Multi-station phased array incoherent scatter radar noise level calculation method

Abstract

The invention belongs to the field of radar detection, relates to a multi-station phased array incoherent scatter radar noise level calculation method, and aims to solve the problem of lack of an effective multi-station incoherent scatter radar noise level calculation method in the prior art. The method comprises the following steps: obtaining a beam cross covariance of a transmitting beam and each receiving beam; determining a distance distribution covariance between the transmitting beam and each receiving beam; determining the scattering volume covariance of the intersection of the transmitting beam and each receiving beam; obtaining a three-dimensional scattering volume integral, and further determining the receiving power and the noise power of the multi-station incoherent scattering radar; determining noise parameters; and calculating the noise level of the multi-station incoherent scatter radar. According to the method, from the angle of beam width, the scattering volume is solved through a covariance matrix method, then the noise level is determined, and the blank of a multi-station phased array incoherent scatter radar noise level calculation method is filled.

Description

Background Art

[0002] The ionosphere is a partially ionized plasma region in the range of 50-60 km to 1000-2000 km above the Earth. It is closely related to human activities in the solar-terrestrial space environment and has a significant impact on radio communications, satellite navigation and positioning, manned space flight, etc. IncoherentScatterRadar , ISR) is currently the most powerful means of ionospheric detection, with strong detection capabilities, multiple parameters, high accuracy, good resolution, and wide altitude coverage. Since 1958, many scholars have studied incoherent scattering radar and confirmed that it can use electron thermal fluctuation scattering signals to measure ionospheric parameters (see references: Dougherty , J . P ., andD . T . Farley (1960), “ Atheoryofincoherentscatteringo fradiowavesbyaplasma ,” Proc. Royal Soc. Lond , vol .259, pp .79–99, Feb 1960. DOI :10.1098 / rspa .1960.0212; Fejer , J . A ., “ Radio - wavescatteringbyanionizedgasinther malequilibrium ,” Journal of Geophysical Research , vol . 65, no . 9, pp . 2635–2636, Sep 1960. DOI : 10.1029 / jz 065 i 009 p 02635; SalpeterE . E ., “ ElectronDensityFluctuati onsinaPlasma ,” Phys Rev,vol .120, no .5, pp .1528-1535. Dec 1960. DOI : 10.1103 / PhysRev .120.1528; RosenbluthMN , RostokerN , " ScatteringofElectromagneticWavesby aNonequilibriumPlasma ,” Physics of Fluids , vol .5, no .7, pp .776-788, Jul 1962, DOI :10.1063 / 1.1724446; Hagfors , T ., “ Densityfluctuationsinaplasmainamagneticfield , withapplicationstotheionosphere ,” Journal of Geophysical Research , vol .66, no .6, Jun 1961. DOI : 10.1029 / JZ 066 i 006 p 01699).

[0003] Incoherent scattering radar obtains ionospheric information by emitting high-power electromagnetic waves and receiving Thomson scattering echoes of electrons (see references: Evans , J . V . (1969), TheoryandpracticeofionospherestudybyThomso nscatterradar , ProceedingsoftheIEEE , 57(4), 4 96–530. https: / / doi.org / 10.1109 / proc.1969.7005;Mathews , J . D . (1984), Theincoherentscatterradarasatoolforstudyi ngtheionosphericD - region , J . Atmos . Sol . Terr . Phys ., 46(11), 975–986. https: / / doi.org / 10.1016 / 0021-9169(84)90004-7) .Europe EISCAT The association operates three ISR radars, of which the UHF radar is a multi-station parabolic incoherent scatter radar (see references: SchlegelK , Moorcroft , D . R . (1989), EISC ATasatristaticauroralradar . JournalofGeophysicalResearchSpacePhysics , 94( A 2):1430-1438. https : / / doi . org / 10.1029 / ja 094 ia 02 p 01430; Wannberg , G ., Wolf , I ., etal .(1997). TheEISCATSvalbardradar : Acasestudyinmodernincoherentscatterradarsystem design . RadioScience , 32(6), 2283–2307. https: / / doi.org / 10.1029 / 97rs01803) . Its transmitting station is located in Tromsø, and its receiving stations are located in Tromsø, Kiruna and Sodankyla. This radar is the world's first multi-station incoherent scattering radar with a parabolic system. This multi-station incoherent scattering radar uses a parabolic antenna and scans through mechanical rotation. It usually takes tens of minutes to switch the direction of the beam. Therefore, it can only detect fixed points and cannot achieve scanning detection. It cannot ensure that the measured ionospheric parameters remain unchanged during the measurement, which has defects in observation. At the same time, a parabolic antenna is used, and the antenna gain does not change with mechanical rotation. Therefore, it does not need to consider the change of its gain with azimuth and elevation angles. Therefore, it is relatively simple in data processing, but its existing formula cannot be directly applied to phased array incoherent scattering radar systems.

[0004] With the development of radar technology, phased array antennas have entered people's field of vision with their advantages of large-scale rapid scanning, fine scanning, flexible controllability and long-term continuous observation. Phased array antennas can achieve millimeter-level beam switching. Therefore, incoherent scattering radars have begun to use phased array antennas to replace traditional parabolic antennas. The United States has proposed AMISR ( Advance dModularIncoherentScatterRadar , Advanced Modular Incoherent Scattering Radar) active phased array radar project, through software control beam, can quickly switch the beam direction in microseconds, improving the time ambiguity problem of traditional parabolic radar (reference literature: ValenticT ., BuonocoreJ ., CousinsM ., HeinselmanC ., JorgensenJ .& KellyJ . etal ,“ AMISR the advanced modular incoherent scatter radar , ” IEEE Internation al Symposium on Phased Array Systems & Technology , Waltham , MA , USA , pp . 659-663, 2013, DOI : 10.1109 / ARRAY .2013.6731908). After completion, the array was placed in Alaska Fairbanks Nearby Poker The observation and research site is being tested and operated, and other arrays are installed in Canada. ResoluteBay, its geographical location is located in high latitudes (see references: Heinselman , C . J ., and M . J . Nicolls (2008), A Bayesian approach to electric field and E - region neutral wind estimation with the Poker Flat Advanced Modul ar Incoherent Scatter Ra dar, Radio Sci., 43, RS5013, https: / / doi.org / 10.1029 / 2007RS003805; Semeter , J ., T . W . Butler , M . Zettergren , C . J . Heinselman , and M . J . Nicolls (2010), Composite imaging of auroral forms and convective flows during a substorm cycle , J . Geophys . Res ., 115, A 08308, doi :10.1029 / 2009 JA 014931). Its two existing radars are both single-station phased array incoherent scattering radars. The single-transmit and single-receive mode cannot accurately measure the ionospheric vector information in the horizontal area. The ionospheric information obtained is incomplete, making it difficult to conduct multi-dimensional detection and analysis.

[0005] In order to achieve multi-dimensional detection, the Institute of Geology and Geophysics of the Chinese Academy of Sciences built a 1-transmitter 3-receiver incoherent scattering detection system on Hainan Island. It is transmitted by the Sanya station in Hainan and received by Sanya, Danzhou Fuke and Wenchang. It is the world's first low-latitude ionosphere multi-station phased array incoherent radar detection system (see references: Yue , X ., Wan , W ., Ning , B ., Jin , L ., Ding , F ., Zhao , B ., etal . (2022). Development of the Sanya incoherent scatter radar and p reliminary results . Journal of Geophysical Research: Space Physics, 127, e2022JA030451. https: / / doi.org / 10.1029 / 2022JA0;Yue, X., Ning, B., Jin, L.,Ding, F., Ke, C., Wang, J., et al. (2024). The Sanya incoherent scatter radar tristatic system and initial experiments. Space Weather , twenty two, e 2024 SW 003963. https : / / doi . org / 10.1029 / 2024 SW 003963). Compared with single-station radar, it can improve detection capability, measure ionospheric drift velocity vector, and provide multi-level, multi-parameter, high-precision ionospheric parameters. China's three-station incoherent scattering radar can not only realize vector measurement of ionospheric drift velocity, but also has the advantages of phased array scanning. It can realize fast scanning within microseconds, ensuring the timeliness of measurement data. At the same time, it can also perform fast large-scale scanning to achieve full-sky detection. However, the phased array system brings many technical difficulties, such as real-time changes in radar electronic scanning phase, gain, and beam width, and the need to achieve common body detection in a wide area. Therefore, the scattering signal to be detected in multi-station incoherent scattering radar detection is very weak, which increases the difficulty of calculating the signal-to-noise ratio; although the existing technology has related results on the signal-to-noise ratio of multi-station incoherent scattering radar, the signal-to-noise ratio calculation is rough. Therefore, not only is it necessary to conduct a more in-depth analysis of the noise level, but also to accumulate the received signal for a certain period of time in order to obtain an effective scattering signal. In summary, there is currently a lack of effective methods for calculating the noise level of multi-station incoherent scattering radars, which cannot provide a reference for actual detection tests. Summary of the invention

[0006] In order to solve the above-mentioned problem in the prior art, that is, the problem that the prior art lacks a method for calculating the noise level of multi-station incoherent scatter radar detection, the first aspect of the present invention proposes a method for calculating the noise level of a multi-station phased array incoherent scatter radar, which is applied to the ionospheric parameter observation of the incoherent scatter radar, and realizes the calculation and spatial distribution analysis of the noise level of important parameters in radar signal and data processing. The method comprises the following steps: S1. Determine the transmit beam covariance and receive beam covariance of the multi-station incoherent scattering radar based on the beam equivalent method, and then obtain the beam cross covariance of the transmit beam and each receive beam; S2. Determine the distance parameter of the beam, and then obtain the distance distribution covariance between the transmit beam and each receive beam; S3, determining the scattering volume covariance of the intersection of the transmit beam and each receive beam based on the beam cross covariance and the distance distribution covariance; S4. Obtaining a three-dimensional scattering volume integral based on the scattering volume covariance according to Gaussian distribution properties; S5. Determine the received power and noise power of the multi-station incoherent scattering radar based on the three-dimensional scattering volume integral; S6. Determine noise parameters, wherein the noise parameters include a delay length and a corresponding delay number, and a non-coherent accumulation number; S7. Calculate the noise level of the multi-station incoherent scatter radar based on the noise parameter, in combination with the received power and the noise power.

[0007] In some preferred embodiments, the transmit beam covariance and receive beam covariance of the incoherent scatter radar are determined based on the beam equivalent method, and the method is as follows: When the beam points to the zenith direction, the beam shape is an axisymmetric Gaussian shape. The standard deviation of the corresponding transmit beam and the standard deviation of the corresponding receive beam are obtained according to the beam parameters of the beam equivalent method, and then the transmit beam covariance and the receive beam covariance are obtained.

[0008] In some preferred embodiments, the three-dimensional scattering volume integral is obtained by: According to the properties of Gaussian distribution, the three-dimensional scattering volume integral is obtained by integrating the scattering volume covariance of the N-dimensional Gaussian distribution : ; in, represents the scattering volume covariance matrix.

[0009] In some preferred embodiments, the received power of the multi-station incoherent scatter radar is determined by: Determining the received power of a multi-station phased array incoherent scattering radar based on three-dimensional scattering volume integration for: ; in, P t is the radar transmitting peak power, N e is the electron density, is the single electron scattering cross section, β is the angle between the transmitted beam and the scattered wave vector, is the wavelength, I T represents the integral of the transmit beam, I R represents the integral of the receive beam.

[0010] In some preferred embodiments, the noise power of a multi-station incoherent scatter radar is determined for: ; in, is the Boltzmann constant, is the system noise temperature, B is the signal bandwidth, is the signal sampling interval.

[0011] In some preferred implementations, the delay number is calculated as follows: In the calculation of multi-station incoherent scattering, the signal is a random signal. Therefore, the delay length is determined according to the transmitted pulse, and combined with the interval, the delay number is obtained. : ; in, For a sampling cycle time, the instant extension degree, is the signal sampling interval.

[0012] In some preferred embodiments, the noise level of a multi-station incoherent scatter radar is calculated by: In multi-station incoherent scatter calculations, the noise level Related to the measurement variance, the noise level is: ; Where A is the maximum value of the zero-delay autocorrelation function, is the measurement variance; When the delay length is fixed, the variance is measured Estimated variance of the autocorrelation function at zero delay Half: ; In the multi-station incoherent scattering calculation, the zero-delay estimation variance of the autocorrelation function is: ; in, is the number of incoherent accumulations, Indicates the signal-to-noise ratio: ; Combining the above formulas, we can get the noise level of the incoherent scattering radar. for: .

[0013] A second aspect of the present invention provides a multi-station phased array incoherent scattering radar noise level calculation system, the system comprising: The scattering volume calculation module is configured to determine the transmit beam covariance and the receive beam covariance of the multi-station incoherent scattering radar based on the beam equivalent method, and then obtain the beam cross covariance between the transmit beam and each receive beam; determine the distance parameter of the beam, and then obtain the distance distribution covariance between the transmit beam and each receive beam; determine the scattering volume covariance of the intersection of the transmit beam and each receive beam based on the beam cross covariance and the distance distribution covariance; A power calculation module is configured to obtain a three-dimensional scattering volume integral based on the scattering volume covariance according to the Gaussian distribution property, and then determine the received power and noise power of the multi-station incoherent scattering radar; The noise level calculation module is configured to determine noise parameters, wherein the noise parameters include a delay length and a corresponding delay number, and a non-coherent accumulation number; based on the noise parameters, combined with the received power and the noise power, the noise level of the multi-station incoherent scattering radar is calculated.

[0014] The third aspect of the present invention provides a noise level calculation device for a multi-station phased array incoherent scattering radar, comprising: at least one processor; and a memory communicatively connected to at least one of the processors; wherein, The memory stores instructions that can be executed by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned method for calculating the noise level of a multi-station phased array incoherent scattering radar.

[0015] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above-mentioned method for calculating the noise level of a multi-station phased array incoherent scattering radar.

[0016] Beneficial effects of the present invention: The noise level calculation method of the present invention can quantitatively calculate the noise level of a multi-station phased array incoherent scattering radar; through the unique method of beam equivalence, it effectively overcomes the key difficulty that the gain of the phased array antenna changes in real time with the azimuth and elevation angles and is difficult to express with a detailed formula; and uses the covariance form to accurately express the scattering volume expression obtained by beam crossing, and describes the change of the beam antenna gain to the greatest extent in a concise form; In the process of calculating the noise level, all aspects of data processing are comprehensively considered, including the number of accumulations, delays, etc., which significantly improves the accuracy and reliability of noise level calculation and realizes the precise calculation and spatial distribution analysis of noise levels, an important parameter in radar signal and data processing; The use of phased array scanning technology combined with multi-station technology can achieve multi-beam synchronous detection and provide full space coverage instantly. It can perform three-dimensional imaging of ion drift velocity vectors across the entire sky in a short period of time, greatly expanding the spatial range and time efficiency of detection. It helps to optimize radar detection schemes and improve radar detection performance, and has important application value and academic significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 It is a flow chart of a method for calculating noise level of a multi-station phased array incoherent scattering radar according to the present invention; Figure 2 ] are the noise levels at different heights of the transmitting station Sanya and the receiving station Fuke in the embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] In view of the difficulty in the prior art that the gain of the phased array antenna changes in real time with the azimuth and elevation angle, it is impossible to use a detailed formula to represent the noise level of the multi-station phased array incoherent scattering radar. The first embodiment of the present invention establishes a method for calculating the incoherent scattering noise level of a multi-station phased array. From the perspective of beam width, the covariance matrix method is used to solve important parameters such as the scattering volume and noise level. At the same time, this method takes into account the corresponding incoherent accumulation times when calculating the autocorrelation function in the incoherent scattering radar, and the scattering volume range can be set according to the actual situation. It can quantitatively calculate the noise level of the multi-station phased array incoherent scattering radar. Figure 1 As shown, the details are as follows: S1. Determination of transmit beam covariance of multi-station incoherent scattering radar based on beam equivalence method and receive beam covariance , and then get the beam cross covariance between the transmit beam and each receive beam ; The method is: ; in, is the transmit beam covariance, is the receive beam covariance, is the beam cross covariance.

[0021] This application calculates the noise level from the perspective of covariance: When the beam points to the zenith, according to antenna theory, the beam shape is an axisymmetric Gaussian shape. The beam width and the standard deviation of the Gaussian distribution have a proportional conversion relationship. According to the beam parameters of the beam equivalent method, the standard deviation of the corresponding transmit beam and the standard deviation of the corresponding receive beam are obtained, and then the transmit beam covariance and the receive beam covariance are obtained. Through the transmit beam and the receive beam represented by the covariance, the covariance result of the cross of the transmit beam and the receive beam can be obtained.

[0022] S2. Determine the distance parameter of the beam, and then obtain the distance distribution covariance between the transmitting beam and each receiving beam .

[0023] S3, based on the beam cross covariance and the distance distribution covariance Determine the scattering volume covariance of the transmit beam and each receive beam intersection , the method is: .

[0024] Since the calculation of the scattering volume requires not only the angle parameter of the beam but also the distance parameter of the beam, the covariance of the scattering volume where two beams intersect can be obtained through the covariance of the distance distribution and the covariance of the beam intersection.

[0025] Furthermore, in order to obtain the received power of multiple phased array stations, it is necessary to solve the antenna gain integral.

[0026] S4. According to the Gaussian distribution property, a three-dimensional scattering volume integral is obtained based on the scattering volume covariance, wherein the method is: According to the properties of Gaussian distribution, the scattering volume covariance of the three-dimensional Gaussian distribution , and obtain the three-dimensional scattering volume integral : ; By establishing a scattering volume calculation formula for multi-station phased array beam crossing, the scattered echo signal can be quantitatively calculated.

[0027] S5. Determine the received power and noise power of the multi-station incoherent scattering radar based on the three-dimensional scattering volume integral, wherein the method is as follows: Based on the three-dimensional scattering volume integration , determine the received power of a multi-station phased array incoherent scatter radar for: ; in, P t is the radar transmitting peak power, N eis the electron density, is the single electron scattering cross section, β is the angle between the transmitted beam and the scattered wave vector, is the wavelength, I T represents the integral of the transmit beam, I R represents the integral of the receive beam; Determining the Noise Power of an Incoherent Scatter Radar for: ; in, is the Boltzmann constant, is the system noise temperature, is the signal bandwidth, is the signal sampling interval.

[0028] In the calculation of multi-station incoherent scattering, due to the complexity of the processing method, it is not enough to simply calculate the ratio of received power to noise power to evaluate the noise level. It is necessary to further consider parameters such as the number of accumulation times and the number of delays.

[0029] S6. Determine noise parameters, where the noise parameters include a delay length and a corresponding delay number, and a non-coherent accumulation number.

[0030] In incoherent scattering calculations, the signal is a random signal. The signal is mainly analyzed through different time delays. Different time delays are unrelated, and different time delays have the same variance. In the analysis process, the time delay length needs to be determined, which can be determined based on the transmitted pulse. is the corresponding time delay number; different time delays usually need to be considered in calculating the autocorrelation function, such as the first time delay, the second time delay, etc.

[0031] Preferably, the duration is calculated as follows: In the calculation of multi-station incoherent scattering, the signal is a random signal. Therefore, the delay length is determined according to the transmitted pulse, and combined with the interval, the delay number is obtained. : ; in, For a sampling cycle time, the instant extension degree, is the signal sampling interval.

[0032] S7. Calculate the noise level of the multi-station incoherent scatter radar based on the noise parameter, in combination with the received power and the noise power.

[0033] In the multi-station incoherent scattering calculation, the maximum value of the autocorrelation function at zero time delay is proportional to the total scattered power of the plasma, so the noise level γ(square root of the average relative variance per unit time delay) is: ; Where A is the maximum value of the zero-delay autocorrelation function, is the actual measurement variance.

[0034] In order to obtain the same variance matrix under different delays, the variance matrix can be expressed as the sum of n items. According to continuity, these items are approximately equal, so the sum is N times that of a single item. Therefore, one item can be replaced by the sum of multiple items and their average value can be taken.

[0035] Therefore, in a specific experiment (i.e., when the delay is fixed), this constant (the actual measurement variance) can be regarded as the zero-delay estimated variance of the autocorrelation function: Half: ; For the zero-delay estimated variance of the autocorrelation function, the signal-to-noise ratio can be expressed as: ; in, is the number of incoherent accumulations, Indicates the signal-to-noise ratio: ; Combining the above formulas, the noise level of a receiving station radar under multi-station incoherent scattering is calculated as: .

[0036] When calculating the noise level of a multi-station incoherent scattering radar, the corresponding number of incoherent accumulations is taken into account when calculating the autocorrelation function, and the scattering volume range can be set according to actual conditions. Through the noise level calculation method of a multi-station incoherent scattering radar, the calculation and spatial distribution analysis of the noise level of important parameters in radar signal and data processing are realized, providing a theoretical basis for radar experimental mode detection.

[0037] According to the above method, no matter it is a three-receiver, four-receiver or other multi-receiver incoherent scattering radar, the noise level of any station can be solved.

[0038] Preferably, in this embodiment, certain data during the operation of Hainan three-station high-power phased array incoherent scattering radar is calculated according to the noise level calculation method of the above-mentioned multi-station incoherent scattering radar, and the noise levels of single station and dual station are plotted according to the calculation results.

[0039] Among them, the single station receiving station is Sanya Station, and the double station receiving station is represented by Fu Ke Station. The results of plotting the noise level of the single station and the double station are as follows Figure 2As shown, it can be seen from the figure that the noise level of Sanya station's self-transmission and self-reception presents a concentric circle distribution. When Sanya station transmits and Fu Ke station receives, it presents an oval structure at 100km, and gradually changes to a concentric circle distribution with increasing altitude. It can be seen from the figure that the noise level of the dual stations within the range of 100km, 300km, and 500km is higher than the noise level of a single station. The main reason is that the receiving station has a small number of antenna units on the array, so the receiving gain is low. In order to achieve data quality similar to that of the transmitting station, the receiving station needs to accumulate more times to reduce the noise level.

[0040] Although the various steps in the above embodiment are described in the above-mentioned order, those skilled in the art can understand that in order to achieve the effect of this embodiment, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple changes are within the scope of protection of the present invention.

[0041] A multi-station phased array incoherent scattering radar noise level calculation system according to a second embodiment of the present invention comprises: The scattering volume calculation module is configured to determine the transmit beam covariance and the receive beam covariance of the multi-station incoherent scattering radar based on the beam equivalent method, and then obtain the beam cross covariance between the transmit beam and each receive beam; determine the distance parameter of the beam, and then obtain the distance distribution covariance between the transmit beam and each receive beam; determine the scattering volume covariance of the intersection of the transmit beam and each receive beam based on the beam cross covariance and the distance distribution covariance; A power calculation module is configured to obtain a three-dimensional scattering volume integral based on the scattering volume covariance according to the Gaussian distribution property, and then determine the received power and noise power of the multi-station incoherent scattering radar; The noise level calculation module is configured to determine noise parameters, wherein the noise parameters include the autocorrelation function noise level, the power profile estimation variance, the delay length and the corresponding number of delays, the number of incoherent accumulations and the number of range gates; based on the noise parameters, combined with the received power and the noise power, the noise level of the multi-station incoherent scattering radar is calculated.

[0042] It should be noted that the above embodiment provides a multi-station phased array incoherent scattering radar noise level calculation system, which is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided 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 the modules or steps, and are not regarded as improper limitations of the present invention.

[0043] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0044] A noise level calculation device for a multi-station phased array incoherent scattering radar according to a third embodiment of the present invention includes: at least one processor; and a memory communicatively connected to at least one of the processors; wherein, The memory stores instructions that can be executed by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned multi-station phased array incoherent scattering radar noise level calculation method.

[0045] A computer-readable storage medium according to a fourth embodiment of the present invention stores computer instructions, and the computer instructions are used to be executed by a computer to implement the above-mentioned method for calculating the noise level of a multi-station phased array incoherent scattering radar.

[0046] Technicians in the relevant technical field can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the electronic device and computer-readable storage medium described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0047] Those skilled in the art should be able to appreciate that the modules and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented with 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), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the technical field. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0048] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0049] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0050] The terms "first", "second", etc. are used to distinguish similar objects rather than to describe or indicate a particular order or sequence.

[0051] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0052] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to 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

1. A method for calculating noise level of multi-station phased array incoherent scattering radar, characterized in that: The method comprises the following steps: S1. Determine the transmit beam covariance and receive beam covariance of the multi-station incoherent scattering radar based on the beam equivalent method, and then obtain the beam cross covariance of the transmit beam and each receive beam; S2. Determine the distance parameter of the beam, and then obtain the distance distribution covariance between the transmit beam and each receive beam; S3, determining the scattering volume covariance of the intersection of the transmit beam and each receive beam based on the beam cross covariance and the distance distribution covariance; S4. Obtaining a three-dimensional scattering volume integral based on the scattering volume covariance according to Gaussian distribution properties; S5. Determine the received power and noise power of the multi-station incoherent scattering radar based on the three-dimensional scattering volume integral; S6. Determine noise parameters, wherein the noise parameters include a delay length and a corresponding delay number, and a non-coherent accumulation number; S7. Calculate the noise level of the multi-station incoherent scatter radar based on the noise parameter, in combination with the received power and the noise power.

2. The method for calculating noise level of multi-station phased array incoherent scattering radar according to claim 1, characterized in that: The transmit beam covariance and receive beam covariance of the incoherent scattering radar are determined based on the beam equivalent method. The method is as follows: When the beam points to the zenith direction, the beam shape is an axisymmetric Gaussian shape. The standard deviation of the corresponding transmit beam and the standard deviation of the corresponding receive beam are obtained according to the beam parameters of the beam equivalent method, and then the transmit beam covariance and the receive beam covariance are obtained.

3. The method for calculating noise level of multi-station phased array incoherent scattering radar according to claim 2, characterized in that: The three-dimensional scattering volume integral is obtained as follows: According to the properties of Gaussian distribution, the three-dimensional scattering volume integral is obtained from the scattering volume covariance of the three-dimensional Gaussian distribution : ； in, represents the scattering volume covariance matrix.

4. The method for calculating noise level of multi-station phased array incoherent scattering radar according to claim 3, characterized in that: The received power of a multi-station incoherent scatter radar is determined as follows: Determining the received power of a multi-station phased array incoherent scattering radar based on three-dimensional scattering volume integration for: ； in, P t is the radar transmitting peak power, N e is the electron density, is the single electron scattering cross section, β is the angle between the transmitted beam and the scattered wave vector, is the wavelength, I T represents the integral of the transmit beam, I R represents the integral of the receive beam.

5. The method for calculating noise level of multi-station phased array incoherent scattering radar according to claim 4, characterized in that: Determining the noise power of a multistatic incoherent scatter radar for: ； in, is the Boltzmann constant, is the system noise temperature, B is the signal bandwidth, is the signal sampling interval.

6. The method for calculating noise level of a multi-station phased array incoherent scattering radar according to any one of claims 1 to 5, characterized in that: The delay number is calculated as follows: In the calculation of multi-station incoherent scattering, the signal is a random signal. Therefore, the delay length is determined according to the transmitted pulse, and combined with the interval, the delay number is obtained. : ； in, For a sampling cycle time, the instant extension degree, is the signal sampling interval.

7. The method for calculating noise level of multi-station phased array incoherent scattering radar according to claim 6, characterized in that: The noise level of a multi-station incoherent scatter radar is calculated as follows: In multi-station incoherent scatter calculations, the noise level Related to the measurement variance, the noise level is: ； Where A is the maximum value of the zero-delay autocorrelation function, is the measurement variance; When the delay is fixed, the measurement variance is the zero-delay estimate variance of the autocorrelation function Half: ； In the multi-station incoherent scattering calculation, the zero-delay estimation variance of the autocorrelation function is: ； in, is the number of incoherent accumulations, Indicates the signal-to-noise ratio: ； Combining the above formulas, we can get the noise level of the incoherent scattering radar. for: 。 8. A multi-station phased array incoherent scatter radar noise level calculation system, according to the multi-station phased array incoherent scatter radar noise level calculation method according to any one of claims 1 to 7, characterized in that: The system comprises: The scattering volume calculation module is configured to determine the transmit beam covariance and the receive beam covariance of the multi-station incoherent scattering radar based on the beam equivalent method, and then obtain the beam cross covariance between the transmit beam and each receive beam; determine the distance parameter of the beam, and then obtain the distance distribution covariance between the transmit beam and each receive beam; determine the scattering volume covariance of the intersection of the transmit beam and each receive beam based on the beam cross covariance and the distance distribution covariance; A power calculation module is configured to obtain a three-dimensional scattering volume integral based on the scattering volume covariance according to the Gaussian distribution property, and then determine the received power and noise power of the multi-station incoherent scattering radar; The noise level calculation module is configured to determine noise parameters, wherein the noise parameters include a delay length and a corresponding delay number, and a non-coherent accumulation number; based on the noise parameters, combined with the received power and the noise power, the noise level of the multi-station incoherent scattering radar is calculated.

9. A noise level calculation device for a multi-station phased array incoherent scattering radar, characterized in that: include: at least one processor; as well as a memory communicatively connected to at least one of the processors; wherein, The memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement the method for calculating the noise level of a multi-station phased array incoherent scattering radar according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the multi-station phased array incoherent scattering radar noise level calculation method according to any one of claims 1 to 7.

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