A near-field beamforming method for spatial ultra-sparse arrays

Abstract

The present invention discloses a method for near-field beam synthesis of a space ultra-sparse array, which includes: constructing a space near-field model of a ground receiver and a space ultra-sparse array subarray; modeling the space ultra-sparse array signal received by the ground receiver to obtain the ground receiver receiving signal; processing the parameter information between the ground receiver and the space ultra-sparse array subarray to obtain the propagation time delay-related phase shift of the ground receiver; processing the ground receiver receiving signal and the propagation time delay-related phase shift of the ground receiver to obtain the receiving signal of the distributed star cluster equivalent subarray; using the near-field three-dimensional matching model to perform beam domain coherent synthesis on the receiving signal of the distributed star cluster equivalent subarray to obtain the space ultra-sparse array near-field beam. The method of the present invention can perform near-field beam synthesis on the space ultra-sparse array signal at the receiver end to enhance the energy intensity of the space ultra-sparse array receiving signal.

Description

Technical Field

[0001] The invention relates to the technical field of satellite communications, and in particular to a spatial ultra-sparse array near-field beamforming method. Background Art

[0002] The principle of distributed antenna array is to install multiple sub-array units with smaller apertures at multiple locations or platforms, and to weight and synthesize the signals of each antenna by achieving signal coherence and utilizing the irrelevance of noise, so as to increase the actual aperture and thus improve the antenna gain. Traditional signal source location algorithms usually assume that the signal source is located in the far field area of ​​the array. When the target is in the far field area of ​​the array, it can be considered that the received signal is a plane wavefront when it arrives at the array, which is only related to the arrival direction. However, due to the distributed sparse node distribution of the distributed constellation, the near field range becomes larger, and when the target is in the near field area of ​​the array, the received signal is a spherical wavefront when it arrives at the array, which is not only related to the arrival direction, but also to the distance between the target and the center of the array. The wavefront of the far-field radiation source is only related to the arrival direction and presents a linear characteristic; while the wavefront of the near-field radiation source is not only related to the arrival direction, but also depends on the distance, and presents a nonlinear characteristic. Therefore, the parameter estimation and beamforming processing of the near field are more complicated than those of the far-field source. The near field needs to estimate the angle and distance of the source at the same time. Summary of the invention

[0003] The technical problem to be solved by the present invention is that, in view of the problem that the angle and distance of the source need to be estimated at the same time in the near field, the present invention proposes a spatial ultra-sparse array near-field beam synthesis method, which models the spatial near-field model of the ground receiver and the spatial ultra-sparse array subarray; mathematically models the spatial ultra-sparse array signal received by the ground receiver; calculates the phase shift associated with the propagation time delay of the ground receiver between a certain spatial ultra-sparse array subarray and the phase reference subarray; calculates the received signal matrix expression of the entire distributed constellation equivalent subarray; finally, uses the near-field three-dimensional matching method to perform beam domain coherent synthesis to achieve energy enhancement and complete the spatial ultra-sparse array near-field beam synthesis. The method of the present invention can perform near-field beam synthesis on the spatial ultra-sparse array signal at the receiver end to enhance the energy intensity of the spatial ultra-sparse array received signal.

[0004] In order to solve the above technical problems, the first aspect of the embodiments of the present invention discloses a spatial ultra-sparse array near-field beamforming method, the method comprising:

[0005] S1, construct the spatial near-field model of the ground receiver and the spatial ultra-sparse array subarray;

[0006] S2, using the spatial near-field model, modeling the spatial ultra-sparse array signal received by the ground receiver to obtain a signal received by the ground receiver;

[0007] S3, obtaining parameter information between the ground receiver and the spatial ultra-sparse array subarray;

[0008] S4, processing parameter information between the ground receiver and the spatial ultra-sparse array subarray to obtain a propagation time delay-related phase shift of the ground receiver;

[0009] S5, processing the received signal of the ground receiver and the phase shift associated with the propagation time delay of the ground receiver to obtain a received signal of an equivalent sub-array of a distributed constellation;

[0010] S6, using a near-field three-dimensional matching model, performing beam-domain coherent synthesis on the received signals of the distributed constellation equivalent sub-array to obtain a spatial ultra-sparse array near-field beam.

[0011] As an optional implementation manner, in the first aspect of the embodiment of the present invention, the space near-field model includes a ground receiver and a distributed constellation;

[0012] The ground receiver is located in the near field region of the spatial ultra-sparse array;

[0013] The distributed star cluster includes K distributed satellites, where K is a positive integer; the distributed star cluster constitutes a large subarray in the space super-sparse array, each distributed satellite constitutes an independent phased array antenna element in the space super-sparse array, and each independent phased array antenna element simultaneously generates a signal to be transmitted to the ground receiver;

[0014] A distributed satellite is selected from the K distributed satellites as the phase reference subarray of the spatial ultra-sparse array, which is numbered as S0, and the other K-1 subarrays of the spatial ultra-sparse array are numbered S1, S2, ..., S K-1 .

[0015] As an optional implementation manner, in the first aspect of the embodiment of the present invention, the ground receiver receives the signal expression as follows:

[0016]

[0017] where x k (t) is the spatial ultra-sparse array S received by the ground receiver at time t k The received signal of the subarray, s k (t) is the spatial super sparse array at time t. k Signal envelope of the subarray, n k (t) represents the spatial ultra-sparse array S received by the receiver at time t k Subarray noise, τ k represents the ground receiver in the space super sparse array S kThe phase shift related to the propagation time delay between the subarray and the phase reference subarray S0, e represents the exponential signal, j is the imaginary unit, j 2 =-1, k = 0, 1,…, K-1.

[0018] As an optional implementation manner, in the first aspect of the embodiment of the present invention, the processing of parameter information between the ground receiver and the spatial ultra-sparse array subarray to obtain the propagation time delay-related phase shift of the ground receiver includes:

[0019] S31, using a propagation time delay related phase shift model, processing parameter information between a ground receiver and a spatial ultra-sparse array subarray to obtain a first related phase shift of the ground receiver;

[0020] The propagation time delay-related phase shift model is:

[0021]

[0022] Among them, τ′ k is the first relevant phase shift of the ground receiver, λ represents the wavelength of the propagated signal, r0, θ, d k and is the parameter information between the ground receiver and the spatial ultra-sparse array subarray, r0 represents the straight-line distance between the ground receiver and the phase reference subarray S0, d k Indicates the S k The straight-line distance between the subarray and the phase reference subarray S0, θ represents the elevation angle from the flat antenna array of the ground receiver to the phase reference subarray S0, Indicates the S k The elevation angle of the subarray relative to the flat antenna array of the phase reference subarray S0 to the phase reference subarray S0;

[0023] S32, optimizing the first related phase shift of the ground receiver by using a phase shift optimization model to obtain a propagation time delay related phase shift of the ground receiver;

[0024] The phase shift optimization model is:

[0025]

[0026] where τ k is the propagation time delay associated phase shift at the ground receiver, τ k Yes In Taylor series expansion is performed at the zero point, and the result obtained by Fresnel approximation is that the propagation time delay-related phase shift of the ground receiver is kThe phase shift related to the propagation time delay between the subarray and the reference subarray S0.

[0027] As an optional implementation manner, in the first aspect of the embodiment of the present invention, the received signal of the distributed constellation equivalent sub-array is:

[0028] X(t)=AS(t)+N(t)

[0029] Where X(t) is the signal vector received by the ground receiver, X(t) = [x0(t) x1(t) … x K-1 (t)] T ,

[0030] where x k (t), k = 0, 1, ..., K-1 is the spatial ultra-sparse array S received by the ground receiver at time t k The received signal of the subarray, N(t) represents the noise vector, N(t) = [n0(t) n1(t) … n K-1 (t)] T , n k (t) represents the spatial ultra-sparse array S received by the receiver at time t k Subarray noise, A represents the steering vector of the near-field source, is the kth component in A, τ k represents the ground receiver in the space super sparse array S k The phase shift related to the propagation time delay between the subarray and the phase reference subarray S0, e represents the exponential signal, j is the imaginary unit, j 2 =-1, r0 represents the straight-line distance between the ground receiver and the phase reference subarray S0, θ represents the elevation angle from the flat antenna array of the ground receiver to the phase reference subarray S0, Indicates the S k The elevation angle of the flat antenna array of the subarray relative to the phase reference subarray S0 to the phase reference subarray S0, T represents the transposition.

[0031] As an optional implementation manner, in the first aspect of the embodiment of the present invention, the use of the near-field three-dimensional matching model to perform beam-domain coherent synthesis on the received signals of the distributed constellation equivalent sub-array to obtain a spatial ultra-sparse array near-field beam includes:

[0032] S61, using a near-field three-dimensional matching model, matching and phase-modulating the received signal of the distributed constellation equivalent sub-array to obtain a phase-modulated signal;

[0033] The near-field three-dimensional matching model is:

[0034] Y(t)=BX(t)+N(t)

[0035] Among them, Y(t) is the phase modulation signal, X(t) is the receiving signal of the equivalent sub-array of the distributed constellation, and B represents the phase modulation vector of the ground receiver. τ k represents the ground receiver in the space super sparse array S k The phase shift associated with the propagation time delay between the subarray and the phase reference subarray S0, k = 0, 1, ..., K-1, e represents the exponential signal, j is the imaginary unit, j 2 =-1, T means transpose;

[0036] S62, performing in-phase superposition synthesis on the phase modulation signal to obtain a spatial ultra-sparse array near-field beam.

[0037] The second aspect of the present invention discloses a computer-storable medium, which stores computer instructions. When the computer instructions are called, they are used to execute some or all of the steps in the spatial ultra-sparse array near-field beamforming method disclosed in the first aspect of an embodiment of the present invention.

[0038] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0039] (1) The present invention synthesizes the near-field beam of the spatial ultra-sparse array, which can fully enhance the received signal strength of the spatial ultra-sparse array;

[0040] (2) The present invention utilizes the three-dimensional information of the spatial ultra-sparse array to accurately align the phase differences of different array elements of the spatial ultra-sparse array. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 It is a flowchart of a spatial ultra-sparse array near-field beamforming method disclosed in an embodiment of the present invention;

[0043] Figure 2 It is a flowchart of another spatial ultra-sparse array near-field beamforming method disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or equipment.

[0046] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0047] The present invention discloses a method for near-field beam synthesis of a space ultra-sparse array, which includes: constructing a space near-field model of a ground receiver and a space ultra-sparse array subarray; using the space near-field model, modeling the space ultra-sparse array signal received by the ground receiver to obtain the ground receiver receiving signal; obtaining parameter information between the ground receiver and the space ultra-sparse array subarray; processing the parameter information between the ground receiver and the space ultra-sparse array subarray to obtain the propagation time delay-related phase shift of the ground receiver; processing the ground receiver receiving signal and the propagation time delay-related phase shift of the ground receiver to obtain the receiving signal of the distributed star cluster equivalent subarray; using the near-field three-dimensional matching model, performing beam domain coherent synthesis on the receiving signal of the distributed star cluster equivalent subarray to obtain the space ultra-sparse array near-field beam. The method of the present invention can perform near-field beam synthesis on the space ultra-sparse array signal at the receiver end to enhance the energy intensity of the space ultra-sparse array receiving signal. The following are detailed descriptions.

[0048] Embodiment 1

[0049] See also Figure 1 , Figure 11 is a flow chart of a spatial ultra-sparse array near-field beamforming method disclosed in an embodiment of the present invention. Figure 1 The described spatial ultra-sparse array near-field beamforming method is applied to the field of satellite communications to solve the problem of low received energy caused by the different phases of the array element signals received by the spatial ultra-sparse array at the receiving end, which is not limited in the embodiments of the present invention. Figure 1 As shown, the spatial ultra-sparse array near-field beamforming method may include the following operations:

[0050] S1, construct the spatial near-field model of the ground receiver and the spatial ultra-sparse array subarray;

[0051] S2, using the spatial near-field model, modeling the spatial ultra-sparse array signal received by the ground receiver to obtain a signal received by the ground receiver;

[0052] S3, obtaining parameter information between the ground receiver and the spatial ultra-sparse array subarray;

[0053] S4, processing parameter information between the ground receiver and the spatial ultra-sparse array subarray to obtain a propagation time delay-related phase shift of the ground receiver;

[0054] S5, processing the received signal of the ground receiver and the phase shift associated with the propagation time delay of the ground receiver to obtain a received signal of an equivalent sub-array of a distributed constellation;

[0055] S6, using a near-field three-dimensional matching model, performing beam-domain coherent synthesis on the received signals of the distributed constellation equivalent sub-array to obtain a spatial ultra-sparse array near-field beam.

[0056] Optionally, the spatial near-field model includes ground receivers and a distributed constellation;

[0057] The ground receiver is located in the near field region of the spatial ultra-sparse array;

[0058] The distributed star cluster includes K distributed satellites, where K is a positive integer; the distributed star cluster constitutes a large subarray in the space super-sparse array, each distributed satellite constitutes an independent phased array antenna element in the space super-sparse array, and each independent phased array antenna element simultaneously generates a signal to be transmitted to the ground receiver;

[0059] A distributed satellite is selected from the K distributed satellites as the phase reference subarray of the spatial ultra-sparse array, which is numbered as S0, and the other K-1 subarrays of the spatial ultra-sparse array are numbered S1, S2, ..., S K-1 .

[0060] Optionally, the signal received by the ground receiver is expressed as:

[0061]

[0062] where x k (t) is the spatial ultra-sparse array S received by the ground receiver at time t k The received signal of the subarray, s k (t) is the spatial super sparse array at time t. k Signal envelope of the subarray, n k (t) represents the spatial ultra-sparse array S received by the receiver at time t k Subarray noise, τ k represents the ground receiver in the space super sparse array S k The phase shift related to the propagation time delay between the subarray and the phase reference subarray S0, e represents the exponential signal, j is the imaginary unit, j 2 =-1, k = 0, 1,…, K-1.

[0063] Optionally, the processing of parameter information between the ground receiver and the spatial ultra-sparse array subarray to obtain a propagation time delay-related phase shift of the ground receiver includes:

[0064] S31, using a propagation time delay related phase shift model, processing parameter information between a ground receiver and a spatial ultra-sparse array subarray to obtain a first related phase shift of the ground receiver;

[0065] The propagation time delay-related phase shift model is:

[0066]

[0067] Among them, τ′ k is the first relevant phase shift of the ground receiver, λ represents the wavelength of the propagated signal, r0, θ, d k and is the parameter information between the ground receiver and the spatial ultra-sparse array subarray, r0 represents the straight-line distance between the ground receiver and the phase reference subarray S0, d k Indicates the S k The straight-line distance between the subarray and the phase reference subarray S0, θ represents the elevation angle from the flat antenna array of the ground receiver to the phase reference subarray S0, Indicates the S k The elevation angle of the subarray relative to the flat antenna array of the phase reference subarray S0 to the phase reference subarray S0;

[0068] S32, optimizing the first related phase shift of the ground receiver by using a phase shift optimization model to obtain a propagation time delay related phase shift of the ground receiver;

[0069] The phase shift optimization model is:

[0070]

[0071] where τ k is the propagation time delay associated phase shift at the ground receiver, τ k Yes In Taylor series expansion is performed at the zero point, and the result obtained by Fresnel approximation is that the propagation time delay-related phase shift of the ground receiver is k The phase shift related to the propagation time delay between the subarray and the reference subarray S0.

[0072] Optionally, the received signal of the distributed constellation equivalent sub-array is:

[0073] X(t)=AS(t)+N(t)

[0074] Where X(t) is the signal vector received by the ground receiver, X(t) = [x0(t) x1(t) … x K-1 (t)] T , where x k (t), k = 0, 1, ..., K-1 is the spatial ultra-sparse array S received by the ground receiver at time t k The received signal of the subarray, N(t) represents the noise vector, N(t) = [n0(t) n1(t) … n K-1 (t)] T , n k (t) represents the spatial ultra-sparse array S received by the receiver at time t k Subarray noise, A represents the steering vector of the near-field source, is the kth component in A, τ k represents the ground receiver in the space super sparse array S k The phase shift related to the propagation time delay between the subarray and the phase reference subarray S0, e represents the exponential signal, j is the imaginary unit, j 2 =-1, r0 represents the straight-line distance between the ground receiver and the phase reference subarray S0, θ represents the elevation angle from the flat antenna array of the ground receiver to the phase reference subarray S0, Indicates the S k The elevation angle of the flat antenna array of the subarray relative to the phase reference subarray S0 to the phase reference subarray S0, T represents the transposition.

[0075] Optionally, the using of the near-field three-dimensional matching model to perform beam-domain coherent synthesis on the received signals of the distributed constellation equivalent sub-array to obtain a spatial ultra-sparse array near-field beam comprises:

[0076] S61, using a near-field three-dimensional matching model, matching and phase-modulating the received signal of the distributed constellation equivalent sub-array to obtain a phase-modulated signal;

[0077] The near-field three-dimensional matching model is:

[0078] Y(t)=BX(t)+N(t)

[0079] Among them, Y(t) is the phase modulation signal, X(t) is the receiving signal of the equivalent sub-array of the distributed constellation, and B represents the phase modulation vector of the ground receiver. τ k represents the ground receiver in the space super sparse array S k The phase shift associated with the propagation time delay between the subarray and the phase reference subarray S0, k = 0, 1, ..., K-1, e represents the exponential signal, j is the imaginary unit, j 2 =-1, T means transpose;

[0080] S62, performing in-phase superposition synthesis on the phase modulation signal to obtain a spatial ultra-sparse array near-field beam.

[0081] It can be seen that the present invention synthesizes the near-field beam of the spatial ultra-sparse array, which can fully enhance the received signal strength of the spatial ultra-sparse array; the present invention utilizes the three-dimensional information of the spatial ultra-sparse array to accurately align the phase difference of different array elements of the spatial ultra-sparse array.

[0082] Embodiment 2

[0083] See also Figure 2 , Figure 2 1 is a flow chart of another spatial ultra-sparse array near-field beamforming method disclosed in an embodiment of the present invention. Figure 2 The described spatial ultra-sparse array near-field beamforming method is applied to the field of satellite communications to solve the problem of low received energy caused by the different phases of the array element signals received by the spatial ultra-sparse array at the receiving end, which is not limited in the embodiments of the present invention. Figure 2 As shown, the spatial ultra-sparse array near-field beamforming method may include the following operations:

[0084] Step 1, modeling the spatial near-field model of the ground receiver and the spatial ultra-sparse array subarray;

[0085] The space ultra-sparse array refers to treating the entire distributed star cluster as a large sub-array. Each satellite in the distributed star cluster is an independent phased array antenna element. Each satellite uses a flat array antenna and ensures that the flat array antenna array surface is parallel to the horizontal plane of the sub-satellite point. The space near field refers to the near field area of ​​the space ultra-sparse array. Considering that the space ultra-sparse array has K distributed satellites, each satellite is an independent phased array antenna element. Each element simultaneously generates a signal and transmits it to the ground receiver. The ground receiver is located in the near field area of ​​the space ultra-sparse array. A distributed satellite is selected as the phase reference sub-array of the space ultra-sparse array and is numbered as S0. The other sub-arrays of the space ultra-sparse array are numbered S1, S2, ..., S K-1 ;

[0086] Step 2, mathematically modeling the spatial ultra-sparse array signal received by the ground receiver;

[0087] The spatial ultra-sparse array S received by the ground receiver k The received signal model of the subarray is as follows

[0088]

[0089] Among them, s k (t) represents the spatial super sparse array S k Signal envelope of the subarray, n k (t) represents the spatial ultra-sparse array S received by the receiver at time t k Subarray noise, τ k represents the ground receiver in the space super sparse array S k The phase shift associated with the propagation time delay between the subarray and the phase reference subarray S0;

[0090] Step 3, calculating the phase shift associated with the propagation time delay between a certain spatial ultra-sparse array subarray and a reference subarray at a ground receiver;

[0091] Ground receiver in space ultra-sparse array S k The phase shift associated with the propagation time delay between the subarray and the phase reference subarray S0

[0092]

[0093] Where λ represents the wavelength of the propagated signal, r0 represents the straight-line distance between the ground receiver and the phase reference subarray S0, and d k Indicates the S k The straight-line distance between the subarray and the phase reference subarray S0, θ represents the elevation angle from the flat antenna array of the ground receiver to the phase reference subarray S0, Indicates the S kThe elevation angle of the flat antenna array of the subarray relative to the phase reference subarray S0 to the phase reference subarray S0 is further expressed as

[0094]

[0095] Since the ground receiver is located in the near field area of ​​the space ultra-sparse array, the above formula is Perform Taylor series expansion at zero and use Fresnel approximation to convert τ k Approximately:

[0096]

[0097] Use the above formula to calculate the ground receiver in the space super sparse array S k The phase shift related to the propagation time delay between the subarray and the reference subarray S0.

[0098] Step 4, calculating the received signal matrix expression of the equivalent sub-array of the entire distributed constellation;

[0099] The received signal of the equivalent sub-array of the entire distributed constellation is expressed as a matrix:

[0100] X(t)=AS(t)+N(t)

[0101] Where X(t) is the signal vector received by the ground receiver and has the following form:

[0102]

[0103] N(t) represents the noise vector and has the following form:

[0104]

[0105] A represents the steering vector of the near-field source, and the steering vector has the following form:

[0106]

[0107] Step 5, using a near-field three-dimensional matching method to perform beam domain coherent synthesis to achieve energy enhancement and complete spatial ultra-sparse array near-field beam synthesis;

[0108] Step 5-1: At the ground receiver, the received signal X(t) of the entire distributed constellation equivalent sub-array is subjected to three-dimensional matching phase modulation, and the phase-modulated signal is expressed as Y(t).

[0109] Y(t)=BX(t)+N(t)

[0110] Β represents the ground receiver phase modulation vector, which has the following form:

[0111]

[0112] Step 5-2, the phase-modulated signals are synthesized by co-phase superposition to complete the spatial ultra-sparse array near-field beamforming.

[0113] It can be seen that the present invention synthesizes the near-field beam of the spatial ultra-sparse array, which can fully enhance the received signal strength of the spatial ultra-sparse array; the present invention utilizes the three-dimensional information of the spatial ultra-sparse array to accurately align the phase difference of different array elements of the spatial ultra-sparse array.

[0114] Embodiment 3

[0115] An embodiment of the present invention discloses a computer-readable storage medium storing a computer program for electronic data exchange, wherein the computer program enables a computer to execute the steps in the spatial ultra-sparse array near-field beamforming method described in Embodiment 1 and Embodiment 2.

[0116] Through the specific description of the above embodiments, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the above technical solution can be essentially or partly contributed to the prior art in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, and the storage medium includes a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electronically erasable rewritable read-only memory (EEPROM), a compact disc (CD-ROM) or other optical disc storage, magnetic disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0117] Finally, it should be noted that the spatial ultra-sparse array near-field beamforming method disclosed in the embodiment of the present invention discloses only a preferred embodiment of the present invention, which is only used to illustrate the technical solution of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A spatial ultra-sparse array near-field beamforming method, characterized in that: The method comprises: S1, construct the spatial near-field model of the ground receiver and the spatial ultra-sparse array subarray; The spatial near-field model includes ground receivers and distributed constellations; The ground receiver is located in the near field region of the spatial ultra-sparse array; The distributed star cluster includes K distributed satellites, where K is a positive integer; the distributed star cluster constitutes a large subarray in the space super-sparse array, each distributed satellite constitutes an independent phased array antenna element in the space super-sparse array, and each independent phased array antenna element simultaneously generates a signal to be transmitted to the ground receiver; A distributed satellite is selected from the K distributed satellites as the phase reference subarray of the spatial ultra-sparse array, which is numbered as S0, and the other K-1 subarrays of the spatial ultra-sparse array are numbered S1, S2, ..., S K-1 ; S2, using the spatial near-field model, modeling the spatial ultra-sparse array signal received by the ground receiver to obtain the ground receiver receiving signal; the ground receiver receiving signal expression is: where x k (t) is the spatial ultra-sparse array S received by the ground receiver at time t k The received signal of the subarray, s k (t) is the spatial super sparse array at time t. k Signal envelope of the subarray, n k (t) represents the spatial ultra-sparse array S received by the receiver at time t k Subarray noise, τ k represents the ground receiver in the space super sparse array S k The phase shift related to the propagation time delay between the subarray and the phase reference subarray S0, e represents the exponential signal, j is the imaginary unit, j 2 = -1, k = 0, 1, ..., K - 1; S3, obtaining parameter information between the ground receiver and the spatial ultra-sparse array subarray, including: S31, using a propagation time delay related phase shift model, processing parameter information between a ground receiver and a spatial ultra-sparse array subarray to obtain a first related phase shift of the ground receiver; The propagation time delay-related phase shift model is: Among them, τ′ k is the first relevant phase shift of the ground receiver, λ represents the wavelength of the propagated signal, r0, θ, d k and is the parameter information between the ground receiver and the spatial ultra-sparse array subarray, r0 represents the straight-line distance between the ground receiver and the phase reference subarray S0, d k Indicates the S k The straight-line distance between the subarray and the phase reference subarray S0, θ represents the elevation angle from the flat antenna array of the ground receiver to the phase reference subarray S0, Indicates the S k The elevation angle of the subarray relative to the flat antenna array of the phase reference subarray S0 to the phase reference subarray S0; S32, optimizing the first related phase shift of the ground receiver by using a phase shift optimization model to obtain a propagation time delay related phase shift of the ground receiver; The phase shift optimization model is: where τ k is the propagation time delay associated phase shift at the ground receiver, τ k Yes In Taylor series expansion is performed at the zero point, and the result obtained by Fresnel approximation is that the propagation time delay-related phase shift of the ground receiver is k The phase shift associated with the propagation time delay between the subarray and the reference subarray S0; S4, processing parameter information between the ground receiver and the spatial ultra-sparse array subarray to obtain a propagation time delay-related phase shift of the ground receiver; S5, processing the received signal of the ground receiver and the phase shift associated with the propagation time delay of the ground receiver to obtain the received signal of the distributed constellation equivalent sub-array; the received signal of the distributed constellation equivalent sub-array is: X(t)=AS(t)+N(t) Where X(t) is the signal vector received by the ground receiver, X(t) = [x0(t) x1(t)…x K-1 (t)] T , where x k (t), k = 0, 1, ..., K-1 is the spatial ultra-sparse array S received by the ground receiver at time t k The received signal of the subarray, N(t) represents the noise vector, N(t) = [n0(t) n1(t)…n K-1 (t)] T , n k (t) represents the spatial ultra-sparse array S received by the receiver at time t k Subarray noise, A represents the steering vector of the near-field source, is the kth component in A, τ k represents the ground receiver in the space super sparse array S k The phase shift related to the propagation time delay between the subarray and the phase reference subarray S0, e represents the exponential signal, j is the imaginary unit, j 2 =-1, r0 represents the straight-line distance between the ground receiver and the phase reference subarray S0, θ represents the elevation angle from the flat antenna array of the ground receiver to the phase reference subarray S0, Indicates the S k The elevation angle of the flat antenna array of the subarray relative to the phase reference subarray S0 to the phase reference subarray S0, T represents the transposition; S6, using a near-field three-dimensional matching model, performing beam-domain coherent synthesis on the received signals of the distributed constellation equivalent sub-array to obtain a spatial ultra-sparse array near-field beam, including: S61, using a near-field three-dimensional matching model, matching and phase-modulating the received signal of the distributed constellation equivalent sub-array to obtain a phase-modulated signal; The near-field three-dimensional matching model is: Y(t)=BX(t)+N(t) Among them, Y(t) is the phase modulation signal, X(t) is the receiving signal of the equivalent sub-array of the distributed constellation, and B represents the phase modulation vector of the ground receiver. τ k represents the ground receiver in the space super sparse array S k The phase shift associated with the propagation time delay between the subarray and the phase reference subarray S0, k = 0, 1, ..., K-1, e represents the exponential signal, j is the imaginary unit, j 2 =-1, T means transpose; S62, performing in-phase superposition synthesis on the phase modulation signal to obtain a spatial ultra-sparse array near-field beam.

2. A computer storable medium, characterized in that: The computer storable medium stores computer instructions, and when the computer instructions are called, they are used to execute the spatial ultra-sparse array near-field beamforming method as claimed in claim 1.

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