CN111610513B - Method, system and device for extracting multi-station incoherent scattering radar signals - Google Patents

Abstract

The invention belongs to the field of signal and information processing, and particularly relates to a method, a system and a device for extracting a multi-station incoherent scattering radar signal, aiming at solving the problem that a scattered signal is difficult to calculate and extract due to the change of a beam cross scattering volume moment. The system method comprises the following steps: calculating the directional diagrams of the grid antenna arrays of the transmitting station and each receiving station; for the grid antenna array of each receiving station, if the grid antenna array of each receiving station and the grid antenna array of the transmitting station are positioned in the same base, acquiring a received scattering signal by using a single-station phased array radar scattering signal acquisition method, and otherwise, acquiring the height of a scattering volume in the direction of a transmitting beam; calculating a scattering volume; integrating the scattering volume with the directional diagrams of the grid antenna arrays of the transmitting station and the receiving station, and calculating the scattering signals received by the grid arrays of the receiving stations by combining the power of a transmitter of the transmitting station; and circularly acquiring the scattering signals received by the grid antenna array of each receiving station. The invention solves the problem that the scattering signal is difficult to calculate and extract.

Description

Method, system and device for extracting multi-station incoherent scattering radar signals

technical field

The invention belongs to the field of signal and information processing, and in particular relates to a method, system and device for extracting multi-station incoherent scattering radar signals.

Background technique

The ionosphere is a part of the ionized plasma area in the range of 50, 60 kilometers to 1,000,000 kilometers above the earth. It is the key level most closely related to human activities in the sun-terrestrial space environment. Human spaceflight, etc. have an important impact. Among all ionospheric detection methods, incoherent scattering radar is by far the most powerful detection method. It has strong detection function, multiple parameters (various fields and particle components), high precision, good resolution, and large height range coverage. and many other advantages.

With the development of radar technology, phased array antennas have entered people's field of vision with their advantages of large-scale fast scanning, fine scanning, flexible and controllable, and long-term continuous observation. Incoherent scattering radars began to use phased array antennas to replace traditional Parabolic antenna, in the 21st century, the United States has carried out a technological innovation, and proposed a new modular active phased array radar project Advanced Modular Incoherent Scatter Radar (AMISR), which can control the radar beam through software so that it can be fast in microseconds. Switching the beam direction greatly improves the problem of time ambiguity caused by the mechanical rotation of the traditional parabolic radar to change the beam direction (refer to: Valentic T., Buonocore J., Cousins M., Heinselman C., Jorgensen J. & Kelly J. et al , "AMISR the advanced incoherent scatter radar," IEEE International Symposium on Phased Array Systems & Technology, Waltham, MA, USA, pp. 659-663, 2013, DOI: 10.1109/ARRAY.2013.6731908). Based on this technology, EISCAT proposes the EISCAT_3D project, which is planned to be a radar system with one transmitter and multiple receivers, which can achieve high spatial and temporal resolution, volume imaging, aperture imaging, etc. (refer to: McCrea I., Aikio A., et al, "The science case for the EISCAT_3D radar," Progress in Earth and Planetary Science, vol.2, no.1, pp.1-63, Feb 2015, DOI: 10.1186/s40645-015-0051-8). At the same time, in Hainan, China, a three-station high-power phased array incoherent scattering radar is under construction. Hainan's 1-transmit and 3-receive multi-station phased array incoherent scattering radar can perform vector measurement of ionospheric drift velocity and provide multi-level, multi-parameter and high-precision ionospheric parameters. It will become the first low-latitude region. Three-received multi-station phased array incoherent scattering radar.

The incoherent scatter radar technology in Europe and the United States is relatively advanced. The existing three-station incoherent scatter radar in Europe uses a parabolic antenna, which takes a long time to mechanically rotate and cannot guarantee that the measurement data remains unchanged during the measurement period. Problems such as poor timeliness and time ambiguity; the existing phased array incoherent scattering radar antennas in the United States have the advantages of phased array measurement, but because they are single-transmit and single-receive, the information of the ionospheric vector cannot be measured, and the obtained ionospheric information It is not comprehensive enough to detect and analyze the ionosphere in more dimensions.

The three-station high-power phased array incoherent scattering radar in Hainan, China can solve the above problems. It can not only realize the vector measurement of the ionospheric drift velocity, provide multi-level, multi-parameter, high-precision ionospheric parameters, but also have the The advantage of array scanning is that it can achieve fast scanning within microseconds, which ensures the timeliness of measurement data. At the same time, it can also perform fast and large-scale scanning to achieve all-sky detection. For parabolic antennas, the beamwidth and antenna gain remain unchanged when mechanically scanned in azimuth and elevation, while for phased array antennas, when electronically scanned in azimuth and elevation, the beamwidth and The antenna gain changes with the beam scan, that is, with the azimuth and elevation angles, which increases the difficulty of calculating the scattering volume, received power and signal-to-noise ratio of multi-station phased array incoherent scattering radars. Therefore, the present invention proposes a multi-station incoherent scattering radar signal extraction method.

SUMMARY OF THE INVENTION

In order to solve the above problem in the prior art, that is, to solve the problem that the scattered signal is difficult to calculate and extract due to the time-to-time variation of the multi-station phased array incoherent scattering radar beam cross-scattering volume, in the first aspect of the present invention, a multi-station phased array is proposed. An incoherent scatter radar signal extraction method, applied to a phased array incoherent scatter radar system with one transmit and multiple receive, the method comprising:

Step S100, for the first array and each second array, based on the vertical and horizontal grid spacings, in combination with the pitch angle and azimuth angle of the scattering point, calculate the corresponding radiation electric field intensity, and combine the pitch angle of the scattering point, Calculate its corresponding pattern; the first array is the grid antenna array of the transmitting station; the second array is the grid antenna array of the receiving station;

Step S200, for each second array, if it is located at the same base as the first array, then based on the power of the transmitter of the transmitting station, its pattern, and the first width and the second width, through the single-station phased array The radar scattered signal acquisition method acquires the received scattered signal, and skips to step S600, otherwise skips to step S300; the first width is the beam width of the elevation plane of the first array; the second width is the beam width perpendicular to the elevation plane beam width;

Step S300, based on the acquired pulse width, the angle between the transmit beam and the receive beam, calculate the height of the transmit beam and the receive beam on the bisector of the angle, and calculate the height of the scattering volume in the transmit beam direction by a preset first method , as the first height;

Step S400, obtaining the bottom area of the scattering volume according to the first width and the second width, and multiplying it by the first height to obtain the scattering volume;

Step S500: Integrate the scattering volume and the directional diagrams corresponding to the first array and the second array, and combine the power of the transmitter of the transmitting station, the elevation angle and the azimuth angle of the first array and the second array to calculate the first array. The scattered signal received by the second array;

Step S600: Steps S200 to S500 are executed cyclically until all the scattering signals received by the second array are obtained.

In some preferred embodiments, if the first array and each of the second arrays are triangular grid antenna arrays, the triangular grid antenna array is divided into matrix grid antenna arrays;

Based on the divided vertical and horizontal grid spacings of each matrix grid antenna array, combined with the elevation angle and azimuth angle of the scattering point, calculate the radiated electric field intensity corresponding to each matrix grid antenna array;

The radiated electric field strengths corresponding to each matrix grid antenna array are added to obtain the radiated electric field strengths of the first array and each of the second arrays.

In some preferred embodiments, in step S100, "combining the pitch angle of the scattering point to calculate its corresponding pattern", the method is as follows:

为散射点的方位角，M、N表示第一阵列、第二阵列的天线单元数，θ₁为波束中心线的俯仰角,

为波束中心线的方位角，k表示波矢，dx、dy表示纵向、横向栅格间距。Among them, f represents the pattern, θ is the pitch angle of the scattering point,

is the azimuth angle of the scattering point, M and N represent the number of antenna elements of the first array and the second array, θ ₁ is the elevation angle of the beam centerline,

is the azimuth angle of the beam centerline, k represents the wave vector, and dx and dy represent the vertical and horizontal grid spacing.

In some preferred embodiments, the scattering volume is an effective scattering volume, and the method for obtaining the height in the direction of the emission beam is:

Among them, ΔR represents the height of the scattering volume in the direction of the transmit beam, c represents the speed of light, τ represents the pulse width, and β represents the angle between the transmit beam and the receive beam.

In some preferred embodiments, in step S400, "according to the first width and the second width, obtain the bottom area of the scattering volume, and multiply it with the first height to obtain the scattering volume", and the method is:

Among them, V is the scattering volume, r ₁ is the distance from the first array to the scattering volume element, Θ is the beam width in the elevation plane, and ψ is the beam width perpendicular to the elevation plane.

In some preferred embodiments, in step S500, the method of "calculating and obtaining the scattered signal received by the second array" is as follows:

Among them, P _r represents the scattering signal of the second array, P _t represents the power of the transmitter at the transmitting station, λ represents the emission wavelength, σ represents the radar scattering cross section of the non-magnetized plasma, η ₁ and η ₂ represent the transmitter and receiver of the transmitting station. The antenna efficiency of the station receiver, r ₂ represents the distance from the second array to the scattering volume element, Θ ₁ , Θ ₂ represent the elevation beam widths of the first array and the second array, ψ ₁ , ψ ₂ represent the first array, the second array The beam widths of the two arrays perpendicular to the elevation plane, _Ne represents the electron density, and f ₁ and f ₂ represent the directional diagrams of the first array and the second array.

In some preferred embodiments, if the first array and the second array are not located at the same base, the calculation method of the corresponding signal-to-noise ratio of the scattered signal of the second array is:

P _N =K _B T _N B

Among them, SNR _bs represents the signal-to-noise ratio of the scattered signal of the second array, KB represents the Boltzmann constant, _TN represents the system noise temperature, and _B represents the receiver operating bandwidth of the receiving station.

In a second aspect of the present invention, a multi-station incoherent scattering radar signal extraction system is proposed, the system includes a pattern acquisition module, a judgment module, a height acquisition module, a scattering volume acquisition module, a scattering signal acquisition module, and a circulation module;

The pattern acquisition module is configured to calculate the corresponding radiation electric field intensity for the first array and each second array based on the vertical and horizontal grid spacing, combined with the pitch angle and azimuth angle of the scattering point, and combine the The pitch angle of the scattering point is calculated, and the corresponding pattern is calculated; the first array is the grid antenna array of the transmitting station; the second array is the grid antenna array of the receiving station;

The judging module is matched to each second array, if it is located at the same base as the first array, based on the power of the transmitter of the transmitting station, its pattern, combined with the first width and the second width, through a single The method for obtaining the scattered signal of the station phased array radar obtains the scattered signal it receives, and jumps to the loop module, otherwise jumps to the height obtaining module; the first width is the beam width of the elevation plane of the first array; the second width is beamwidth perpendicular to the elevation plane;

The height acquisition module is configured to calculate the height of the transmit beam and the receive beam on the angle bisector based on the acquired pulse width and the angle between the transmit beam and the receive beam, and calculate the height of the transmit beam in the direction of the transmit beam by a preset first method. The height of the scattering volume, as the first height;

The scattering volume acquiring module is configured to obtain the bottom area of the scattering volume according to the first width and the second width, and multiply the scattering volume by the first height;

The scattering signal acquisition module is configured to perform integral operation on the scattering volume and the patterns corresponding to the first array and the second array, and combine the power of the transmitter of the transmitting station, the pitch angles of the first array and the second array and the Azimuth, calculate the scattered signal received by the second array;

The circulation module is configured to execute the judgment module-scattered signal acquisition module cyclically until all the scattered signals received by the second array are obtained.

In a third aspect of the present invention, a storage device is provided, wherein a plurality of programs are stored, and the program applications are loaded and executed by a processor to realize the above-mentioned method for extracting multi-station incoherent scattering radar signals.

In a fourth aspect of the present invention, a processing device is proposed, including a processor and a storage device; the processor is adapted to execute various programs; the storage device is adapted to store multiple programs; the programs are adapted to be loaded by the processor And execute to realize the above-mentioned multi-station incoherent scattering radar signal extraction method.

Beneficial effects of the present invention:

(1) The present invention solves the problem that the scattered signal is difficult to calculate and extract due to the instantaneous change of the cross-scattering volume of the multi-station phased array incoherent scattering radar beam. The present invention divides the multi-station phased array incoherent scattering radar into single-station incoherent scattering radar (transmitting station and receiving station are located in the same base) and dual-station incoherent scattering radar (transmitting station and receiving station are not located in the same base) . For a single station, the scattered signal received by the grid antenna array of the receiving station is obtained based on the single-station phased array radar scattering signal acquisition method; for a double station, the influence of the pulse width and beam width on the scattering volume is analyzed, so as to calculate the double station radar's effect. Effective scattering volume. Integrate the effective scattering volume with the pattern of the grid antenna array of the transmitting station and the receiving station. According to the integration result, combined with the power of the transmitter of the transmitting station, the scattered signal received by the grid antenna array of the receiving station is obtained, that is, the echo power. . It realizes the combination of phased array and multi-station incoherent scattering radar, and has the outstanding advantages of many measurement parameters, wide coverage space, and high temporal and spatial resolution.

(2) The multi-directional echo information of the same scattering volume can be obtained by using the present invention, which means that the complete vector of the ion drift velocity can be obtained by measuring the multi-directional ion line-of-sight drift velocity. Providing the ability to measure multiple vectors of plasma velocity allows researchers to obtain the instantaneous latitude and longitude structure of the plasma velocity field. In addition, studying the variation of the velocity field with height will help to reveal the underlying structure of the thermosphere. In particular, combining these radar systems with data from other instruments can create a database dedicated to the study of neutral atmospheres.

(3) Using phased array scanning technology, combined with multi-base station technology, multi-beam synchronous detection can be carried out, providing instant full-space coverage, and 3D imaging of ion drift velocity vectors in the entire sky in a short period of time. It can also directly detect the plasma density, composition, temperature, and drift velocity at almost the entire ionosphere height with high precision, and can also indirectly detect the temperature, wind field, electric field, etc. of the background neutral atmosphere, and study the atmosphere-ionosphere-magnetic field. Layer system energy and mass transport and solar wind-magnetosphere interaction effects. When the radar uses a single beam, it is difficult to continuously observe space debris to obtain good statistics. Using rapid and large-scale scanning, a more comprehensive database of meteors and space debris can be established, and speed and position information can be improved.

(4) Multi-station incoherent scattering radar detection greatly promotes the research on the coupling of atmosphere/ionosphere/thermosphere in the area where the radar is located, and has important application prospects in short-wave communication, satellite communication and navigation. Using multi-station incoherent scattering radar to monitor the ionospheric electron density in real time, by developing the ionospheric current reporting mode, it can be used for radio wave propagation correction of satellite positioning and navigation such as my country's Beidou system to improve the service accuracy and quality of related applications.

Description of drawings

Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments taken with reference to the following drawings.

1 is a schematic flowchart of a method for extracting multi-station incoherent scattering radar signals according to an embodiment of the present invention;

2 is a schematic diagram of a framework of a multi-station incoherent scattering radar signal extraction system according to an embodiment of the present invention;

3 is a schematic diagram of the effect of dividing a triangular grid antenna into a matrix grid antenna array according to an embodiment of the present invention;

4 is a schematic diagram of a scattering volume obtained based on pulse width according to an embodiment of the present invention;

5 is a schematic diagram of a scattering volume obtained based on a beam width according to an embodiment of the present invention;

6 is a schematic diagram of the distribution of signal-to-noise ratios of scattered signals obtained by a single station with a height of 300KM and different pulse widths according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of the distribution of the signal-to-noise ratio of scattered signals obtained by dual-station 300KM heights with different pulse widths according to an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages 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 accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not All examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the related invention, but not to limit the invention. In addition, it should be noted that, for the convenience of description, only the parts related to the related invention are shown in the drawings.

It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict.

The multi-station incoherent scattering radar signal extraction method of the present invention is applied to a phased array incoherent scattering radar system with one transmit and multiple reception, as shown in FIG. 1 , and includes the following steps:

Step S100, for the first array and each second array, based on the vertical and horizontal grid spacings, in combination with the pitch angle and azimuth angle of the scattering point, calculate the corresponding radiation electric field intensity, and combine the pitch angle of the scattering point, Calculate its corresponding pattern; the first array is the grid antenna array of the transmitting station; the second array is the grid antenna array of the receiving station;

Step S200, for each second array, if it is located at the same base as the first array, then based on the power of the transmitter of the transmitting station, its pattern, and the first width and the second width, through the single-station phased array The radar scattered signal acquisition method acquires the received scattered signal, and skips to step S600, otherwise skips to step S300; the first width is the beam width of the elevation plane of the first array; the second width is the beam width perpendicular to the elevation plane beam width;

Step S300, based on the acquired pulse width, the angle between the transmit beam and the receive beam, calculate the height of the transmit beam and the receive beam on the bisector of the angle, and calculate the height of the scattering volume in the transmit beam direction by a preset first method , as the first height;

Step S400, obtaining the bottom area of the scattering volume according to the first width and the second width, and multiplying it by the first height to obtain the scattering volume;

Step S500: Integrate the scattering volume and the directional diagrams corresponding to the first array and the second array, and combine the power of the transmitter of the transmitting station, the elevation angle and the azimuth angle of the first array and the second array to calculate the first array. The scattered signal received by the second array;

Step S600: Steps S200 to S500 are executed cyclically until all the scattering signals received by the second array are obtained.

In order to more clearly describe the multi-station incoherent scattering radar signal extraction method of the present invention, each step in an embodiment of the method of the present invention will be described in detail below with reference to the accompanying drawings.

Step S100, for the first array and each second array, based on the vertical and horizontal grid spacings, in combination with the pitch angle and azimuth angle of the scattering point, calculate the corresponding radiation electric field intensity, and combine the pitch angle of the scattering point, Calculate its corresponding pattern; the first array is the grid antenna array of the transmitting station; the second array is the grid antenna array of the receiving station.

In this embodiment, a phased array incoherent scattering radar system with one transmission and multiple reception is a phased array incoherent scattering radar system constructed by one transmitting station and multiple receiving stations, such as the Hainan three-station high-power phased array incoherent scattering radar system. Coherent Scattering Radar System. The Sanya transmitting station antenna of Hainan three-station phased array incoherent scattering radar is composed of 8320 antenna units, with 104 antenna units in the horizontal direction and 80 antenna units in the vertical direction. Arranged in a triangle, the horizontal spacing is 500mm, and the vertical spacing is 380mm. The front radiation units are arranged in a triangle with staggered orientations. The maximum diameter of the front is 40.5 meters × 39.52 meters. The two receiving stations of Fuke and Qiongshan are composed of 4096 antenna units. There are 64 antenna units horizontally and 64 antenna units vertically. The horizontal spacing is 500mm and the vertical spacing is 380mm. The area is 32.5m×24.32m . Since the antenna array (array) of the Sanya incoherent scattering radar system is designed in the form of a triangular grid, it is necessary to deduce from the matrix grid front to obtain the antenna front expression in the form of a triangular grid, that is, the triangular grid array is divided into two There are two matrix grid fronts, and the radiation electric fields of the two matrix grids are solved separately, and then the radiation electric fields of the triangular grid fronts are obtained by adding them up, and the pattern function expression of the triangular grid fronts can be obtained further. details as follows:

As shown in Figure 3, both the transmitting station and the receiving station are the triangular grid phased array (antenna array) shown in the figure, and the triangular grid array is divided into two matrix grid fronts, that is, the triangular grid in Figure 3 For the matrix grid front and the matrix grid front composed of squares, the radiation electric field strengths of the two matrix grids are calculated respectively, and then the radiation electric field strength of the triangular grid front is obtained by adding them together. References may be made: Balanis, C.A. (2005), Antenna Theory: Analysis and Design, Wiley-Interscience, Hoboken, N.J.

Among them, the calculation method of the radiation electric field intensity of each matrix grid front is shown in formula (1) (2):

表示散射点的方位角，j表示虚部。Among them, E1 and E2 represent the radiated electric field strength of the matrix grid antenna array, M/2 represents the number of lateral antenna elements, and 2dx is the lateral spacing. The number of antennas is halved, the horizontal spacing is doubled, N represents the number of vertical antenna elements, dy is the vertical spacing, k=2π/λ, represents the wave vector, λ represents the emission wavelength, m represents different values from 1 to M/2, n represents different values from 1 to N, θ represents the pitch angle of the scattering point,

represents the azimuth of the scattering point, and j represents the imaginary part.

E2 is represented by E1, as shown in formula (3)(4)(5):

为发射波束中心线方位角。Among them, θ ₁ is the pitch angle of the centerline of the transmitting beam,

is the azimuth of the centerline of the transmit beam.

The sum E of the radiated electric field strengths of the two matrix grids is shown in formula (6):

In other embodiments, if the antenna elements of the phased array incoherent scattering radar system with one transmission and multiple reception are not arranged in a triangular grid on the outside of the reflective panel of the structural sub-array, then directly based on the horizontal and vertical grid spacing, Calculate the radiation electric field strength, which will not be described here.

The pattern f of the triangular grid antenna array can be obtained by the radiated electric field strength, as shown in formula (7):

According to the above, it can be known that the number of antenna elements of the Sanya transmitting station M1=104, N1=80, the spacing dx=0.38, dy=0.5, the antenna elements of the Fuke and Qiongshan receiving stations M2=64, N2=64, and the spacing dx= 0.38, dy=0.5. Therefore, the pattern of the grid antenna array of the transmitting station and the receiving station is shown in formula (8) (9):

Among them, f1 represents the pattern of the grid antenna array of the transmitting station, and f2 represents the pattern of the grid antenna array of the receiving station.

Step S200, for each second array, if it is located at the same base as the first array, then based on the power of the transmitter of the transmitting station, its pattern, and the first width and the second width, through the single-station phased array The radar scattered signal acquisition method acquires the received scattered signal, and skips to step S600, otherwise skips to step S300; the first width is the beam width of the elevation plane of the first array; the second width is the beam width perpendicular to the elevation plane beam width.

In this embodiment, it is determined whether the first array and the second array belong to a single-station radar (that is, located at the same base) or a dual-station radar. If the scattered signal received by the second array is a dual-station radar, the effective scattering volume is calculated first.

The scattered signal P _s received by the incoherent scattering radar is shown in formula (10):

Among them, P _t is the peak power of radar transmission, r ₁ is the distance from the transmitting station to the scattering volume element, r ₂ is the distance from the receiver of the receiving station to the scattering volume element, G ₁ is the transmit antenna gain, G ₂ The receive antenna gain, λ is the emission wavelength, σ is the scattering cross section of a single electron, _Ne is the electron density, V is the scattering volume element, dV is the unit scattering volume element, and the transmission line loss term is ignored here. where σ is the radar cross section of the non-magnetized plasma, as shown in Equation (11):

是电子离子的温度比。Among them, σ _e is the radar scattering cross section of electrons, α=4πD/λ, D is the plasma Debye length, which depends on the ionospheric characteristics of the area where the radar is located, and is also affected by seasonal changes,

is the electron-ion temperature ratio.

The phased array antenna gain G is expressed as formula (12):

但是由于波束扫描增益会发生变化，所以需要乘以归一化功率方向图函数f，同时还要乘以天线的效率η。根据天线波束范围Ω定义，可以表示出Ω＝s/r²＝(π·r·Θ·r·ψ)/(4·r²)。where A _e is the effective area of the antenna, Ω is the solid angle, η is the antenna efficiency, Θ is the beam width of the elevation plane, ψ is the beam width perpendicular to the elevation plane, f is the pattern of the antenna array, and r is the distance from the antenna to the scattering point. distance, according to the gain formula, the gain in the direction of maximum gain is equal to

However, since the beam scanning gain will change, it needs to be multiplied by the normalized power pattern function f, and also by the efficiency η of the antenna. According to the definition of the antenna beam range Ω, it can be expressed that Ω=s/r ² =(π·r·Θ·r·ψ)/(4·r ² ).

Therefore, in the phased array incoherent scattering radar system with one transmit and multiple receive, the calculation of the scattered signal P _ms of the single-station phased array radar is shown in formula (13):

For the specific derivation process, please refer to the literature: Murdin J., "SNR for the EISCAT UHF system," Kiruna Geophysical Institute Report. 78:1, 1978 and literature: J. Swoboda, J. Semeter & P. Erickson, "Space-time ambiguity functions for electronically scanned ISR applications," Radio Science, vol. 50, pp. 415-430, May. 2015, DOI: 10.1002/2014RS005620.

The receiver noise power P _N of the incoherent scattering radar is defined as: P _N =K _B T _N B, where K _B is the Boltzmann constant, T _N is the system noise temperature, and B is the working bandwidth of the receiver at the receiving station.

The signal-to-noise ratio SNR _ms of the scattered signal received by the single-station phased array radar is calculated as shown in formula (14):

The calculation method of the beam width Θ of the elevation plane is shown in the following formula:

Among them, β _x represents the phase difference in the x-direction array, and β _y represents the phase difference in the y-direction array.

The beamwidth ψ perpendicular to the elevation plane is calculated as shown in formula (22):

Using the above formula, the beam width of the grid antenna array of the transmitting station and the receiving station can be obtained. The beam width is related to the azimuth and elevation angles of the central beam. According to the formula, the beam widths corresponding to different azimuth and elevation angles can be obtained. According to the formula It can be known that the beam width in the normal direction of the front is the narrowest.

According to the position of the scattering point, the azimuth angle and elevation angle of the transmitting beam and the azimuth angle and the elevation angle of the receiving beam can be obtained. According to the geometric relationship, the receiving beam azimuth angle and The expression of the pitch angle is shown in formula (23)(24)(25)(26)(27):

表示接收站相对于发射站的方位角，θ₂表示接收波束中心线俯仰角，

表示接收波束中心线方位角。Among them, L represents the distance between the transmitting station and the receiving station,

represents the azimuth angle of the receiving station relative to the transmitting station, θ ₂ represents the elevation angle of the centerline of the receiving beam,

Indicates the azimuth of the centerline of the receive beam.

Step S300, based on the acquired pulse width, the angle between the transmit beam and the receive beam, calculate the height of the transmit beam and the receive beam on the bisector of the angle, and calculate the height of the scattering volume in the transmit beam direction by a preset first method , as the first height.

In this embodiment, in calculating the effective scattering volume, there are two cases, one is the scattering volume determined by the pulse width, and the other is the scattering volume determined by the beam width.

First calculate the scattering volume determined by the pulse width, that is, the scattering volume obtained by the intersection of the two beams is not the real scattering volume, part of which is the real effective scattering volume, which is mainly affected by the pulse width, and its effective scattering volume The bottom area of φ is determined by the transmitted beam, and the height of the effective scattering volume is determined by the pulse width. The two work together to form the scattering volume, as shown in Figure 4. The black area is the effective scattering volume, and the red area is the intersection area of two beams (Transmitting beam: transmitting beam, Receiving beam: receiving beam). It can be seen that the effective scattering volume is smaller than the beam intersection area. The remainder of Figure 4 is explained below.

According to the relationship between the two-station radar (the transmitting station and the receiving station are not located in the same base), on the ellipse with the transmitting station and the receiving station as the focus, the sum of the distance from the transmitting station to the target and the distance from the target to the receiving station is a fixed value, The height in the direction of the angle bisector of the transmit beam and the receive beam can be obtained by using the geometric relationship (refer to: S. Satoh and J. Wurman, "Accuracy of Wind Fields Observed by a Bistatic Doppler Radar Network," Journal of Atmospheric & Oceanic Technology, vol. .20, pp.1077-1091, Aug.2003), as shown in formula (28):

Among them, h represents the height in the direction of the angle bisector of the transmitting beam and the receiving beam, c represents the speed of light, τ represents the pulse width, and β represents the angle between the transmitting beam and each receiving beam.

Based on the height of the transmit beam and each receive beam on the angle bisector, calculate the height of the scattering volume in the direction of the transmit beam, as shown in equation (29):

where ΔR is the height of the scattering volume in the direction of the transmit beam.

Then calculate the scattering volume determined by the beam width, that is, when the pulse width is large enough to exceed the range covered by the intersection of the two beams, at this time, the scattering volume is determined by the intersection range of the two beams. As shown in Figure 5: The shaded part in Figure 5 is the scattering volume, and Figure 5 is represented as a plane figure. The scattering volume determined by the beam width and the scattering volume determined by the pulse width have the same bottom area, which are both determined by the transmitted beam. The scattering volume determined by the beam width and the high acquisition method of the scattering volume determined by the pulse width are the same, and will not be described here.

Step S400, obtaining the bottom area of the scattering volume according to the first width and the second width, and multiplying it by the first height to obtain the scattering volume.

In this embodiment, the bottom area of the scattering volume is formed by an ellipse formed by the beam width of the elevation plane of the transmit beam and the beam width perpendicular to the elevation plane. Based on the multiplication of the obtained base area and the height of the scattering volume in the direction of the transmit beam, the scattering volume, ie the effective scattering volume, is obtained, as shown in formula (30):

where V represents the scattering volume and r ₁ represents the distance from the first array to the scattering voxel.

Step S500: Integrate the scattering volume and the directional diagrams corresponding to the first array and the second array, and combine the power of the transmitter of the transmitting station, the elevation angle and the azimuth angle of the first array and the second array to calculate the first array. The scattered signal received by the second array.

In this embodiment, an integral operation is performed on the scattering volume corresponding to the second array, the pattern of the second array, and the pattern of the first array, as shown in formulas (31) and (32):

The integration range is determined according to the angle definition, as shown in equations (33) (34) (35):

For the scattering volume determined by the beam width, since the scattering volume is calculated integrally with the pattern function to obtain the effective scattering volume in different situations, when the scattering volume is calculated by the integral method, the scattering volume determined by the pulse width can be used for both scattering volumes. The formula is calculated, because the antenna pattern function f in the integral formula is 0 outside the beam receiving range, so even if the pulse width is large enough to exceed the beam crossing coverage, the pattern function f is 0 because the beam cannot cover the place. So the whole integral is calculated in terms of beamwidth.

Based on the results of each integral operation, combined with the power of the transmitter of the transmitting station, the pitch angle and the azimuth angle of the first array and the second array, the scattered signal received by the second array is calculated. details as follows:

The calculation of the scattered signal P _r of the dual-station (that is, the transmitting station and the receiving station are not located in the same base) phased array radar is shown in formula (36):

Among them, Θ ₁ and Θ ₂ represent the beam widths of the elevation plane of the transmitting station and the receiving station, and ψ ₁ and ψ ₂ represent the beam widths of the transmitting station and the receiving station that are perpendicular to the elevation plane.

The signal-to-noise ratio SNR _bs of the scattered signal received by the dual-station phased array radar is calculated as shown in formula (37):

Step S600: Steps S200 to S500 are executed cyclically until all the scattering signals received by the second array are obtained.

In this embodiment, the received scattered signals of each of the second arrays are sequentially acquired.

In addition, in the process of analyzing the signal-to-noise ratio, it is necessary to use the simulation parameters of the multi-station phased array incoherent scattering radar, as shown in Table 1, set the longitude range of the signal-to-noise ratio distribution plane to 105°E-115°E, The interval is 0.2°, the latitude range is 15°N-25°N, and the interval is 0.2°. In the multi-station incoherent scattering radar system, it is transmitted by the Sanya station SY, and received by the Sanya station, Fuke station FK and Qiongshan station QS, so it is necessary to analyze the situation of SY-SY single station, as well as the two double stations SY-FK, SY-QS is also the case of multi-station, as shown in Table 1:

Table 1

In the case of a single station, different transmit pulse widths will affect the received scattered signal, which further affects the signal-to-noise ratio of the radar system. Figure 6 shows the 100us, 300us, 500us, and 700us pulsewidths at a height of 300km (pulseWidth) at the Sanya station. The change of the signal-to-noise ratio, lon represents longitude, and lat represents latitude. By comparing and analyzing the signal-to-noise ratio of the phased array antenna with different pulse widths, it can be found that the signal-to-noise ratio is distributed in a circle with the Sanya station as the center, and the signal-to-noise ratio gradually decreases with the distance from the Sanya station. The signal-to-noise ratio is inversely proportional to the distance. At the same detection height, the farther away from the Sanya station, the greater the distance between the target and the receiving station of the transmitting station. Therefore, the distance increases and the signal-to-noise ratio decreases. The second reason is the distance from Sanya. The farther the station is, the larger the zenith angle of the beam scanning, and the corresponding beam width is also increasing. According to the derivation formula, it can be known that the signal-to-noise ratio is inversely proportional to the beam width, so the beam width increases and the signal-to-noise ratio decreases. At the same height, as the pulse width gradually increases, the signal-to-noise ratio gradually increases, mainly because the pulse width increases, the scattering volume related to the pulse width increases, and the signal-to-noise ratio increases. However, as the pulse width increases, the corresponding range resolution becomes larger, and the corresponding small-scale detection becomes more and more difficult, so the pulse width needs to be reasonably selected in the subsequent detection mode design.

In the case of dual stations, that is, the Sanya station transmits, and the Fuke and Qiongshan stations receive. Gram stands for discussion on behalf of the representative. Figure 7 below shows the signal-to-noise ratio distribution of Fuke station at 100us, 300us, 500us, and 700us pulse widths at a height of 300km.

Analyzing the distribution of SY-FK signal-to-noise ratio, it can be seen that the signal-to-noise ratio is centered on Sanya and Fuke stations, showing an elliptical distribution. It is because the signal-to-noise ratio is inversely proportional to the distance. At the same detection height, the farther from the Sanya station and the Fuke station, the greater the distance between the target and the receiving station of the transmitting station, so the distance increases and the signal-to-noise ratio decreases. The second reason is that the farther from the two stations, the larger the zenith angle of the beam scanning, and the corresponding beam width is also larger and larger, the signal-to-noise ratio is inversely proportional to the beam width, so the beam width increases and the signal-to-noise ratio decreases. It can be seen from Figure 7 that as the pulse width increases, the shape of the signal-to-noise ratio distribution is gradually elongated along the line connecting the transmitting station and the receiving station. The main reason is that with the increase of the pulse width, the scattering volume gradually increases, which is The change of the connection direction between the station and the receiving station is more obvious than other areas.

The signal-to-noise ratio distribution rules of single-station and multi-station are somewhat different. First, compare the signal-to-noise ratio distribution of single-station and double-station. For the dual stations, mainly because the number of antennas at the Sanya station is large, the corresponding antenna receiving beams are smaller than the receiving beam widths of the two stations in Fuke and Qiongshan. According to the formula, the beam width is inversely proportional to the signal-to-noise ratio. , the smaller the receiving beam width, the greater the signal-to-noise ratio; the second reason is that the Sanya station transmits and receives the same antenna beam, and the antenna beam of the Fuke and Qiongshan stations crosses the antenna beam of the Sanya station. The scattering volume of the Sanya station is smaller than that of the Sanya station, and the signal-to-noise ratio of the Sanya station is greater than that of the Fuke and Qiongshan stations. The difference between the two-station SNR distribution and the single-station SNR distribution is that the single-station SNR is mainly determined by parameters such as the location of the Sanya station, while the dual-station SNR needs to consider the influence of parameters such as the location of the two stations. When the detection height is the same, comparing the changes of the signal-to-noise ratio of different pulse widths, it can be found that at the beginning, as the pulse width gradually increases, the signal-to-noise ratio of a single station increases. The associated scattering volume increases, and thus the signal-to-noise ratio. However, for the dual-station phased array incoherent scattering radar, as the pulse width gradually increases, the signal-to-noise ratio first increases, and then when the pulse width increases to a certain extent, the signal-to-noise ratio remains unchanged. The volume is determined by the previous pulse width instead of the beam width, and the signal-to-noise ratio is almost unchanged even if the pulse width is increased.

A multi-station incoherent scattering radar signal extraction system according to the second embodiment of the present invention, as shown in FIG. 2 , includes: a pattern acquisition module 100, a judgment module 200, a height acquisition module 300, a scattering volume acquisition module 400, a scattering signal an acquisition module 500 and a loop module 600;

The pattern acquisition module 100 is configured to calculate the corresponding radiated electric field intensity for the first array and each second array based on the vertical and horizontal grid spacing, combined with the pitch angle and azimuth angle of the scattering point, and combine the The pitch angle of the scattering point is calculated, and the corresponding pattern is calculated; the first array is the grid antenna array of the transmitting station; the second array is the grid antenna array of the receiving station;

The judging module 200 cooperates with each second array, if it is located in the same base as the first array, based on the power of the transmitter of the transmitting station, its pattern, and the first width and the second width, through the The single-station phased array radar scattering signal acquisition method obtains the received scattering signal, and jumps to the loop module, otherwise jumps to the height acquisition module; the first width is the elevation beam width of the first array; the second width is the beam width perpendicular to the elevation plane;

The height acquisition module 300 is configured to calculate the height of the transmit beam and the receive beam on the angle bisector based on the acquired pulse width, the angle between the transmit beam and the receive beam, and calculate the height on the transmit beam by a preset first method. The height of the scattering volume in the direction, as the first height;

The scattering volume acquiring module 400 is configured to obtain the bottom area of the scattering volume according to the first width and the second width, and multiply the scattering volume by the first height;

The scattering signal acquisition module 500 is configured to perform integral operation on the scattering volume and the patterns corresponding to the first array and the second array, and combine the power of the transmitter of the transmitting station and the pitch angles of the first array and the second array. and the azimuth angle, calculate the scattered signal received by the second array;

The circulation module 600 is configured to execute the judgment module 200-scattered signal acquisition module 500 cyclically until all the scattered signals received by the second array are obtained.

Those skilled in the technical field can clearly understand that, for the convenience and brevity of description, for the specific working process and related description of the system described above, reference may be made to the corresponding process in the foregoing method embodiments, which will not be repeated here.

It should be noted that the multi-station incoherent scattering radar signal extraction system provided by the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be allocated to different functional modules as required. To complete, that is, the modules or steps in the embodiments of the present invention are decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or can be further split into multiple sub-modules to complete all or part of the functions described above. . The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing each module or step, and should not be regarded as an improper limitation of the present invention.

A storage device according to a third embodiment of the present invention stores a plurality of programs, and the programs are suitable for being loaded by a processor and implementing the above-mentioned method for extracting multi-station incoherent scattering radar signals.

A processing device according to a fourth embodiment of the present invention includes a processor and a storage device; the processor is adapted to execute various programs; the storage device is adapted to store multiple programs; the programs are adapted to be loaded and executed by the processor In order to realize the above-mentioned multi-station incoherent scattering radar signal extraction method.

Those skilled in the technical field can clearly understand that, for the convenience and brevity of description, the specific working process and related description of the storage device and processing device described above can refer to the corresponding process in the foregoing method example, which is not repeated here. Repeat.

Those skilled in the art should be aware that the modules and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software or a combination of the two, and the programs corresponding to the software modules and method steps Can be placed in random access memory (RAM), internal memory, read only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or as known in the art in any other form of storage medium. In order to clearly illustrate the interchangeability of electronic hardware and software, the components and steps of each example have been described generally in terms of functionality in the foregoing description. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may use different methods of implementing the described functionality for each particular application, but such implementations should not be considered beyond the scope of the present invention.

The terms "first," "second," etc. are used to distinguish between similar objects, and are not used to describe or indicate a particular order or sequence.

The term "comprising" or any other similar term is intended to encompass a non-exclusive inclusion such that a process, method, article or device/means comprising a list of elements includes not only those elements but also other elements not expressly listed, or Also included are elements inherent to these processes, methods, articles or devices/devices.

So far, the technical solutions of the present invention have been described with reference to the preferred embodiments shown in the accompanying drawings, however, those skilled in the art can easily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims (9)

1. a multi-station incoherent scattering radar signal extraction method, applied to the phased array incoherent scattering radar system of one transmission and multiple reception, is characterized in that, the method comprises: Step S100, for the first array and each second array, based on the vertical and horizontal grid spacings, in combination with the pitch angle and azimuth angle of the scattering point, calculate the corresponding radiation electric field intensity, and combine the pitch angle of the scattering point, Calculate its corresponding pattern; the first array is the grid antenna array of the transmitting station; the second array is the grid antenna array of the receiving station; Step S200, for each second array, if it is located at the same base as the first array, then based on the power of the transmitter of the transmitting station, its pattern, and the first width and the second width, through the single-station phased array The radar scattered signal acquisition method acquires the received scattered signal, and skips to step S600, otherwise skips to step S300; the first width is the beam width of the elevation plane of the first array; the second width is the beam width perpendicular to the elevation plane beam width; Step S300, based on the acquired pulse width, the angle between the transmit beam and the receive beam, calculate the height of the transmit beam and the receive beam on the bisector of the angle, and calculate the height of the scattering volume in the transmit beam direction by a preset first method , as the first height; Wherein, the scattering volume is an effective scattering volume, and the method for obtaining the height in the direction of the emission beam is:

Among them, ΔR represents the height of the scattering volume in the direction of the transmitting beam, c represents the speed of light, τ represents the pulse width, and β represents the angle between the transmitting beam and the receiving beam; Step S400, obtaining the bottom area of the scattering volume according to the first width and the second width, and multiplying it by the first height to obtain the scattering volume; Step S500: Integrate the scattering volume and the directional diagrams corresponding to the first array and the second array, and combine the power of the transmitter of the transmitting station, the elevation angle and the azimuth angle of the first array and the second array to calculate the first array. The scattered signal received by the second array; Step S600: Steps S200 to S500 are executed cyclically until all the scattering signals received by the second array are obtained. 2. The multi-station incoherent scattering radar signal extraction method according to claim 1, wherein if the first array and each second array are triangular grid antenna arrays, the triangular grid antenna array is divided into matrix grid antenna array; Based on the divided vertical and horizontal grid spacings of each matrix grid antenna array, combined with the elevation angle and azimuth angle of the scattering point, calculate the radiated electric field intensity corresponding to each matrix grid antenna array; The radiated electric field strengths corresponding to each matrix grid antenna array are added to obtain the radiated electric field strengths of the first array and each of the second arrays. 3. The multi-station incoherent scattering radar signal extraction method according to claim 1, wherein in step S100, "combining the elevation angle of the scattering point, calculate its corresponding pattern", and the method is:

Among them, f represents the pattern, θ is the pitch angle of the scattering point,

is the azimuth angle of the scattering point, M and N represent the number of horizontal and vertical antenna elements of the first array or the second array, θ ₁ is the elevation angle of the beam centerline,

is the azimuth angle of the beam centerline, k represents the wave vector, and dx and dy represent the vertical and horizontal grid spacing. 4. The method for extracting multi-station incoherent scattering radar signals according to claim 3, wherein in step S400 "according to the first width and the second width, the bottom area of the scattering volume is obtained, and the bottom area is obtained with the first width and the second width. A height is multiplied to get the scattering volume", the method is:

Among them, V represents the scattering volume, r ₁ represents the distance from the first array to the scattering volume element, Θ represents the beam width of the elevation plane, and ψ represents the beam width perpendicular to the elevation plane. 5. The multi-station incoherent scattering radar signal extraction method according to claim 4, characterized in that, in step S500, "calculate the scattering signal received by the second array", and the method is:

Among them, P _r represents the scattered signal received by the second array, P _t represents the power of the transmitter at the transmitting station, λ represents the emission wavelength, σ represents the radar scattering cross section of the non-magnetized plasma, η ₁ and η ₂ represent the transmitter at the transmitting station, The antenna efficiency of the receiver at the receiving station, r ₂ represents the distance from the second array to the scattering volume element, Θ ₁ , Θ ₂ represent the elevation beam widths of the first array and the second array, ψ ₁ , ψ ₂ represent the first array, The beam width of the second array perpendicular to the elevation plane, _Ne represents the electron density, and f ₁ and f ₂ represent the directional diagrams of the first array and the second array. 6 . The method for extracting multi-station incoherent scattering radar signals according to claim 5 , wherein if the first array and the second array are not located at the same base, the scattering signal of the second array is The corresponding signal-to-noise ratio is calculated as:

P _N =K _B T _N B Among them, SNR _bs represents the signal-to-noise ratio of the scattered signal of the second array, KB represents the Boltzmann constant, _TN represents the system noise temperature, and _B represents the receiver operating bandwidth of the receiving station. 7. A multi-station incoherent scattering radar signal extraction system, characterized in that the system comprises: a pattern acquisition module, a judgment module, a height acquisition module, a scattering volume acquisition module, a scattered signal acquisition module, and a circulation module; The pattern acquisition module is configured to calculate the corresponding radiation electric field intensity for the first array and each second array based on the vertical and horizontal grid spacing, combined with the pitch angle and azimuth angle of the scattering point, and combine the The pitch angle of the scattering point is calculated, and the corresponding pattern is calculated; the first array is the grid antenna array of the transmitting station; the second array is the grid antenna array of the receiving station; The judging module is matched to each second array, if it is located at the same base as the first array, based on the power of the transmitter of the transmitting station, its pattern, combined with the first width and the second width, through a single The method for obtaining the scattered signal of the station phased array radar obtains the scattered signal it receives, and jumps to the loop module, otherwise jumps to the height obtaining module; the first width is the beam width of the elevation plane of the first array; the second width is beamwidth perpendicular to the elevation plane; The height acquisition module is configured to calculate the height of the transmit beam and the receive beam on the angle bisector based on the acquired pulse width and the angle between the transmit beam and the receive beam, and calculate the height of the transmit beam in the direction of the transmit beam by a preset first method. The height of the scattering volume as the first height; Wherein, the scattering volume is an effective scattering volume, and the method for obtaining the height in the direction of the emission beam is:

Among them, ΔR represents the height of the scattering volume in the direction of the transmitting beam, c represents the speed of light, τ represents the pulse width, and β represents the angle between the transmitting beam and the receiving beam; The scattering volume acquiring module is configured to obtain the bottom area of the scattering volume according to the first width and the second width, and multiply the scattering volume by the first height; The scattering signal acquisition module is configured to perform integral operation on the scattering volume and the patterns corresponding to the first array and the second array, and combine the power of the transmitter of the transmitting station, the pitch angles of the first array and the second array and the Azimuth, calculate the scattered signal received by the second array; The circulation module is configured to execute the judgment module-scattered signal acquisition module cyclically until all the scattered signals received by the second array are obtained. 8. A storage device, wherein a plurality of programs are stored, wherein the program application is loaded and executed by a processor to realize the multi-station incoherent scattering radar signal extraction method according to any one of claims 1-6 . 9. A processing device, comprising a processor and a storage device; the processor is adapted to execute each program; the storage device is adapted to store a plurality of programs; characterized in that the program is adapted to be loaded and executed by the processor to The method for extracting multi-station incoherent scattering radar signals according to any one of claims 1 to 6 is realized.

Images