Airborne radar outfield array plane diagnosis and measurement system and method

Abstract

The invention provides an airborne radar external field array plane diagnosis and measurement system and method. The system comprises a supporting mechanism and a movable square cabin arranged on a carrier. A mechanical arm is arranged in the movable square cabin and provided with a movable support and a test probe. The method comprises the following steps: collecting a far-region total radiation field in normal and fault states; for each radiation unit, phase coordinate translation is carried out on the collected total field, so that the origin of a coordinate system is located at the physical center of the unit, and a translated far-region total radiation field is obtained; performing spherical wave expansion, and inversely solving a mode expansion coefficient; angular domain data are selected, a ratio is calculated, an average value is taken, and an inversion amplitude phase in a fault state is obtained; the inversion amplitude phase of each unit is compared with the normal state of the unit, the fault position is positioned, and the fault type is judged. According to the invention, the fault unit can be accurately positioned, the reliability and performance of the system are improved, the diagnosis cost is reduced, the anti-interference capability is enhanced, and the fault diagnosis efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to an airborne radar outfield array surface diagnosis and measurement system and method. Background Art

[0002] The goal of phased array antenna fault diagnosis is to locate the fault position of the phased array antenna, that is, to accurately identify the location of the faulty antenna unit so that it can be repaired or replaced in time to maintain the performance of the entire antenna system. Fault diagnosis methods are mainly divided into two categories: internal detection and external detection.

[0003] Internal detection methods usually rely on built-in sensors or monitoring systems to directly monitor the status of each antenna unit. This method can provide real-time feedback, but the disadvantage is that it is costly. In addition, the internal detection method does not fully consider the mutual coupling effect between antenna units, resulting in false alarms, missed alarms, and difficulty in accurately locating certain faults.

[0004] The external detection method relies on field testing, that is, analyzing the radiation pattern of the near field to infer which units may have faults. However, if the phased array antenna to be tested is large and needs to be tested outdoors, the outdoor test system is generally built in a relatively open area, the electromagnetic environment is complex and uncontrollable, and the test site has multipath interference problems such as ground reflection and diffraction, which will affect the accuracy of fault location.

[0005] In the related art, the patent application with patent number CN201711168212 discloses a method for diagnosing an array antenna, which determines whether the array element is faulty by calculating the array element pattern, the position of the center of the array element pattern, the position of the first two points, and the difference between the first measurement data and the reference aperture field excitation. If the difference is greater than the preset threshold, the array element is determined to be a faulty array element, and if the difference is less than the preset threshold, the array element is determined to be a normal array element. This method may be limited by the calibration accuracy of the measurement point, and this method may still be affected by multipath interference during testing, resulting in limited accuracy in array antenna fault diagnosis. Summary of the invention

[0006] The present invention provides an airborne radar outfield array surface diagnosis measurement system and method, which solves the problem of how to improve the accuracy of array antenna fault diagnosis in the related art.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions:

[0008] In a first aspect, an airborne radar outfield array diagnostic measurement system is provided, comprising:

[0009] A supporting mechanism and a mobile cabin arranged on a carrier;

[0010] The support mechanism is used to install the device under test and provide height adjustment and azimuth adjustment;

[0011] The mobile cabin includes an openable and closable robotic arm cabin and a control cabin. A multi-degree-of-freedom robotic arm is arranged in the robotic arm cabin. A test probe is arranged on the robotic arm for interacting with the antenna of the device under test. The robotic arm is configured with a mobile bracket, and the mobile bracket is used to provide displacement of the robotic arm in the X, Y, and Z directions. The robotic arm and the mobile bracket perform scanning actions during the test probe test process. The control cabin is used to accommodate users to perform phased array antenna fault diagnosis operations.

[0012] In a first possible implementation of the first aspect, the diagnostic measurement system also includes a digital filtering module, which is used to translate the coordinate origin of the antenna radiation pattern to the physical center of the antenna by mathematical means, and eliminate environmental reflections of the test field by digital microwave darkroom filtering technology.

[0013] In a second possible implementation manner of the first aspect, the diagnostic measurement system further includes a software subsystem, and the software subsystem includes airborne radar external field array diagnostic measurement software and airborne radar external field array diagnostic analysis software;

[0014] The airborne radar field array diagnostic measurement software is used for rapid calibration and testing of phased array antennas throughout their life cycle, including planar near-field testing and single-point calibration, to achieve automated rapid testing and display test results in real time;

[0015] The airborne radar external field array diagnostic analysis software is used for data processing after the planar near field test is completed.

[0016] In a third possible implementation manner of the first aspect, the diagnostic measurement system further includes a control subsystem, and the control subsystem includes an RTC real-time controller, a data processing computer, and a control computer;

[0017] The RTC real-time controller is used to manage complex timing control;

[0018] The data processing computer and the control computer are used to run the software subsystem and process data.

[0019] In a fourth possible implementation of the first aspect, the diagnostic measurement system further includes a radio frequency subsystem, which includes a receiver, a standard gain antenna, a radio frequency box, and a phase-stable test cable; the receiver is responsible for generating an excitation signal and collecting test data; the standard gain antenna is used as a reference; the radio frequency box controls the switching of transmit and receive states and adjusts the dynamic range of the system; and the phase-stable test cable is used to ensure phase stability during signal transmission.

[0020] In a second aspect, a method for diagnosing and measuring an airborne radar external field array is provided, and the method performs external field array diagnosing and measuring based on the test system as described in the first aspect, comprising:

[0021] Collect the far-field total radiation field of the phased array antenna in normal and fault conditions;

[0022] For each radiating element in the phased array, phase coordinate translation is performed on the far-zone total radiation field in the normal state and the fault state, so that the origin of the coordinate system is moved to the physical center position of the radiating element to be diagnosed, and the far-zone total radiation field after translation is obtained;

[0023] Performing spherical wave expansion on the translated far-zone total radiation field, and inversely solving the corresponding mode expansion coefficients from the spherical wave expansion;

[0024] Selecting angular domain data and calculating the radiation intensity ratio at the corresponding angles in the normal state and the fault state, and obtaining the average value of all the calculated radiation intensity ratios to obtain the inverted amplitude and phase of the phased array antenna in the fault state;

[0025] The inversion amplitude and phase of each unit in a fault state are compared with the excitation amplitude and phase information of the unit in a normal state to locate the fault position and determine the fault type.

[0026] In a first possible implementation manner of the second aspect, a near-field to far-field transformation formula considering the influence of the probe is:

[0027]

[0028]

[0029] in:

[0030]

[0031]

[0032] In the formula, α0 represents the complex amplitude of the incident wave, x, y, d are the three basis coordinates of the plane coordinate system, k represents the wave number, is the pattern function, Δl is the dipole length, b0′ is the electric field amplitude, is the intermediate variable, j is the imaginary number symbol, Γ L is the reflection coefficient from the probe to the load, Γ P is the reflection coefficient when the probe is transmitting, G p is the probe gain.

[0033] Based on the first possible implementation manner of the second aspect, in a second possible implementation manner of the second aspect, the directional pattern function before coordinate translation is: The origin of the coordinate is the measurement center o, and the directional diagram function after the coordinate translation is The origin of the coordinate system is the physical center o1 of unit 1. is the phase pattern with point o as the origin of coordinates, is a unit vector. The direction diagram after translation is as follows:

[0034]

[0035] in, is the directional diagram function before coordinate translation, o is the measurement center, is the directional diagram function after coordinate translation, o1 is the physical center of unit 1, is the phase pattern with point o as the origin of coordinates, is a unit vector and j is an imaginary number.

[0036] Based on the second possible implementation manner of the second aspect, in a third possible implementation manner of the second aspect, performing spherical wave expansion on the translated far-zone total radiation field, and inversely solving corresponding mode expansion coefficients from the spherical wave expansion includes:

[0037] Far field pattern Perform spherical wave expansion, and the expansion expression is as follows:

[0038]

[0039] Unit 1's radiation array field The tangential component of is expressed as:

[0040]

[0041] in, To eliminate the far-field pattern affected by multipath effects, and is the coefficient of spherical wave expansion mode, m and n represent the mode number, and j is the sign of the imaginary number; is the mn-term TE outgoing wave mode, is the mn-term TE incident wave mode, is the mn-term transverse magnetic wave TM outgoing wave mode, is the mn-term transverse magnetic wave TM incident wave mode; is the spherical wave expansion coefficient of the mn term of the TE outgoing wave, is the spherical wave expansion coefficient of the mn term of the incident TE wave, is the spherical wave expansion coefficient of the mn term of the transverse magnetic TE outgoing wave, is the spherical wave expansion coefficient of the mn term of the incident transverse magnetic TE wave.

[0042] Based on the third possible implementation manner of the second aspect, in a fourth possible implementation manner of the second aspect, selecting angular domain data and calculating radiation intensity ratios at corresponding angles in a normal state and a fault state, and obtaining an average value of all calculated radiation intensity ratios to obtain an inverted amplitude and phase of the phased array antenna in a fault state, including:

[0043] Assuming that each radiating element of an N-element phased array antenna is excited with unit amplitude, the total radiation field in the far zone is Using pattern filtering technology, The radiation array field of the i-th unit is separated from For the same N-element phased array antenna, assuming that the excitation amplitude of each radiating element is A = [A1, A2, ..., AN-1, AN], and the excitation phase is B = [B1, B2, ..., BN-1, BN], the total radiation field in the far zone is recorded as Using pattern filtering technology, The radiation array field of the i-th unit is separated from

[0044] and It is the radiation array field of the same antenna unit at different feeding times. Select part of the angular domain of the same surface as the initial inversion data. Select the inversion surface as θ = 90° surface. Select the inversion angular domain Calculate the ratio of the corresponding angles:

[0045]

[0046] The excitation inversion amplitude of the i-th unit is α i , the excitation inversion phase is β i :

[0047]

[0048]

[0049] in, is the total far field of the N-element phased array antenna with unit amplitude excitation, is the far-field total field of the N-element phased array antenna with excitation amplitude A and excitation phase B, θ is the inversion surface, is the inversion angle domain, α i is the excitation inversion amplitude of the i-th unit, β i is the excitation inversion phase.

[0050] This application uses a combination of a support mechanism and a mechanical arm to achieve planar near-field testing; uses digital microwave darkroom filtering technology to suppress the influence of clutter in the field environment; and uses a phased array antenna amplitude phase reversal calculation method based on pattern filtering technology to locate faulty components in just a few tests, thereby detecting and diagnosing the performance of the entire machine in the field environment. At the same time, this test system has a mobile function that can be transported over long distances, and is suitable for full life cycle detection and testing of airborne radar antennas. Specifically:

[0051] 1. The vehicle-mounted robotic arm is used to perform near-field and far-field sampling of electromagnetic data by combining a support mechanism and a robotic arm. The robotic arm has a positioning accuracy of 0.5mm RMS and accurate positioning accuracy. Through precise processing of far-field data, the specific faulty unit can be located more accurately, and the fault type can be determined.

[0052] 2. This application is simple and reliable to operate, easy to set up, and has strong site adaptability; it can perform fault detection without affecting the normal operation of the system. It is suitable for different types of phased array antennas and can play a role in both communication and radar applications. Compared with the internal detection method, this method does not require the installation of additional sensors or monitoring equipment for each antenna unit, thereby reducing cost and complexity.

[0053] 3. By performing near-field and far-field sampling of electromagnetic data through a vehicle-mounted robotic arm and suppressing the influence of spatial multipath effects on the diagnostic results through algorithms and hardware configurations, full life cycle airborne radar field array diagnosis can be achieved; by regularly using the diagnostic method of this application, an effective maintenance plan can be established to prevent potential problems and extend the service life of the antenna system.

[0054] 4. This application uses an amplitude-phased array antenna back-transduction calculation method based on pattern filtering. With only a few tests, it is possible to separate the radiation fields of each unit of the phased array antenna and quickly determine the fault type and fault location, thereby improving the diagnostic efficiency and reducing costs of the phased array antenna. Timely detection and repair of faulty units can greatly improve the overall reliability and performance stability of the phased array antenna, and reduce the degradation of system performance caused by single unit failures. In commercial and military applications, timely repair of faults can avoid economic losses caused by system downtime, and may even affect the outcome of a battle on the battlefield. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A test state reference diagram of an airborne radar outfield array diagnostic measurement system provided in an embodiment of the present application;

[0056] Figure 2 A three-dimensional diagram of a mechanical subsystem provided in an embodiment of the present application;

[0057] Figure 3 A three-dimensional diagram of another mechanical subsystem provided in an embodiment of the present application;

[0058] Figure 4 A framework diagram of an airborne radar outfield array diagnostic measurement system provided in an embodiment of the present application;

[0059] Figure 5 A control block diagram of an RTC real-time controller provided in an embodiment of the present application;

[0060] Figure 6 A schematic flow chart of an integrated field dynamic test method for an airborne radar antenna provided in an embodiment of the present application;

[0061] Figure 7 A surface field distribution diagram of an airborne radar external field array diagnostic analysis software provided in an embodiment of the present application;

[0062] Figure 8 A probe correction interface of an airborne radar field array diagnostic analysis software provided in an embodiment of the present application;

[0063] Fig. 9 An analysis algorithm selection interface for an airborne radar outfield array diagnostic analysis software provided in an embodiment of the present application;

[0064] Fig.10 A schematic diagram of the smallest sphere of a digital wave absorbing technology provided in an embodiment of the present application. DETAILED DESCRIPTION

[0065] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose, the technical solutions in the embodiments of the present application are clearly described. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0066] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0067] The description of the method flow in the specification of the present application and the steps of the flowchart in the drawings of the present specification do not have to be strictly executed according to the step numbers, and the method steps can be executed in a different order. Moreover, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0068] The following is a detailed description of the airborne radar outfield array diagnostic measurement system and method provided in the embodiments of the present application in conjunction with the accompanying drawings and preferred embodiments.

[0069] First, the application scenarios of the airborne radar external field array diagnostic measurement system and method according to the embodiments of the present application are described in detail.

[0070] Phased array antennas have advantages that are difficult to achieve with a single antenna, such as strong directivity, high gain, low sidelobe level, and narrow beam width. They have been widely used in fields such as radar and communications. However, due to the complex electromagnetic environment, long-term operation, and exposure to outdoor environments, phased array antenna unit failures are inevitable. The failure of a phased array antenna unit will cause the array's far-field pattern to be distorted, the sidelobe level and nulls to increase, the directivity to decrease, the beamforming algorithm to be damaged, and the anti-interference ability to decrease. Timely discovery and repair of phased array antenna failures in production and life will reduce economic losses, and in a highly information-based modern battlefield it can even be the key to determining the outcome of a battle. Therefore, it is particularly important to confirm the location of the damaged unit through the far-field response of the array to maintain the performance of the phased array antenna array system.

[0071] The internal detection method of phased array fault diagnosis is costly, complex, and does not fully consider the mutual coupling between antenna units and units. The mutual coupling effect has a significant impact on antenna performance, which changes the effective impedance, radiation pattern, and gain characteristics of a single antenna unit. When one or more antenna units fail, not only the unit itself is affected, but the surrounding units are also indirectly affected due to mutual coupling. Due to the existence of mutual coupling, even if a unit is actually working properly, the failure of its neighboring units may cause the unit to exhibit abnormal behavior and be mistakenly judged as a faulty unit. Conversely, a unit may actually have a fault, but due to the mutual coupling effect, the impact of the unit on the overall performance is masked by other units, resulting in the inability to accurately identify the faulty unit. Even if it can be determined that a fault exists, ignoring the mutual coupling effect may make it difficult to accurately locate the exact location of the fault. For example, the signal change of an actual faulty unit may be sensed and reflected by nearby units, causing the diagnostic system to believe that multiple units have problems at the same time. Therefore, when the internal detection scheme considers how to correct or compensate for the impact of the mutual coupling effect, it is achieved through more complex modeling and algorithms. However, doing so will obviously increase the complexity and cost of the system.

[0072] For external detection methods, including indoor testing and outdoor testing, the indoor test system is generally built in a microwave darkroom. By laying absorbing materials on the walls around the microwave darkroom, the electromagnetic waves irradiated on the surrounding walls are greatly weakened or absorbed, thus forming a relatively pure ideal test environment. However, when the electrical size of the antenna to be tested is large, the size of the microwave darkroom may be difficult to meet the conditions.

[0073] Outdoor test systems are generally built in relatively open areas, where the electromagnetic environment is complex and uncontrollable. There are problems such as ground reflection and diffraction in the test site. The ground reflection during the test can be minimized by setting up the antenna, such as the antenna elevated method, ground reflection method or slant range field method. At present, field tests usually use an elevated test method. When using this test method, the antenna under test and the auxiliary antenna are set up at a certain height to reduce the reflection interference generated by the ground and the surrounding environment. However, traditional field test methods often fail to fully consider the dynamic characteristics of the antenna during actual use, and therefore cannot provide a complete performance evaluation. In addition, setting up and moving the antenna is time-consuming and labor-intensive.

[0074] In response to the above-mentioned problems such as limited indoor space, inaccurate field test results, poor adaptability of the test site to different test requirements and scenarios, and improving the diagnostic efficiency and reducing costs of phased array antennas, the present application proposes a method for outdoor array diagnostic measurement of airborne radars. The system adopts a combination of a support mechanism and a mechanical arm, and applies a phased array antenna amplitude phase evolution calculation method based on pattern filtering technology. Only a few tests are required to locate the faulty component, thereby detecting and diagnosing the performance of the entire machine in an outdoor field environment, and is suitable for full life cycle detection and testing of airborne radar antennas.

[0075] See also Figure 1-5 The present application embodiment provides an airborne radar outfield array diagnostic measurement system, such as Figure 1-5 As shown, the diagnostic measurement system of the embodiment of the present application includes: a mechanical subsystem, a radio frequency subsystem, a software subsystem and a control subsystem.

[0076] The mechanical subsystem includes a support mechanism 1 and a mobile cabin 2 arranged on a carrier; the support mechanism 1 is used to install the device to be tested, and provides height adjustment and azimuth adjustment to meet the test requirements at different heights; the mobile cabin 2 ensures that the entire system can be conveniently moved to the test site through the carrier, and the mobile cabin 2 includes an openable and closable mechanical arm cabin 201 and a control cabin 202. A mechanical arm 3 with multiple degrees of freedom is arranged in the mechanical arm cabin 201, and the mechanical arm 3 is equipped with a mobile bracket 4. The mobile bracket 4 is used to provide displacement of the mechanical arm 3 in the X, Y, and Z directions. The mechanical arm 3 and the mobile bracket 4 perform scanning actions during the test; the control cabin 202 is used to accommodate users to perform diagnostic measurement operations, and the radio frequency subsystem, control subsystem, and software subsystem are arranged in the control cabin 202. The mechanical subsystem also includes an optical positioning device to assist in achieving precise positioning.

[0077] The RF subsystem includes a receiver, a test probe, a standard gain antenna, a RF box, and a phase-stable test cable. The receiver is responsible for generating an excitation signal and collecting test data; the test probe is set on the mechanical arm 3 to interact with the antenna of the device under test and collect electromagnetic data; the standard gain antenna is used as a reference; the RF box controls the switching of the receiving and transmitting states and adjusts the dynamic range of the system; the phase-stable test cable ensures the phase stability during signal transmission.

[0078] The software subsystem includes airborne radar external field array diagnostic measurement software, digital filter module and airborne radar external field array diagnostic analysis software. The main functions of the airborne radar external field array diagnostic measurement software are: rapid calibration and testing of phased array antennas throughout their life cycle, with planar near-field testing and single-point calibration functions, which can realize automated rapid testing and display test results in real time. In specific implementation, in the initial interface of the airborne radar external field array diagnostic measurement software, select planar near-field test to perform airborne radar external field array diagnostic measurement, and test products in various test scenarios and test states.

[0079] After the planar near-field test is completed, the airborne radar external field array diagnostic analysis software can be used for data processing. The software has: a. Data analysis interface. After the test is completed, select data analysis to enter the data analysis interface, including planar near-field and far-field transformation and aperture field data conversion, so as to realize data transformation and processing functions in various test scenarios and test states. b. Diagnostic interface. The software has high-precision aperture field data processing from near field directly to aperture field, realizing the fault and diagnosis function of phased array radiation unit. c. Probe correction interface. The test software can perform calibration tests on the RF link and probe. During the test, you can choose to import external probe pattern data to correct the test data. Probe correction is performed in the post-processing interface. You can choose default correction and custom probe correction. Among them, custom probe correction can choose to import external probe pattern data to correct the test data. d. Parameter analysis interface. The airborne radar field array diagnostic analysis software can analyze the measured data, including directivity coefficient, beam width, zero point position, zero point depth, sidelobe position, sidelobe level, cross polarization, circular polarization, axial ratio analysis function, etc. After selecting the required analysis algorithm, click to execute the algorithm to analyze the data. e. Data import and export interface. Since the raw data is binary processed during the test, the data export can be supported in the data viewing module. The user can choose to export the currently displayed data or the raw data of the entire project. If the entire project is exported, the exported data is classified according to the state, and each state is written into a file. In addition, the software has a report output function, which can realize the automatic report generation of the test data's directional diagram (including near field, far field, mouth field, equipotential line directional diagram, etc.) and indicators.

[0080] The control subsystem includes the RTC real-time controller, data processing computer and control computer. The RTC real-time controller is the core control component used to manage complex timing control; the data processing computer and control computer are used to run the software subsystem and process data.

[0081] Exemplarily, the lifting height of the support mechanism 1 is 4.5m, and the effective stroke of the robot arm 3 in the Y direction is 1.5m. When the support mechanism 1 is not raised, the lowest point of the probe on the robot arm 3 is 3m from the ground. When the support mechanism 1 and the robot arm 3 are both raised to the highest point, the probe is 9m from the ground. Therefore, the robot arm 3 and the lifting platform can cooperate to achieve a total scanning range of 6m in the Y direction. The test probe realizes precise positioning of the measuring point through the robot arm 3.

[0082] During the test, the support mechanism 1 is raised by a hydraulic device every time the robot arm 3 scans 1.5m, and the robot arm 3 continues to scan the next 1.5m until the data collection on one Y axis is completed. At the same time, the robot arm 3 can also extend 5m in the X direction as needed.

[0083] When the system tests the low-frequency antenna to be tested, the device to be tested is fixedly mounted on the support mechanism 1, and the mechanical arm 3 is placed at a position about 10m away from the center of the turntable. The mechanical arm 3 scans in the Y direction, and the turntable rotates in azimuth, thereby realizing the cylindrical near-field test. At the same time, the turntable only rotates in azimuth, and the quasi-far-field test in azimuth can also be realized.

[0084] When the system tests the high-frequency antenna under test, the device under test is installed on the support mechanism 1, and the mechanical arm 3 is placed next to the device under test and extended 5 meters away, so that the test probe is as close to the antenna surface as possible. The antenna of the device under test is rotated in the azimuth plane through the support mechanism 1, and the mechanical arm 3 scans in the Y direction, thereby realizing the cylindrical near-field test of the high-frequency antenna.

[0085] In the specific implementation process, the entire system is placed in a cabin of about 5m×2.5m×2.5m when folded and transported, namely, a mobile cabin 2, which includes a mechanical arm cabin 201 and a control cabin 202, and the cabin is placed on a transport vehicle. The mechanical arm cabin 201 is used to store the mechanical arm 3, and the operator can operate the test system in the control cabin 202; the transport vehicle can quickly reach the test site, then open the back of the cabin and the ceiling, adjust the support level, and unfold the mechanical arm 3; the operator can select the cylindrical near-field test (airborne radar antenna integrated test) and the far-field test (including quasi-far-field test) in the initial interface of the software, and then initialize the test equipment and inject test parameters into the test equipment.

[0086] The main functions of the airborne radar antenna integrated test and detection software are: to test the performance of the whole machine in the field environment, with cylindrical near-field test function, can realize automatic rapid test, and display the test results in real time. The main functions of the rapid quasi-far-field test software are: to realize rapid test and real-time display under quasi-far-field conditions; to analyze the measurement data, including directivity coefficient, beam width, zero point position, zero point depth, sidelobe position, sidelobe level, cross polarization, circular polarization, axial ratio analysis function, etc.

[0087] See also Figure 5 The present application embodiment provides an airborne radar outfield array diagnostic measurement method, such as Figure 5 As shown, the diagnostic measurement method of the embodiment of the present application performs external field array diagnostic measurement based on the above-mentioned diagnostic measurement system, including:

[0088] Step S1, collecting the far-field total radiation field of the phased array antenna in normal state and fault state.

[0089] Collecting the far-field total radiation field of a fault-free phased array antenna fed by a unit amplitude source Collecting the far-field total radiation field of the phased array antenna in a fault state

[0090] Step S2, for each radiating element in the phased array, phase coordinate translation is performed on the far-zone total radiation field in normal state and fault state respectively, so that the origin of the coordinate system is moved to the physical center position of the radiating element to be diagnosed, and the translated far-zone total radiation field is obtained.

[0091] The far-field total radiation field and Perform phase coordinate translation so that the origin of the coordinate system falls on the physical center of the radiation unit to be diagnosed, and obtain the total far-field after translation. and For each radiating element in the phased array, repeat the above steps to obtain the field of each radiating array element in the phased array antenna. and

[0092] Step S3, performing spherical wave expansion on the translated far-zone total radiation field, and inversely solving the corresponding mode expansion coefficients from the spherical wave expansion.

[0093] The total radiation field in the far zone after translation is and Perform spherical wave expansion and inversely solve for the mode expansion coefficients.

[0094] Step S4, selecting angular domain data and calculating the radiation intensity ratio at the corresponding angles in the normal state and the fault state, and obtaining the average value of all calculated radiation intensity ratios to obtain the inverted amplitude and phase of the phased array antenna in the fault state.

[0095] According to experience, the field data of the radiation array in a part of the angular domain are selected as the initial inversion data, and the calculation and The ratio of the corresponding angles is then calculated, and the average value of the ratio is then calculated to obtain the inverted amplitude and phase of the phased array antenna under the fault state, where the inverted amplitude and phase is the amplitude and phase information obtained by inversion.

[0096] Step S5, comparing the inversion amplitude and phase of each unit in the fault state with the excitation amplitude and phase information of the unit in the normal state, locating the fault position and determining the fault type.

[0097] The inversion amplitude and phase of each unit is compared with the excitation amplitude and phase of the corresponding unit of the phased array when there is no fault, so as to locate the fault location and determine the fault type. The specific fault type may include complete unit failure, partial performance degradation, etc.

[0098] Specifically, the above steps are:

[0099] Planar near-field measurement technology uses a probe antenna to measure the amplitude and phase of the field on the aperture plane of the antenna under test. The sampling plane aperture is a plane that is only 3 to 10 wavelengths away from the antenna array. According to the electromagnetic field plane wave expansion theory, the radiation far field of the antenna is calculated to obtain the radiation characteristic parameters of the phased array antenna. The principle of planar near-field and far-field transformation is as follows:

[0100] The near-field to far-field transformation formula considering the influence of the probe is:

[0101]

[0102]

[0103] in:

[0104]

[0105]

[0106] In the formula, α0 represents the complex amplitude of the incident wave, x, y, d are the three basis coordinates of the plane coordinate system, k represents the wave number, is the pattern function, Δl is the dipole length, b0′ is the electric field amplitude, is the intermediate variable, j is the imaginary number symbol, Γ L is the reflection coefficient from the probe to the load, Γ P is the reflection coefficient when the probe is transmitting, G p is the probe gain.

[0107] Coordinate translation acquisition

[0108] Based on the data of near-field and far-field transformation, the coordinate translation technology is applied to process the far-field pattern expression, that is, the coordinate origin during measurement is translated to the center of the target to be measured. The pattern function before coordinate translation is The origin of the coordinate is the measurement center o, and the directional diagram function after the coordinate translation is The origin of the coordinate system is the physical center o1 of unit 1. is the phase pattern with point o as the origin of coordinates, is a unit vector. The direction diagram after translation is as follows:

[0109]

[0110] in, is the directional diagram function before coordinate translation, o is the measurement center, is the directional diagram function after coordinate translation, o1 is the physical center of unit 1, is the phase pattern with point o as the origin of coordinates, is a unit vector and j is an imaginary number.

[0111] The radiation array field of the unit to be diagnosed is obtained by using digital microwave darkroom filtering technology

[0112] Far-field pattern with multipath effects Perform spherical wave expansion, and the expansion expression is as follows:

[0113]

[0114] According to the principle of digital wave absorption technology, all mode coefficients are expanded for the total radiation field after translation. The radiation information of unit 1 is mainly concentrated in the low-order mode coefficients. The mode order N1 is determined by the minimum sphere radius R1 of unit 1, as shown in Figure 7 As shown in the figure, the first N1 items in the mode coefficients are retained by the mode filtering technology, and the radiation array field of unit 1 can be The tangential component of is expressed as:

[0115]

[0116] That is, the purpose of separating the radiation array field of unit 1 from the total radiation far field of the array antenna is that the radiation array field at this time is based on a coordinate system with o1 as the origin.

[0117] in, To eliminate the far-field pattern affected by multipath effects, and are the coefficients of spherical wave expansion modes, m and n represent the number of modes, and j is the symbol of the imaginary number. is the mn-term TE outgoing wave mode, is the mn-term TE incident wave mode, is the mn-term transverse magnetic wave TM outgoing wave mode, is the mn-term transverse magnetic wave TM incident wave mode; is the spherical wave expansion coefficient of the mn term of the TE outgoing wave, is the spherical wave expansion coefficient of the mn term of the incident TE wave, is the spherical wave expansion coefficient of the mn term of the transverse magnetic TE outgoing wave, is the spherical wave expansion coefficient of the mn term of the incident transverse magnetic TE wave; j is the sign of the imaginary number.

[0118] Get the radiation array field of each unit in the phased array antenna.

[0119] Assuming that each radiating element of an N-element phased array antenna is excited with unit amplitude, the total radiation field in the far zone is Using pattern filtering technology, The radiation array field of the i-th unit is separated from For the same N-element phased array antenna, assuming that the excitation amplitude of each radiating element is A = [A1, A2, ..., AN-1, AN], and the excitation phase is B = [B1, B2, ..., BN-1, BN], the total radiation field in the far zone is recorded as Using pattern filtering technology, The radiation array field of the i-th unit is separated from

[0120] and It is the radiation array field of the same antenna unit at different feeding times. Select part of the angular domain of the same surface as the initial inversion data. For example, select the inversion surface as θ = 90° and the inversion angular domain selection Calculate the ratio of the corresponding angles:

[0121]

[0122] The excitation inversion amplitude of the i-th unit is α i , the excitation inversion phase is β i :

[0123]

[0124]

[0125] By repeating the above process, the excitation amplitude and phase of all elements of the phased array antenna can be inverted.

[0126] in, is the total far field of the N-element phased array antenna with unit amplitude excitation, is the far-field total field of the N-element phased array antenna with excitation amplitude A and excitation phase B, θ is the inversion surface, is the inversion angle domain, α i is the excitation inversion amplitude of the i-th unit, β i is the excitation inversion phase.

[0127] Exemplarily, the operation process of this application is described below through a specific example.

[0128] Step 1: The test vehicle arrives at the test site and is ready to start testing.

[0129] The system consists of mechanical subsystem, control subsystem, software subsystem and test accessories. The mechanical subsystem includes a mechanical arm 3, a lifting platform, a mobile cabin 2 platform and an optical positioning device; the radio frequency subsystem includes a receiver, a test probe, a standard gain antenna, a radio frequency box and a phase-stable test cable; the control subsystem includes an RTC real-time controller, two computers and control cables; the software subsystem includes airborne radar antenna integrated test detection software, fast quasi-far-field measurement software, a digital filter module and phase-free measurement analysis software. The entire system is placed in a cabin of about 5m×2.5m×2.5m when folded and transported, including a mechanical arm cabin 201 and a control cabin 202, and the cabin is placed on a transport vehicle. The mechanical arm cabin 201 is used to store the mechanical arm 3. The operator can operate the test system in the control cabin 202, and the transport vehicle can quickly reach the test site, then open the back of the cabin and the ceiling, adjust the support level, and unfold the mechanical arm 3.

[0130] Step 2: Scan and sample the antenna on the target side.

[0131] like Figure 1 As shown, when the system tests the low-frequency antenna to be tested, the product to be tested is installed on the support mechanism 1, and the mechanical arm 3 is placed at a position about 10m away from the center of the turntable. The mechanical arm 3 scans in the Y direction, and the turntable rotates in azimuth, thereby realizing the cylindrical near-field test. At the same time, the turntable only rotates in azimuth, and the quasi-far-field test of the azimuth can also be realized; as shown in the figure, when the system tests the high-frequency antenna to be tested, the product to be tested is installed on the support mechanism 1, and the mechanical arm 3 is placed next to the product to be tested, extending a distance of 5m, so that the test probe is as close to the antenna surface to be tested as possible. The antenna to be tested realizes azimuth rotation through its own pan-tilt platform, and the mechanical arm 3 scans in the Y direction, thereby realizing the cylindrical near-field test of the high-frequency antenna. During the test, every time the mechanical arm 3 scans 1.5m, the hydraulic platform rises 1.5m in a large step, and the mechanical arm 3 continues to scan the next 1.5m until the data collection on a Y axis is completed. At the same time, the mechanical arm 3 can also extend a distance of 5m in the X direction as needed. The lifting height of the lifting platform is 4.5m, and the effective stroke of the robot arm 3 in the Y direction is 1.5m. When the lifting platform is not raised, the lowest point of the probe on the robot arm 3 is 3m away from the ground. When the lifting platform and the robot arm 3 are both raised to the highest point, the probe is 9m away from the ground. Therefore, the robot arm 3 and the lifting platform can cooperate to achieve a total scanning range of 6m in the Y direction. The test probe can achieve accurate positioning of the measuring point through the robot arm 3.

[0132] Step 3: Complete the generation, amplification, transmission, reception and testing of RF signals in the RF link during the field dynamic test process through the RF subsystem.

[0133] The product to be tested is placed on the support mechanism 1 to achieve rotation in the azimuth plane. The test probe can achieve precise positioning of the measurement point through the mechanical arm 3. The real-time controller RTC, as the core control component of the system, realizes complex timing control during the test process. The receiver provides an excitation signal and collects test data as a receiver. The RF box at the antenna end / probe end mainly realizes the switching of the receiving and transmitting state and the adjustment of the dynamic range of the system. In a scanning process, multi-wave position and multi-frequency point tests can be performed, and the system can also select continuous wave test or pulse test according to the needs of the product to be tested.

[0134] Step 4: Complete the timing control of mechanical equipment and RF equipment through the control subsystem.

[0135] like Figure 5 As shown, the lifting device of the mechanical arm 3 and the antenna turntable adopts LAN to realize data transmission and control, and the real-time positioning signal adopts TTL level signal; the antenna turntable adopts LAN to realize data transmission and control, and the real-time positioning signal adopts TTL level signal; the control of the receiver adopts LAN, and the underlying layer of the LAN control method adopts TCP / IP protocol, and the control is relatively flexible and fast. In the process of receiver testing, TTL level signal control is used to borrow a mobile phone for external triggering test; the control of the wave control extension also adopts LAN for data transportation, wave control monitoring, etc., and the wave position and frequency switching adopt TTL level signal to realize the rapid switching of wave position and frequency; the control sampling SPI protocol of the radio frequency box can realize the rapid switching of the switch radio frequency box.

[0136] Step 5: Software subsystem operation.

[0137] Airborne radar field array diagnostic measurement software:

[0138] Operators can select the planar near-field test in the initial interface of the software to conduct diagnostic measurements of the airborne radar array surface, and test products in various test scenarios and test states. The main functions of the airborne radar array surface diagnostic measurement software are: rapid calibration and testing of phased array antennas throughout their life cycle, with planar near-field testing and single-point calibration functions, which can realize automated rapid testing and display test results in real time.

[0139] Airborne radar field array diagnostic analysis software:

[0140] The software has: (1) Data analysis interface. After the test is completed, select Data Analysis to enter the data analysis interface, including the planar near-field and far-field transformation and the aperture field data conversion, so as to realize the data transformation and processing functions under various test scenarios and test conditions. (2) Diagnosis interface. The software has high-precision aperture field data processing from the near field directly to the aperture field, realizing the fault and diagnosis functions of the phased array radiation unit, such as Figure 8(3) Probe correction interface. The test software can perform calibration tests on the RF link and probe, such as Fig. 9 As shown, during the test, you can choose to import external probe pattern data to correct the test data. Probe correction is performed in the post-processing interface. You can choose between default correction and custom probe correction. Custom probe correction can choose to import external probe pattern data to correct the test data. (4) Parameter analysis interface. The airborne radar field array diagnostic analysis software can analyze the measurement data, including directivity coefficient, beam width, zero point position, zero point depth, side lobe position, side lobe level, cross polarization, circular polarization, axial ratio analysis functions, etc. Fig.10 As shown, after selecting the required analysis algorithm, click on the execute algorithm to analyze the data. (5) Data import and export interface. Since the raw data is binary processed during the test process, the data can be exported in the data viewing module. The user can choose to export the currently displayed data or the raw data of the entire project. If the entire project is exported, the exported data is classified by state, and each state is written into a file. In addition, the software has a report output function, which can realize the automatic report generation of the test data's directional diagram (including near field, far field, mouth field, equipotential line directional diagram, etc.) and indicators.

[0141] This application uses a combination of a support mechanism and a mechanical arm to achieve planar near-field testing; uses digital microwave darkroom filtering technology to suppress the influence of clutter in the field environment; and uses a phased array antenna amplitude phase reversal calculation method based on pattern filtering technology to locate faulty components in just a few tests, thereby detecting and diagnosing the performance of the entire machine in the field environment. At the same time, this test system has a mobile function that can be transported over long distances, and is suitable for full life cycle detection and testing of airborne radar antennas. Specifically:

[0142] 1. The vehicle-mounted robotic arm is used to perform near-field and far-field sampling of electromagnetic data by combining a support mechanism and a robotic arm. The robotic arm has a positioning accuracy of 0.5mm RMS and accurate positioning accuracy. Through precise processing of far-field data, the specific faulty unit can be located more accurately, and the fault type can be determined.

[0143] 2. This application is simple and reliable to operate, easy to set up, and has strong site adaptability; it can perform fault detection without affecting the normal operation of the system. It is suitable for different types of phased array antennas and can play a role in both communication and radar applications. Compared with the internal detection method, this method does not require the installation of additional sensors or monitoring equipment for each antenna unit, thereby reducing cost and complexity.

[0144] 3. By performing near-field and far-field sampling of electromagnetic data through a vehicle-mounted robotic arm and suppressing the influence of spatial multipath effects on the diagnostic results through algorithms and hardware configurations, full life cycle airborne radar field array diagnosis can be achieved; by regularly using the diagnostic method of this application, an effective maintenance plan can be established to prevent potential problems and extend the service life of the antenna system.

[0145] 4. This application uses an amplitude-phased array antenna back-transduction calculation method based on pattern filtering. With only a few tests, it is possible to separate the radiation fields of each unit of the phased array antenna and quickly determine the fault type and fault location, thereby improving the diagnostic efficiency and reducing costs of the phased array antenna. Timely detection and repair of faulty units can greatly improve the overall reliability and performance stability of the phased array antenna, and reduce the degradation of system performance caused by single unit failures. In commercial and military applications, timely repair of faults can avoid economic losses caused by system downtime, and may even affect the outcome of a battle on the battlefield.

[0146] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0147] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. Airborne radar outfield array diagnostic measurement system, characterized in that: include: A supporting mechanism and a mobile cabin arranged on a carrier; The support mechanism is used to install the device under test and provide height adjustment and azimuth adjustment; The mobile cabin includes an openable and closable robotic arm cabin and a control cabin. A multi-degree-of-freedom robotic arm is arranged in the robotic arm cabin. A test probe is arranged on the robotic arm for interacting with the antenna of the device under test. The robotic arm is configured with a mobile bracket, and the mobile bracket is used to provide displacement of the robotic arm in the X, Y, and Z directions. The robotic arm and the mobile bracket perform scanning actions during the test probe test process. The control cabin is used to accommodate users to perform phased array antenna fault diagnosis operations.

2. The airborne radar outfield array diagnostic measurement system according to claim 1, characterized in that: The diagnostic measurement system also includes a digital filtering module, which is used to translate the coordinate origin of the antenna pattern to the physical center of the antenna by mathematical means, and eliminate the environmental reflection of the test field by digital microwave darkroom filtering technology.

3. The airborne radar outfield array diagnostic measurement system according to claim 1, characterized in that: The diagnostic measurement system also includes a software subsystem, which includes airborne radar external field array diagnostic measurement software and airborne radar external field array diagnostic analysis software; The airborne radar field array diagnostic measurement software is used for rapid calibration and testing of phased array antennas throughout their life cycle, including planar near-field testing and single-point calibration, to achieve automated rapid testing and display test results in real time; The airborne radar external field array diagnostic analysis software is used for data processing after the planar near field test is completed.

4. The airborne radar outfield array diagnostic measurement system according to claim 1, characterized in that: The diagnostic measurement system also includes a control subsystem, which includes an RTC real-time controller, a data processing computer and a control computer; The RTC real-time controller is used to manage complex timing control; The data processing computer and the control computer are used to run the software subsystem and process data.

5. The airborne radar outfield array diagnostic measurement system according to claim 1, characterized in that: The diagnostic measurement system also includes a radio frequency subsystem, which includes a receiver, a standard gain antenna, a radio frequency box and a phase-stable test cable; the receiver is responsible for generating an excitation signal and collecting test data; the standard gain antenna is used as a reference; the radio frequency box controls the switching of the transmit and receive states and adjusts the dynamic range of the system; the phase-stable test cable is used to ensure phase stability during signal transmission.

6. An airborne radar outfield array diagnostic measurement method, characterized in that: Performing outfield array diagnostic measurement based on the test system according to any one of claims 1 to 5 comprises: Collect the far-field total radiation field of the phased array antenna in normal and fault conditions; For each radiating element in the phased array, phase coordinate translation is performed on the far-zone total radiation field in the normal state and the fault state, so that the origin of the coordinate system is moved to the physical center position of the radiating element to be diagnosed, and the far-zone total radiation field after translation is obtained; Performing spherical wave expansion on the translated far-zone total radiation field, and inversely solving the corresponding mode expansion coefficients from the spherical wave expansion; Selecting angular domain data and calculating the radiation intensity ratio at the corresponding angles in the normal state and the fault state, and obtaining the average value of all the calculated radiation intensity ratios to obtain the inverted amplitude and phase of the phased array antenna in the fault state; The inversion amplitude and phase of each unit in a fault state are compared with the excitation amplitude and phase information of the unit in a normal state to locate the fault position and determine the fault type.

7. The airborne radar outfield array diagnostic measurement method according to claim 6, characterized in that: The near-field to far-field transformation formula considering the influence of the probe is: in: In the formula, α0 represents the complex amplitude of the incident wave, x, y, d are the three basis coordinates of the plane coordinate system, k represents the wave number, is the directivity function, Δl is the dipole length, b′0 is the electric field amplitude, is the intermediate variable, j is the imaginary number symbol, Γ L is the reflection coefficient from the probe to the load, Γ P is the reflection coefficient when the probe is transmitting, G p is the probe gain.

8. The airborne radar outfield array diagnostic measurement method according to claim 7, characterized in that: The directional pattern function before coordinate translation is The origin of the coordinate is the measurement center o, and the directional diagram function after the coordinate translation is The origin of the coordinate system is the physical center o1 of unit 1. is the phase pattern with point o as the origin of coordinates, is a unit vector. The direction diagram after translation is as follows: in, is the directional diagram function before coordinate translation, o is the measurement center, is the directional diagram function after coordinate translation, o1 is the physical center of unit 1, is the phase pattern with point o as the origin of coordinates, is a unit vector and j is an imaginary number.

9. The airborne radar outfield array diagnostic measurement method according to claim 8, characterized in that: Performing spherical wave expansion on the translated far-zone total radiation field, and inversely solving the corresponding mode expansion coefficients from the spherical wave expansion, including: Far field pattern Perform spherical wave expansion, and the expansion expression is as follows: Unit 1's radiation array field The tangential component of is expressed as: in, To eliminate the far-field pattern affected by multipath effects, and is the coefficient of spherical wave expansion mode, m and n represent the mode number, and j is the sign of the imaginary number; is the mn-term TE outgoing wave mode, is the mn-term TE incident wave mode, is the mn-term transverse magnetic wave TM outgoing wave mode, is the mn-term transverse magnetic wave TM incident wave mode; is the spherical wave expansion coefficient of the mn term of the TE outgoing wave, is the spherical wave expansion coefficient of the mn term of the incident TE wave, is the spherical wave expansion coefficient of the mn term of the transverse magnetic TE outgoing wave, is the spherical wave expansion coefficient of the mn term of the incident transverse magnetic TE wave.

10. The airborne radar outfield array diagnostic measurement method according to claim 9, characterized in that: Selecting angular domain data and calculating the radiation intensity ratio at the corresponding angles in the normal state and the fault state, and obtaining the average value of all the calculated radiation intensity ratios to obtain the inverted amplitude and phase of the phased array antenna in the fault state, including: Assuming that each radiating element of an N-element phased array antenna is excited with unit amplitude, the total radiation field in the far zone is Using pattern filtering technology, The radiation array field of the i-th unit is separated from For the same N-element phased array antenna, assuming that the excitation amplitude of each radiating element is A = [A1, A2, ..., AN-1, AN], and the excitation phase is B = [B1, B2, ..., BN-1, BN], the total radiation field in the far zone is recorded as Using pattern filtering technology, The radiation array field of the i-th unit is separated from and It is the radiation array field of the same antenna unit at different feeding times. Select part of the angular domain of the same surface as the initial inversion data. Select the inversion surface as θ = 90° surface. Select the inversion angular domain Calculate the ratio of the corresponding angles: The excitation inversion amplitude of the i-th unit is α i , the excitation inversion phase is β i : in, is the total far-field field of the N-element phased array antenna with unit amplitude excitation, is the far-field total field of the N-element phased array antenna with excitation amplitude A and excitation phase B, θ is the inversion surface, is the inversion angle domain, α i is the excitation inversion amplitude of the i-th unit, β i is the excitation inversion phase.

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