CN114325630A - Target scattering matrix measurement method based on antenna spatial domain polarization characteristics - Google Patents

Target scattering matrix measurement method based on antenna spatial domain polarization characteristics Download PDF

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CN114325630A
CN114325630A CN202210002979.0A CN202210002979A CN114325630A CN 114325630 A CN114325630 A CN 114325630A CN 202210002979 A CN202210002979 A CN 202210002979A CN 114325630 A CN114325630 A CN 114325630A
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polarization
target
antenna
scattering
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刘芳
白杨
吕鸣
侯浩浩
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Beijing Institute of Environmental Features
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Abstract

The invention relates to a target scattering matrix measurement method based on antenna spatial domain polarization characteristics, which comprises the following steps: researching the spatial polarization characteristic distribution of the antenna, and analyzing the spatial polarization characteristic of a typical rectangular aperture antenna; starting from a space characterization model of antenna polarization characteristics, constructing a target single-station scattering measurement error transfer model based on the antenna space polarization characteristics; testing and verifying by using a typical standard body with known polarization scattering characteristics, and verifying the testing precision by extracting a full polarization scattering matrix of a target of the standard body; according to the target scattering matrix measurement method based on the antenna airspace polarization characteristics, a more accurate full-polarization scattering matrix error transfer model is constructed through error analysis of a traditional calibration method based on a point target, a typical standard body is calibrated, a full-polarization scattering matrix is extracted, and test accuracy is verified.

Description

Target scattering matrix measurement method based on antenna spatial domain polarization characteristics
Technical Field
The invention relates to the technical field of scattering matrix measurement, in particular to a target scattering matrix measurement method based on antenna spatial domain polarization characteristics.
Background
The polarization scattering matrix represents all information of the polarization scattering characteristics of the target and supports classification and identification of the radar target. The antenna is the only polarization modulator and polarization receptor in the scattering test system, the space polarization characteristic directly influences the calibration mode and the calibration precision of the full polarization scattering measurement, and the polarization characteristic of the antenna is the functional of frequency and space position and is related to the form of the antenna aperture. The change rule of the polarization characteristic of the antenna radiation field along with the space can be defined as the antenna space polarization characteristic. When the scattering characteristics of the radar target are measured, if the space polarization characteristics of the antenna can be accurately mastered, the polarization distribution of an electromagnetic field of the target to be measured, which is irradiated by a test area, can be mastered.
Currently, in the traditional measurement of a target complete polarization scattering matrix, a common aperture antenna spatial polarization characteristic characterization study is firstly developed, the spatial polarization characteristic of a rectangular aperture antenna is analyzed, and an antenna polarization characteristic spatial characterization model suitable for a scattering test is constructed; and then constructing a target complete polarization scattering matrix measurement error transfer model based on the antenna space polarization characteristics, and finally calibrating the polarization error of the typical body target according to the constructed polarization error transfer model to obtain a complete polarization scattering matrix after polarization calibration. Conventional calibration methods do not take into account the spatial polarization distribution of the antenna, and therefore result in errors introduced by conventional point target-based calibration methods.
In view of the above disadvantages, it is desirable to provide a method for measuring a target scattering matrix based on an antenna spatial polarization characteristic, so as to remove the influence of an antenna spatial polarization characteristic error, construct a target full-polarization scattering matrix error transfer model, and improve the measurement accuracy of the scattering matrix.
Disclosure of Invention
The invention aims to solve the technical problem that errors introduced by the traditional point target-based calibration method influence the measurement of a target scattering matrix.
In order to solve the technical problem, the invention provides a target scattering matrix measurement method based on antenna spatial domain polarization characteristics, which comprises the following steps: analyzing the space polarization characteristic of the rectangular aperture antenna; constructing a target complete polarization scattering matrix based on space polarization characteristics, and measuring a polarization error transfer model; and carrying out polarization error calibration on a typical target body according to the error transfer model to obtain a polarization scattering matrix after polarization calibration.
Preferably, the step of analyzing the spatial polarization characteristic of the rectangular aperture antenna further includes the following steps:
obtaining the electric field E of the rectangular aperture antenna at the pitching angleθObtaining the electric field of the rectangular aperture antenna at the azimuth angle
Figure BDA0003454088510000021
According to the electric field E at the pitch angleθAnd electric field at azimuthal angle
Figure BDA0003454088510000022
Calculating the space domain polarization ratio rho under the condition of uniformly distributed rectangular caliber and the condition of non-uniformly distributed rectangular caliber,
Figure BDA0003454088510000023
preferably, the electric field E at the pitch angleθAnd electric field at azimuthal angle
Figure BDA0003454088510000024
The calculation is as follows:
the length of the rectangular aperture of the antenna is LxThe width of the rectangular aperture of the antenna is LyThe electric field with rectangular aperture is in the y direction,
Figure BDA0003454088510000025
Figure BDA0003454088510000026
wherein, θ and
Figure BDA0003454088510000027
respectively representing a pitch angle and an azimuth angle, r is a propagation distance, k0Is wave number, fyIs the spatial frequency in the y-direction.
Preferably, in the case of calculating the uniformly distributed rectangular aperture, the uniformly distributed rectangular aperture electric field is,
Figure BDA0003454088510000028
Figure BDA0003454088510000031
Figure BDA0003454088510000032
wherein the content of the first and second substances,
Figure BDA0003454088510000033
Figure BDA0003454088510000034
at this time, the spatial domain polarization ratio is,
Figure BDA0003454088510000035
under the condition of calculating the non-uniformly distributed rectangular caliber, the non-uniform rectangular caliber electric field is,
Figure BDA0003454088510000036
Figure BDA0003454088510000037
a, b represent the length and width of the rectangular aperture, in which case the spatial polarization ratio is,
Figure BDA0003454088510000038
preferably, the step of constructing a target complete polarization scattering matrix based on spatial polarization characteristics and measuring a polarization error transfer model comprises the following processes:
constructing a full polarization measurement model based on the target broadband scattering center,
Figure BDA0003454088510000039
where M represents the target echo test data and R, T represents the multiplicative error matrices for the receive and transmit channels, respectively; a. theRAnd ATRepresenting the polarization vectors of the receiving and transmitting antennas; rTnAnd RRnRespectively represents the antenna distance from the nth scattering center to the transmitting end and the receiving end, RT0And RR0Respectively representing the antenna distances from the geometric center of the target to the transmitting end and the receiving end; i isNOISEFor additive noise, STRepresenting the true scattering matrix of the target, SEA scattering matrix representing interference clutter, λ representing a wavelength;
and decomposing the fully polarized measurement model into fully polarized scattering responses of single scattering centers, wherein the test system response corresponding to the nth scattering center can be expressed as:
Figure DA00034540885167532420
in the formula, HH represents a horizontal transmission horizontal reception polarization mode, VV represents a vertical transmission vertical reception polarization mode, HV represents a horizontal transmission vertical reception polarization mode, VH represents a vertical transmission horizontal reception polarization mode,
Figure BDA0003454088510000042
represents the angle between the line connecting the scattering center and the phase center of the antenna and the normal direction of the mouth surface, IAIs a spatially polarized characteristic of the antenna.
Preferably, when the target is a single-point target, the orthogonal polarization difference of the antenna irradiating the target is a fixed value, and is regarded as a polarization characteristic of the normal direction of the oral surface; when the target is a multi-scattering center target, the antenna radiation polarization characteristic information corresponding to different scattering centers is
Figure BDA0003454088510000043
As a function of (c).
Preferably, when measuring with non-far field conditions, it is necessary to look ahead on the spatial polarization characteristic I of the antennaAAnd (7) correcting.
Preferably, the step of obtaining the polarization-calibrated polarization scattering matrix by calibrating the polarization error of the typical target according to the error transfer model includes the following processes,
the received voltage of the antenna to the target may be expressed as,
Figure BDA0003454088510000044
wherein, A represents signal amplitude, is a value determined by receiver processing gain and elements except scattering cross section in radar equation, but is irrelevant to system polarization and target polarization scattering matrix; the target polarization scattering matrix is
Figure BDA0003454088510000045
S11When the vector network analyzer is used for testing, the target scattering coefficient of 1 channel is used for transmitting, and the target scattering coefficient of 1 channel is used for receiving, S12When the vector network analyzer is used for testing, the target scattering coefficient of 1 channel is used for transmitting, and 2 channels are used for receiving, S21When the vector network analyzer is used for testing, the target scattering coefficient of 2 channels is used for transmitting, and 1 channel is used for receiving, S22When the vector network analyzer is used for testing, 2 channels are used for transmitting, the target scattering coefficients of the 2 channels are used for receiving,
Figure BDA0003454088510000051
and htPolarization vectors for the transmitting and receiving antennas of the radar, respectively, there being h for the case of a common antenna for transmitting and receivingr＝ht；
The radar receiving target echo is subjected to space domain Fourier transform to obtain a space frequency spectrum,
Figure BDA0003454088510000052
in the formula (f)θAnd
Figure BDA0003454088510000053
the spatial frequency in the pitching direction and the spatial frequency in the azimuth direction respectively represent the frequency of a spatial frequency spectrum obtained by performing Fourier transform on a radar receiving target echo when the antenna scans in the pitching direction and the azimuth direction;
the system voltage is brought into an integral expression to obtain,
Vr(fψ)＝k11(fψ)S11+k12(fψ)S12+k21(fψ)S21+k22(fψ)S22，
where k is the azimuthal spatial frequency
Figure BDA0003454088510000054
A corresponding spatial beam;
selecting a plurality of airspace frequency points, constructing a linear equation set and solving the equation set by calculating the corresponding coefficients of the received echo voltage frequency spectrum and each element of the scattering matrix corresponding to each frequency point, and obtaining the polarization scattering matrix of the target.
The invention also provides a target scattering matrix measuring device based on the spatial polarization characteristic of the antenna, which comprises a memory and a processor, wherein the memory comprises: wherein the memory is used for storing executable program codes; the processor is used for reading executable program codes stored in the memory to execute the target scattering matrix measurement method based on the spatial polarization characteristics of the antenna.
The invention also provides a computer readable storage medium, which stores a computer program, wherein the computer program is executed by a processor to implement a target scattering matrix measurement method based on the spatial polarization characteristics of the antenna.
By implementing the target scattering matrix measuring method based on the antenna airspace polarization characteristics, a more accurate full polarization scattering matrix error transfer model is constructed through error analysis of a traditional calibration method based on a point target, a typical standard body is calibrated, a full polarization scattering matrix is extracted, and the test precision is verified.
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FIG. 1 is a flowchart of a target scattering matrix measurement method based on spatial polarization characteristics of an antenna according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a rectangular aperture of a target scattering matrix measurement method based on spatial polarization characteristics of an antenna according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a target placement error of a target scattering matrix measurement method based on spatial polarization characteristics of antennas according to an embodiment of the present invention;
FIG. 4 is an experimental flowchart of a target scattering matrix measurement method based on spatial polarization characteristics of an antenna according to an embodiment of the present invention;
FIG. 5 is a structural diagram of a target scattering matrix measurement device based on spatial polarization characteristics of an antenna according to an embodiment of the present invention;
fig. 6 is a structural diagram of a computer-readable storage medium of a target scattering matrix measurement method based on spatial polarization characteristics of an antenna according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
FIG. 1 is a flowchart of a target scattering matrix measurement method based on spatial polarization characteristics of an antenna according to an embodiment of the present invention; as shown in fig. 1, the method for measuring a target scattering matrix based on spatial polarization characteristics of an antenna according to an embodiment of the present invention includes the following steps; step S01: analyzing the space polarization characteristic of the rectangular aperture antenna; step S02: constructing a target complete polarization scattering matrix based on space polarization characteristics, and measuring a polarization error transfer model; step S03: carrying out polarization error calibration on a typical target body according to the error transfer model to obtain a polarization scattering matrix after polarization calibration; step S04: and carrying out experimental analysis on the typical standard body and verifying the precision.
The target scattering matrix measurement method based on the antenna airspace polarization characteristic analyzes the space polarization characteristic of a rectangular aperture antenna, constructs a target full polarization scattering matrix measurement error transfer model based on the antenna space polarization characteristic, and finally carries out polarization error calibration on a typical target according to the constructed polarization error transfer model to obtain a polarization-calibrated full polarization scattering matrix. By researching the space domain polarization characteristic of the antenna, the method eliminates the error introduced by the traditional calibration method based on the point target and constructs a more accurate error transfer model of the fully polarized scattering matrix to improve the measurement precision.
FIG. 2 is a schematic diagram of a rectangular aperture of a target scattering matrix measurement method based on spatial polarization characteristics of an antenna according to an embodiment of the present invention; as shown in FIG. 2, in step S01, the rectangular aperture has a length and a width Lx，LyAssuming that the aperture electric field is in the y-direction, then:
Figure BDA0003454088510000071
Figure BDA0003454088510000072
wherein the content of the first and second substances,theta and
Figure BDA0003454088510000073
respectively representing a pitch angle and an azimuth angle, r is a propagation distance, k0Is wave number, fyIs the spatial domain frequency in the y-direction,
Figure BDA0003454088510000074
considering the uniformly distributed rectangular aperture first, the so-called uniformly distributed rectangular aperture, as the name implies, is that the amplitude and phase of the aperture field are uniform on the physical aperture. The uniform rectangular aperture electric field is:
Figure BDA0003454088510000075
the radiation field for obtaining the uniformly distributed rectangular caliber is as follows:
Figure BDA0003454088510000081
Figure BDA0003454088510000082
wherein the content of the first and second substances,
Figure BDA0003454088510000083
Figure BDA0003454088510000084
at this time, the spatial domain polarization ratio is,
Figure BDA0003454088510000085
it can be seen that the polarization ratio of a uniform aperture antenna is a function of the spatial angular coordinate.
For the non-uniformly distributed aperture field, the most typical one is cosine distribution, taking the aperture field which is cosine distributed along the x direction and uniform distributed along the y direction as an example, the following can be obtained:
Figure BDA0003454088510000086
Figure BDA0003454088510000087
at this time, the spatial domain polarization ratio is still,
Figure BDA0003454088510000088
this shows that for a rectangular aperture, the spatial polarization ratio has the same form, whether it is uniformly distributed or not.
In the method for measuring the target scattering matrix based on the spatial polarization characteristic of the antenna, step S02 includes the following steps.
The space polarization characteristic research of the reflector antenna and the compact range antenna system is carried out, an antenna polarization characteristic space representation model suitable for the scattering test is constructed, and the mapping relation between the antenna polarization distribution and the target response in the half space is formed.
And according to the indoor complete polarization scattering measurement model, researching the space polarization characteristics of the complete polarization scattering test system antenna. Under the condition of single station and double stations, a complete polarization measurement model based on a target broadband scattering center is as follows:
Figure BDA0003454088510000091
where M represents the target echo test data and R, T represents the multiplicative error matrices for the receive and transmit channels, respectively; a. theRAnd ATDelegate receptionAnd a polarization vector of the transmitting antenna; rTnAnd RRnRespectively represents the antenna distance from the nth scattering center to the transmitting end and the receiving end, RT0And RR0Respectively representing the antenna distances from the geometric center of the target to the transmitting end and the receiving end; i isNOISEFor additive noise, STRepresenting the true scattering matrix of the target, SERepresents the scattering matrix of the interference clutter and λ represents the wavelength. The matrix A represents the matrix of the antenna radiation, the antenna is the space radiation, therefore representing the space domain, the true scattering matrix STThe polarization characteristic is determined as a fully polarized scattering matrix. STThe scattering matrix of the real target to be solved is solved through a measurement data M matrix. The equation is the transfer model, and R, A, T, I is the error matrix, i.e., the error of the transfer.
And decomposing into a fully polarized scattering response of a single scattering center, wherein the response of the test system corresponding to the nth scattering center can be expressed as:
Figure DA00034540885167622037
in the formula I0For additive errors, HH represents the horizontal transmission horizontal reception polarization mode, VV represents the vertical transmission vertical reception polarization mode, HV represents the horizontal transmission vertical reception polarization mode, VH represents the vertical transmission horizontal reception polarization mode,
Figure BDA0003454088510000093
represents the angle between the line connecting the scattering center and the phase center of the antenna and the normal direction of the mouth surface, IAIs a spatially polarized characteristic of the antenna.
Because the radiation characteristics of the antenna are different in polarization characteristics represented at different spatial positions, when the target is a single-point target (the above formula is an error transfer formula under the condition of a multi-scattering center, and is an expansion of the single target, and m is 1, namely a single point), the orthogonal polarization difference of the antenna irradiation target can be considered as a fixed value, and the orthogonal polarization difference can be close to the polarization characteristic of the normal direction of the mouth surface as much as possible; when the target is a multi-scattering center target, the antenna radiation polarization characteristic information corresponding to different scattering centers is different and is a function of the included angle between the connecting line of the scattering center and the antenna phase center and the normal direction of the mouth surface.
This angle is amplified when measured using non-far-field conditions, and the far-field transform extrapolation of the near-field calibration data directly conveys the polarization non-ideality of the antenna at large deflection angles to the target polarization matrix. Most of the dual-station polarization scatterometry inevitably uses a near-field test scheme, so that the spatial polarization characteristic I of the antenna needs to be subjected to forewardAAnd (7) correcting.
In the method for measuring the target scattering matrix based on the spatial polarization characteristic of the antenna, step S03 includes the following steps.
According to the radar polarization theory, under the horizontal and vertical polarization basis (h, v), the receiving voltage of the antenna to the target can be expressed as,
Figure BDA0003454088510000101
wherein, A represents signal amplitude, is a value determined by receiver processing gain and elements except scattering cross section in radar equation, but is irrelevant to system polarization and target polarization scattering matrix; the target polarization scattering matrix is S11、S12、S21、S22Composed matrix, S11When the vector network analyzer is used for testing, the target scattering coefficient of 1 channel is used for transmitting, and the target scattering coefficient of 1 channel is used for receiving, S12When the vector network analyzer is used for testing, the target scattering coefficient of 1 channel is used for transmitting, and 2 channels are used for receiving, S21When the vector network analyzer is used for testing, the target scattering coefficient of 2 channels is used for transmitting, and 1 channel is used for receiving, S22When the vector network analyzer is used for testing, 2 channels are used for transmitting, the target scattering coefficients of the 2 channels are used for receiving,
Figure BDA0003454088510000102
and htPolarization vectors for the transmitting and receiving antennas of the radar, respectively, there being h for the case of a common antenna for transmitting and receivingr＝ht。
The radar receiving target echo is subjected to space domain Fourier transform to obtain a space frequency spectrum,
Figure BDA0003454088510000103
in the formula (f)θAnd
Figure BDA0003454088510000104
the spatial frequency in the pitching direction and the spatial frequency in the azimuth direction respectively represent the frequency of a spatial frequency spectrum obtained by performing Fourier transform on a radar receiving target echo when the antenna scans in the pitching direction and the azimuth direction;
the system voltage is brought into an integral expression to obtain,
Vr(fψ)＝k11(fψ)S11+k12(fψ)S12+k21(fψ)S21+k22(fψ)S22，
where k is the azimuthal spatial frequency
Figure BDA0003454088510000111
A corresponding spatial beam;
it can be seen that the antenna receives the frequency spectrum V of the voltagerIs a function of the elements of the target polarization scattering matrix and the coefficients of the elements are related to the polarization ratio of the antenna. Therefore, several key spatial frequency points can be selected, a linear equation set is constructed and solved by calculating the corresponding coefficients of the received echo voltage spectrum and the elements of the scattering matrix corresponding to each frequency point, and the polarization scattering matrix of the target is obtained.
In the method for measuring the target scattering matrix based on the spatial polarization characteristic of the antenna, step S04 includes the following steps. FIG. 3 is a schematic diagram of a target placement error of a target scattering matrix measurement method based on spatial polarization characteristics of antennas according to an embodiment of the present invention; fig. 4 is an experimental flowchart of a target scattering matrix measurement method based on spatial polarization characteristics of an antenna according to an embodiment of the present invention.
Carrying out experimental analysis on the typical metal ball and verifying the precision; aiming at the space polarization distribution rule of the rectangular aperture antenna, an experiment is carried out aiming at a typical spherical target under the condition that the pitching angle is zero, and at the moment, the space domain polarization ratio is a function of the frequency f and the azimuth angle phi. In the experiment, a working mode of small-angle azimuth angles, namely phi in a certain small-angle area and frequency scanning is selected, and in the mode, the antenna space polarization vector h is only a function of phi, and amplitude errors caused by small-angle differences are ignored.
Figure BDA0003454088510000112
Figure BDA0003454088510000113
h is the spatial polarization vector of the antenna, and if the target is located off the irradiation center, as can be seen from the spatial polarization characteristic distribution of the antenna, if the data is calibrated according to the conventional calibration method, that is, according to the antenna polarization method located at the scattering center, errors are inevitably caused. The target placing effect diagram is shown in fig. 3, and the experimental flow chart is shown in fig. 4. In the target ball experiment process, the conditions are set as follows, the frequency is 8.5GHz-11.5GHz, the azimuth angle deviation is 10 degrees, and the pitching angle is 0 degree.
Experimental results show that the scattering echo deviation of the ball at the deviated position is large, the polarization scattering matrix effect is good after the antenna space polarization calibration and calibration, the same polarization results of HH and VV tend to be close, and the error is small compared with the true value; the amplitude difference between the homopolarity and the cross-polarization is separated to be about 30 dB. The result is ideal.
FIG. 5 is a block diagram of a target scattering matrix measurement device based on spatial polarization characteristics of an antenna according to the present description; referring now to fig. 5, a schematic diagram of a target scattering matrix measurement device 300 based on spatial polarization characteristics of antennas suitable for implementing embodiments of the present disclosure is shown. The electronic devices in the embodiments of the present disclosure may include, but are not limited to, mobile terminals such as mobile phones, notebook computers, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), in-vehicle terminals (e.g., car navigation terminals), and the like, and fixed terminals such as digital TVs, desktop computers, and the like. The electronic device shown in fig. 5 is only an example, and should not bring any limitation to the functions and the scope of use of the embodiments of the present disclosure.
As shown in fig. 5, the electronic device 300 may include a processing means (e.g., a central processing unit, a graphics processor, etc.) 301 that may perform various appropriate actions and processes in accordance with a program stored in a Read Only Memory (ROM)302 or a program loaded from a storage means 308 into a Random Access Memory (RAM) 303. In the RAM303, various programs and data necessary for the operation of the electronic apparatus 300 are also stored. The processing device 301, the ROM 302, and the RAM303 are connected to each other via a bus 304. An input/output (I/O) interface 305 is also connected to bus 304.
Generally, the following devices may be connected to the I/O interface 305: input devices 306 including, for example, a touch screen, touch pad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; an output device 307 including, for example, a Liquid Crystal Display (LCD), a speaker, a vibrator, and the like; storage devices 308 including, for example, magnetic tape, hard disk, etc.; and a communication device 309. The communication means 309 may allow the electronic device 300 to communicate wirelessly or by wire with other devices to exchange data. While fig. 5 illustrates an electronic device 300 having various means, it is to be understood that not all illustrated means are required to be implemented or provided. More or fewer devices may alternatively be implemented or provided.
In particular, according to an embodiment of the present disclosure, the processes described above with reference to the flowcharts may be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising program code for performing the method illustrated in the flow chart. In such an embodiment, the computer program may be downloaded and installed from a network through the communication means 309, or installed from the storage means 308, or installed from the ROM 302. The computer program, when executed by the processing device 301, performs the above-described functions defined in the methods of the embodiments of the present disclosure.
FIG. 6 is a block diagram of one embodiment of a computer-readable storage medium of a method for target scattering matrix measurement based on spatial polarization characteristics of an antenna according to the present description; as shown in fig. 6, a computer-readable storage medium 40, having non-transitory computer-readable instructions 41 stored thereon, in accordance with an embodiment of the present disclosure. When executed by a processor, the non-transitory computer readable instructions 41 perform all or part of the steps of the method for measuring a target scattering matrix based on spatial polarization characteristics of an antenna according to the embodiments of the present disclosure.
It should be noted that the computer readable medium in the present disclosure can be a computer readable signal medium or a computer readable storage medium or any combination of the two. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples of the computer readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the present disclosure, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In contrast, in the present disclosure, a computer readable signal medium may comprise a propagated data signal with computer readable program code embodied therein, either in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: electrical wires, optical cables, RF (radio frequency), etc., or any suitable combination of the foregoing.
The computer readable medium may be embodied in the electronic device; or may exist separately without being assembled into the electronic device.
The computer readable medium carries one or more programs which, when executed by the electronic device, cause the electronic device to: constructing a basic page, wherein a page code of the basic page is used for constructing an environment required by the operation of the business page and/or realizing the same abstract workflow in the same business scene; constructing one or more page templates, wherein the page templates are used for providing code templates for realizing service functions in service scenes; generating a final page code of each page of the business scene through code conversion of a specific function of each page of the business scene based on the corresponding page template; and combining the generated final page code of each page into the page code of the basic page to generate the code of the service page.
Alternatively, the computer readable medium carries one or more programs which, when executed by the electronic device, cause the electronic device to: constructing a basic page, wherein a page code of the basic page is used for constructing an environment required by the operation of the business page and/or realizing the same abstract workflow in the same business scene; constructing one or more page templates, wherein the page templates are used for providing code templates for realizing service functions in service scenes; generating a final page code of each page of the business scene through code conversion of a specific function of each page of the business scene based on the corresponding page template; and combining the generated final page code of each page into the page code of the basic page to generate the code of the service page.
Computer program code for carrying out operations for aspects of the present disclosure may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C + +, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The units described in the embodiments of the present disclosure may be implemented by software or hardware. Where the name of a unit does not in some cases constitute a limitation of the unit itself, for example, the first retrieving unit may also be described as a "unit for retrieving at least two internet protocol addresses".
According to the target scattering matrix measurement method based on the antenna airspace polarization characteristics, a more accurate full-polarization scattering matrix error transfer model is constructed through error analysis of a traditional calibration method based on a point target, a typical standard body is calibrated, a full-polarization scattering matrix is extracted, and test accuracy is verified.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A target scattering matrix measurement method based on antenna spatial domain polarization characteristics is characterized by comprising the following steps:
analyzing the space polarization characteristic of the rectangular aperture antenna;
constructing a target complete polarization scattering matrix based on the space polarization characteristic, and measuring a polarization error transfer model;
and carrying out polarization error calibration of a typical target body according to the error transfer model to obtain a polarization scattering matrix after polarization calibration.
2. The method for measuring the target scattering matrix based on the spatial polarization characteristic of the antenna according to claim 1, wherein the step of analyzing the spatial polarization characteristic of the rectangular-caliber antenna further comprises the following steps:
obtaining the electric field E of the rectangular aperture antenna at the pitching angleθObtaining the electric field of the rectangular aperture antenna at the azimuth angle
Figure FDA0003454088500000011
According to the electric field E at the pitch angleθAnd electric field at azimuthal angle
Figure FDA0003454088500000012
Calculating the space domain polarization ratio rho under the condition of uniformly distributed rectangular caliber and the condition of non-uniformly distributed rectangular caliber,
Figure FDA0003454088500000013
wherein, θ and
Figure FDA0003454088500000014
representing the pitch angle and azimuth angle, respectively.
3. The method for measuring the scattering matrix of the target based on the spatial polarization characteristics of the antenna according to claim 2, wherein the electric field E at the elevation angleθAnd electric field at azimuthal angle
Figure FDA0003454088500000015
The calculation is as follows:
the length of the rectangular aperture of the antenna is LxThe width of the rectangular aperture of the antenna is LyThe electric field with rectangular aperture is in the y direction,
Figure FDA0003454088500000016
Figure FDA0003454088500000017
where r is the propagation distance, k0Is wave number, fyIs the spatial frequency in the y directionAnd (4) rate.
4. The method for measuring the scattering matrix of the target based on the spatial polarization characteristics of the antenna according to claim 3,
under the condition of calculating the uniformly distributed rectangular calibers, the uniformly distributed rectangular calibers electric field is,
Figure FDA0003454088500000021
Figure FDA0003454088500000022
wherein the content of the first and second substances,
Figure FDA0003454088500000023
Figure FDA0003454088500000024
at this time, the spatial domain polarization ratio is,
Figure FDA0003454088500000025
under the condition of calculating the non-uniformly distributed rectangular caliber, the non-uniform rectangular caliber electric field is,
Figure FDA0003454088500000026
Figure FDA0003454088500000027
wherein a and b represent the rectangular apertureLength and width of (E)0The value of the electric field amplitude of the antenna radiation at the origin, at this time the spatial polarization ratio,
Figure FDA0003454088500000028
5. the method for measuring the target scattering matrix based on the spatial polarization characteristic of the antenna according to claim 1, wherein the step of constructing the target fully-polarized scattering matrix based on the spatial polarization characteristic and measuring the polarization error transfer model comprises the following processes:
constructing a full polarization measurement model based on the target broadband scattering center,
Figure FDA0003454088500000031
where M represents the target echo test data and R, T represents the multiplicative error matrices for the receive and transmit channels, respectively; a. theRAnd ATRepresenting the polarization vectors of the receiving and transmitting antennas; rTnAnd RRnRespectively represents the antenna distance from the nth scattering center to the transmitting end and the receiving end, RT0And RR0Respectively representing the antenna distances from the geometric center of the target to the transmitting end and the receiving end; i isNOISEFor additive noise, STRepresenting the true scattering matrix of the target, SEA scattering matrix representing interference clutter, λ representing a wavelength;
and decomposing the fully polarized measurement model into fully polarized scattering responses of single scattering centers, wherein the test system response corresponding to the nth scattering center can be expressed as:
Figure FDA0003454088500000032
in the formula I0For additive errors, HH represents the horizontal transmit horizontal receive polarization mode, VV represents the verticalA direct transmission vertical reception polarization mode, HV denotes a horizontal transmission vertical reception polarization mode, VH denotes a vertical transmission horizontal reception polarization mode,
Figure FDA0003454088500000033
represents the angle between the line connecting the scattering center and the phase center of the antenna and the normal direction of the mouth surface, IAIs a spatially polarized characteristic of the antenna.
6. The method for measuring the target scattering matrix based on the spatial polarization characteristic of the antenna according to claim 5, wherein when the target is a single-point target, the orthogonal polarization difference of the target irradiated by the antenna is a fixed value and is regarded as a polarization characteristic of the normal direction of the oral surface; when the target is a multi-scattering center target, the antenna radiation polarization characteristic information corresponding to different scattering centers is
Figure FDA0003454088500000034
As a function of (c).
7. The method as claimed in claim 5, wherein the spatial polarization characteristic of the antenna is measured by using a non-far-field condition, and the spatial polarization characteristic I of the antenna is measured in advanceAAnd (7) correcting.
8. The method for measuring the target scattering matrix based on the spatial polarization characteristics of the antenna according to any one of claims 1-7, wherein the step of calibrating the polarization error of a typical target body according to the error transfer model to obtain the polarization scattering matrix after polarization calibration comprises the following processes,
the received voltage of the antenna to the target may be expressed as,
Figure FDA0003454088500000041
wherein A represents the signal amplitude and is divided by the receiver processing gain and the radar equationThe values determined by all elements outside the irradiation cross section area are independent of the system polarization and the target polarization scattering matrix; the target polarization scattering matrix is
Figure FDA0003454088500000042
S11When the vector network analyzer is used for testing, the target scattering coefficient of 1 channel is used for transmitting, and the target scattering coefficient of 1 channel is used for receiving, S12When the vector network analyzer is used for testing, the target scattering coefficient of 1 channel is used for transmitting, and 2 channels are used for receiving, S21When the vector network analyzer is used for testing, the target scattering coefficient of 2 channels is used for transmitting, and 1 channel is used for receiving, S22When the vector network analyzer is used for testing, 2 channels are used for transmitting, the target scattering coefficients of the 2 channels are used for receiving,
Figure FDA0003454088500000043
and htPolarization vectors for the transmitting and receiving antennas of the radar, respectively, there being h for the case of a common antenna for transmitting and receivingr＝ht；
The radar receiving target echo is subjected to space domain Fourier transform to obtain a space frequency spectrum,
Figure FDA0003454088500000044
in the formula (f)θAnd
Figure FDA0003454088500000045
the spatial frequency in the pitching direction and the spatial frequency in the azimuth direction respectively represent the frequency of a spatial frequency spectrum obtained by performing Fourier transform on a radar receiving target echo when the antenna scans in the pitching direction and the azimuth direction;
the system voltage is brought into an integral expression to obtain,
Vr(fψ)＝k11(fψ)S11+k12(fψ)S12+k21(fψ)S21+k22(fψ)S22，
where k is the azimuthal spatial frequency
Figure FDA0003454088500000046
A corresponding spatial beam;
selecting a plurality of airspace frequency points, constructing a linear equation set and solving the equation set by calculating the corresponding coefficients of the received echo voltage frequency spectrum and each element of the scattering matrix corresponding to each frequency point, and obtaining the polarization scattering matrix of the target.
9. An apparatus for measuring a scattering matrix of an object based on spatial polarization characteristics of an antenna, comprising a memory and a processor: wherein the memory is to store executable program code; the processor is used for reading the executable program codes stored in the memory to execute the target scattering matrix measurement method based on the spatial polarization characteristics of the antenna according to any one of claims 1 to 8.
10. A computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the method for measuring an object scattering matrix based on spatial polarization characteristics of an antenna according to any one of claims 1 to 8.
CN202210002979.0A 2022-01-04 2022-01-04 Target scattering matrix measurement method based on antenna spatial domain polarization characteristics Pending CN114325630A (en)

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