A short wave antenna performance test system

Abstract

The application relates to the technical field of mobile communication base stations, and particularly discloses a short-wave antenna performance test system for testing the performance of a short-wave antenna of a mobile communication base station, which comprises a transmitter connected with the measured short-wave antenna, a drone, a field strength meter and a ground monitoring terminal; the transmitter is used for transmitting a single-frequency point signal of a specified short-wave frequency and monitoring the output forward power and backward power; the drone is used for providing the longitude, latitude and elevation of the center point of the short-wave antenna; the field strength meter is carried by the drone and is used for receiving the signal emitted by the measured antenna and performing spectrum analysis and field strength measurement operation; the monitoring frequency of the field strength meter comprises the frequency of the transmitter; the ground monitoring terminal is used for collecting the monitoring measurement information of the drone and the transmitter, combining the antenna transmission frequency and the field strength obtained by the field strength meter, calculating and drawing an antenna directional diagram, and calculating the gain; the application solves the problems of difficult measurement of the spatial directional diagram and the gain of the short-wave antenna and environmental interference, and realizes high-precision and full-space-coverage short-wave antenna performance test.

Description

Technical Field

[0001] This invention relates to the field of mobile communication base station technology, and more specifically to a performance testing system for shortwave antennas used in mobile communication base stations. Background Technology

[0002] Due to their large size, existing shortwave antennas are mostly fixed in the antenna field and cannot be measured in the laboratory. Existing large shortwave antennas can be measured on the ground using an antenna and a spectrum analyzer (or receiver). However, since the main transmission direction of shortwave antennas is towards the air, ground monitoring can only understand the antenna performance at the ground, and therefore cannot understand the antenna pattern and gain in space.

[0003] Therefore, the antenna pattern and gain of existing large shortwave antennas are further improved by using a wideband field strength probe mounted on a UAV. Utilizing the UAV's capabilities for accurate positioning and planned path navigation, the spatial electric field distribution and antenna field shape of the shortwave antenna are measured and obtained through theoretical calculations or simulations. For example, there is a UAV-based shortwave antenna gain measurement method in the prior art (application number 202410385145.1). However, in practical applications, this method still has the following shortcomings:

[0004] (1) Conventionally, a UAV equipped with a broadband field strength probe is used to measure shortwave antennas. However, the frequency cannot be measured to confirm that the measured field strength is only emitted by the antenna under test. This method is suitable for scenarios where only the antenna under test emits a signal and the field strength is greater than the detection limit of the probe.

[0005] (2) The detection limit of conventional probes is usually 0.2V / m. This field strength requirement is too high for most shortwave antennas. Only large shortwave transmitting antennas or those in the near field can generate such a large field strength. Therefore, it is not suitable for many shortwave antenna scenarios.

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

[0007] (4) In the prior art, the measurement of gain often depends on preset tracks or manual measurement, which cannot be dynamically corrected. Moreover, it 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, it cannot obtain key parameters such as sidelobe level and beamwidth. In actual use, it can only reflect the gain in the main lobe direction and cannot fully evaluate the actual coverage capability of the antenna. Therefore, it is not suitable for shortwave antenna performance testing in complex environments.

[0008] Therefore, this application proposes a shortwave antenna performance testing system to solve the above-mentioned technical problems. Summary of the Invention

[0009] The main objective of this invention is to provide a shortwave antenna performance testing system to solve the technical problems mentioned in the background art.

[0010] The present invention solves the above-mentioned technical problems by adopting the following technical solutions:

[0011] A shortwave antenna performance testing system, comprising:

[0012] The transmitter, as a ground-based transmitting device, has a shortwave antenna connected to its output end. This antenna can be a receiving antenna or a transmitting antenna, used to transmit a single-frequency signal at a specified shortwave frequency, and simultaneously monitor the forward and backward power of the output.

[0013] The drone serves as a monitoring point, providing the longitude, latitude, and elevation of the shortwave antenna's center point.

[0014] The field strength meter, carried by a drone, consists of a three-axis orthogonal ring magnetic field antenna and a spectrum analysis module. It has spectrum analysis and field strength measurement capabilities. It is used to receive signals 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.

[0015] The drone transmits information such as monitoring frequency, monitoring field strength, longitude, latitude, and elevation to the ground monitoring terminal in real time via wireless transmission.

[0016] The ground monitoring terminal is used to collect monitoring and measurement information from the UAV and the transmitter, analyze and measure the antenna transmission frequency and field strength obtained by the field strength meter, calculate and draw the antenna radiation pattern, and express the calculated gain in decibels based on the azimuth and elevation components of the actual distance and electric field strength. The ground monitoring terminal is synchronized with the transmitter and the UAV.

[0017] Preferably, during the shortwave antenna performance test, the monitoring point is set in the far-field region. When monitoring in the far-field region, the distance S between the monitoring point and the antenna should be greater than or equal to the greater of 5 times the operating frequency and 5 times the maximum antenna size. In this case, the monitoring point can be considered to be in the far-field region. For shortwave antennas, considering the reflection of the ground at the maximum antenna size, the condition for determining whether the monitoring point is in the far-field region is:

[0018] S≥max(5λ+5D max )

[0019]

[0020] Where S is the distance between the monitoring point and the shortwave antenna under test, and D... maxH is the maximum antenna size of the shortwave antenna under test, L is the installation height of the shortwave antenna under test, W is the length of the shortwave antenna under test, and W is the width of the shortwave antenna under test.

[0021] Preferably, during the shortwave antenna performance testing operation, the UAV's flight trajectory is set to a circle or semicircle centered on the shortwave antenna under test (longitude, latitude, altitude) to perform the antenna pattern drawing operation. Specifically, the UAV's flight trajectory includes:

[0022] When the antenna pattern is set to a horizontal antenna pattern, the UAV flight trajectory is set to a horizontal circle with an altitude 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.

[0023] When the antenna pattern is set to a vertical antenna pattern, the UAV flight trajectory is set to a vertical semicircle that crosses the center point of the antenna. The radius of the semicircle is the same as the radius of the flight monitoring sphere, which is R.

[0024] Preferably, the shortwave antenna under test is configured as a linear antenna, and the main emission direction is usually perpendicular to the antenna element. For some antennas, the main emission direction is along the direction of the antenna element.

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

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

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

[0028] The azimuth angle of the monitoring point is obtained by using vertical antenna pattern data and 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.

[0029] Plot the gain variation curve of the shortwave antenna under test to obtain the vertical and horizontal antenna radiation patterns.

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

[0031] At the azimuth angle is and At that time, with the shortwave antenna under test as the center, the vertical semicircle of the antenna element perpendicular to the shortwave antenna under test is used as the flight monitoring trajectory. Several waypoints are set, and the flight trajectory between waypoints is set as a vertical arc. During the flight of the UAV along the flight monitoring trajectory, the pitch angle of the UAV is changed to monitor. At this time, the elevation angle α corresponding to the maximum field strength is set as the main emission elevation angle.

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

[0033] If the main emission elevation angle α ≤ 70°, then the azimuth angle is changed, and a horizontal circle with radius R and elevation angle α, centered on the shortwave antenna under test, is used as the flight monitoring trajectory. A series of waypoints are set on the horizontal circle, and horizontal arcs are set between the waypoints. The UAV is used to monitor while maintaining a constant elevation angle during flight along the flight monitoring trajectory, and finally the horizontal antenna radiation pattern at the main emission elevation angle is obtained.

[0034] If the main elevation angle α > 70°, it indicates that the antenna is at a high elevation angle. In this case, the horizontal antenna pattern shows that the main elevation angle α is set to 70° in the measurement process.

[0035] Preferably, the gain calculation process for the shortwave antenna under test includes:

[0036] The drone monitoring data and the transmitter monitoring data are integrated into a data record based on the data collection time.

[0037] The actual distance r between the monitoring point and the antenna center point is calculated from the longitude, latitude, and altitude of the monitoring point, as well as the longitude, latitude, and altitude of the antenna center point.

[0038] By subtracting the backward power from the transmitter's forward power and considering the insertion loss from the antenna feed line, the net input power P at the antenna port can be calculated. in ;

[0039] The azimuth angle is calculated and obtained. Gain at elevation angle θ The maximum gain is taken as the antenna gain. The calculation formula is:

[0040]

[0041] Among them, azimuth angle To monitor the azimuth angle of the monitoring point relative to the center point of the antenna, The field strength is the field strength measured by the field strength meter.

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

[0043] Drawing the measured azimuth angle The gain curve of the antenna as a function of elevation angle θ is obtained by using polarized coordinates to obtain the vertical antenna pattern.

[0044] Plot the gain as a function of azimuth angle at the elevation angle θ0. The changing curves are plotted using polarimetric coordinates to obtain the horizontal antenna pattern.

[0045] Preferably, the external structure of the triaxial orthogonal ring magnetic field antenna is vertically downward from the fuselage, and the overall isotropic index of the UAV and field strength meter is optimized to be <1.5dB.

[0046] Preferably, the frequency range of the system is set to cover the 2MHz-30MHz shortwave band, the electric field measurement sensitivity is set to 1mV / m, the data acquisition rate is set to more than 5 acquisitions per second, and the transmitter output power is set to 10W, so as to support the UAV and the field strength meter to perform monitoring operations during flight.

[0047] As can be seen from the above technical solution, the present invention provides a shortwave antenna performance testing system. Compared with the prior art, the present invention has the following advantages:

[0048] 1. This invention uses a field strength meter equipped with a triaxial orthogonal loop magnetic field antenna and a spectrum analysis module mounted on a UAV, and combines far-field monitoring and synchronous calculation to solve problems such as the difficulty in measuring the spatial radiation pattern and gain of shortwave antennas and environmental interference. Through gain calculation evaluation and efficient and high-precision drawing of the spatial radiation pattern, high-precision, full-space coverage shortwave antenna performance testing is achieved.

[0049] 2. This invention comprehensively considers antenna size, height, and mirror effect to determine the monitoring point in the far field region, which can ensure that the monitoring point meets the radiation field distribution law, thereby ensuring the validity of the measurement data, solving the problem of large measurement error in the near field region, and improving the accuracy of antenna gain calculation.

[0050] 3. By setting the continuous flight trajectory of the UAV along a horizontal circle and a vertical semicircle and using non-hovering measurement, the present invention can realize the continuous deployment of monitoring points, improve data acquisition efficiency, and facilitate the rapid drawing of high-resolution antenna patterns.

[0051] 4. This invention dynamically correlates the forward and backward power of the transmitter and calculates the gain by combining field strength and distance. It can transform environmental factors into quantitative parameters, which facilitates the analysis of complex field strengths and solves the defects of traditional gain calculation that rely on empirical models, thereby achieving automated and standardized gain evaluation.

[0052] 5. This invention uses the azimuth and elevation components of the actual distance and electric field strength to represent the calculated gain in decibels, which can improve the accuracy of gain calculation and the flexibility of applicable scenarios. Furthermore, when drawing vertical and horizontal radiation patterns, it combines multi-angle data to comprehensively display the antenna radiation characteristics, making it suitable for shortwave antenna performance testing and optimization in complex environments.

[0053] It should be understood that the descriptions in this section are not intended to identify key or essential features of embodiments of the invention, nor are they intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Of course, implementing any product of the invention does not necessarily require achieving all of the advantages described above simultaneously. Attached Figure Description

[0054] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

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

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

[0057] Figure 3 This is a schematic diagram of the UAV's flight trajectory under the antenna pattern measurement state of this invention;

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

[0059] Figure 5 Examples of antenna radiation patterns in the prior art are shown below: the left image is a three-dimensional antenna radiation pattern example, the upper right image is a horizontal plane antenna radiation pattern example, and the lower right image is a vertical plane antenna radiation pattern example. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] For details in the embodiments, please refer to Figures 1 to 5 .

[0062] like Figure 1 and Figure 2 As shown in the embodiment of the present invention, a shortwave antenna performance testing system includes a drone, which is equipped with a three-axis omnidirectional frequency-selective field strength meter (including a spectrum analyzer and antenna), a ground receiving monitoring terminal, ground transmitting equipment, a drone ground station, and a shortwave vertical polarization receiving standard antenna, wherein:

[0063] Ground-based transmitting equipment (transmitter) outputs to the shortwave antenna under test. 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 specific shortwave frequency, a single-frequency signal. The transmitter monitors the forward and backward power of the output.

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

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

[0066] The time synchronization of the drone, ground monitoring terminal, and transmitter can accurately correlate field strength, power, and location data, thereby eliminating time delay errors, ensuring the reliability of data acquisition, and ensuring the accuracy of antenna pattern calculation and drawing, as well as the final gain calculation.

[0067] It needs to be explained that the most important role of the UAV is as a platform, carrying a field strength meter to reach the predetermined monitoring points in space. It is the carrier for flight monitoring, providing the entire monitoring process with monitoring time, point information (including longitude, latitude, and altitude), as well as flight status information such as waypoints, flight speed, and heading angle. It then transmits this information, along with the field strength monitoring data from the field strength meter, back to the ground monitoring terminal one by one with a timestamp. During operation, the UAV flies horizontally or vertically around the shortwave antenna under test according to the flight monitoring plan. The field strength meter on the UAV measures the electric field strength E(r, θ, φ) generated by the transmitting antenna at a spatial point in the far field region with a distance r, an elevation angle θ, and an azimuth angle φ. Using information such as field strength, distance, and transmission power, the antenna directivity coefficient corresponding to each monitoring point (azimuth angle φ, elevation angle θ) centered on the shortwave antenna under test is calculated.

[0068] Furthermore, it should be noted that in actual use, the vertically polarized receiving antenna is used to verify the measurement data with the UAV's onboard field strength meter. The optimized antenna settings on the UAV are as follows: Figure 4The triaxial orthogonal loop magnetic field antenna shown consists of three orthogonal loop coils. The antenna's external structure extends vertically downwards from the drone, ensuring the overall isotropic nature of the drone. The overall isotropic index of the antenna (including the drone) is set to <1.5dB, which can guarantee the isotropic nature of the measurement from a physical structure perspective. During the measurement process, it ensures the consistency of field strength measurement under different drone orientations, thus avoiding antenna directional interference. Compared with traditional electric field antennas, the magnetic field measured by this system using a magnetic field antenna is less affected by the distortion of the drone's body. Therefore, it can ensure that the field strength measurement is not affected by the drone's attitude, thus ensuring the reliability of data acquisition in complex electromagnetic environments.

[0069] In summary, by mounting a field strength meter consisting of a triaxial orthogonal loop magnetic field antenna on a UAV, the distortion effect of the UAV fuselage on the electromagnetic field can be effectively eliminated, improving the measurement accuracy. This solves the problem of difficulty in measuring the radiation pattern and gain of traditional shortwave antennas, and enables high-precision performance testing of large shortwave antennas and antenna arrays.

[0070] Furthermore, the system's measurement frequency range is set to cover the 2MHz-30MHz shortwave band, the electric field measurement sensitivity is set to 1mV / m, the data acquisition rate is set to more than 5 acquisitions per second, and the transmitter output power is set to 10W to support monitoring operations during flight without requiring hovering. This facilitates horizontal circular flight or vertical semi-circular flight around the antenna in the far field region of the shortwave antenna under test. At this time, the frequency and field strength transmitted by the antenna can be measured and combined with the acquired longitude, latitude, and elevation information to draw the antenna radiation pattern and gain.

[0071] Therefore, by designing a continuous flight path for the UAV along a horizontal circle and a vertical semicircle (non-hovering measurement), it is possible to continuously deploy monitoring points, thereby improving data acquisition efficiency, solving the problem of insufficient density of traditional fixed-point measurement, and facilitating the rapid drawing of high-resolution antenna patterns.

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

[0073] In an electromagnetic field, the metallic medium distorts the electric field (the electric field lines are perpendicular to the metal surface). Therefore, the magnetic medium causes the magnetic field distribution around it to be distorted. As a result, the drones used in this system typically use metal and carbon fiber components, but basically do not have magnetic media.

[0074] At this point, using a magnetic field antenna is less affected by the field distortion of the drone's fuselage compared to using an electric field antenna. Specific tests include:

[0075] (I) Precision Adjustment:

[0076] In the transmitting state of the shortwave antenna under test, at the same point in the far field region 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 shortwave antenna under test is measured, and multiplied by the antenna coefficient to obtain the electric field strength of the signal.

[0077] The electric field strength of the signal emitted by the shortwave antenna under test was measured at the same location and altitude using a shortwave antenna performance testing UAV system.

[0078] Comparing the electric field strength measured by the two measuring devices, a difference of less than 2dB is considered to meet the measurement accuracy requirements.

[0079] (II) Measurement Records:

[0080] During the measurement process, adjust the direction of the loop antenna in both the horizontal and vertical directions to find the direction with the highest measured level, and record the measured level.

[0081] The monitored level value (dBμV) is multiplied by the electric field antenna coefficient to obtain the electric field strength in dBμV / m, which can then be converted to the electric field strength in V / m.

[0082] The test data are as follows:

[0083] The ground-based transmitting equipment (transmitter) outputs to a bipolar antenna. The bipolar antenna is the transmitting antenna. The frequency, forward power, and backward power of the transmitted signal are measured. The power radiated from the antenna is obtained by subtracting the backward power from the forward power. First, an active loop antenna is connected to a ground-based receiving and monitoring device at a certain distance from the bipolar antenna to measure the electromagnetic field signal level emitted by the bipolar antenna. This level is then converted to electric field strength in V / m. The calculation formula is: Electric field strength (V / m) = 10^((Level (dBm) + Antenna coefficient (dB1 / m) + 107) / 20) * 0.000001. This electric field strength measured by the loop antenna is used as the reference electric field strength. Then, a UAV (equipped with the receiving and monitoring device) measures the electric field strength at the same point and altitude as the loop antenna. This measurement is then compared with the reference electric field strength obtained by the loop antenna to verify the accuracy of the UAV's measurement. The accurate measurement data is as follows:

[0084]

[0085] (III) Conclusion:

[0086] It is evident that when the aforementioned dipole antenna operates at frequencies of 5MHz and 14MHz, at the same location, the electric field strength measured by the shortwave antenna performance UAV testing system is essentially consistent with the electric field strength measured by the loop antenna (including ground receiving monitoring equipment). The electric field strength measurements of the UAV testing system at 5MHz and 14MHz deviate from the loop antenna measurements by -0.2dB and 0.48dB, respectively, indicating that the measurement accuracy of the shortwave antenna performance UAV testing system meets the 2dB requirement, meaning the measurement error achieved by this system is very small.

[0087] In practice, the operation procedure of this shortwave antenna performance testing system includes:

[0088] Step 1: Determine the location of the monitoring point.

[0089] It should be noted that, according to conventional theory, antenna pattern and gain measurements for shortwave antennas should be taken in the far-field region, with the greater the test distance, the better. However, from a practical engineering perspective, tests cannot be conducted at infinite distances, and too close a distance will also lead to inaccurate measurement patterns. Therefore, based on the actual shortwave antenna performance testing requirements, this system determines the most suitable monitoring point locations for its testing applications to meet the needs of practical engineering testing. The specific operation is as follows:

[0090] During the system's shortwave antenna performance test, the monitoring point is set in the far-field region. In the far-field region, the distance S between the monitoring point and the antenna should be greater than or equal to the greater of 5 times the operating frequency and 5 times the maximum antenna size. In this case, the monitoring point can be considered to be in the far-field region. For shortwave antennas, considering the reflection of the ground at the maximum antenna size, the criteria for determining whether the monitoring point is in the far-field region are:

[0091] S≥max(5λ+5D max )

[0092]

[0093] Where S is the distance between the monitoring point and the shortwave antenna under test, and D... max H is the maximum antenna size of the shortwave antenna under test, L is the installation height of the shortwave antenna under test, W is the length of the shortwave antenna under test, and W is the width of the shortwave antenna under test.

[0094] In summary, by adopting the far-field distance calculation formula (which comprehensively considers antenna size, height, and mirror effect), it is possible to determine that the monitoring point is located in the far-field region, ensuring 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 region, and improving the accuracy of antenna gain calculation.

[0095] The second step is to set the drone's flight path.

[0096] During the shortwave antenna performance test, the UAV's flight trajectory is set to a circle or semicircle centered on the shortwave antenna under test (longitude, latitude, altitude) to perform antenna pattern plotting. The UAV's flight trajectory references... Figure 3 Specifically, it includes:

[0097] When the antenna pattern is set to a horizontal antenna pattern, the UAV flight trajectory is set to a horizontal circle with an altitude 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 antenna pattern is set to a vertical antenna pattern, the UAV flight trajectory is set to a vertical semicircle that crosses the center point of the antenna. The radius of the semicircle is the same as the radius of the flight monitoring sphere, which is R.

[0099] At this time, the shortwave antenna under test is set as a linear antenna, and the main emission direction is usually perpendicular to the direction of the antenna element. For some antennas, the main emission direction is along the direction of the antenna element.

[0100] In summary, this application dynamically generates tracks using geometric formulas, which are directly related to the antenna elevation angle.

[0101] The third step is to calculate and evaluate the gain of the shortwave antenna under test, and then perform the antenna pattern drawing operation.

[0102] The specific process includes:

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

[0104] The measurement process for vertical antenna pattern data at this time includes:

[0105] At the azimuth angle is and In this method, with the shortwave antenna under test as the center, a vertical semicircle perpendicular to the antenna element is used as the flight monitoring trajectory. Several waypoints are set, and vertical arcs are set between the waypoints. The UAV is used to monitor the field strength by changing its pitch angle and attitude during flight along the monitoring trajectory. The elevation angle α corresponding to the maximum field strength is set as the main emission elevation angle. In other words, in vertical pattern measurement, the UAV continuously scans by dynamically changing its pitch angle and attitude to obtain the main emission elevation angle corresponding to the maximum field strength in real time. A fixed elevation angle is maintained during horizontal pattern measurement. Therefore, this application supports dynamic elevation angle adjustment and enables continuous measurement.

[0106] At this point, by dynamically adjusting the UAV's attitude to cover a wider range of elevation angles, the main emission elevation angle of the antenna is accurately captured. The main emission elevation angle (α) is determined based on actual measurement data, rather than relying on a preset value, ensuring that the gain calculation is consistent with the actual radiation characteristics of the antenna.

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

[0108] The measurement process for horizontal antenna pattern data at this time includes:

[0109] If the main beam elevation angle α ≤ 70°, then change the azimuth angle and use a horizontal circle with radius R and elevation angle α as the center of the shortwave antenna under test as the flight monitoring trajectory. Set a series of waypoints on the horizontal circle, and set a horizontal arc for the flight trajectory between waypoints. Use the UAV to fly along the flight monitoring trajectory while keeping the elevation angle constant to monitor, and finally obtain the horizontal antenna radiation pattern at the main beam elevation angle.

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

[0111] At this time, the flight trajectory reference includes measuring the vertical antenna radiation pattern and analyzing the vertical antenna radiation pattern. Figure 3 The antenna is mounted at position Zp, with the ground plane below. The blue circle represents the horizontal monitoring trajectory, while the green semicircle represents the vertical monitoring trajectory, which is the semicircle perpendicular to the ground plane directly above the antenna.

[0112] (3) Obtain the azimuth angle of the monitoring point by using the vertical antenna pattern data and the horizontal antenna pattern data, and calculate the gain of the shortwave antenna under test by combining the monitoring data of the UAV and the field strength meter.

[0113] The gain calculation process for the shortwave antenna under test at this time includes:

[0114] The drone monitoring data and the transmitter monitoring data are integrated into a data record based on the data collection time.

[0115] The actual distance r between the monitoring point and the antenna center point is calculated from the longitude, latitude, and altitude of the monitoring point, as well as the longitude, latitude, and altitude of the antenna center point.

[0116] By subtracting the backward power from the transmitter's forward power and considering the insertion loss from the antenna feed line, the net input power P at the antenna port can be calculated. in ;

[0117] The azimuth angle is calculated and obtained. Gain at elevation angle θ The maximum gain is taken as the antenna gain. The gain is then calculated in decibels based on the azimuth and elevation components of the actual distance and electric field strength. The calculation formula is:

[0118]

[0119] Among them, azimuth angle To monitor the azimuth angle of the monitoring point relative to the center point of the antenna, The field strength is the field strength measured by the field strength meter.

[0120] In summary, by dynamically correlating the forward and backward power of the transmitter and combining field strength and distance to calculate gain, environmental factors can be transformed into quantitative parameters, which facilitates the analysis of complex field strengths. This addresses the shortcomings of traditional gain calculations that rely on empirical models, enabling automated and standardized gain assessment. Furthermore, by setting up a co-frequency monitoring mechanism between the transmitter and the field strength meter, the problem of field strength attribution in multi-signal environments can be solved, achieving accurate measurement of the target antenna signal only in complex electromagnetic environments.

[0121] Furthermore, it should be noted that, compared to the conventional gain calculation method in the prior art (a method for measuring the gain of a shortwave antenna based on an unmanned aerial vehicle, application number 202410385145.1), although the overall calculation direction is the same, the prior art cannot match engineering standards (such as dBd / dBi) in practical applications and is cumbersome to operate. This application, however, is superior in that it can directly output the gain value in decibels, seamlessly connecting with antenna gain standards (such as dBd / dBi) in engineering practice, thus eliminating the need for additional conversion and simplifying the data processing flow. Additionally, this application also utilizes dynamic optimization of the main beam elevation angle... This approach ensures that gain calculations are based on the actual maximum radiation direction, rather than pre-set assumptions, thereby improving accuracy. Furthermore, the proposed solution can adapt to positional changes during the dynamic flight of the UAV, avoiding distance errors caused by flight deviations and enabling dynamic adjustment of gain results during UAV flight. In summary, compared to the static formulas and simplified models proposed in the prior art, this application significantly improves the accuracy of gain calculations and the flexibility of applicable scenarios through multi-dimensional parameter integration and dynamic optimization. Moreover, by combining multi-angle data when drawing vertical and horizontal radiation patterns, it comprehensively demonstrates the antenna radiation characteristics, making it suitable for shortwave antenna performance testing and optimization in complex environments.

[0122] (4) Plot the gain variation curve of the shortwave antenna under test to obtain the vertical and horizontal antenna radiation patterns. The vertical and horizontal antenna radiation patterns can be referenced from existing antenna radiation pattern formats, such as... Figure 5 As shown, the left image is an example of a 3D antenna pattern, the upper right image is an example of a horizontal antenna pattern, and the lower right image is an example of a vertical antenna pattern.

[0123] The process for drawing the vertical and horizontal antenna radiation patterns at this time includes:

[0124] Drawing the measured azimuth angle The gain curve of the antenna as a function of elevation angle θ is obtained by using polarized coordinates to obtain the vertical antenna pattern.

[0125] Plot the gain as a function of azimuth angle at the elevation angle θ0. The changing curves are plotted using polarimetric coordinates to obtain the horizontal antenna pattern.

[0126] In summary, the operation process of this shortwave antenna performance testing system involves using a field strength meter equipped with a triaxial orthogonal loop magnetic field antenna and a spectrum analysis module mounted on a UAV. Combined with far-field monitoring and synchronous calculation, it can solve the problems of spatial radiation pattern and gain measurement difficulties and environmental interference in existing technologies for shortwave antennas. Through gain calculation evaluation and efficient and high-precision drawing of spatial radiation pattern, it achieves high-precision, full-space coverage shortwave antenna performance testing.

[0127] Furthermore, it can be further pointed out that the measurement scheme adopted by this system can be applied not only to shortwave antennas, especially shortwave receiving antennas, but also to the performance testing of large antenna arrays. The radiation pattern measurement flight can be used with different flight monitoring sphere radii, and the larger the radius, the better the effect. In practical use, it is not necessarily necessary to determine the measurement based on 5 times the wavelength or 5 times the maximum antenna size.

[0128] Furthermore, the vertically polarized receiving standard antenna used in this system was selected based on the actual test application requirements and is not a structure that the device must adopt.

[0129] On another aspect, the ground monitoring terminal used in this invention is equipped with a computer-readable storage medium that stores a computer program. When the computer program is executed by a processor, the processor performs corresponding calculation operation steps based on the above-mentioned system.

[0130] On another aspect, the ground monitoring terminal used in this invention includes a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, the processor performs corresponding calculation operation steps based on the above-mentioned system.

[0131] In another embodiment provided in this application, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to perform any calculation operation step based on the above-described shortwave antenna performance testing system.

[0132] It is understood that the system provided in the embodiments of the present invention corresponds to the method provided in the embodiments of the present invention, and the explanation, examples and beneficial effects of the relevant content can be referred to the corresponding parts of the above methods.

[0133] This application also provides an electronic device, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, communication interface, and memory communicate with each other via the communication bus.

[0134] Memory, used to store computer programs;

[0135] When the processor executes the program stored in the memory, it performs any computational operation step based on the aforementioned shortwave antenna performance testing system.

[0136] The communication bus mentioned in the above-mentioned electronic devices can be a standard bus for interconnecting peripheral components or an extended industrial standard structure bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc.

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

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

[0139] The processors mentioned above can be general-purpose processors, including central processing units, network processors, etc.; they can also be digital signal processors, application-specific integrated circuits, field-programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0140] It should also be noted that electronic devices include terminal devices, which can also be called terminals, user equipment, mobile stations, mobile terminals, etc. Terminal devices can be mobile phones, smart TVs, wearable devices, tablets, computers with wireless transceiver capabilities, virtual reality terminal devices, augmented reality terminal devices, wireless terminals in industrial control, wireless terminals in autonomous driving, wireless terminals in remote surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, and so on. The embodiments of this application do not limit the specific technologies or device forms used in the terminal devices.

[0141] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially 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, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more 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., a solid-state drive).

[0142] 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 principles of the present invention should be included within the protection scope of the present invention.

[0143] Furthermore, it should be noted that if any directional indication (such as up, down, left, right, front, back, etc.) is involved in the embodiments of the present invention, the directional indication is only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0144] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, in the embodiments of this invention, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. A shortwave antenna performance testing system, characterized in that, include: The transmitter, as a ground-based transmitting device, has a shortwave antenna connected to its output end for transmitting a single-frequency signal at a specified shortwave frequency, and simultaneously monitoring the forward and backward power of the output. The drone serves as a monitoring point, providing the longitude, latitude, and elevation of the shortwave antenna's center point. The field strength meter, carried by a drone, consists of a three-axis orthogonal ring magnetic field antenna and a spectrum analysis module. It is used to receive signals emitted by the antenna under test and perform spectrum analysis and field strength measurement. 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 from the UAV and the transmitter, analyze and measure the antenna transmission frequency and field strength obtained by the field strength meter, calculate and draw the antenna radiation pattern, and express the calculated gain in decibels based on the azimuth and elevation components of the actual distance and electric field strength. The ground monitoring terminal is synchronized with the transmitter and the UAV. During the shortwave antenna performance test operation, the monitoring point is set in the far-field region. The criterion for determining that the monitoring point is located in the far-field region is: in, The distance between the monitoring point and the shortwave antenna being measured. The maximum antenna size of the shortwave antenna under test. The installation height of the shortwave antenna under test. The length of the shortwave antenna being measured. λ is the width of the shortwave antenna under test, and λ is the wavelength of the operating frequency. During the shortwave antenna performance testing operation, the UAV's flight trajectory is set to a circle or semicircle centered on the shortwave antenna under test, for drawing the antenna radiation pattern. Specifically, the UAV's flight trajectory includes: When the antenna pattern is set to a horizontal antenna pattern, the UAV flight trajectory is correspondingly set to an altitude of [missing information]. ,radius A horizontal circle, in which The radius of the flight monitoring sphere for the horizontal antenna pattern. The elevation angle of the horizontal antenna pattern; When the antenna pattern is set to a vertical antenna pattern, the UAV flight trajectory is correspondingly set as a vertical semicircle crossing the antenna center point, with the radius of the semicircle being the same as the radius of the flight monitoring sphere. ; The shortwave antenna under test is set as a wire antenna, and the process for drawing the antenna pattern includes: Measure and analyze the vertical antenna radiation pattern data to obtain the main emission elevation angle; Measure the horizontal antenna radiation pattern data at the main firing elevation angle; The azimuth angle of the monitoring point is obtained by using vertical antenna pattern data and 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. Plot the gain variation curve of the shortwave antenna under test to obtain the vertical and horizontal antenna radiation patterns; The gain calculation process for the shortwave antenna under test includes: The drone monitoring data and the transmitter monitoring data are integrated into a data record based on the data collection time. The actual distance r between the monitoring point and the antenna center point is calculated from the longitude, latitude, and altitude of the monitoring point, as well as the longitude, latitude, and altitude of the antenna center point. By subtracting the backward power from the transmitter's forward power and considering the insertion loss from the antenna feed line, the net input power at the antenna port can be calculated. ; The azimuth angle is calculated and obtained. and elevation angle Gain below And take the maximum gain as the antenna gain, gain The calculation formula is: in To monitor the azimuth angle of the monitoring point relative to the center point of the antenna, The field strength measured by the field strength meter; The measurement process for the vertical antenna pattern data includes: At the azimuth angle is and At this time, with the shortwave antenna under test as the center, a vertical semicircle perpendicular to the antenna element of the shortwave antenna under test is set as the flight monitoring trajectory. Several waypoints are set, and vertical arcs are set between the waypoints. The UAV is used to monitor the field strength by changing its pitch angle while flying along the flight monitoring trajectory. At this time, the elevation angle corresponding to the maximum field strength is obtained. Set as the main firing elevation angle; The measurement process for the horizontal antenna pattern data includes: Change the azimuth angle, with the shortwave antenna under test as the center, R as the radius, and the elevation angle as... A horizontal circle is used as the flight monitoring trajectory. A series of waypoints are set on the horizontal circle, and horizontal arcs are set in the flight path between the waypoints. The UAV is used to monitor the flight along the flight monitoring trajectory while keeping the pitch angle constant, and finally obtains the horizontal antenna pattern at the main elevation angle. If the main firing elevation angle Then the main firing elevation angle Set the elevation angle to 70° in the measurement process.

2. The shortwave antenna performance testing system as described in claim 1, characterized in that, The drawing process for the vertical and horizontal antenna radiation patterns includes: Drawing the measured azimuth angle Gain with pitch angle The changing curves are plotted using polarimetric coordinates to obtain the vertical antenna radiation pattern; Drawing the measurement angle of elevation Below, the gain varies with the azimuth angle. The changing curves are plotted using polarimetric coordinates to obtain the horizontal antenna pattern.

3. The shortwave antenna performance testing system as described in claim 1, characterized in that, The external structure of the triaxial orthogonal ring magnetic field antenna is vertically downward from the fuselage, and the overall isotropic index of the UAV and field strength meter is optimized to be <1.5dB.

4. The shortwave antenna performance testing system as described in claim 1, characterized in that, The system measures frequencies ranging from 2MHz to 30MHz in the shortwave band, with an electric field measurement sensitivity of 1mV / m, a data acquisition rate of more than 5 acquisitions per second, and a transmitter output power of 10W, to support the monitoring operations performed by the UAV and the field strength meter during flight.

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