Phased array radar far-field automatic test method, device and equipment and storage medium

Abstract

The invention provides a phased array radar far-field automatic testing method, device and equipment and a storage medium, and belongs to the field of automation, and the method comprises the steps: initializing a phased array radar, a frequency spectrograph and a three-dimensional turntable, starting the phased array radar, and calculating a theoretical value group; a target optimal angle is determined through stepping scanning of the three-dimensional rotary table, the phased array radar is controlled to rotate to the target optimal angle through the three-dimensional rotary table, the phased array radar is sequentially switched to a horizontal polarization mode and a vertical polarization mode, emission testing is completed, and testing data of the emission testing are recorded; and performing a receiving test on the phased array radar, recording test data of the receiving test, and comparing all the test data with the theoretical value group to determine a far-field test result. According to the technical scheme of the embodiment of the invention, the automatic test of the phased array radar is realized through the measurement and control host, and the time for switching the polarization mode and adjusting the angle of the phased array radar is shortened, so that the test period is shortened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radar engineering, and in particular to a phased array radar far field automatic testing method, device, equipment and storage medium. BACKGROUND

[0002] Large active phased array radar is a high-end mechatronic device that combines modern phased array radar technology, very large scale integrated circuits, all-solid-state transceiver units, high-speed computers, and high-speed optoelectronic communication technology. In the production and testing process of the radar field, far field testing is the core process for verifying the radiation performance and receiving sensitivity of the radar antenna, and directly determines the factory quality and operational effectiveness of the phased array radar.

[0003] In the prior art, far field testing of the phased array radar is completed by manual operation. In the far field testing process, the parameters of the spectrum analyzer and the signal source are first configured by manual operation, then the azimuth and elevation angles of the phased array radar are adjusted, the horizontal polarization mode and the vertical polarization mode of the phased array radar are switched, and the data is read by manual naked eye and recorded. However, the existing far field testing method completed by manual operation relies on manual plugging and unplugging of cables or manual control of the turntable to switch the vertical polarization mode and the horizontal polarization mode of the phased array radar, and relies on manual adjustment of the angle of the phased array radar. The time required for single switching of the polarization mode and single adjustment of the angle is long, resulting in a long testing period, which cannot meet the mass production requirements of the manufacturer for the phased array radar. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a phased array radar far field automatic testing method, device, equipment and storage medium, which realizes automatic testing of the phased array radar through a test control host, shortens the time for switching the polarization mode and adjusting the angle of the phased array radar, thereby improving the testing efficiency and shortening the testing period.

[0005] In a first aspect, an embodiment of the present application provides a phased array radar far field automatic testing method applied to a test control host, wherein the test control host is respectively connected in communication with a phased array radar, a spectrum analyzer and a three-dimensional turntable, the phased array radar is installed on the three-dimensional turntable, the spectrum analyzer is connected in communication with the phased array radar, and the method comprises: initializing the phased array radar, the spectrum analyzer and the three-dimensional turntable, starting the phased array radar, and calculating a theoretical value set; determining a target optimal angle through step-by-step scanning of the three-dimensional turntable, controlling the phased array radar to rotate to the target optimal angle through the three-dimensional turntable, switching the phased array radar to a horizontal polarization mode and a vertical polarization mode in turn, completing transmission testing, and recording testing data of the transmission testing; The phased array radar is tested, test data of the receiving test is recorded, and all test data is compared with the theoretical value group respectively to determine a far field test result.

[0006] According to some embodiments of the application, the measurement and control host is in communication connection with a signal source; The phased array radar, the spectrum analyzer and the three-dimensional turntable are initialized, including: The measurement and control host is in communication connection with a server of the phased array radar, the signal source, the spectrum analyzer and the three-dimensional turntable, parameters of the phased array radar are configured, and radar parameters of the phased array radar are loaded, wherein the parameters of the phased array radar include a horizontal scanning range, a vertical scanning range and a polarization switching sequence, the radar parameters include transmitting parameters of the phased array radar, a single beam width and a number of multi-beams; A far field test distance of the phased array radar is obtained, and the far field test distance is adjusted to meet a far field requirement, wherein an expression of the far field requirement is R≥2D² / λ, R is the far field test distance, D is an aperture of the phased array radar, and λ is a far field test wavelength of the phased array radar.

[0007] According to some embodiments of the application, the measurement and control host includes a device control layer, a process scheduling layer and a data processing layer in communication connection in sequence, the device control layer is used to provide an interface for communication connection of the phased array radar, the spectrum analyzer, the three-dimensional turntable, the signal source and the measurement and control host, and the data processing layer includes a theoretical value calculation module; Theoretical value groups are calculated, including: The process scheduling layer calls the theoretical value calculation module, the theoretical value calculation module obtains an antenna gain of the phased array radar, the far field test distance and total loss, obtains a power of the signal source, and determines a free space loss; The theoretical value calculation module respectively calculates a medium wave transmitting theoretical value, a short wave transmitting theoretical value and a medium wave receiving theoretical value, and the medium wave transmitting theoretical value, the short wave transmitting theoretical value and the medium wave receiving theoretical value form the theoretical value group; Wherein, an expression of the medium wave transmitting theoretical value is a=TP+G-L f -L total , an expression of the short wave transmitting theoretical value is b=TP+G-L total , and an expression of the medium wave receiving theoretical value is c=W+G-L f -L total , a is the medium wave transmitting theoretical value, b is the short wave transmitting theoretical value, c is the medium wave receiving theoretical value, TP is the transmitting power, G is the antenna gain, L fFor the free space loss, L total The total loss is W, and the power of the signal source is W.

[0008] According to some embodiments of the present invention, the data processing layer further includes an optimal angle optimization module; Determining the optimal angle of the target through the step-scanning of the three-dimensional turntable includes: The process scheduling layer calls the optimal angle optimization module, which performs a coarse scan within the horizontal scanning range. The spectrum analyzer records multiple first horizontal scanning powers and determines the azimuth angle corresponding to the largest first horizontal scanning power as the first optimal horizontal angle. Based on the first optimal horizontal angle and the coarse scan step size, the horizontal fine scan range is determined. The upper limit of the horizontal fine scan range is the sum of the first optimal horizontal angle and the coarse scan step size, and the lower limit of the horizontal fine scan range is the difference between the first optimal horizontal angle and the coarse scan step size. The phased array radar is finely scanned within the horizontal fine scan range. The spectrum analyzer records multiple second horizontal scan powers and determines the azimuth and elevation angles corresponding to the largest second horizontal scan power as the first optimal angle. The phased array radar is converted to a vertical polarization mode. A coarse scan is performed within the vertical scanning range of the phased array radar to determine the first optimal vertical angle. Based on the first optimal vertical angle and the coarse scan step size, a fine vertical scan range is determined. A fine scan is performed within the fine vertical scan range to determine the second optimal angle. The average value of the first optimal angle and the second optimal angle is determined as the target optimal angle.

[0009] According to some embodiments of the present invention, the phased array radar is sequentially switched to horizontal polarization mode and vertical polarization mode to complete the launch test, and the test data of the launch test is recorded, including: Based on any polarization mode of the phased array radar, the phased array radar is controlled to sequentially transmit multiple single-beam shortwave signals, multiple single-beam shortwave signals, multiple multi-beam medium-wave signals, and multiple multi-beam shortwave signals, and the spectrum analyzer collects multiple sets of transmission data; Based on all the aforementioned transmission data, the average power of horizontal single-beam medium-wave transmission, the average power of horizontal single-beam short-wave transmission, the average power of horizontal multi-beam medium-wave transmission, the average power of horizontal multi-beam short-wave transmission, the average power of vertical single-beam medium-wave transmission, the average power of vertical single-beam short-wave transmission, the average power of vertical multi-beam medium-wave transmission, and the average power of vertical multi-beam short-wave transmission are determined. All test data includes the average power of horizontal single-beam medium-wave transmission, the average power of horizontal single-beam short-wave transmission, the average power of horizontal multi-beam medium-wave transmission, the average power of horizontal multi-beam short-wave transmission, the average power of vertical single-beam medium-wave transmission, the average power of vertical single-beam short-wave transmission, the average power of vertical multi-beam medium-wave transmission, and the average power of vertical multi-beam short-wave transmission.

[0010] According to some embodiments of the present invention, the phased array radar is subjected to reception tests, and the test data of the reception tests is recorded, including: Based on any polarization mode of the phased array radar, the signal source is controlled to sequentially transmit multiple single-beam medium-wave signals and multiple multi-beam short-wave signals, and the phased array radar sequentially transmits all the single-beam medium-wave signals received to the spectrum analyzer. The spectrum analyzer outputs multiple single-beam receiving test powers based on all the single-beam medium wave signals, determines the single-beam receiving average power based on all the receiving test powers, and determines the multi-beam receiving average power based on all the multi-beam shortwave signals. The total test data includes the single-beam receiving average power and the multi-beam receiving average power.

[0011] According to some embodiments of the present invention, the data processing layer further includes a result determination module, and the measurement and control host further includes a visualization layer that is communicatively connected to the data processing layer; All test data were compared with the theoretical value set to determine the far-field test results, including: The process scheduling layer calls the result determination module, which obtains the theoretical value group and all test data. When the difference between the average power of the horizontal single-beam medium-wave transmission, the average power of the horizontal multi-beam medium-wave transmission, the average power of the vertical single-beam medium-wave transmission, and the average power of the vertical multi-beam medium-wave transmission and the theoretical value of medium-wave transmission is less than a preset threshold, and when the difference between the average power of the horizontal single-beam shortwave transmission, the average power of the horizontal multi-beam shortwave transmission, the average power of the vertical single-beam shortwave transmission, and the average power of the vertical multi-beam shortwave transmission and the theoretical value of shortwave transmission is less than or equal to the preset threshold, the phased array radar passes the transmission test. When the difference between the average power of the single-beam reception and the average power of the multi-beam reception and the theoretical value of the medium-wave reception are both less than or equal to the preset threshold, the phased array radar passes the reception test. The visualization layer determines the far-field test results based on the transmission and reception test results, generates a real-time test curve based on all test data, and displays the test curve.

[0012] In a second aspect, embodiments of the present invention provide an automated far-field testing device for a phased array radar, comprising at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, the instructions being executed by the at least one control processor to enable the at least one control processor to perform the automated far-field testing method for a phased array radar as described in the first aspect above.

[0013] Thirdly, embodiments of the present invention provide an electronic device including the phased array radar far-field automated testing device as described in the second aspect above.

[0014] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions for executing the phased array radar far-field automated testing method as described in the first aspect above.

[0015] The automated far-field testing method for phased array radar according to embodiments of the present invention has at least the following beneficial effects: Initializing the phased array radar, the spectrum analyzer, and the three-dimensional turntable; starting the phased array radar; calculating theoretical value sets; determining the optimal target angle through step scanning using the three-dimensional turntable; controlling the phased array radar to rotate to the optimal target angle using the three-dimensional turntable; sequentially switching the phased array radar to horizontal polarization mode and vertical polarization mode; completing the transmission test; recording the transmission test data; performing a reception test on the phased array radar; recording the reception test data; and comparing all test data with the theoretical value sets to determine the far-field test results. According to the technical solution of embodiments of the present invention, the telemetry and control host achieves precise control of the azimuth and elevation angles of the phased array radar through the three-dimensional turntable, acquires electronic data during the far-field test process through the spectrum analyzer, and quickly and directly switches the polarization mode of the phased array radar by controlling it, thereby shortening the time for switching polarization modes and adjusting angles, and thus shortening the time required for far-field testing and the test cycle. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the telemetry and control host, phased array radar, three-dimensional turntable and spectrum analyzer provided in one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a measurement and control host provided in another embodiment of the present invention; Figure 3 This is a flowchart of an automated far-field testing method for phased array radar provided in another embodiment of the present invention; Figure 4 This is a complete flowchart of the embedded process in the process scheduling layer provided in another embodiment of the present invention; Figure 5 This is a structural diagram of a phased array radar far-field automated testing device provided in another embodiment of the present invention. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0019] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0020] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0021] This invention provides an automated far-field testing method, apparatus, device, and storage medium for phased array radar. The automated far-field testing method includes: initializing the phased array radar, the spectrum analyzer, and the three-dimensional turntable; starting the phased array radar and calculating a theoretical value set; determining the optimal target angle through step scanning using the three-dimensional turntable; controlling the phased array radar to rotate to the optimal target angle using the three-dimensional turntable; sequentially switching the phased array radar to horizontal polarization mode and vertical polarization mode to complete a transmission test and recording the transmission test data; performing a reception test on the phased array radar and recording the reception test data; and comparing all test data with the theoretical value set to determine the far-field test results. According to the technical solution of the present invention, the telemetry and control host realizes precise control of the azimuth and elevation angles of the phased array radar through a three-dimensional turntable, acquires electronic data during the far-field test through a spectrum analyzer, and controls the phased array radar to quickly and directly switch the polarization mode of the phased array radar, thereby shortening the time for the phased array radar to switch polarization modes and adjust angles, thus shortening the time required for far-field testing and the test cycle.

[0022] First, the method of this embodiment of the invention is applied to the measurement and control host, referring to... Figure 1 In this embodiment, the telemetry and control host is communicatively connected to the phased array radar 10, the spectrum analyzer 30, and the three-dimensional turntable 20. The phased array radar 10 is installed on the three-dimensional turntable 20, and the spectrum analyzer 30 is communicatively connected to the phased array radar 10.

[0023] It should be noted that the hardware architecture of this invention is a closed-loop system consisting of a phased array radar 10, a three-dimensional turntable 20, and a measurement and control host. The phased array radar 10 is a dual-polarization active phased array radar under test, supporting remote switching between horizontal and vertical polarization modes, and equipped with an SSH control interface. The far-field test environment for the phased array radar 10 is an anechoic chamber or open field that meets the far-field conditions.

[0024] It should be noted that the three-dimensional turntable 20 is equipped with a phased array radar 10, which is used to adjust the angle of the phased array radar 10. It supports TCP / IP and FINS protocols. The azimuth rotation range of the three-dimensional turntable 20 is 0-360°, the elevation range is -10° to 10°, and the control accuracy is ±0.05°.

[0025] It should be noted that the spectrum analyzer 30 supports the VISA protocol for acquiring signal strength. The telemetry and control host is equipped with automation software that connects to the above devices through multi-protocol interfaces, enabling centralized control of the phased array radar 10, the 3D turntable 20, and the spectrum analyzer 30. The multi-protocol interfaces include SSH / VISA / TCP / IP.

[0026] In addition, the telemetry and control host is connected to the signal source 40. The signal source 40 is a programmable signal source such as the Keysight N5183B, which supports the VISA protocol and is used to provide standard input in the reception test of the far-field test of the phased array radar 10.

[0027] Additionally, refer to Figure 2 The telemetry and control host includes a device control layer, a process scheduling layer, and a data processing layer that are sequentially connected in communication. The device control layer provides an interface for the communication connection between the phased array radar 10, the spectrum analyzer 30, the 3D turntable 20, and the signal source 40 and the telemetry and control host. The data processing layer includes a theoretical value calculation module, an optimal angle optimization module, and a result determination module. The telemetry and control host also includes a visualization layer that is connected in communication with the data processing layer.

[0028] It should be noted that the telemetry and control host adopts a layered modular design, comprising an equipment control layer, a process scheduling layer, and a data processing layer. The equipment control layer encapsulates the control protocols for the phased array radar 10, the 3D turntable 20, the spectrum analyzer 30, and the signal source 40, providing unified interfaces such as set_polarization(H) and scan_angle(az_range, el_range). The process scheduling layer schedules operations according to a preset far-field test procedure, supporting retry in case of anomalies. The preset far-field test procedure is "startup → theoretical calculation → functional verification → optimization → transmission test → reception test". The data processing layer includes a theoretical value calculation module, an optimal angle optimization module, and a result determination module. The theoretical value calculation module automatically calculates theoretical values ​​based on the phased array radar parameters (gain, frequency) and environmental parameters (range, loss). The radar parameters include the phased array radar 10's transmission parameters, single beamwidth, number of multiple beams, gain, and frequency. The environmental parameters include the far-field test range and free space loss. The optimal angle optimization module is used to locate the angle corresponding to the maximum power of the transmitted signal of the phased array radar 10 by using coarse and fine scan step sizes. In this invention, the coarse scan step size is 1° and the fine scan step size is 0.1°. The result judgment module is used to compare the test data with the theoretical value set and determine whether the phased array radar 10 passes the far-field transmission and reception tests according to a preset threshold (±2dB). In this invention, the preset threshold is ±2dB. The visualization layer is used to display the test curves, the status of the phased array radar 10, the status of the 3D turntable 20, and the status of the spectrum analyzer 30 in real time, and automatically generate a far-field test report in PDF format.

[0029] The following is based on Figures 1 to 2 The measurement and control host shown further illustrates the technical solution of the embodiment of the present invention.

[0030] Reference Figure 3 , Figure 3This is a flowchart of an automated far-field testing method for phased array radar provided in an embodiment of the present invention. The automated far-field testing method for phased array radar includes, but is not limited to, the following steps: S10: Initialize the phased array radar, spectrum analyzer, and 3D turntable; start the phased array radar; calculate the theoretical value set.

[0031] It should be noted that the phased array radar of the present invention is a dual-polarization active phased array radar. The method of the present invention is used to automatically test the far-field performance of dual-polarization active phased array radar and can be extended to the far-field testing field of various phased array antennas. The far-field performance includes gain, radiation pattern, polarization isolation and beam consistency.

[0032] It should be noted that after initializing the phased array radar, spectrum analyzer, and 3D turntable, and starting the phased array radar, if the 3D turntable loses connection with the telemetry and control host, the host will re-establish communication with the turntable after a preset interval. This process will repeat three times. If re-establishing the communication connection fails, all test data before the 3D turntable lost connection with the host will be automatically recorded, and an alarm will be issued. Alternatively, if the power value output by the spectrum analyzer differs significantly from the theoretical value set (e.g., more than 10 dB), the phased array radar or signal source will be controlled to re-emitter the test signal, and the angle will be measured again.

[0033] It should be noted that before conducting far-field testing on the phased array radar, the effectiveness of the 3D turntable, the polarization mode switching of the phased array radar, and the spectrum analyzer were first tested; network card receiver information, disk space usage, memory usage, whether components could be pinged, firmware version verification, hardware operation status, and optical path speed measurement were also checked.

[0034] S20 determines the optimal angle of the target by stepping scan using a three-dimensional turntable, controls the phased array radar to rotate to the optimal angle of the target by the three-dimensional turntable, switches the phased array radar to horizontal polarization mode and vertical polarization mode in sequence, completes the launch test, and records the test data of the launch test.

[0035] It should be noted that in the process of determining the optimal angle of the target, the phased array radar is scanned in both horizontal and vertical polarization modes, and the azimuth and elevation angles corresponding to the strongest transmission signal of the phased array radar are locked through manual fitting.

[0036] It should be noted that in the far-field test, multi-scenario tests were conducted; for any polarization mode of the phased array radar, transmission and reception tests were performed sequentially for single-beam medium wave, single-beam short wave, multi-beam medium wave, and multi-beam short wave.

[0037] S30: Perform reception tests on the phased array radar, record the test data, and compare all the test data with the theoretical value set to determine the far-field test results.

[0038] It should be noted that large active phased array radars are high-end electromechanical equipment that integrates modern phased array radar technology, very large-scale integrated circuits, all-solid-state transceiver units, high-speed computers, and high-speed optoelectronic communication technology. In the production and testing process of radar, far-field testing is the core procedure for verifying the radiation performance and receiving sensitivity of radar antennas, directly determining the radar's factory quality and combat effectiveness.

[0039] Currently, far-field testing requires manual adjustment of the azimuth and elevation angles of the phased array radar, switching of its polarization state, configuration of the spectrum analyzer and signal source parameters, and recording of data. This manual operation is inefficient and highly dependent on manual intervention, with a testing cycle of up to 6 hours for a single dual-polarization phased array radar, which cannot meet the far-field testing requirements of mass production scenarios. Furthermore, testing a single radar requires two people working together, resulting in high labor costs. Large errors in manual readings and adjustments to the phased array radar's angles lead to a test error rate as high as 8%-12%. Switching the phased array radar's polarization mode relies on manual cable plugging / unplugging or manual turntable control, which is time-consuming per switch, and the large synchronization deviation between the two polarizations results in insufficient accuracy in testing key indicators such as polarization isolation, indicating poor polarization testing coordination. Simultaneously, far-field test data requires manual entry into tables, which is prone to omissions and errors, and cannot be linked to equipment status and environmental parameters, leading to difficulties in problem tracing and chaotic data management.

[0040] This invention achieves automated far-field testing of dual-polarization active phased array radar through a hardware collaborative architecture, software control system, and full-process scheduling logic, solving the problems of low efficiency, poor accuracy, and chaotic data management in existing manual far-field testing. The entire process of phased array radar startup, angle adjustment, polarization switching, automatic control of the spectrum analyzer, signal source, and 3D turntable, as well as data acquisition, is automated through a telemetry and control host, eliminating manual intervention, reducing test error rates, and saving labor costs. It also optimizes the dual-polarization testing coordination of phased array radar, shortening the polarization mode switching time to less than 10 seconds, and utilizes the 3D turntable to enable automated testing of the phased array radar. The angular synchronization deviation is controlled within ±0.1°, improving the polarization isolation test accuracy to ±0.5dB. It integrates multiple testing scenarios for phased array radar, including single-beam testing, dual-beam testing, medium-wave testing, short-wave testing, transmission testing, and reception testing, shortening the testing cycle of a single phased array radar to 2 hours, improving far-field testing efficiency, meeting mass production requirements, and automatically adapting to different models of dual-polarization phased array radars. It constructs an integrated data chain for real-time acquisition, automatic analysis, qualification judgment, and data archiving, enabling traceability of test data, solving the problem of test data errors and omissions, and improving the efficiency of problem tracing.

[0041] In another embodiment, step S10 initializes the phased array radar, the spectrum analyzer, and the three-dimensional turntable, including but not limited to the following steps: S11, the telemetry and control host establishes a communication connection with the phased array radar's server, signal source, spectrum analyzer, and three-dimensional turntable, configures the phased array radar parameters, and loads the phased array radar's radar parameters. The phased array radar parameters include the horizontal scanning range, vertical scanning range, and polarization switching sequence, while the radar parameters include the phased array radar's transmission parameters, single beamwidth, and number of multi-beams. S12, obtain the far-field test range of the phased array radar, adjust the far-field test range to meet the far-field requirements, where the expression for the far-field requirements is: R≥2D² / λ, where R is the far-field test range, D is the aperture of the phased array radar, and λ is the far-field test wavelength of the phased array radar.

[0042] It should be noted that the telemetry and control host connects to the phased array radar server via SSH, and connects to the spectrum analyzer and signal source via GPIB cable. The 3D turntable connects to the telemetry and control host via network cable and FINS protocol. The phased array radar parameters are configured, determining its horizontal scanning range to be 340° to 360°, its vertical scanning range to be -5° to 5°, and its polarization switching sequence to switch from horizontal polarization mode to vertical polarization mode. The preset threshold is set to ±2dB.

[0043] It should be noted that the telemetry and control host calls `radar_connect()` to establish an SSH connection with the phased array radar, sends `RADAR:START` to start the radar, waits 300 seconds for the phased array radar to warm up, and the phased array radar returns "Status:Ready" to the telemetry and control host. After the telemetry and control host completes the communication connection with the 3D turntable, spectrum analyzer, and signal source, it calls `device_init()` to verify whether the connection of the 3D turntable, spectrum analyzer, and signal source is normal. The 3D turntable, spectrum analyzer, and signal source return the device model to the telemetry and control host. The radar parameters are loaded. The phased array radar has a transmit power of 10dBm, a single beamwidth of 3°, and a multi-beam count of 3.

[0044] It should be noted that the telemetry and control host sends `set_angle(az=5°, el=2°)` to the 3D turntable. The 3D turntable rotates to the specified angle, and after 3 seconds, it sends `get_angle()` to the 3D turntable. The 3D turntable returns the actual angle (5.01°, 2.00°) to the telemetry and control host. The error between the angle command and the actual angle of the 3D turntable is ≤0.05°, which is less than the preset error requirement, and the 3D turntable passes the verification. Then, `set_polarization(V)` is sent to the phased array radar. After 8 seconds, the phased array radar returns "V-POL Ready" to the telemetry and control host, indicating a successful switch, meaning the polarization mode switch of the phased array radar is correct. A communication connection is established between the signal source and the spectrum analyzer. The signal source is controlled to output a 3GHz, -30dBm verification signal. The spectrum analyzer reads the power of the verification signal as 30.1dBm, with a deviation ≤0.1dB, which is less than the preset error requirement, and the signal source and spectrum analyzer pass the verification.

[0045] It should be noted that when conducting far-field tests on phased array radars in open areas, the far-field test distance of the phased array radars must meet the far-field requirements.

[0046] In another embodiment, in step S10, the calculation of the theoretical value set includes, but is not limited to, the following steps: S13, the process scheduling layer calls the theoretical value calculation module, which obtains the antenna gain, far-field test distance and total loss of the phased array radar, obtains the power of the signal source, and determines the free space loss; S14, the theoretical value calculation module calculates the theoretical values ​​of medium wave transmission, short wave transmission, and medium wave reception respectively, and the theoretical values ​​of medium wave transmission, short wave transmission, and medium wave reception form a theoretical value group; The theoretical values ​​for medium-wave transmission are expressed as: a = TP + G - Lf - Ltotal; the theoretical values ​​for short-wave transmission are expressed as: b = TP + G - Ltotal; and the theoretical values ​​for medium-wave reception are expressed as: c = W + G - Lf - Ltotal. Here, a represents the theoretical value for medium-wave transmission, b represents the theoretical value for short-wave transmission, c represents the theoretical value for medium-wave reception, TP represents the transmit power, G represents the antenna gain, Lf represents the free space loss, Ltotal represents the total loss, and W represents the power of the signal source.

[0047] It should be noted that free space loss is an environmental parameter of phased array radar. (Refer to...) Figure 4 The calling order of the process scheduling layer is as follows: Figure 4 As shown, the theoretical value calculation module, the optimal angle optimization module, and the result judgment module are called in sequence.

[0048] For example, with an antenna gain of 35dB, a far-field test distance of 80m, a total loss of 0.8dB, a signal source power of -30dB, and a free space loss of 100.04dB, the theoretical value for medium-wave transmission is 10 + 35 - 100.04 - 0.8 = -55.84dB, the theoretical value for short-wave transmission is 10 + 35 - 0.8 = -44.2dBm, and the theoretical value for medium-wave reception is -30 + 35 - 100.04 - 0.8 = -95.84dBm.

[0049] In another embodiment, in step S20, the optimal angle of the target is determined by the three-dimensional turntable step-scan, including but not limited to the following steps: S21, the process scheduling layer calls the optimal angle optimization module. The optimal angle optimization module performs a coarse scan within the horizontal scanning range. The spectrum analyzer records multiple first horizontal scan powers and determines the azimuth angle corresponding to the largest first horizontal scan power as the first horizontal optimal angle. The horizontal fine scan range is determined based on the first horizontal optimal angle and the coarse scan step size. The upper limit of the horizontal fine scan range is the sum of the first horizontal optimal angle and the coarse scan step size, and the lower limit of the horizontal fine scan range is the difference between the first horizontal optimal angle and the coarse scan step size. S22, perform fine scanning of the phased array radar within the horizontal fine scanning range, the spectrum analyzer records multiple second horizontal scanning powers, and determines the azimuth and elevation angles corresponding to the largest second horizontal scanning power as the first optimal angle; S23, the phased array radar is converted to vertical polarization mode, and a coarse scan is performed within the vertical scanning range of the phased array radar to determine the first optimal vertical angle. Based on the first optimal vertical angle and the coarse scan step size, the vertical fine scan range is determined. A fine scan is performed within the vertical fine scan range to determine the second optimal angle. The average value of the first optimal angle and the second optimal angle is determined as the target optimal angle.

[0050] It should be noted that the process scheduling layer calls the optimal angle optimization module. This module determines the coarse scan step size and the fine scan step size, converts the phased array radar to horizontal polarization mode, and within the horizontal scanning range of the phased array radar, the 3D turntable rotates by the coarse scan step size, controlling the phased array radar to send the first horizontal scan signal. The spectrum analyzer reads the first horizontal scan power until the 3D turntable has traversed the horizontal scanning range. The coarse scan step size is greater than the fine scan step size. The optimal angle optimization module determines the azimuth angle corresponding to the maximum horizontal scan power as the first optimal horizontal angle. Based on the first optimal horizontal angle and the coarse scan step size, it determines the horizontal fine scan range. The upper limit of the horizontal fine scan range is the sum of the first optimal horizontal angle and the coarse scan step size, and the lower limit is the difference between the first optimal horizontal angle and the coarse scan step size. Within the horizontal fine scan range, the three-dimensional turntable scans in steps of fine scan step size. The phased array radar sends a second horizontal scan signal, and the spectrum analyzer records all the second horizontal scan power. Based on the azimuth angle of the three-dimensional turntable and the fitting of all horizontal scan power, the first optimal angle is determined. The first optimal angle includes the first optimal azimuth angle and the first optimal elevation angle. The horizontal scan power value corresponding to the first optimal angle is the largest. The phased array radar is converted to vertical polarization mode. Within the vertical scanning range of the phased array radar, a three-dimensional turntable is controlled to scan in steps with a coarse scan step size to determine the first optimal vertical angle. Based on the first optimal vertical angle and the coarse scan step size, the vertical fine scan range is determined. Within the vertical fine scan range, the three-dimensional turntable is controlled to scan in steps with a fine scan step size to determine the second optimal angle. Based on the first and second optimal angles, the target optimal angle is determined. The second optimal angle includes the second optimal azimuth angle and the second optimal elevation angle. The target optimal angle includes the target optimal azimuth angle and the target optimal elevation angle. The target optimal azimuth angle is the sum of the first and second optimal azimuth angles divided by two, and the target optimal elevation angle is the sum of the first and second optimal elevation angles divided by two.

[0051] For example, the 3D turntable is controlled to traverse the horizontal scanning range in 1° increments. The spectrum analyzer collects the first horizontal scanning power for two seconds at each angle. Among all the first horizontal scanning powers, the maximum first horizontal scanning power is -55.2dBm, at which point the azimuth angle is 349°. This 349° is determined as the first optimal horizontal angle. The sum of the first optimal horizontal angle and the coarse scan step size is 350°, and the difference between the first optimal horizontal angle and the coarse scan step size is 348°. The horizontal fine scan range is (348°, 350°). Fine scanning is performed within the horizontal fine scan range in 0.1° increments. Based on all the second horizontal scanning powers and corresponding angles recorded by the spectrum analyzer, the azimuth angle of the second optimal angle is fitted to be 349.2°, and the elevation angle is 0.1°. Repeat the above steps to determine the second optimal angle: azimuth angle is 349.1° and elevation angle is 0.05°; based on the first and second optimal angles, determine the target's optimal angle: azimuth angle is 349.15° and elevation angle is 0.075°.

[0052] In another embodiment, in step S20, the phased array radar is sequentially switched to horizontal polarization mode and vertical polarization mode to complete the launch test and record the test data, including but not limited to the following steps: S24, based on any polarization mode of the phased array radar, controls the phased array radar to sequentially transmit multiple single-beam shortwave signals, multiple single-beam shortwave signals, multiple multi-beam medium wave signals, and multiple multi-beam shortwave signals, and the spectrum analyzer collects multiple sets of transmission data; S25. Based on all transmission data, determine the average power of horizontal single-beam medium-wave transmission, horizontal single-beam short-wave transmission, horizontal multi-beam medium-wave transmission, horizontal multi-beam short-wave transmission, vertical single-beam medium-wave transmission, vertical single-beam short-wave transmission, vertical multi-beam medium-wave transmission, and vertical multi-beam short-wave transmission. Among them, all test data include the average power of horizontal single-beam medium-wave transmission, horizontal single-beam short-wave transmission, horizontal multi-beam medium-wave transmission, horizontal multi-beam short-wave transmission, vertical single-beam medium-wave transmission, vertical single-beam short-wave transmission, vertical multi-beam medium-wave transmission, and vertical multi-beam short-wave transmission.

[0053] For example, when the phased array radar is in horizontal polarization mode, the single-beam medium wave transmission strategy is automatically invoked, and the phased array radar transmits a 3GHz single-beam medium wave signal. The spectrum analyzer collects 10 sets of data, and the average power of the horizontal single-beam medium wave transmission is calculated to be -55.7dBm based on all the data. The horizontal polarization mode transmission test and the vertical polarization mode test of single-beam shortwave, multi-beam medium wave, and multi-beam shortwave are completed in sequence.

[0054] It should be noted that in the horizontal polarization mode of the phased array radar, the spectrum analyzer determines the average horizontal single-beam shortwave transmission power based on the data collected from the phased array radar transmitting single-beam shortwave signals, the average horizontal multi-beam medium-wave transmission power based on the data collected from the phased array radar transmitting multi-beam medium-wave signals, and the average horizontal multi-beam shortwave transmission power based on the data collected from the phased array radar transmitting multi-beam shortwave signals; the same applies in the vertical polarization mode.

[0055] In another embodiment, in step S30, a reception test is performed on the phased array radar, and the test data of the reception test is recorded, including but not limited to the following steps: S31, based on any polarization mode of the phased array radar, controls the signal source to sequentially transmit multiple single-beam medium-wave signals and multiple multi-beam short-wave signals, and the phased array radar will send all the single-beam medium-wave signals received in sequence to the spectrum analyzer. S32, the spectrum analyzer outputs multiple single-beam receiving test powers based on all single-beam medium wave signals, determines the average single-beam receiving power based on all receiving test powers, and determines the average multi-beam receiving power based on all multi-beam shortwave signals. Among them, all test data includes the average single-beam receiving power and the average multi-beam receiving power.

[0056] For example, in the horizontal polarization mode of the phased array radar, the single-beam medium-wave reception strategy is automatically invoked to control the signal source to output a small signal of 3GHz and -30dBm. After being received by the phased array radar, the signal is output to the spectrum analyzer. Based on all the data collected by the spectrum analyzer, the average value of the horizontal single-wave reception average power is -95.7dBm.

[0057] In another embodiment, in step S30, all test data are compared with the theoretical value set to determine the far-field test results, including but not limited to the following steps: S33, the process scheduling layer calls the result judgment module. The result judgment module obtains the theoretical value group and all test data. When the difference between the average power of the horizontal single-beam medium wave transmission, the average power of the horizontal multi-beam medium wave transmission, the average power of the vertical single-beam medium wave transmission, and the average power of the vertical multi-beam medium wave transmission and the theoretical value of medium wave transmission is less than the preset threshold, and when the difference between the average power of the horizontal single-beam shortwave transmission, the average power of the horizontal multi-beam shortwave transmission, the average power of the vertical single-beam shortwave transmission, and the average power of the vertical multi-beam shortwave transmission and the theoretical value of shortwave transmission is less than or equal to the preset threshold, the phased array radar passes the transmission test. S34. When the difference between the average power of single-beam reception and the average power of multi-beam reception and the theoretical value of medium-wave reception are both less than or equal to the preset threshold, the phased array radar passes the reception test. S35, the visualization layer determines the far-field test results based on the transmission test results and the reception test results, generates real-time test curves based on all test data, and displays the test curves.

[0058] It should be noted that after the far-field test, all test data is written to the database and compared with the theoretical value set. For example, the average power of the horizontal single-beam medium-wave transmission is -55.7 dBm, with a deviation of 0.14 dB from the theoretical value, which is less than the preset threshold; the average power of the horizontal single-beam reception is -95.7 dBm, with a deviation of 0.14 dB from the theoretical value, which is also less than the preset threshold. When the phased array radar passes the transmission and reception tests, and the phased array radar passes the far-field test, the far-field test results are generated and exported as a PDF. The far-field test results include equipment information for the phased array radar, the spectrum analyzer, the 3D turntable, and the signal source; a comparison table of the theoretical value set and all test data; optimization curves; and the test results for all test items.

[0059] like Figure 5 As shown, Figure 5 This is a structural diagram of an automated far-field testing device for phased array radar provided in one embodiment of the present invention. The present invention also provides an automated far-field testing device for phased array radar, comprising: The processor 401 can be implemented using a general-purpose central processing unit (CPU), microprocessor, application specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application. The memory 402 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 402 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 402 and called and executed by the processor 401 to execute the phased array radar far-field automated testing method of the embodiments of this application. Input / output interface 403 is used to implement information input and output; The communication interface 404 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). Bus 405 transmits information between various components of the device (e.g., processor 401, memory 402, input / output interface 403, and communication interface 404); The processor 401, memory 402, input / output interface 403 and communication interface 404 are connected to each other within the device via bus 405.

[0060] This application also provides an electronic device, including the phased array radar far-field automated testing device as described above.

[0061] This application embodiment also provides a storage medium, which is a computer-readable storage medium, storing a computer program that, when executed by a processor, implements the above-described phased array radar far-field automated testing method.

[0062] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof. The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate, and may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0063] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0064] The above provides a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. An automated far-field testing method for phased array radar, characterized in that, The method is applied to a telemetry and control host, which is communicatively connected to a phased array radar, a spectrum analyzer, and a 3D turntable. The phased array radar is mounted on the 3D turntable, and the spectrum analyzer is communicatively connected to the phased array radar. The method includes: Initialize the phased array radar, the spectrum analyzer, and the three-dimensional turntable; start the phased array radar; and calculate the theoretical value set. The optimal angle of the target is determined by step scanning using the three-dimensional turntable. The phased array radar is then controlled to rotate to the optimal angle of the target using the three-dimensional turntable. The phased array radar is then switched to horizontal polarization mode and vertical polarization mode in sequence to complete the launch test and record the test data. The phased array radar was subjected to reception tests, and the test data was recorded. All test data were compared with the theoretical value set to determine the far-field test results.

2. The automated far-field testing method for phased array radar according to claim 1, characterized in that, The measurement and control host is communicatively connected to the signal source; Initializing the phased array radar, the spectrum analyzer, and the three-dimensional turntable includes: The telemetry and control host establishes a communication connection with the phased array radar server, the signal source, the spectrum analyzer, and the three-dimensional turntable to configure the parameters of the phased array radar and load the radar parameters of the phased array radar. The parameters of the phased array radar include the horizontal scanning range, the vertical scanning range, and the polarization switching sequence. The radar parameters include the transmission parameters of the phased array radar, the single beamwidth, and the number of multi-beams. Obtain the far-field test range of the phased array radar, and adjust the far-field test range to meet the far-field requirements. The expression for the far-field requirements is: R≥2D² / λ, where R is the far-field test range, D is the aperture of the phased array radar, and λ is the far-field test wavelength of the phased array radar.

3. The automated far-field testing method for phased array radar according to claim 2, characterized in that, The telemetry and control host includes a device control layer, a process scheduling layer, and a data processing layer that are connected in sequence. The device control layer provides an interface for the communication connection between the phased array radar, the spectrum analyzer, the three-dimensional turntable, and the signal source and the telemetry and control host. The data processing layer includes a theoretical value calculation module. Calculate the theoretical value set, including: The process scheduling layer calls the theoretical value calculation module, which obtains the antenna gain, far-field test distance and total loss of the phased array radar, obtains the power of the signal source, and determines the free space loss. The theoretical value calculation module calculates the theoretical values ​​for medium-wave transmission, short-wave transmission, and medium-wave reception, respectively. The theoretical values ​​for medium-wave transmission, short-wave transmission, and medium-wave reception constitute the theoretical value group. The expression for the theoretical value of medium-wave emission is: a = TP + GL f -L total The expression for the theoretical value of shortwave transmission is: b = TP + GL total The expression for the theoretical value of the medium-wave receiver is: c = W + GL f -L total a is the theoretical value for medium-wave transmission, b is the theoretical value for short-wave transmission, c is the theoretical value for medium-wave reception, TP is the transmit power, G is the antenna gain, and L... f For the free space loss, L total The total loss is W, and the power of the signal source is W.

4. The automated far-field testing method for phased array radar according to claim 3, characterized in that, The data processing layer also includes an optimal angle optimization module; Determining the optimal angle of the target through the step-scanning of the three-dimensional turntable includes: The process scheduling layer calls the optimal angle optimization module, which performs a coarse scan within the horizontal scanning range. The spectrum analyzer records multiple first horizontal scanning powers and determines the azimuth angle corresponding to the largest first horizontal scanning power as the first optimal horizontal angle. Based on the first optimal horizontal angle and the coarse scan step size, the horizontal fine scan range is determined. The upper limit of the horizontal fine scan range is the sum of the first optimal horizontal angle and the coarse scan step size, and the lower limit of the horizontal fine scan range is the difference between the first optimal horizontal angle and the coarse scan step size. The phased array radar is finely scanned within the horizontal fine scan range. The spectrum analyzer records multiple second horizontal scan powers and determines the azimuth and elevation angles corresponding to the largest second horizontal scan power as the first optimal angle. The phased array radar is converted to a vertical polarization mode. A coarse scan is performed within the vertical scanning range of the phased array radar to determine the first optimal vertical angle. Based on the first optimal vertical angle and the coarse scan step size, a fine vertical scan range is determined. A fine scan is performed within the fine vertical scan range to determine the second optimal angle. The average value of the first optimal angle and the second optimal angle is determined as the target optimal angle.

5. The automated far-field testing method for phased array radar according to claim 3, characterized in that, The phased array radar was sequentially switched to horizontal polarization mode and vertical polarization mode to complete the launch test. The test data of the launch test was recorded, including: Based on any polarization mode of the phased array radar, the phased array radar is controlled to sequentially transmit multiple single-beam shortwave signals, multiple single-beam shortwave signals, multiple multi-beam medium-wave signals, and multiple multi-beam shortwave signals, and the spectrum analyzer collects multiple sets of transmission data; Based on all the aforementioned transmission data, the average power of horizontal single-beam medium-wave transmission, the average power of horizontal single-beam short-wave transmission, the average power of horizontal multi-beam medium-wave transmission, the average power of horizontal multi-beam short-wave transmission, the average power of vertical single-beam medium-wave transmission, the average power of vertical single-beam short-wave transmission, the average power of vertical multi-beam medium-wave transmission, and the average power of vertical multi-beam short-wave transmission are determined. All test data includes the average power of horizontal single-beam medium-wave transmission, the average power of horizontal single-beam short-wave transmission, the average power of horizontal multi-beam medium-wave transmission, the average power of horizontal multi-beam short-wave transmission, the average power of vertical single-beam medium-wave transmission, the average power of vertical single-beam short-wave transmission, the average power of vertical multi-beam medium-wave transmission, and the average power of vertical multi-beam short-wave transmission.

6. The automated far-field testing method for phased array radar according to claim 5, characterized in that, The phased array radar was subjected to reception testing, and the test data was recorded, including: Based on any polarization mode of the phased array radar, the signal source is controlled to sequentially transmit multiple single-beam medium-wave signals and multiple multi-beam short-wave signals, and the phased array radar sequentially transmits all the single-beam medium-wave signals received to the spectrum analyzer. The spectrum analyzer outputs multiple single-beam receiving test powers based on all the single-beam medium wave signals, determines the single-beam receiving average power based on all the receiving test powers, and determines the multi-beam receiving average power based on all the multi-beam shortwave signals. The total test data includes the single-beam receiving average power and the multi-beam receiving average power.

7. The automated far-field testing method for phased array radar according to claim 6, characterized in that, The data processing layer also includes a result determination module, and the measurement and control host also includes a visualization layer that is communicatively connected to the data processing layer. All test data were compared with the theoretical value set to determine the far-field test results, including: The process scheduling layer calls the result determination module, which obtains the theoretical value group and all test data. When the difference between the average power of the horizontal single-beam medium-wave transmission, the average power of the horizontal multi-beam medium-wave transmission, the average power of the vertical single-beam medium-wave transmission, and the average power of the vertical multi-beam medium-wave transmission and the theoretical value of medium-wave transmission is less than a preset threshold, and when the difference between the average power of the horizontal single-beam shortwave transmission, the average power of the horizontal multi-beam shortwave transmission, the average power of the vertical single-beam shortwave transmission, and the average power of the vertical multi-beam shortwave transmission and the theoretical value of shortwave transmission is less than or equal to the preset threshold, the phased array radar passes the transmission test. When the difference between the average power of the single-beam reception and the average power of the multi-beam reception and the theoretical value of the medium-wave reception are both less than or equal to the preset threshold, the phased array radar passes the reception test. The visualization layer determines the far-field test results based on the transmission and reception test results, generates a real-time test curve based on all test data, and displays the test curve.

8. An automated far-field testing device for phased array radar, characterized in that, It includes at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, which, when executed by the at least one control processor, enable the at least one control processor to perform the phased array radar far-field automated testing method as described in any one of claims 1 to 7.

9. An electronic device, characterized in that, Includes the phased array radar far-field automated testing device as described in claim 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the phased array radar far-field automated testing method as described in any one of claims 1 to 7.

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