Near-field high-temperature RCS test system and test method thereof in complex environment

Abstract

The application discloses a near-field high-temperature RCS testing system and a testing method thereof under complex environment and belongs to the technical field of radar stealth material testing. The testing system comprises a vector network analyzer, a transmitting antenna, a receiving antenna, a temperature control device, a target to be tested, a rotary table, a motor control module, a temperature control module, a computer, a wave-absorbing plate and a large metal plate. During testing, the large metal plate is used for calibration, and then multi-point testing is carried out. Then, a time domain gating technology is used to filter out many interference signals and multiple reflections of electromagnetic waves in the complex environment, so that useful signals in the target body RCS testing are extracted. Finally, the testing results of the multiple points are vector superposed through comprehensive plane wave technology. The high-temperature testing system has the characteristics of large dynamic range, high testing precision, good testing stability, low use and maintenance cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radar stealth material testing, and particularly relates to a high-temperature near-field RCS testing system and a testing method thereof using comprehensive plane wave technology and time-domain gating technology in a complex environment. BACKGROUND

[0002] Radar cross section (Radar Cross Section) is an important detection object of the stealth performance of modern weapons. With the rapid development of radar wave absorption technology, radar scattering testing of target components is also increasingly valued. In addition, military powers have established advanced experimental testing systems, so developing and applying radar wave absorption to improve the attack and survival capabilities of modern weapon systems and improve overall combat capability has become an important part of the military development of various countries, that is, component radar scattering testing technology is an important method for evaluating the radar wave absorption stealth performance of targets.

[0003] Currently, the RCS of a target is mainly studied through theoretical analysis and calculation and actual engineering testing. In actual operation, the RCS of some simple-shaped objects can be given an analytical expression by means of some reasonable approximations through electromagnetic theory. However, the RCS solving process of these simple objects is also very complex and tedious, and there is currently no good theoretical method to obtain the analytical expression of the RCS of complex objects. Therefore, it is necessary to actually test the RCS of complex objects.

[0004] Currently, related RCS testing researches are all carried out on targets at normal temperature, and there are few RCS tests on high-temperature targets. In the fields of satellite communication, electronic countermeasures and the like, some radar stealth components have obvious high-temperature characteristics, so measuring the RCS of a target at a high temperature is an indispensable work in accurately evaluating and designing the stealth performance of radar components, and therefore, the RCS high-temperature testing of a target has become a problem that must be solved in the development of stealth technology, and therefore, the RCS testing method and testing device need to be researched. Secondly, a high-temperature target cannot be tested in a darkroom environment because the wave absorption material in the darkroom is flammable, and there are many interference signals in a non-darkroom environment, so how to extract the useful RCS signals from the many interference signals has become an urgent problem to be solved. SUMMARY

[0005] In view of the problems existing in the background art, the purpose of the present application is to provide a near-field high-temperature RCS test system and a test method thereof in a complex environment. The test system uses two double-ridge horn antennas as receiving and transmitting units, which have the characteristics of wide frequency band and high gain. Then, multi-point testing is performed after calibration using a large metal plate, and then the time-domain gating technology is used to filter out many interference signals and multiple reflections of electromagnetic waves in the complex environment, so as to extract useful signals in the RCS test of the target. Finally, the test results of multiple points are vector superimposed through the comprehensive plane wave technology. The test system in the present application realizes automatic real-time testing through the computer control of the vector network analyzer, the turntable and the temperature control module.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0007] A near-field high-temperature RCS test system in a complex environment, comprising a vector network analyzer, a transmitting antenna, a receiving antenna, a temperature control device, a target to be tested, a turntable, a motor control module, a temperature control module, a computer, a wave-absorbing plate and a large metal plate.

[0008] The two test ports of the vector network analyzer are connected to the transmitting antenna and the receiving antenna respectively.

[0009] The transmitting antenna and the receiving antenna are arranged side by side, and the radiation port faces the target to be tested.

[0010] The large metal plate is placed between the temperature control device and the transmitting and receiving antennas, and is in close contact with the temperature control device.

[0011] The wave-absorbing plate is placed between the transmitting antenna and the receiving antenna, and is used to reduce the mutual coupling between the two antennas.

[0012] The computer is connected to the vector network analyzer and reads the test data, and is connected to the motor control module and the temperature control module and sends control signals.

[0013] The motor control module controls the turntable to rotate at a constant speed under the drive of the control signal.

[0014] The temperature control module controls the temperature control device to heat and keep warm the internal space under the drive of the control signal.

[0015] The temperature control device comprises a heat preservation shell and a heating assembly. The heat preservation shell is internally provided with a cavity structure for placing the target to be tested. The heating assembly is used to heat the internal space of the heat preservation shell.

[0016] The upper part of the turntable extends into the cavity structure of the heat preservation shell.

[0017] The target to be tested is fixed to the top of the turntable and rotates with it.

[0018] Further, the distance between the transmitting antenna and the receiving antenna and the target to be measured is greater than the inductive field area of the antenna: that is, greater than or equal to Where D = max{antenna aperture, target length}, and lambda represents the wavelength corresponding to the measured frequency.

[0019] Further, the heat preservation shell is made of a material with a dielectric constant less than 2, which can greatly reduce the multiple scattering of electromagnetic waves.

[0020] The application also provides a method for testing the RCS of a radar stealth target based on the above-mentioned test system, comprising the following steps:

[0021] Step 1. The internal space of the temperature control device is heated to a set temperature and kept stable by the computer-controlled temperature control module.

[0022] Step 2. Align the transceiver antenna with the center position of the target to be measured, then place a large metal plate between the temperature control device and the transceiver antenna, and use a vector network analyzer to calibrate the response.

[0023] Step 3. Remove the large metal plate, keep the transceiver antenna position unchanged, and test the target to be measured, and use a vector network analyzer to read the original signal data.

[0024] Step 4. Process the original signal data measured in step 3 by time domain gating algorithm to obtain effective signal data.

[0025] Step 5. Move the transceiver antenna in the same plane and keep its relative position, test the target to be measured again, read the original signal data of this test by a vector network analyzer, and process it by time domain gating technology to obtain the effective signal data of this test.

[0026] Step 6. Repeat step 5 to obtain at least 9 effective signal data.

[0027] Step 7. Remove the target to be measured, repeat steps 3-5 to obtain at least 9 cavity data.

[0028] Step 8. Vector superposition is performed on all effective signal data by comprehensive plane wave technology to obtain equivalent effective signal data, vector superposition is performed on all cavity data by comprehensive plane wave technology to obtain background data, the equivalent effective signal data and the background data are subtracted to reduce the influence of background noise, and finally the RCS of the target to be measured is calculated.

[0029] The principle of the application is:

[0030] The application takes the temperature control device and the complex environment as a whole, and after using the large metal plate response calibration, the de-embedding effect of the temperature control device is achieved, and the dynamic range of the overall system is improved. The application tests the transmitting and receiving antennas in the same plane for multiple times, then separately uses the time domain gate gating algorithm to process the test data, and then according to the comprehensive plane wave technology, the vector superposition is carried out, and the near-field test is realized. The application can perform high-temperature RCS test in a non-darkroom environment, and the reflection signal of the target to be tested can be observed more easily, so that the problem that the useful signal cannot be distinguished from many interference signals is avoided.

[0031] Therefore, by adopting the technical scheme, the application has the beneficial effects:

[0032] The application innovatively proposes a near-field high-temperature RCS test system and a test method in a complex environment, and applies the comprehensive plane wave technology and the time domain gate gating algorithm to the RCS test of the radar stealth target, so that the high-temperature near-field test of the high-temperature RCS test in the non-darkroom environment is realized. The application also combines the large metal plate calibration technology and the time domain gate gating algorithm, and can well extract the useful signal of the radar stealth target from many interference signals. Meanwhile, the RCS high-temperature test system designed by the application has the characteristics of large dynamic range, high test precision, good test stability, and low use and maintenance cost. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A diagram of the dielectric constant of the heat preservation shell changing with frequency.

[0034] Figure 2 A principle diagram of the time domain gate gating algorithm in the application.

[0035] Figure 3 A schematic diagram of multi-point scanning of the antenna in the same plane in the application.

[0036] Figure 4 A schematic diagram of the near-field high-temperature RCS test system in a complex environment in the application.

[0037] Figure 5 A test flowchart of the near-field high-temperature RCS test system in a complex environment in the application.

[0038] Figure 6 An RCS normal temperature test result curve of a 300mm diameter metal ball placed under a heating device at 18-40GHz.

[0039] In the figure, 1 is a vector network analyzer, 2 is a first cable, 3 is a second cable, 4 is a receiving antenna, 5 is a transmitting antenna, 6 is a temperature control device, 7 is a target to be tested, 8 is a turntable, 9 is a motor control module, 10 is a temperature control module, 11 is a computer, 12 is an absorbing plate, and 13 is a large metal plate. DETAILED DESCRIPTION

[0040] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with embodiments and drawings.

[0041] The present application provides a near-field high-temperature RCS test system in a complex environment, and a schematic diagram of the overall structure of the system is shown in the figure, which comprises a vector network analyzer, a transmitting antenna, a receiving antenna, a temperature control device, a target to be measured, a turntable, a motor control module, a temperature control module, a computer, a wave-absorbing plate and a large metal plate. Figure 4

[0042] The two test ports of the vector network analyzer are connected to the transmitting antenna and the receiving antenna through cables respectively.

[0043] The transmitting antenna and the receiving antenna are a pair of double-ridge horn transmitting-receiving antennas and are placed side by side, with the radiation port facing the target to be measured and the distance between the radiation port and the target to be measured being 2m; this kind of antenna has a wide frequency band and high gain, and the measured data is more suitable for processing using a time-domain gate selection algorithm.

[0044] The large metal plate is placed between the temperature control device and the transmitting-receiving antenna and is in close contact with the temperature control device. Using the large metal plate for response calibration can obtain the reflection peak of the target to be measured in the time domain stage and improve the overall test dynamic range of the system.

[0045] The wave-absorbing plate is placed between the transmitting antenna and the receiving antenna and is used to reduce the mutual coupling between the two antennas.

[0046] The computer is connected to the vector network analyzer through a network cable and reads the test data; the computer is connected to the motor control module and the temperature control module through data cables and sends control signals.

[0047] The motor control module controls the turntable to rotate at a constant speed under the drive of the control signal.

[0048] The temperature control module controls the temperature control device to heat and keep warm the internal space under the drive of the control signal.

[0049] The temperature control device comprises a heat preservation shell and a heating assembly; the heat preservation shell is made of M-1260 aluminum silicate fiber plate and has a hollow structure inside for placing the target to be measured; the heating assembly is used to heat the internal space of the heat preservation shell. Figure 1 A diagram showing the change of the dielectric constant of the heat preservation shell with frequency, and a material with a dielectric constant less than 2 can greatly reduce the multiple scattering of electromagnetic waves.

[0050] The upper part of the turntable extends into the hollow structure of the heat preservation shell.

[0051] ​The to-be-tested target is fixed on the top of the turntable and rotates with the turntable.

[0052] The embodiment also provides a radar stealth target RCS testing method based on the above testing system, and the method comprises the following steps:

[0053] Step 1. The internal space of the temperature control device is heated to a set temperature and kept stable by the computer controlling the temperature control module.

[0054] Step 2. The transceiving antenna is aligned with the center position of the to-be-tested target, then a large metal plate is placed between the temperature control device and the transceiving antenna, and response calibration is performed by using a vector network analyzer.

[0055] Step 3. The large metal plate is removed, the transceiving antenna position is kept unchanged, and the to-be-tested target is tested, and original signal data are read by using the vector network analyzer.

[0056] Step 4. The original signal data measured in step 3 are processed by using a time domain gate technology to obtain effective signal data.

[0057] Step 5. The transceiving antenna is moved in the same plane and the relative position is kept unchanged, the to-be-tested target is tested again, original signal data of this test are read by using the vector network analyzer, and effective signal data of this test are obtained by processing through the time domain gate technology.

[0058] Step 6. Step 5 is repeated to obtain 18 effective signal data.

[0059] Step 7. The to-be-tested target is removed, steps 3-5 are repeated to obtain 18 cavity data.

[0060] Step 8. All effective signal data are vector superimposed by using a comprehensive plane wave technology to obtain equivalent effective signal data, all cavity data are vector superimposed by using the comprehensive plane wave technology to obtain background data, the equivalent effective signal data and the background data are vector subtracted to reduce the influence of background noise, and finally the RCS of the to-be-tested target is calculated.

[0061] The near-field high-temperature RCS testing device in a complex environment adopted by the embodiment needs to use a time domain gate technology to extract target useful signals, because the testing antenna is arranged in a non-darkroom environment, and the role of the time domain gate technology is as follows Figure 2 , Figure 2 It is shown that the time domain gate technology can filter out direct coupling signals between the transceiving antenna and interference signals of an external environment, and can directly extract effective signals of the to-be-tested target; in order to meet the requirement of near-field testing, the transceiving antenna is Figure 3 scanned and tested, Figure 3It is shown that the transmitting and receiving antennas are horizontally moved or vertically moved in the same plane according to the 'yi' shape to carry out plane scanning, and then the target is tested, the result of each test is processed in the time domain gate, and then the vector superposition is carried out through the comprehensive plane wave technology, so that the spherical wave of the near-field test is superimposed to be approximately the plane wave of the far field; the near-field high-temperature test RCS system test process under the complex environment adopted by the present application is as shown in Figure 5 .

[0062] The metal ball is actually tested by adopting the system, and after the test system is built according to the structure Figure 4 , the normal temperature test is carried out under the condition of adding the heat insulation device according to the test process Figure 5 , and finally the test result of the metal ball is as shown in Figure 6 , Figure 6 It is shown that the test result is consistent with the theoretical result, and the feasibility of the system is verified.

[0063] The above is only a specific embodiment of the present application, any feature disclosed in the specification can be replaced by other equivalent or similar purpose alternative features unless specifically described; all features disclosed or all steps in the method or process can be combined in any way, except for mutually exclusive features and / or steps.

Claims

1. A near-field high-temperature RCS test system in a complex environment, characterized in that, The system comprises a vector network analyzer, a transmitting antenna, a receiving antenna, a temperature control device, a target to be measured, a turntable, a motor control module, a temperature control module, a computer, a wave absorbing plate, and a large metal plate. The two test ports of the vector network analyzer are connected to the transmitting antenna and the receiving antenna respectively. The transmitting antenna and the receiving antenna are arranged side by side, and the radiation port faces the target to be measured. The large metal plate is placed between the temperature control device and the transmitting and receiving antennas, and is in close contact with the temperature control device. The wave absorbing plate is placed between the transmitting antenna and the receiving antenna. The computer is connected to the vector network analyzer and reads the test data, and is also connected to the motor control module and the temperature control module and sends control signals. The motor control module controls the turntable to rotate at a constant speed under the drive of the control signals. The temperature control module controls the temperature control device to heat and keep the internal space under the drive of the control signals. The temperature control device comprises a heat preservation shell and a heating assembly. The heat preservation shell is a hollow structure for placing the target to be measured, and the heating assembly is used to heat the internal space of the heat preservation shell. The upper part of the turntable extends into the hollow structure of the heat preservation shell. The target to be measured is fixed on the top of the turntable and rotates with it.

2. The near-field high-temperature RCS test system in a complex environment of claim 1, wherein, The distance between the transmitting antenna and the receiving antenna and the target to be measured satisfies greater than or equal to Where D = max{antenna aperture, target length}, and λ represents the wavelength corresponding to the measured frequency.

3. The near-field high-temperature RCS test system in a complex environment according to claim 1 or 2, characterized in that, The heat preservation shell is made of a material with a dielectric constant less than 2.

4. A method for near-field high-temperature RCS testing in a complex environment, characterized in that, The test method is based on the test system of claim 1 or 2, comprising the following steps: Step 1. The computer controls the temperature control module to heat the internal space of the temperature control device to a set temperature and keep it stable. Step 2. Align the transmitting and receiving antennas with the center of the target to be measured, then place the large metal plate between the temperature control device and the transmitting and receiving antennas, and use the vector network analyzer to calibrate the response. Step 3. Remove the large metal plate, keep the position of the transmitting and receiving antennas unchanged, test the target to be measured, and use the vector network analyzer to read the original signal data. Step 4. Process the original signal data obtained in step 3 by time domain gating algorithm to obtain effective signal data. Step 5. Move the transmitting and receiving antennas in the same plane while keeping their relative positions, test the target to be measured again, read the original signal data of this test by the vector network analyzer, and process it by time domain gating algorithm to obtain the effective signal data of this test. Step 6. Repeat step 5 to obtain at least 9 effective signal data. Step 7. Remove the target to be measured, repeat steps 3-5 to obtain at least 9 cavity data. Step 8. Vector superposition is performed on all effective signal data by using the comprehensive plane wave technology to obtain equivalent effective signal data. Vector superposition is performed on all cavity data by using the comprehensive plane wave technology to obtain background data. The equivalent effective signal data and the background data are subtracted to reduce the influence of background noise, and finally the RCS of the target to be measured is calculated.

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