CN115113166A - A test method, device and electronic equipment for a drone-borne Lumberg ball target - Google Patents

Abstract

The invention provides a method and a device for testing unmanned aerial vehicle-mounted luneberg target mapping and electronic equipment. The method comprises the following steps: and acquiring a background echo signal of the current test environment. And acquiring first calibration body echo signals of different rotation angles of the calibration body. And acquiring first target echo signals of the unmanned aerial vehicle with the luneberg balls at different rotation angles. And subtracting the background echo signal from the first calibration body echo signal to obtain a second calibration body echo signal with different rotation angles after background cancellation. And subtracting the background echo signal from the first target echo signal to obtain a second target echo signal. And calculating the RCS value of the calibration body at the same rotation angle, multiplying the RCS value by the second target echo signal and dividing the second calibration body echo signal by the RCS value to obtain the RCS distribution of each rotation angle of the unmanned aerial vehicle-mounted luneberg ball. The method calculates RCS distribution by subtracting the background echo signal of the current test environment, cancels the influence of the background on the calibration body echo signal and the target echo signal, and reduces the test error of RCS distribution characteristics under a high-frequency K wave band.

Description

A test method, device and electronic equipment for a drone-borne Lumberg ball target

technical field

The invention relates to the technical field of military equipment, in particular to a test method, device and electronic equipment for an unmanned aerial vehicle-borne Lumberg ball target.

Background technique

A radar passive target is a device with a specific Radar Cross Section (RCS) distribution characteristic. The RCS distribution characteristics of the radar passive target in the designated space area under the irradiation of the designated frequency radar wave are equivalent to the simulated target. It is usually used to simulate aircraft and warships and cause interference to enemy radars. Radar passive targets include spheres, corner reflectors and Lumberg spheres.

Lumber spheres are also called Lumber lenses, which are usually composed of more than 5 layers of media with different dielectric constants. It has a larger RCS and a wider coverage angle of the secondary radiation direction, and the stable spatial angle range of the RCS value is greater than 110°. The Lunberg ball has good performance, small size and light weight, and can be used as a drone-borne target.

The main method to measure the RCS of the UAV-borne Luneberg sphere target is to determine the RCS distribution of the UAV-borne Luneberg sphere by comparing the UAV-borne Luneberg sphere target with the known calibration body of the RCS under the same test conditions. characteristic. For the test of the RCS distribution characteristics of the UAV-borne Luneberg sphere, in the X-band, such as 10Ghz, the existing test methods can be more accurate. However, for the K-band with a higher frequency, such as the 24GHz band, due to the influence of background noise, the test error of the existing calibration body test method is relatively large.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a method, device and electronic equipment for testing an unmanned aerial vehicle-borne Luneberg ball target, so as to solve the problem of large error in the test of the K-band RCS distribution characteristics of the unmanned aerial vehicle-borne Luneberg ball target.

In a first aspect, an embodiment of the present invention provides a method for testing a drone-borne Lumberg ball target, including:

Obtain the background echo signal of the current test environment.

Obtain the echo signals of the first calibration body at different rotation angles in the horizontal direction of the calibration body under the current test environment.

Obtain the echo signals of the first target at different rotation angles in the horizontal direction of the UAV-borne Lumberg ball in the current test environment.

The background echo signal is subtracted from the first calibration volume echo signal to obtain a second calibration volume echo signal with different rotation angles after background cancellation.

The background echo signal is subtracted from the first target echo signal to obtain a second target echo signal with different rotation angles after background cancellation.

Calculate the RCS value of the calibration body under the same rotation angle, multiply the echo signal of the second target by the echo signal of the second calibration body, and obtain the RCS distribution of each rotation angle of the UAV-borne Lumberg sphere.

In a possible implementation manner, after acquiring the background echo signal of the current test environment, the method further includes:

The background echo signal is subjected to inverse fast Fourier transform, a distance gate and a fast Fourier transform are added, and the signal after filtering out the clutter interference outside the distance gate is used as the background echo signal.

After acquiring the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment, the method further includes:

Perform inverse fast Fourier transform on the first calibration body echo signal, add distance gate and fast Fourier transform, and use the signal after filtering out clutter interference outside the distance gate as the first calibration body echo Signal.

After the acquisition of the first target echo signals of different rotation angles in the horizontal direction of the drone-borne Lumberg ball in the current test environment, the method further includes:

Perform inverse fast Fourier transform, adding distance gate and fast Fourier transform on the first target echo signal, and use the signal after filtering out clutter interference outside the range gate as the first target echo signal.

In a possible implementation manner, performing inverse fast Fourier transform on the background echo signal, adding distance gate and fast Fourier transform, filtering out the signal after clutter interference outside the distance gate Before being used as the background echo signal, it also includes:

In the same test environment, test the echo signal of the object under test and remove the echo signal of the object under test.

The inverse fast Fourier transform is performed on the echo signal of the measured object and the echo signal from which the measured object is removed.

Compare the echo signal of the measured object after inverse fast Fourier transform and the echo signal of the measured object to obtain the corresponding time range of the measured object on the time axis in the time domain coordinate system.

Take the obtained time range as the range of the distance gate.

In a possible implementation manner, the scaling body is a trihedral corner reflector.

The obtaining of the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment includes:

The echo signals of different rotation angles in the horizontal direction of the trihedral corner reflector in the current test environment are obtained as the echo signals of the first calibration body.

In a possible implementation manner, the rotation angle of the trihedral corner reflector facing the antenna of the test signal source is 0°, and the rotation angle of the trihedral corner reflector in the horizontal direction ranges from -20° to 20°.

In a possible implementation manner, in the calculation, the RCS value of the calibration body under the same rotation angle is multiplied by the echo signal of the second target and divided by the echo signal of the second calibration body, so as to obtain the UAV-borne Lumberg After the RCS distribution of each rotation angle of the ball, it also includes:

Smooth filtering is performed on the RCS distribution to obtain the RCS distribution of each rotation angle of the UAV-borne Lumberg ball after eliminating the interference of the UAV arm.

In a possible implementation manner, the smoothing window of the smoothing filtering is greater than or equal to 1° and less than or equal to 2°.

In a second aspect, an embodiment of the present invention provides a test device for an unmanned aerial vehicle-borne Lumberg ball target, including:

The background echo acquisition module is used to acquire the background echo signal of the current test environment.

The calibration body echo acquisition module is used to obtain the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment.

The target echo acquisition module is used to acquire the first target echo signals of different rotation angles in the horizontal direction of the drone-borne Lumberg ball in the current test environment.

A calibration body background cancellation module, configured to subtract the background echo signal from the first calibration body echo signal to obtain a second calibration body echo signal with different rotation angles after background cancellation.

The target background cancellation module is used for subtracting the background echo signal from the first target echo signal to obtain a second target echo signal with different rotation angles after background cancellation.

The RCS distribution calculation module is used to calculate the RCS value of the calibration body under the same rotation angle, multiplied by the echo signal of the second target and divided by the echo signal of the second calibration body. RCS distribution.

In a third aspect, an embodiment of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, when the processor executes the computer program The steps of the method described above in the first aspect or any possible implementation manner of the first aspect are implemented.

In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, implements the first aspect or any of the first aspect above. A possible implementation of the steps of the described method.

Embodiments of the present invention provide a method, device and electronic device for testing a drone-borne Lumberg ball target. The method includes acquiring a background echo signal of a current testing environment. Obtain the echo signals of the first calibration body at different rotation angles in the horizontal direction of the calibration body under the current test environment. Obtain the echo signals of the first target at different rotation angles in the horizontal direction of the UAV-borne Lumberg ball in the current test environment. The background echo signal is subtracted from the first calibration body echo signal to obtain the second calibration body echo signal with different rotation angles after background cancellation. The background echo signal is subtracted from the first target echo signal to obtain the second target echo signal with different rotation angles after background cancellation. Calculate the RCS value of the calibration body under the same rotation angle, multiply the echo signal of the second target by the echo signal of the second calibration body, and obtain the RCS distribution of each rotation angle of the UAV-borne Lumberg sphere. The present invention calculates the RCS distribution by subtracting the background echo signal of the current test environment, offsets the influence of the background on the calibration body echo signal and the target echo signal, and reduces the test error of the RCS distribution characteristics in the high frequency K-band .

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only for the present invention. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is an application scenario diagram of the test method provided by the embodiment of the present invention;

2 is a schematic diagram of a cross-sectional structure of a Lumber ball provided by an embodiment of the present invention;

Fig. 3 is a kind of Lunberg sphere RCS distribution characteristic diagram that the embodiment of the present invention provides;

Fig. 4 is the realization flow chart of a kind of unmanned aerial vehicle carrying Lunberg ball target test method provided by the embodiment of the present invention;

5 is a schematic structural diagram of a UAV-carrying Lunberg ball provided by an embodiment of the present invention;

Fig. 6 is the one-dimensional range image of the time domain echo signal plus the distance gate provided by the embodiment of the present invention;

FIG. 7 is a one-dimensional range image after the time-domain echo signal plus the range gate provided by an embodiment of the present invention;

FIG. 8 is a flow chart of test data processing of a drone-borne Lumberg ball target provided by an embodiment of the present invention;

Fig. 9 is the test result diagram of unmanned aerial vehicle carrying Lunberg ball target provided by the embodiment of the present invention;

10 is a schematic structural diagram of a drone-borne Lumberg ball target testing device provided by an embodiment of the present invention;

FIG. 11 is a schematic diagram of an electronic device provided by an embodiment of the present invention.

Detailed ways

In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are set forth in order to provide a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to make the objectives, technical solutions and advantages of the present invention clearer, the following descriptions will be given through specific embodiments in conjunction with the accompanying drawings.

A radar passive target is a device with a specific Radar Cross Section (RCS) distribution characteristic. The RCS distribution characteristics of the radar passive target in the designated space area under the irradiation of the designated frequency radar wave are equivalent to the simulated target. It is usually used to simulate aircraft and warships and cause interference to enemy radars. Radar passive targets include spheres, corner reflectors and Lumberg spheres.

The target testing method provided by the embodiment of the present invention can be applied to various application scenarios, and these scenarios involve RCS testing of the UAV-borne Lumberg target, and the specific application scenarios are not limited herein. Exemplarily, FIG. 1 is an application scenario diagram of the testing method provided by the embodiment of the present invention. As shown in FIG. 1 , a test system to which the test method provided by the embodiment of the present invention is applicable includes: a microwave anechoic chamber, a radar transceiver antenna, a turntable and a low-scattering bracket placed in the microwave anechoic chamber, and a vector network analyzer placed outside the microwave anechoic chamber , turntable controller and computer. The low scatter holder is used to place the object under test. The inner walls of the anechoic chamber can absorb radar waves and are used to simulate infinite space. During measurement, the baseband signal generated by the vector network analyzer is amplified by the power amplifier, and then the radar signal is sent out by the radar transceiver antenna. The radar signal is reflected by the measured object to generate an echo signal, and the radar transceiver antenna receives the echo signal and transmits it to the vector network analyzer for measurement. The turntable controller can control the turntable to drive the low-scattering support and the measured object to rotate, so as to measure the echo signals of the measured object at different rotation angles. Exemplarily, the turntable is a one-dimensional horizontal rotation turntable, and the one-dimensional horizontal rotation turntable rotates horizontally under the control of a turntable controller to obtain echo signals of the measured object at different rotation angles.

Lumber spheres are also called Lumber lenses, which are usually composed of more than 5 layers of media with different dielectric constants. Lumberg spheres can reflect incident signals with different incident angles against the incident direction to form echo signals. 2 is a schematic diagram of a cross-sectional structure of a Luneberg sphere provided by an embodiment of the present invention. Referring to FIG. 2 , the Lunberg sphere exemplarily includes 5 layers of dielectrics and reflective surfaces with different dielectric constants. On the cross-sectional structure, media with different dielectric constants are arranged in a ring shape from the inside to the outside. The Lumberg sphere reflects the incident signal to form an echo signal, wherein the direction of the echo signal is opposite to the direction of the incident signal. FIG. 3 is a characteristic diagram of the RCS distribution of a Lumber sphere provided by an embodiment of the present invention. Referring to FIG. 3 , the vertical axis is the RCS value of the echo signal, the horizontal axis is the incident angle of the incident signal, and an angle of 0° means that the incident side faces the front of the Lumberg sphere. The Lombard sphere has a large RCS and a wide coverage angle of the secondary radiation direction, and the stable spatial angle range of the RCS value is greater than 110°. The Lunberg ball has good performance, small size and light weight, and can be used as a drone-borne target.

The main method to measure the RCS of the UAV-borne Luneberg sphere target is to determine the RCS distribution of the UAV-borne Luneberg sphere by comparing the UAV-borne Luneberg sphere target with the known calibration body of the RCS under the same test conditions. characteristic. For the test of the RCS distribution characteristics of the UAV-borne Luneberg sphere, in the X-band, such as 10Ghz, the existing test methods can be more accurate. However, for the K-band with a higher frequency, such as the 24GHz band, due to the influence of background noise, the test error of the existing calibration body test method is relatively large.

FIG. 4 is a flow chart of the realization of a method for testing a drone-borne Lumberg ball target provided by an embodiment of the present invention. Referring to Figure 4:

The embodiment of the present invention provides a test method for a drone-borne Lumberg ball target, comprising:

In step S1, the background echo signal of the current test environment is acquired. Exemplarily, when the object to be tested is not placed on the low-scattering support, the reflected signal in the microwave anechoic chamber is tested to obtain the background echo signal. Exemplarily, the background echo signals at different rotation angles of the turntable are tested, and the background echo signals at different rotation angles are obtained. Exemplarily, the frequency band of the radar wave emitted by the radar transceiver antenna is the K-band. Exemplarily, the echo signal is a spectral signal, that is, the signal power at different frequencies. Exemplarily, the background echo signal is obtained by measuring the forward transmission coefficient (ie, the scattering coefficient) S ₂₁ signal by a vector network analyzer. The larger the echo power, the larger the forward transmission coefficient _S21 .

In step S2, the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment are acquired. A calibration body is an object whose RCS properties are known. Exemplarily, the calibration body is a sphere. Exemplarily, the calibration body is placed on the low-scattering support, and the turntable drives the low-scattering support and the calibration body to rotate to achieve different rotation angles in the horizontal direction. Exemplarily, a calibration body is placed on the low-scattering support, and reflected signals of different rotation angles of the turntable are tested to obtain echo signals of the first calibration body. RCS can be defined as 4π times the ratio of the scattered power of the measured object to the receiving antenna within a unit solid angle to the power density of the incident wave on the target.

In step S3, the first target echo signals of different rotation angles in the horizontal direction of the drone-borne Lumberg ball in the current test environment are acquired. FIG. 5 is a schematic structural diagram of a drone-borne Lumberg ball according to an embodiment of the present invention. Referring to FIG. 5 , the Lumber ball mounted on the drone may be installed under the UAV, and the direction of the 0° attitude angle of the Lumbe ball is directed toward the front of the UAV. UAV-borne Lombard balls can be used as passive radar targets. Exemplarily, the drone-carried Lumber ball is placed on the low-scattering bracket, and the turntable drives the low-scattering bracket and the drone-carrying Luneberg ball to rotate to achieve different rotation angles in the horizontal direction. Exemplarily, a drone-carried Lumberg ball is placed on a low-scattering bracket, and the reflected signals of different rotation angles of the turntable are tested to obtain the first target echo signal.

In step S4, the background echo signal is subtracted from the first calibration volume echo signal to obtain a second calibration volume echo signal with different rotation angles after background cancellation. Exemplarily, the background echo signal is the signal of the turntable at different rotation angles, and the first calibration object echo signal and the background echo signal at the same rotation angle are subtracted to obtain the first background echo signal at different rotation angles after background cancellation. The second calibration body echo signal.

In step S5, the background echo signal is subtracted from the first target echo signal to obtain a second target echo signal with different rotation angles after background cancellation. Exemplarily, the background echo signal is the signal of the turntable at different rotation angles, and the first target echo signal and the background echo signal under the same rotation angle are subtracted to obtain the second target with different rotation angles after background cancellation. echo signal.

Disassembling and assembling the DUT will cause the test system to change, which in turn causes the background echo signal to change, especially during high-frequency testing. Exemplarily, the background echo signal is tested before the calibration body is installed, and after the calibration body is installed and tested, the background echo signal is subtracted from the echo signal of the first calibration body to obtain the first calibration body at different rotation angles after background cancellation. The second calibration body echo signal.

Exemplarily, the background echo signal is tested before installing the drone-borne Lumberg ball, and after the drone-borne Lumbe ball is installed and tested, the background echo signal is subtracted from the first target echo signal to obtain background cancellation. The echo signals of the second target at different rotation angles. Test the background echo signal before installing a certain object to be tested, so as to avoid the background condition that has been changed during the process of disassembling and assembling other objects under test, resulting in test errors.

In step S6, the RCS value of the calibration body under the same rotation angle is calculated, multiplied by the second target echo signal and divided by the echo signal of the second calibration body, to obtain the RCS distribution of each rotation angle of the drone-borne Lumber sphere .

According to the obtained echo signal of the second calibration body and the echo signal of the second target, a comparison method is used to calculate the RCS of the target to be tested. The comparison method is to use an object with a known RCS value as the calibration body. _Under the same test conditions, the scattering parameters S21 of the calibration body and the target to be measured are measured respectively, and the calibration body is used to calibrate the target to be measured. RCS value. The relationship between the scattering parameter S ₂₁ and the echo power of the echo signal is as follows:

表示矢量网络分析仪测得的定标体的散射系数。

表示矢量网络分析仪测得的无人机载龙伯球靶标的散射系数。根据雷达方程，靶标回波信号功率正比于靶标RCS，所以靶标的RCS值可以表示为：

Represents the scattering coefficient of the calibration volume measured by the vector network analyzer.

Represents the scattering coefficient of the drone-borne Lumberg target measured by the vector network analyzer. According to the radar equation, the power of the target echo signal is proportional to the target RCS, so the RCS value of the target can be expressed as:

The σ _target represents the RCS value of the drone-borne Lumberg target. The σ _{calibration body} represents the RCS value of the calibration body, and the RCS value of the calibration body at a certain rotation angle is a known value. The echo power of the P _target represents the echo power of the echo signal of the UAV-borne Lumberg sphere target. The P _{calibration body echo power} represents the echo power of the echo signal of the calibration body.

Calculate the RCS value of the calibration body at a certain rotation angle, multiply the echo signal of the second target, and divide the echo signal of the second calibration body to obtain the RCS value of the UAV-borne Lumberg sphere target at this rotation angle. Calculate the RCS value of each rotation angle, and obtain the RCS distribution of the UAV-borne Lumberg target at different rotation angles.

The embodiment of the present invention provides a method for testing an unmanned aerial vehicle-borne Lombard ball target by subtracting the background echo signal of the current test environment and then calculating the RCS distribution, which cancels the effect of the background on the echo signal of the calibration body and the echo signal of the target. It reduces the test error of the RCS distribution characteristics in the high frequency K-band.

In a possible implementation manner, after acquiring the background echo signal of the current test environment, the method further includes:

The background echo signal is subjected to inverse fast Fourier transform, distance gate and fast Fourier transform are added, and the signal after filtering out the clutter outside the distance gate is used as the background echo signal. That is, the background echo signal is subjected to inverse fast Fourier transform to obtain the background echo signal of the time domain coordinate system. A distance gate is added to the background echo signal of the time domain coordinate system, and the clutter interference other than the distance gate is filtered out, and the background echo signal of the time domain coordinate system after filtering out the interference is obtained. Fast Fourier transform is performed on the background echo signal of the time domain coordinate system after filtering out the interference, and the obtained signal after distance gate processing is used as the background echo signal.

After acquiring the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment, the method further includes:

The first calibration body echo signal is subjected to inverse fast Fourier transform, a distance gate and a fast Fourier transform are added, and the signal after filtering out clutter interference outside the distance gate is used as the first calibration body echo signal. That is, the inverse fast Fourier transform is performed on the first calibration volume echo signal to obtain the first calibration volume echo signal in the time domain coordinate system. A distance gate is added to the first calibration body echo signal of the time domain coordinate system, and clutter interference other than the distance gate is filtered out, and the first calibration body echo signal of the time domain coordinate system after filtering the interference is obtained. Fast Fourier transform is performed on the first calibration body echo signal of the time domain coordinate system after filtering out the interference, and the obtained signal processed by the distance gate is used as the first calibration body echo signal.

After obtaining the first target echo signals of different rotation angles in the horizontal direction of the UAV-borne Lumberg ball in the current test environment, the method also includes:

Perform inverse fast Fourier transform on the first target echo signal, add distance gate and fast Fourier transform, and use the signal after filtering out clutter interference outside the range gate as the first target echo signal. That is, inverse fast Fourier transform is performed on the first target echo signal to obtain the first target echo signal in the time domain coordinate system. A distance gate is added to the first target echo signal in the time domain coordinate system, and clutter interference other than the distance gate is filtered out to obtain the first target echo signal in the time domain coordinate system after filtering out the interference. Fast Fourier transform is performed on the first target echo signal of the time domain coordinate system after filtering out the interference, and the obtained signal processed by the distance gate is used as the first target echo signal.

Exemplarily, in the current test environment, the same range gate is used to perform range gate processing on the above background echo signal, the first target body echo signal and the first target echo signal.

The distance gate processing method provided by the embodiment of the present invention converts each measured frequency domain echo signal into a time domain echo signal, adds a suitable distance gate, filters out signals other than the distance gate, and then converts it into a frequency domain echo signal wave signal. By performing distance gate processing on each echo signal, clutter interference signals other than the distance gate are filtered out.

FIG. 6 is a one-dimensional range image of a time domain echo signal plus a range front door provided by an embodiment of the present invention. FIG. 7 is a one-dimensional range image diagram of a time domain echo signal after adding a range gate according to an embodiment of the present invention. 6 and 7, the horizontal axis is time, the vertical axis is the amplitude of the echo signal, the transmission speed of radio waves is the speed of light, and the horizontal axis time can represent the size of the distance. The distance gate is the time range in the horizontal axis of the time domain coordinate. The transmission distance corresponding to 0 to 100ns is 0 to 15 meters. The target peak is near the 65ns position. Exemplarily, after adding a range gate of 55ns to 75ns, the clutter signal other than the range gate is filtered out.

In a possible implementation, the background echo signal is subjected to inverse fast Fourier transform, distance gate and fast Fourier transform are added, and the signal after filtering out clutter interference outside the distance gate is used as the background echo Before the signal, also include:

In the same test environment, test the echo signal of the object under test and remove the echo signal of the object under test.

The inverse fast Fourier transform is performed on the echo signal of the measured object and the echo signal from which the measured object is removed.

Compare the echo signal of the measured object after inverse fast Fourier transform and the echo signal of the measured object to obtain the corresponding time range of the measured object on the time axis in the time domain coordinate system.

Take the obtained time range as the range of the distance gate.

Exemplarily, the echo signal is the scattering coefficient S ₂₁ parameter measured by a vector network analyzer. After the _S21 parameter is changed in time domain (IFFT), a one-dimensional range image can be obtained, the horizontal axis is time, and the vertical axis is amplitude. The specific location information expression of the measured target is:

p=T*C/2

Among them, p is the distance from the measured target to the radar transmitting antenna, and T is the time interval from the transmitted signal to the received signal. Exemplarily, first place the calibration body, measure S ₂₁ of the calibration body, and perform IFFT conversion on the measured data, so that a real-time one-dimensional distance image of the measured target can be obtained. Remove the S ₂₁ of the calibrated body measurement background, and then perform IFFT transformation, to obtain a one-dimensional range image that does not include the target. Comparing the two, the graph with the target stands out as a spike compared to the graph without the target. Taking the position of this peak as the center, a certain time range is selected as the range of the distance gate. Referring to FIG. 7 , the transmission distance corresponding to 0 to 100 ns is 0 to 15 meters. The target peak is near the 65ns position. Exemplarily, after adding a range gate of 55ns to 75ns, the clutter signal other than the range gate is filtered out.

In the method for selecting a distance gate provided by the embodiment of the present invention, by comparing the echo signals of the measured object and the absence of the measured object in the time domain coordinate system, it is confirmed that the measured object is on the horizontal axis time axis in the time domain echo signal. For the corresponding position, the time range corresponding to the above position is taken as the range of the distance gate.

In the embodiment of the present invention, the influence of the background of the test environment on the test result can be eliminated by using background cancellation and distance gate processing. In order to ensure that the test error is not greater than ±1.5dB, the signal level of the measured target and the calibration object should be higher than the ambient background signal level by more than 16dB.

In a possible implementation manner, the calibration body is a trihedral corner reflector. Obtaining the echo signals of the first calibration body with different rotation angles in the horizontal direction of the calibration body under the current test environment, including: acquiring the echo signals of the trihedral corner reflectors at different rotation angles in the horizontal direction under the current test environment, as the first calibration body echo signal.

The trihedral corner reflector is usually a concave structure composed of three metal flat plates orthogonal to each other. The trihedral corner reflector has three planes, and the triple internal reflection formed can have a wide scattering pattern in the three-dimensional space, and the manufacturing method is simple. , the cost is low, but the stable spatial angle range of its RCS value is only about 30°. Compared with the calibration sphere, the trihedral corner reflector cannot satisfy the stable RCS value in the 180° angle range, so the calibration sphere is usually used as the calibration body. The RCS of the scaled sphere is constant over the entire sphere. The RCS value is positively related to the area of the sphere. If a larger RCS value, such as 10dB ² , is required, the diameter of the sphere should reach more than 3.5m. However, for the K-band with higher frequency, such as the 24GHz frequency point, because of the higher frequency, the average value of S ₂₁ of the calibration ball (-25dBsm) is about -45dB, while the average value of S ₂₁ of the background is about -55dB. The ratio is less than 10dBsm, and the test error is greater than 3dB, which cannot meet the test requirements of the microwave anechoic chamber.

The trihedral corner reflector is used as the calibration body. The stable space angle range of the corner reflector not exceeding 3dB is -20°~20°, and the test error is less than 1dB, which meets the evaluation index. In addition, when evaluating the angular range of the UAV nose or arm, the RCS distribution characteristics in the forward angle range of -15° to 15° are generally evaluated, and the trihedral angle reflector used for calibration meets the corresponding angle range index. Exemplarily, the RCS of the trihedral corner reflector is 10 dBsm.

The embodiment provided by the present invention improves the signal-to-noise ratio between the calibration body and the background and reduces the test error while satisfying the test angle range of the RCS distribution characteristics of the UAV by using the trihedral corner reflector as the calibration body.

In a possible implementation manner, the rotation angle of the trihedral corner reflector facing the antenna of the test signal source is 0°, and the rotation angle of the trihedral corner reflector in the horizontal direction ranges from -20° to 20°.

In a possible implementation manner, the RCS value of the calibration body under the same rotation angle is calculated, multiplied by the echo signal of the second target and divided by the echo signal of the second calibration body. After the RCS distribution of the rotation angle, it also includes: performing smooth filtering processing on the RCS distribution to obtain the RCS distribution of each rotation angle of the drone-borne Lumberg ball after eliminating the interference of the drone arm.

During the research and development process, the inventors of the present application found that the RCS test result of the UAV-carried Lumbe ball is too different from the simulation result, and the RCS value at the corresponding target peak differs by more than 5dB. The reason for the large difference is that there is mutual reflection between the UAV arm and the Luneberg sphere at high frequencies, resulting in mutual interference, which makes it impossible to accurately measure the RCS distribution characteristics of the Lumber sphere and the UAV combination. For example, at the frequency of 24GHz, the test of the vector network analyzer fluctuates more than 3dB at the same point.

In the embodiment provided by the present invention, the obtained RCS distribution is subjected to smoothing filtering, and the error between the smoothed test result and the simulation result is within 2dB, which reduces the error of the test result. Compared with the simulation results, the accuracy of the test method is verified at the same time.

In a possible implementation manner, the smoothing window of the smoothing filtering is greater than or equal to 1° and less than or equal to 2°.

In a possible implementation manner, an embodiment of the present invention provides a method for processing test data based on a target carried by an unmanned aerial vehicle. FIG. 8 is a flowchart of testing data processing of a drone-borne Lumberg ball target provided by an embodiment of the present invention. Referring to FIG. 8 , the above data processing method includes: obtaining the _S21 parameter of the calibration body in the range gate. Obtain the _S21 parameters of the scaled body background within the distance gate. The _S21 parameter of the calibration body is subtracted from the background _S21 parameter of the calibration body, as the S21 parameter of the calibration body after the background interference is removed. Obtain the _S21 parameter within the distance gate of the measured target. Obtain the measured target background within the S ₂₁ parameter within the range gate. The S ₂₁ parameter of the measured target is subtracted from the measured target background S ₂₁ parameter, as the S ₂₁ parameter of the measured target after the background interference is removed. Calculate the _S21 parameter of the measured target minus the _S21 parameter of the calibration body plus the RCS of the calibration body to obtain the RCS value of the measured target.

FIG. 9 is a graph showing the test result of the drone-borne Lumberg ball target provided by the embodiment of the present invention. Referring to Figure 9, the input start frequency of the vector network analyzer is 23GHz, the cutoff frequency is 25GHz, the sampling period is 29s, the number of sampling points is 3601, the intermediate frequency bandwidth is _1kHz , and the parameter S21 is selected for testing. Based on the horizontal placement of the Lumber ball target carried by the UAV, the measured RCS peaks appear at -135°, -90°, -45°, 0°, 45° at the frequency of 24GHz for the Lumber ball and UAV combination. , around 90° and 135°. The RCS value at -135° is -5.192dBsm, the RCS value at -45° is -3.76dBsm, the RCS value at 45° is -3.512dBsm, the RCS value at 135° is -5.405dBsm, and the RCS value at -90° It is -7.587dBsm, the RCS value of 90° is -7.332dBsm, and the RCS value of 0° is 1.31dBsm.

The embodiment of the present invention provides a test method based on an unmanned aerial vehicle-borne Lumberg sphere target. The calibration body measures the RCS value and the RCS distribution characteristics in a designated space area in a microwave anechoic chamber. Through the background cancellation technology and the distance gate processing method, Reduce reflections from backgrounds and other objects in the dark room. The data is collected by the vector network analyzer and the comparison method is used to obtain the more accurate maximum RCS value and RCS distribution characteristics, which realizes the accurate measurement of the target carried by the UAV.

It should be understood that the size of the sequence numbers of the steps in the above embodiments does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

The following are apparatus embodiments of the present invention, and for details that are not described in detail, reference may be made to the above-mentioned corresponding method embodiments.

FIG. 10 is a schematic structural diagram of an unmanned aerial vehicle-borne Lumberg ball target testing device provided by an embodiment of the present invention. For the convenience of description, only the parts related to the embodiments of the present invention are shown, and the details are as follows:

10 , an embodiment of the present invention provides an unmanned aerial vehicle-borne Lumberg ball target testing device 2, including:

The background echo acquisition module 21 is used to acquire the background echo signal of the current test environment.

The calibration body echo acquisition module 22 is configured to acquire the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment.

The target echo acquisition module 23 is used to acquire the first target echo signals of different rotation angles in the horizontal direction of the drone-borne Lumberg ball in the current test environment.

The calibration body background cancellation module 24 is used for subtracting the background echo signal from the first calibration body echo signal to obtain the second calibration body echo signal with different rotation angles after background cancellation.

The target background cancellation module 25 is configured to subtract the background echo signal from the first target echo signal to obtain the second target echo signal with different rotation angles after background cancellation.

The RCS distribution calculation module 26 is used to calculate the RCS value of the calibration body under the same rotation angle, multiplied by the second target echo signal and divided by the echo signal of the second calibration body, to obtain each rotation angle of the drone-borne Lumberg sphere The RCS distribution of .

In the embodiment of the present invention, the RCS distribution is calculated after subtracting the background echo signal of the current test environment, which offsets the influence of the background on the echo signal of the calibration body and the echo signal of the target, and reduces the influence of the RCS distribution characteristics in the high frequency K-band. test error.

In a possible implementation manner, the above-mentioned test device 2 further includes:

The background distance gate processing module is used to perform inverse fast Fourier transform, add distance gate and fast Fourier transform on the background echo signal after acquiring the background echo signal of the current test environment, and filter out the distance gate. The signal after clutter interference is used as the background echo signal.

The calibration body distance gate processing module is used to perform fast Fourier inverse on the first calibration body echo signals after obtaining the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment. Transform, add distance gate and fast Fourier transform, and take the signal after filtering out the clutter interference outside the distance gate as the first calibration body echo signal.

The target range gate processing module is used to perform inverse fast Fourier transform on the first target echo signal after obtaining the first target echo signals of different rotation angles in the horizontal direction of the drone-borne Lumber ball in the current test environment. The distance gate and fast Fourier transform are added, and the signal after filtering out the clutter outside the distance gate is used as the first target echo signal.

In a possible implementation manner, the above-mentioned testing device further includes:

The distance gate selection module is used to test the echo signal of the tested object and remove the echo signal of the tested object respectively under the same test environment. The inverse fast Fourier transform is performed on the echo signal of the measured object and the echo signal from which the measured object is removed. Compare the echo signal of the measured object after inverse fast Fourier transform and the echo signal of the measured object to obtain the corresponding time range of the measured object on the time axis in the time domain coordinate system. Take the obtained time range as the range of the distance gate.

In a possible implementation manner, the calibration body is a trihedral corner reflector. The calibration body echo acquisition module is specifically used to obtain echo signals of different rotation angles in the horizontal direction of the trihedral corner reflector in the current test environment, as the first calibration body echo signals.

In a possible implementation manner, the rotation angle of the trihedral corner reflector facing the antenna of the test signal source is 0°, and the rotation angle of the trihedral corner reflector in the horizontal direction ranges from -20° to 20°.

In a possible implementation manner, the above-mentioned test device 2 further includes:

The smoothing processing module is used to calculate the RCS value of the calibration body under the same rotation angle, multiply the echo signal of the second target by the echo signal of the second calibration body, and obtain the RCS value of each rotation angle of the UAV-borne Lumber sphere. After the RCS distribution, smooth filtering is performed on the RCS distribution to obtain the RCS distribution of each rotation angle of the UAV-borne Lumbe ball after eliminating the interference of the UAV arm.

In a possible implementation manner, the smoothing window of the smoothing filtering is greater than or equal to 1° and less than or equal to 2°.

FIG. 11 is a schematic diagram of an electronic device provided by an embodiment of the present invention. As shown in FIG. 11 , the electronic device 3 of this embodiment includes: a processor 30 , a memory 31 , and a computer program 32 stored in the memory 31 and executable on the processor 30 . When the processor 30 executes the computer program 32, the steps in each of the above-mentioned embodiments of the UAV-borne Luneberg sphere target testing method are implemented, for example, steps S1 to S6 shown in FIG. 4 . Alternatively, when the processor 30 executes the computer program 32, the functions of the modules/units in each of the foregoing apparatus embodiments, such as the functions of the modules 21 to 26 shown in FIG. 10, are implemented.

Exemplarily, the computer program 32 can be divided into one or more modules/units, and the one or more modules/units are stored in the memory 31 and executed by the processor 30 to complete the this invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 32 in the electronic device 3 . For example, the computer program 32 may be divided into modules 21 to 26 shown in FIG. 10 .

The electronic device 3 may be a computing device such as a desktop computer, a notebook, a palmtop computer, and a cloud server. The electronic device 3 may include, but is not limited to, a processor 30 and a memory 31 . Those skilled in the art can understand that FIG. 11 is only an example of the electronic device 3, and does not constitute a limitation on the electronic device 3, and may include more or less components than the one shown, or combine some components, or different components For example, the electronic device may further include an input and output device, a network access device, a bus, and the like.

The so-called processor 30 may be a central processing unit (Central Processing Unit, CPU), and may also be other general-purpose processors, digital signal processors (Digital Signal Processors, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), Field-Programmable Gate Array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 31 may be an internal storage unit of the electronic device 3 , such as a hard disk or a memory of the electronic device 3 . The memory 31 may also be an external storage device of the electronic device 3, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) equipped on the electronic device 3 card, flash card (Flash Card) and so on. Further, the memory 31 may also include both an internal storage unit of the electronic device 3 and an external storage device. The memory 31 is used to store the computer program and other programs and data required by the electronic device. The memory 31 can also be used to temporarily store data that has been output or will be output.

Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. Module completion, that is, dividing the internal structure of the device into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment may be integrated in one processing unit, or each unit may exist physically alone, or two or more units may be integrated in one unit, and the above-mentioned integrated units may adopt hardware. It can also be realized in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing from each other, and are not used to limit the protection scope of the present application. For the specific working processes of the units and modules in the above-mentioned system, reference may be made to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

In the foregoing embodiments, the description of each embodiment has its own emphasis. For parts that are not described or described in detail in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

In the embodiments provided by the present invention, it should be understood that the disclosed apparatus/electronic device and method may be implemented in other manners. For example, the above-described embodiments of the apparatus/electronic device are only illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units. Or components may be combined or may be integrated into another system, or some features may be omitted, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

The integrated modules/units, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium. Based on this understanding, the present invention can implement all or part of the processes in the methods of the above embodiments, and can also be completed by instructing relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the program is executed by the processor, the steps of the above-mentioned embodiments of the method for testing the Lumberg ball target carried by the unmanned aerial vehicle can be implemented. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file or some intermediate form, and the like. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, removable hard disk, magnetic disk, optical disk, computer memory, Read-Only Memory (ROM) , Random Access Memory (Random Access Memory, RAM), electric carrier signal, telecommunication signal and software distribution medium, etc.

The above-mentioned embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it is still possible to implement the foregoing implementations. The technical solutions described in the examples are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the within the protection scope of the present invention.

Claims (10)

1. an unmanned aerial vehicle carrying Lunberg ball target test method, is characterized in that, described method comprises: Obtain the background echo signal of the current test environment; Obtain the echo signals of the first calibration body at different rotation angles in the horizontal direction of the calibration body under the current test environment; Obtain the echo signals of the first target at different rotation angles in the horizontal direction of the drone-borne Lumberg ball in the current test environment; subtracting the background echo signal from the first calibration body echo signal to obtain a second calibration body echo signal with different rotation angles after background cancellation; subtracting the background echo signal from the first target echo signal to obtain a second target echo signal with different rotation angles after background cancellation; Calculate the RCS value of the calibration body under the same rotation angle, multiply the echo signal of the second target by the echo signal of the second calibration body, and obtain the RCS distribution of each rotation angle of the UAV-borne Lumberg sphere. 2. a kind of unmanned aerial vehicle carrying Lunberg ball target test method according to claim 1, is characterized in that, after obtaining the background echo signal of current test environment, also comprises: Perform inverse fast Fourier transform on the background echo signal, add a distance gate and fast Fourier transform, and use the signal after filtering out clutter interference outside the distance gate as a background echo signal; After acquiring the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment, the method further includes: Perform inverse fast Fourier transform on the first calibration body echo signal, add distance gate and fast Fourier transform, and use the signal after filtering out clutter interference outside the distance gate as the first calibration body echo Signal; After the acquisition of the first target echo signals of different rotation angles in the horizontal direction of the drone-borne Lumberg ball in the current test environment, the method further includes: Perform inverse fast Fourier transform, adding distance gate and fast Fourier transform on the first target echo signal, and use the signal after filtering out clutter interference outside the range gate as the first target echo signal. 3. a kind of unmanned aerial vehicle carrying Lunberg ball target test method according to claim 2 is characterized in that, in described background echo signal is carried out inverse fast Fourier transform, adding distance gate and fast Fourier Lie transform, before taking the signal after filtering out the clutter interference outside the distance gate as the background echo signal, it also includes: In the same test environment, test the echo signal of the object to be tested and remove the echo signal of the object to be tested; Perform inverse fast Fourier transform on the echo signal of the measured object and the echo signal from which the measured object is removed; Compare the echo signal of the measured object after inverse fast Fourier transform and the echo signal of the measured object to obtain the corresponding time range of the measured object on the time axis in the time domain coordinate system; Take the obtained time range as the range of the distance gate. 4. a kind of unmanned aerial vehicle carrying Lunberg ball target test method according to claim 3, is characterized in that, described calibration body is trihedral angle reflector; The obtaining of the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment includes: The echo signals of different rotation angles in the horizontal direction of the trihedral corner reflector in the current test environment are obtained as the echo signals of the first calibration body. 5. a kind of unmanned aerial vehicle carrying Lunberg ball target test method according to claim 4 is characterized in that, with the rotation angle that the trihedral angle reflector is facing the direction of the test signal source antenna is 0°, and the trihedral angle reflects The horizontal rotation angle of the device ranges from -20° to 20°. 6. a kind of unmanned aerial vehicle carrying Lunberg ball target test method according to claim 1, is characterized in that, in described calculating the RCS value of the calibration body under the same rotation angle is multiplied by the second target echo signal division Using the echo signal of the second calibration body to obtain the RCS distribution of each rotation angle of the UAV-borne Luneberg sphere, it also includes: Smooth filtering is performed on the RCS distribution to obtain the RCS distribution of each rotation angle of the UAV-borne Lumberg ball after eliminating the interference of the UAV arm. 7 . The method for testing a drone-borne Lumberg sphere target according to claim 6 , wherein the smoothing window of the smoothing filter is greater than or equal to 1° and less than or equal to 2°. 8 . 8. An unmanned aerial vehicle-carrying Lumberg ball target testing device, characterized in that, comprising: The background echo acquisition module is used to acquire the background echo signal of the current test environment; The calibration body echo acquisition module is used to obtain the first calibration body echo signals of different rotation angles in the horizontal direction of the calibration body under the current test environment; The target echo acquisition module is used to acquire the first target echo signals of different rotation angles in the horizontal direction of the UAV-borne Lumberg ball in the current test environment; a calibration body background cancellation module, configured to subtract the background echo signal from the first calibration body echo signal to obtain a second calibration body echo signal with different rotation angles after background cancellation; a target background cancellation module, configured to subtract the background echo signal from the first target echo signal to obtain a second target echo signal with different rotation angles after background cancellation; The RCS distribution calculation module is used to calculate the RCS value of the calibration body under the same rotation angle, multiplied by the echo signal of the second target and divided by the echo signal of the second calibration body. RCS distribution. 9. An electronic device comprising a memory, a processor and a computer program stored in the memory and running on the processor, wherein the processor implements the above rights when executing the computer program The steps of the test method for the unmanned aerial vehicle-borne Lumberg ball target described in any one of 1 to 7 are required. 10. A computer-readable storage medium storing a computer program, characterized in that, when the computer program is executed by a processor, the computer program realizes the above-mentioned no The steps of the test method for the human airborne Lumberg sphere target.

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