, including a processor, a communication interface, a memory, and a communication bus. Among them, the processor, the communication interface, and the memory complete communication with each other through the communication bus.

[0134] The memory is used to store a computer program.

[0135] When the processor is used to execute the program stored in the memory, it performs any calculation operation step based on the above short-wave antenna performance test system.

[0136] The communication bus mentioned in the above electronic device may be a peripheral component interconnect standard bus or an extended industry standard architecture bus, etc. This communication bus can be divided into an address bus, a data bus, a control bus, etc.

[0137] The communication interface is used for communication between the above electronic device and other devices.

[0138] The memory may include a random access memory, and may also include a non-volatile memory, such as at least one disk memory. Optionally, the memory may also be at least one storage device located far from the aforementioned processor.

[0139] The above-mentioned processor may be a general-purpose processor, including a central processing unit, a network processor, etc.; it may also be a digital signal processor, an application-specific integrated circuit, a field programmable gate array, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0140] It should also be noted that the electronic device further includes a terminal device, which can also be referred to as a terminal, a user equipment, a mobile station, a mobile terminal, etc. The terminal device may be a mobile phone, a smart TV, a wearable device, a tablet computer, a computer with wireless transceiver function, a virtual reality terminal device, an augmented reality terminal device, a wireless terminal in industrial control, a wireless terminal in unmanned driving, a wireless terminal in remote surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, and so on. The embodiments of the present application do not limit the specific technologies and specific device forms adopted by the terminal device.

[0141] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server or data center that includes one or more integrated available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium, or a semiconductor medium (e.g., solid-state drive), etc.

[0142] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0143] In addition, it should be noted that if there are directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0144] In addition, if there are descriptions such as "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" that appears throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, scenario B, or the scenario where A and B are satisfied simultaneously. In addition, in the embodiments of the present invention, "a plurality" means two or more. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

Claims

1. A shortwave antenna performance test system, characterized in that: include: The transmitter, as a ground transmitting device, has a shortwave antenna under test connected to its output end, and is used to transmit a single-frequency signal of a specified shortwave frequency and simultaneously monitor the output forward power and backward power; The drone, as a monitoring point, is used to provide the longitude, latitude, and elevation of the shortwave antenna center point; The field strength meter is carried by a drone and consists of a three-axis orthogonal circular magnetic field antenna and a spectrum analysis module. It is used to receive the signal emitted by the antenna under test and perform spectrum analysis and field strength measurement operations. The monitoring frequency setting of the field strength meter includes the transmitter frequency. The ground monitoring terminal is used to collect monitoring and measurement information of the UAV and the transmitter, calculate and draw the antenna radiation pattern by combining the antenna transmission frequency and field strength obtained by the field strength meter analysis measurement, and calculate the gain in decibel form based on the actual distance and the azimuth and elevation components of the electric field strength. The ground monitoring terminal is synchronized with the transmitter and the UAV.

2. The shortwave antenna performance test system as claimed in claim 1, characterized in that: During the shortwave antenna performance test operation performed by the system, the monitoring point is set in the far field area. The determination condition that the monitoring point is in the far field area is: S≥max(5λ+5D max ) Where S is the distance between the monitoring point and the shortwave antenna under test, D max is the maximum antenna size of the shortwave antenna under test, H is the installation height of the shortwave antenna under test, L is the length of the shortwave antenna under test, and W is the width of the shortwave antenna under test.

3. The shortwave antenna performance test system according to claim 1, characterized in that: During the shortwave antenna performance test operation performed by the system, the flight trajectory of the drone is set to a circle or a semicircle with the shortwave antenna under test as the center point, which is used to perform the antenna pattern drawing operation, wherein the flight trajectory of the drone specifically includes: When the antenna pattern drawing is set to a horizontal antenna pattern, the UAV flight trajectory is correspondingly set to a horizontal circle with a height from the ground of h=r×sinθ+H and a radius of r=R×cosθ, where R is the flight monitoring sphere radius of the horizontal antenna pattern, and θ is the elevation angle of the horizontal antenna pattern; When the antenna pattern is drawn as a vertical antenna pattern, the UAV flight trajectory is correspondingly set to a vertical semicircle crossing the center point of the antenna, and the radius of the semicircle is the same as the radius of the flight monitoring sphere, which is R.

4. The shortwave antenna performance test system as claimed in claim 3, characterized in that: The shortwave antenna to be tested is set as a linear antenna, and the drawing operation process of the antenna pattern includes: Measure and analyze vertical antenna pattern data to obtain the main emission elevation angle; Measure the horizontal antenna pattern data at the main beam elevation angle; The azimuth of the monitoring point is obtained through the vertical antenna pattern data and the horizontal antenna pattern data, and the gain of the shortwave antenna under test is calculated by combining the monitoring data of the UAV and the field strength meter; Draw the gain change curve of the shortwave antenna under test and obtain the vertical antenna radiation pattern and the horizontal antenna radiation pattern.

5. The shortwave antenna performance test system as claimed in claim 4, characterized in that: The measurement process of the vertical antenna pattern data includes: In azimuth and When the shortwave antenna under test is taken as the center, a vertical semicircle perpendicular to the antenna vibrator of the shortwave antenna under test is used as the flight monitoring trajectory, and several waypoints are set. Vertical arcs are set on the flight trajectory between the waypoints. The pitch angle of the drone is changed during the flight along the flight monitoring trajectory for monitoring. At this time, the elevation angle α corresponding to the maximum field strength is set as the main shooting elevation angle.

6. The shortwave antenna performance test system as claimed in claim 5, characterized in that: The measurement process of the horizontal antenna pattern data includes: Change the azimuth angle, take the shortwave antenna under test as the center, set a horizontal circle with R as the radius and an elevation angle of α as the flight monitoring trajectory, set a series of waypoints on the horizontal circle, set a horizontal arc on the flight trajectory between the waypoints, use the drone to keep the pitch angle unchanged during the flight along the flight monitoring trajectory, and finally obtain the horizontal antenna pattern at the main shooting elevation angle If the main shooting elevation angle α>70 ° , the main shooting elevation angle α is set to 70° elevation in the measurement process.

7. The shortwave antenna performance test system as claimed in claim 4, characterized in that: The gain calculation process of the shortwave antenna under test includes: Integrate the drone monitoring data and transmitter monitoring data into data records based on the data collection time; The actual distance r between the monitoring point and the antenna center point is calculated based on the longitude, latitude and altitude of the monitoring point and the longitude, latitude and altitude of the antenna center point; Subtracting the backward power from the transmitter forward power and taking into account the insertion loss caused by the antenna feeder, the net input power P at the antenna port can be calculated. in ; Calculate and obtain the azimuth and the gain at elevation angle θ The maximum gain is taken as the gain of the antenna. The calculation formula is: in is the azimuth of the monitoring point relative to the center of the antenna, It is the field strength measured by the field strength meter.

8. The shortwave antenna performance test system as claimed in claim 4, characterized in that: The process of drawing the vertical antenna pattern and the horizontal antenna pattern includes: Plotting measurement azimuths The curve of gain changing with elevation angle θ, and using polarization coordinates to obtain the vertical antenna radiation pattern; Plot the gain versus azimuth at the measured elevation angle θ0 The curve of the change is plotted and the polarization coordinates are used to obtain the horizontal antenna pattern.

9. The shortwave antenna performance test system according to claim 1, characterized in that: The three-axis orthogonal annular magnetic field antenna has an external structure that extends vertically downward from the fuselage, and the overall isotropy index of the UAV and the field strength meter is optimized to be <1.5dB.

10. The shortwave antenna performance test system according to claim 1, characterized in that: The frequency range of the system measurement is set to cover the 2MHz-30MHz shortwave frequency band, the electric field measurement sensitivity is set to 1mV / m, the data acquisition rate is set to more than 5 times per second, and the transmitter output power is set to 10W to support the drone and the field strength meter as a whole to perform monitoring operations during flight.

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