A two-dimensional pattern testing method using a planar near-field fast inversion method

Abstract

The application discloses a two-dimensional directional diagram testing method adopting a planar near-field fast inversion method, and comprises the following steps: S1, a near-field testing system is built; S2, a control terminal of the testing system is used to control a testing radar, so that an active phased array antenna of the testing radar works in a receiving state and is directed to a direction to be tested; S3, a probe is made to perform array scanning according to a specified path; S4, the control terminal of the testing system is used to control a vector network tester, and testing data is automatically recorded; S5, according to the testing data collected by the vector network tester, two-dimensional directional diagram inversion calculation is performed, and a directional diagram inversion result of the beam pointing direction is obtained. The two jobs of near-field calibration and near-field directional diagram testing can be simultaneously completed in a near-field testing environment, the testing data obtained through the near-field directional diagram testing is used for near-field directional diagram inversion, and a directional diagram result of the active phased array antenna is derived, so that the testing efficiency of the active phased array is improved. Therefore, the method is suitable for popularization and application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of active phased array antenna testing, and particularly relates to a two-dimensional pattern testing method using a planar near-field fast inversion method. BACKGROUND

[0002] The precision of active phased array antenna testing affects the angle measurement performance of a radar, so active phased array antenna testing is an important work of phased array radar testing. The existing far-field active phased array antenna testing method needs to coordinate a far-field anechoic chamber to complete the testing, and the tester needs to coordinate a far-field testing anechoic chamber meeting the testing requirements, and also needs to re-erect equipment in the far field after completing near-field data calibration to complete far-field testing preparation work; and the far-field testing process is relatively complicated, and it is very difficult to erect and disassemble for a large-size active phased array antenna. The method of antenna pattern near-field inversion can complete the near-field calibration and near-field pattern testing at the same time in a near-field testing environment, the testing data obtained through the near-field pattern testing is used for near-field pattern inversion to deduce the active phased array antenna pattern result, the testing efficiency of the active phased array is improved, and the method has high engineering practicability.

[0003] The existing near-field pattern inversion technology mainly depends on probe compensation theory, uses the relationship between the near-field and the far-field pattern that is a Fourier transform, and performs inversion transformation by calculating a binary first-order equation set through twice measurement of the same system, so the inversion method is complicated and the calculation amount is large. SUMMARY

[0004] The application aims to provide a two-dimensional pattern testing method using a planar near-field fast inversion method, which is mainly used for quickly verifying the implementation of the two-dimensional pattern of an active phased array radar and improving the testing efficiency of the active phased array antenna.

[0005] To achieve the above object, the technical scheme adopted by the application is as follows:

[0006] A two-dimensional pattern testing method using a planar near-field fast inversion method, comprising the following steps:

[0007] S1, a near-field testing system is built, and the connection of testing instruments and equipment is completed in a near-field testing anechoic chamber;

[0008] S2, a control terminal of the testing system is used to control a testing radar, so that the active phased array antenna of the testing radar works in a receiving state and is directed to a direction to be tested;

[0009] S3, the control terminal of the testing system is used to control a probe motor of the testing system, so that the probe is array scanned according to a specified path;

[0010] S4, controlling the vector network tester by the control terminal of the test system to make the vector network tester work normally and automatically record the test data;

[0011] S5, performing two-dimensional directional diagram inversion calculation according to the test data collected by the vector network tester to obtain the directional diagram inversion result of the beam pointing downward.

[0012] Further, in the present application, the test system comprises a test platform, a test radar erected on the test platform, a vector network tester connected with the test radar through a radio frequency cable, a control cabinet terminal connected with the vector network tester and the test radar and used for controlling the beam pointing of the radar and the working state of the vector network tester, a signal source for emitting a single-frequency continuous wave signal of a frequency band to be tested, a probe connected with the signal source and used for performing array scanning, and a probe motor connected with the probe and the control terminal and used for controlling the movement of the probe.

[0013] Further, in step S2, the near-field calibration test of the test radar is completed before the test radar is controlled.

[0014] Further, in step S3, the array scanning adopts a rectangular grid scanning mode.

[0015] Further, in step S4, the data recorded by the vector network tester comprises the amplitude and phase information of the radio frequency output signal of the test radar, the motor position information, and the amplitude and phase information of the radio frequency signal radiated through the antenna;

[0016] wherein the probe motor moves along the x-axis direction with a spacing Δx and samples N x points along the x-axis; the probe motor moves along the y-axis direction with a spacing Δy and samples N y points along the y-axis; after the data collection is completed, there are N x × N y points of data in total.

[0017] Further, in step S5, the data inversion calculation step is:

[0018] S51, calculating the wave path complex value compensation value of the probe to the array plane under the rectangular coordinate system;

[0019] S52, calculating the distance compensation value of the probe to the reference point, and the calculation formula is:

[0020] x-axis distance compensation value d x : d x =r×sin(β);

[0021] y-axis distance compensation value d y : d y =r×cos(β)×sin(α);

[0022] z-axis distance compensation value d z : d z = r x cos (β) x cos (α) ;

[0023] Wherein, r is the vertical distance from the probe to the array, α is the beam azimuth pointing angle of the array, and β is the beam elevation pointing angle of the array.

[0024] S53, the distance compensation value of the probe to each sampling position is calculated, and the calculation formula is:

[0025]

[0026] Wherein, Px, Py and Pz are the coordinates of the array element (P x , y , z ) ;

[0027] S54, the amplitude compensation value of each sampling position is calculated, and the calculation formula is:

[0028]

[0029] S54, the phase compensation value of each sampling position is calculated, and the calculation formula is:

[0030] d pha = exp (2πj x d r / λ) ;

[0031] Wherein, λ is the wavelength of the radio frequency signal, and j is the imaginary number mark.

[0032] S55, the wave path amplitude and phase compensation value of the probe to each sampling position of the array is calculated, and the calculation formula is:

[0033] d com = d amp x d pha ;

[0034] S56, the inversion result amplitude and phase value Beam of each sampling position after compensation is calculated, and the calculation formula is:

[0035] Beam = d com x d ori ;

[0036] Wherein, d ori is the test result of the vector network tester at a certain test point.

[0037] S57, the amplitude and phase value calculation of each sampling position of the entire array is completed, and the directional diagram inversion result under the beam pointing direction is obtained.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] Compared with the far-field antenna pattern test method of the active phased array antenna, the test method is simple, the inversion precision is high, the two-dimensional antenna pattern inversion calculation can be realized, compared with other near-field pattern inversion technologies, the calculation speed is fast, the method is convenient, the realization situation of the two-dimensional pattern of the active phased array radar can be quickly verified, and the test efficiency of the active phased array antenna is improved. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The principle block diagram of the near-field inversion test system used in the application.

[0041] Figure 2 The schematic diagram of the rectangular grid scanning adopted in the embodiment of the application.

[0042] Figure 3 The near-field antenna pattern inversion result of the array antenna in the embodiment of the application.

[0043] Figure 4 The three-dimensional near-field antenna pattern inversion result of the array antenna of a certain wave band. DETAILED DESCRIPTION

[0044] The application will be further described below in combination with the accompanying drawings and embodiments, and the modes of the application include but are not limited to the following embodiments.

[0045] As shown in the accompanying drawings and embodiments, the application discloses a two-dimensional pattern test method using a planar near-field fast inversion method, including the following steps: Figure 1

[0046] S1, a near-field test system is built, the radar to be tested is erected on the equipment test platform, the radar to be tested is an active phased array radar; a probe of a suitable frequency band is selected and connected with a signal source, the signal source emits a single-frequency continuous wave signal of the frequency band to be tested; the radar output and the road radio frequency signal are connected with a vector network analyzer through a radio frequency cable, the vector network analyzer collects the amplitude and phase information of the output radar radio frequency signal. A control terminal is connected with the radar and the vector network analyzer, used for controlling the beam pointing of the test radar, controlling the working state of the vector network tester, and recording the amplitude and phase information obtained by the vector network analyzer in real time; the control terminal is also connected with the probe motor, used for controlling the movement of the probe; the connection of the instruments and equipment is completed in the near-field test darkroom, except for the probe antenna, the radar antenna and the same position, the excess exposed positions are tightly covered with wave-absorbing materials.

[0047] S2, under the condition that the radar has completed the near-field calibration test, the control terminal of the test system is used to control the test radar, so that the active phased array antenna of the test radar works in the receiving state and points to the direction to be tested. ​

[0048] S3, the control terminal controls the probe motor to make the test probe move according to the agreed route and step, and generally we select the rectangular grid scanning mode for testing, the scanning range is greater than the size of the antenna array surface, and the scanning step is less than half a wavelength.

[0049] S4, the control terminal controls the vector network analyzer to work in the normal test mode, the vector network analyzer can collect the amplitude and phase information of the radar radio frequency output signal and transmit them to the control terminal, and the control terminal records the motor position information and the amplitude and phase information of the radio frequency signal radiated through the antenna in real time according to the agreed data format.

[0050] The probe motor moves along the x-axis direction with a spacing Δx, and N x point data are sampled along the x-axis; the probe motor moves along the y-axis direction with a spacing Δy, and N y point data are sampled along the y-axis; after the data collection is completed, there are N x ×N y point data in total.

[0051] S5, according to the test data collected by the vector network analyzer, two-dimensional directional diagram inversion calculation is performed;

[0052] The N x ×N y point vector network analyzer data collected and recorded are subjected to data inversion calculation. α is the beam azimuth pointing angle of the array, and β is the beam elevation pointing angle of the array.

[0053] Firstly, the wave path complex value compensation value of the probe to the array in the rectangular coordinate system is calculated.

[0054] In the rectangular coordinate system, r is the perpendicular distance from the probe to the array, and the distance compensation value formula of the probe to the reference point is:

[0055] The x-axis distance compensation value d x : d x =r×sin(β)

[0056] The y-axis distance compensation value d y : d y =r×cos(β)×sin(α)

[0057] The z-axis distance compensation value d z : d z =r×cos(β)×cos(α)

[0058] In the rectangular coordinate system, the coordinates of the array element are (P x , P y , P z ), and the distance compensation value formula of the probe to each sampling position is:

[0059]

[0060] The formula for the amplitude compensation value at each sampling location is:

[0061]

[0062] The formula for the phase compensation value at each sampling position for a radio frequency signal with wavelength λ is:

[0063] d pha =exp(2πj×d) r / λ)

[0064] Where j is the imaginary number flag.

[0065] The formula for the path amplitude and phase compensation values ​​at each sampling position from the probe to the array is:

[0066] d com =d amp ×d pha

[0067] Then, at a certain test point, the vector network tester measured the test result as d. ori Calculate the amplitude and phase value Beam of the inversion result at each sampling position after compensation. The calculation formula is as follows:

[0068] Beam=d com ×d ori

[0069] Finally, the amplitude and phase values ​​at each sampling position of the entire array are calculated, and the beam pattern inversion result is obtained by pointing downwards.

[0070] like Figure 3 As shown, taking a beam azimuth angle α pointing to -10° and a beam elevation angle β pointing to -20° as an example, the antenna array calibration and pattern inversion calculation are completed according to the method of this invention to obtain the near-field antenna pattern inversion result of a certain band array antenna. The near-field inverted pattern is accurately calculated through near-field test data, and the beam pointing angle of the pattern is consistent with the beam setting value.

[0071] Figure 4 The inversion result of the three-dimensional near-field antenna pattern of a certain band array antenna when the beam azimuth angle α points to -10° and the beam elevation angle β points to -20°. For example... Figure 4 As shown, antenna array calibration and pattern inversion calculation are completed according to the method of the present invention. The near-field inversion pattern can be accurately calculated from near-field test data, and the beam pointing angle of the pattern is consistent with the beam setting value.

[0072] Compared with the far-field antenna pattern test method of the active phased array antenna, the test method is simple, the inversion precision is high, the inversion calculation of the two-dimensional antenna pattern can be realized, compared with other near-field pattern inversion technologies, the calculation speed is fast, the method is convenient, the implementation situation of the two-dimensional pattern of the active phased array radar can be quickly verified, and the test efficiency of the active phased array antenna is improved.

[0073] The above embodiment is only one of the preferred embodiments of the application and should not be used to limit the protection scope of the application, but any modification or polishing without substantial meaning made within the main design idea and spirit of the application, the technical problems solved are still consistent with the application, and should be included in the protection scope of the application.

Claims

1. A two-dimensional pattern test method using a planar near-field fast inversion method, characterized by, The method comprises the following steps: S1, a near-field test system is built, and connection of test instruments and equipment is completed in a near-field test darkroom; S2, a control terminal of the test system is used to control the test radar, so that an active phased array antenna of the test radar works in a receiving state and is directed to a direction to be tested; S3, the control terminal of the test system is used to control a probe motor of the test system, so that the probe is array scanned according to a specified path; S4, the control terminal of the test system is used to control a vector network tester, so that the vector network tester normally works and automatically records test data; S5, according to the test data collected by the vector network tester, two-dimensional directional diagram inversion calculation is performed, and a directional diagram inversion result of the test radar under a beam pointing direction is obtained; wherein, the data inversion calculation step is: S51, a wave path complex value compensation value of the probe to the array panel under a rectangular coordinate system is calculated, comprising: S5101, a distance compensation value of the probe to a reference point is calculated, and a calculation formula is: X-axis distance compensation value d x : d x = r x sin(β); Y-axis distance compensation value d y : d y = r x cos(β) x sin(α); z-axis distance compensation value d z : d z = r x cos(β) x cos(α); Wherein, r is a perpendicular distance of the probe to the array panel, α is a beam azimuth pointing angle of the array panel, and β is a beam elevation pointing angle of the array panel; S5102, a distance compensation value of the probe to each sampling position is calculated, and a calculation formula is: Wherein, Px, Py, Pz are coordinates of the array element (P x ,P y ,P z ); S5103, an amplitude compensation value of each sampling position is calculated, and a calculation formula is: S5104, a phase compensation value of each sampling position is calculated, and a calculation formula is: d pha = exp(2πj x d r / λ); Wherein, λ is a radio frequency signal wavelength, and j is an imaginary number mark; S5105, a wave path amplitude and phase compensation value of the probe to each sampling position of the array panel is calculated, and a calculation formula is: d com = d amp × d pha ; S52, an inversion result amplitude and phase value Beam of each sampling position after compensation is calculated, and a calculation formula is: Beam = d com x d ori ; wherein d ori is the test result of the vector network analyzer at the test point; S53, amplitude and phase value calculation of each sampling position of the whole array panel is completed, and the directional diagram inversion result under the beam pointing direction is obtained.

2. The two-dimensional pattern testing method using the planar near-field fast inversion method according to claim 1, characterized in that, The test system comprises a test platform, a test radar erected on the test platform, a vector network tester connected with the test radar through a radio frequency cable, a control cabinet terminal connected with the vector network tester and the test radar and used for controlling beam pointing of the radar and working states of the vector network tester, a signal source used for transmitting a single-frequency continuous wave signal of a frequency band to be tested, a probe connected with the signal source and used for array scanning, and a probe motor connected with the probe and the control terminal and used for controlling movement of the probe.

3. The two-dimensional pattern testing method using the planar near-field fast inversion method according to claim 2, characterized in that, In step S2, near-field calibration test of the test radar is completed before the test radar is controlled.

4. The two-dimensional pattern testing method using the planar near-field fast inversion method according to claim 3, characterized in that, In step S3, the array scanning adopts a rectangular grid scanning mode.

5. The two-dimensional pattern testing method using the planar near-field fast inversion method according to claim 4, characterized in that, In step S4, the data recorded by the vector network tester comprises amplitude and phase information of a radio frequency output signal of the test radar, motor position information and corresponding amplitude and phase information of the radio frequency signal radiated through the antenna. Wherein, the probe motor moves along the x-axis direction, interval Δx, and common sampling N along the x-axis x Point data; the probe motor moves along the y-axis direction, interval Δy, and common sampling N along the y-axis y Point data; after completing data acquisition, there are N x ×N y Point data.

Images