Virtual array surface forming method of mathematical multi-beam spherical phased array antenna

Abstract

The invention discloses a virtual array plane forming method of a mathematical multi-beam spherical phased array antenna, which comprises the following steps of: controlling the geometric dimension of a sub-array so as to control the influence of aperture transit time of array elements in the sub-array within an effective range, that is, adopting a phase compensation method without considering the influence of aperture transit in the sub-array, beamforming in the sub-array is completed; beamforming of the spherical array antenna is completed among the sub-arrays in the activated area according to a time delay compensation method; wherein only phase compensation synthesis is carried out between array elements in the sub-array; and time delay compensation synthesis is carried out among the sub-arrays. According to the invention, the beamforming requirement of the digital beam spherical phased-array antenna on the broadband signal can be realized, and the realization method is simple.

Description

Technical Field

[0001] The invention relates to the technical field of spherical phased array antennas, and in particular to a virtual array surface forming method of a mathematical multi-beam spherical phased array antenna. Background Art

[0002] Digital multi-beam spherical phased array antennas use a multi-beam working mode to track and control multiple targets in space simultaneously in the entire airspace. In recent years, they have received increasing attention in the research of new antennas and have become a hot area in the research of new antennas.

[0003] A key technical problem in the design of digital multi-beam phased array antennas is how to complete digital beamforming. Traditionally, digital multi-beam phased array antennas form beams by adjusting the phase of the digital signals of each channel of the antenna so that the phase of the digital signals received by each beam is consistent. Since the signal processing using complex signal phase weighting is very mature in theory and simple in engineering implementation, this beamforming method is widely used in the engineering implementation of phased array antennas. However, there is a problem with this method. Although this method of only adjusting the channel phase has no problem with the beamforming of narrowband signals, due to the existence of dispersion, the beamforming of broadband signals implemented by this method often causes signal distortion, causing problems in the back-end signal processing. Therefore, for the beamforming of broadband signals, it is necessary to adjust the delay difference of each channel. However, in implementation, since the system resources consumed by adjusting the signal delay are large, it is difficult to perform delay processing on each channel in engineering practice. Summary of the invention

[0004] In view of this, the present invention provides a virtual array surface forming method for a mathematical multi-beam spherical phased array antenna. The method combines two beam synthesis methods of adjusting the delay difference and the phase difference, and is not only applicable to the digital beam synthesis of narrowband signals of digital multi-beam phased array antennas, but also applicable to digital beam signals of wideband signals. The virtual array surface forming technology of the mathematical multi-beam phased array antenna proposed in the present invention aims to provide a simple, reliable and easy-to-implement beam synthesis method for digital multi-beam phased array antennas. The method does not require any external equipment to be added, and is applicable to both wideband signals and narrowband signals, so it is easy to design a digital multi-beam phased array antenna system that meets the index requirements in engineering practice.

[0005] The present invention discloses a virtual array surface forming method of a mathematical multi-beam spherical phased array antenna, which comprises:

[0006] The geometric dimensions of the subarray are controlled to control the influence of the aperture transit time of the array elements in the subarray within an effective range, that is, the influence of the aperture transit does not need to be considered in the subarray, and the phase compensation method is used to complete the beam synthesis in the subarray; then the beam synthesis of the spherical array antenna is completed between the subarrays in the activated area according to the delay compensation method; among them, only phase compensation synthesis is performed between the array elements in the subarray; and delay compensation synthesis is performed between the subarrays.

[0007] Furthermore, the controlling of the geometric dimensions of the sub-array to control the influence of the aperture transit time of the array elements in the sub-array within an effective range includes:

[0008] The angle between the incoming wave direction of the subarray on the boundary of the activation area and the normal line of the subarray is the activation area angle θ A is the largest, that is, the aperture transit time of the subarray on the boundary of the activation area is the largest, and the aperture transit influence factor K at the subarray is calculated to determine the geometric size of the subarray.

[0009] Further, the calculating of the aperture transition influence factor K at the subarray to determine the geometric size of the subarray includes:

[0010] According to the antenna design receiving and transmitting signal bandwidth B, the activation area angle θ of the digital beam spherical phased array antenna A The size of and the maximum distance d between array elements in the subarray are used to obtain the aperture transition influence factor K;

[0011] According to the aperture transit influence factor K, the geometric dimensions of the subarray are calculated.

[0012] Furthermore, the aperture transit influence factor K is obtained by the following formula:

[0013]

[0014] The maximum distance d between array elements in a subarray is obtained by the following formula:

[0015]

[0016] Where c is the speed of light.

[0017] Furthermore, the phase compensation method is used to complete the beamforming in the subarray, including:

[0018] Suppose a sub-matrix contains n array elements: X1, X2, …, X n ; Taking the center point O of the sub-array as the reference, the kth array element X of the sub-array k The phase difference between the receiving and transmitting signals and the center point O is the phase compensation value ΔΦ(X k ); Based on the phase compensation value of the sub-array, the beamforming of all array elements in the sub-array is completed.

[0019] Furthermore, the beamforming of all array elements in the subarray is completed based on the phase compensation value of the subarray, including:

[0020] The beamforming signal within the subarray is obtained by the following formula:

[0021]

[0022] Among them, S 子阵 (t) is the beam synthesis signal of the subarray, S k (t) is the transmit and receive signal of the kth array element in the sub-array.

[0023] Furthermore, the beam synthesis of the spherical array antenna is completed according to the delay compensation method between the sub-arrays in the activation area, including:

[0024] The time delay compensation method is used between the sub-arrays in the activation area, that is, the spatial delay of each sub-array receiving and transmitting signal is compensated to the same value. It is geometrically equivalent to virtualizing each sub-array in the activation area on a plane perpendicular to the receiving and transmitting signals, and then completing the beam synthesis of the array.

[0025] Further, the beam synthesis of the array is completed, including:

[0026] The coordinates of the beam pointing point on the array surface corresponding to the activation area of ​​the spherical array antenna are (x0, y0, z0), and the activation area contains m sub-arrays: Z1, Z2, …, Z h ,…,Z m ; Take subarray Z h The center point coordinates (x h ,y h ,z h ) is the submatrix Z h The coordinates of the subarray Z are based on the beam pointing point. h The delay difference between the receiving and transmitting signals and the beam pointing point is the delay compensation value Δτ h Based on the delay compensation value of each sub-array receiving and transmitting signal, the beam synthesis of all sub-arrays on the array surface is completed.

[0027] Furthermore, the beamforming of all sub-arrays on the array plane is completed based on the delay compensation value of each sub-array receiving and transmitting signal, including:

[0028] The beam synthesis of all sub-arrays on the array is completed by the following formula:

[0029]

[0030] Among them, S 合成 (t) is the composite signal of all sub-arrays in the activation area, S 子阵h(t) is the transmit and receive signal of the hth subarray in the activation area.

[0031] Furthermore, in a subarray, the maximum distance between array elements is set to the subarray length, and the activation area of ​​the digital beam spherical phased array antenna is a cone formed by taking the center of the spherical array as the vertex, the beam pointing as the central axis, and the angle with the central axis as the activation area angle, that is, an area is divided on the antenna array surface, namely, the activation area; wherein the activation area angle is the angle between the incoming wave direction of the subarray on the boundary of the activation area and the normal of the subarray.

[0032] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0033] 1. Solve the problem of beam synthesis of wide signals by digital multi-beam spherical phased array antenna. The present invention obtains the maximum subarray size of the spherical phased array antenna subarray according to a certain relationship between signal bandwidth and transit time, and finally completes the beam forming of the spherical array antenna by performing phase compensation synthesis only between array elements within the subarray and delay compensation synthesis between subarrays. This method can meet the needs of digital beam spherical phased array antenna for beam synthesis of broadband signals, solving a key problem in the design of digital multi-beam spherical phased array antenna system.

[0034] 2. Simple implementation, less resource occupation, and reduced system design cost. The present invention does not require complex circuits, and the implementation method is relatively simple. The present invention only uses the original equipment of the system without adding additional equipment, and realizes the virtual array surface forming function of the phased array antenna system through software algorithms, which is convenient for automatic operation and reduces the system design cost.

[0035] 3. Traditionally, digital multi-beam phased array antennas generally use a beam synthesis method that performs complex signal phase weighting on channel signals. However, due to the influence of aperture crossing of phased array signal synthesis, for broadband signals, if only the channel phase weighted beam synthesis method is used, the beam synthesis signal will be distorted, affecting the back-end signal processing. Therefore, this phase weighted beam synthesis method is not applicable to broadband signals. The method of the present invention can meet the needs of digital multi-beam spherical phased array antennas for beam synthesis of broadband signals; using this method, a digital multi-beam phased array antenna system that meets the index requirements can be designed in engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is a schematic diagram of beam forming of traditional digital multi-beam spherical phased array antenna.

[0038] Figure 2 It is a schematic diagram of virtual array surface forming of a digital multi-beam spherical phased array antenna according to an embodiment of the present invention.

[0039] Figure 3 It is a schematic diagram of a subarray structure of a digital multi-beam spherical phased array antenna according to an embodiment of the present invention.

[0040] Figure 4 It is a schematic diagram of calculating sub-array transit time of a digital multi-beam spherical phased array antenna according to an embodiment of the present invention.

[0041] Figure 5 It is a schematic diagram of a phase-compensated synthetic beam within a sub-array of a digital multi-beam spherical phased array antenna according to an embodiment of the present invention.

[0042] Figure 6 It is a schematic diagram of inter-subarray delay compensation synthetic beams of subarrays of a digital multi-beam spherical phased array antenna according to an embodiment of the present invention.

[0043] Figure 7 It is a schematic diagram of a beamforming algorithm for virtual array shaping of a digital multi-beam spherical phased array antenna according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described in conjunction with the accompanying drawings and embodiments, and the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present invention.

[0045] See also Figure 1 In engineering, subarrays are usually polyhedral planar arrays, and multiple subarrays are eventually spliced ​​into a spherical phased array antenna. Figure 1As shown in the figure, the digital multi-beam spherical phased array antenna activates a sub-array in a circular area on the spherical surface with the beam pointing as the center to participate in beam forming, and each sub-array contains multiple independent receiving and transmitting array elements. When the digital multi-beam spherical phased array antenna points the beam to the target, the path lengths of the receiving and transmitting signals between each array element in the activation area and the target are different, and there is a path difference, that is, the spatial delay difference of the receiving and transmitting signals. This spatial delay will cause the phase offset of the signal at different frequency points within the signal bandwidth to be inconsistent, that is, the aperture crossing phenomenon occurs. For narrowband signals, the phase difference caused by the spatial delay difference of each array element in the activation area of ​​the spherical phased array antenna at each frequency point within the signal bandwidth is small and negligible, so the traditional beamforming algorithm only compensates the phase of each sub-array element. However, for broadband signals, since the spatial delay difference of each array element causes a large phase difference at each frequency point within the signal bandwidth, the aperture crossing phenomenon of the phased array antenna signal cannot be ignored, that is, the traditional phased array antenna beamforming method is not suitable for broadband signals.

[0046] See also Figure 2 and Figure 3 , the present invention adopts a virtual array surface forming technology to solve the beam synthesis problem of digital multi-beam spherical phased array antenna for broadband signals. Since the aperture transit time is related to the spacing between array elements, we can control the geometric dimensions of the subarray and control the influence of the aperture transit time of the array elements in the subarray within an effective range, that is, there is no need to consider the influence of aperture transit within the subarray and adopt a phase compensation method. Since the influence of aperture transit is inevitable between subarrays, a delay compensation method is adopted, that is, the spatial delay of each subarray receiving and transmitting signal is compensated to the same value, which is geometrically equivalent to virtualizing each subarray in the activation area on a plane perpendicular to the receiving and transmitting signals. As Figure 2 As shown, by compensating the spatial delay of each sub-array, the sub-arrays in the activation area of ​​the digital multi-beam spherical phased array antenna are virtualized as a plane array in space that is perpendicular to the beam pointing.

[0047] like Figure 3 As shown, beam synthesis is divided into two steps. First, for the sub-arrays in the activated area, the synthetic signals of the sub-arrays are formed according to the method of phase compensation within the sub-arrays. Then, the final beam signals are synthesized between the sub-arrays in the activated area according to the method of delay compensation.

[0048] See also Figure 4 and Figure 5 , according to the antenna design receive and transmit signal bandwidth B, the digital beam spherical phased array antenna activation area angle θ A The size of and aperture transition influence factor K are used to calculate the geometric dimensions of the subarray design. Figure 3 As shown in , in a subarray, the maximum distance d between array elements is set to the subarray length. Figure 4 As shown in the figure, the activation area of ​​the digital beam spherical phased array antenna is the center of the spherical array as the vertex, the beam pointing as the central axis, and the angle with the central axis as the activation area angle θ A , and a cone is formed to divide an area on the antenna array. Figure 5 As shown in the figure, the angle between the incoming wave direction of the subarray on the boundary of the activation area and the normal line of the subarray is the largest, so the aperture transit time of the subarray on the boundary of the activation area is the largest, so we only need to calculate the aperture transit influence factor K at this location to determine the geometric size of the subarray. The algorithm is as follows:

[0049] according to

[0050]

[0051] The maximum size of the subarray is:

[0052]

[0053] Wherein, c is the speed of light, and the aperture transit influence factor K is K≤0.2.

[0054] For example: Take B = 100MHz, θ A =45 degrees, K = 0.2, the maximum size of the subarray is d = 0.85 meters. According to this design, the influence of aperture crossing can be ignored in the subarray, and the beam synthesis in the subarray adopts the phase compensation method.

[0055] See also Figure 6 ,like Figure 6 As shown, suppose a sub-array contains n array elements: X1, X2, ..., X n Taking the center point O of the sub-array as the reference, any element X of the sub-array k The phase difference between the receiving and transmitting signals and the center point O is the phase compensation value ΔΦ(X k ). Therefore, the beamforming algorithm within the subarray is as follows:

[0056]

[0057] Among them, S 子阵 (t) is the composite signal of the sub-array, S k (t) is the transmit and receive signal of the kth array element in the sub-array.

[0058] See also Figure 7 ,like Figure 7 As shown, let us assume that the coordinates of the beam pointing point on the spherical array antenna are (x0, y0, z0), and the beam activation area contains m sub-arrays: Z1, Z2, …, Z m For any submatrix Z h , with the coordinates of the center point of the subarray (xh ,y h ,z h ) is the coordinate of the subarray. Based on the beam pointing point, the subarray Z h The delay difference between the receiving and transmitting signals and the beam pointing point is the delay compensation value Δτ h Therefore, the beamforming algorithm between subarrays is as follows:

[0059]

[0060] Among them, S 合成 (t) is the composite signal of all activated sub-arrays, S 子阵h (t) is the transmit and receive signal of the hth sub-array in the activated sub-array.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A virtual array surface forming method for a mathematical multi-beam spherical phased array antenna, characterized in that: include: The geometric dimensions of the subarray are controlled to control the influence of the aperture transit time of the array elements in the subarray within an effective range, that is, the influence of the aperture transit does not need to be considered in the subarray, and the phase compensation method is used to complete the beam synthesis in the subarray; then the beam synthesis of the spherical array antenna is completed between the subarrays in the activated area according to the delay compensation method; among them, only phase compensation synthesis is performed between the array elements in the subarray; and delay compensation synthesis is performed between the subarrays.

2. The method according to claim 1, characterized in that The controlling of the geometric dimensions of the sub-array to control the influence of the aperture transit time of the array elements in the sub-array within an effective range includes: The angle between the incoming wave direction of the subarray on the boundary of the activation area and the normal line of the subarray is the activation area angle θ A is the largest, that is, the aperture transit time of the subarray on the boundary of the activation area is the largest, and the aperture transit influence factor k at the subarray is calculated to determine the geometric size of the subarray.

3. The method according to claim 2, characterized in that The step of calculating the aperture transition influence factor k at the subarray to determine the geometric size of the subarray includes: According to the antenna design receiving and transmitting signal bandwidth B, the activation area angle θ of the digital beam spherical phased array antenna A The size of and the maximum distance d between array elements in the subarray are used to obtain the aperture transition influence factor K; According to the aperture transit influence factor K, the geometric dimensions of the subarray are calculated.

4. The method according to claim 3, characterized in that The aperture transit influence factor K is obtained by the following formula: The maximum distance d between array elements in a subarray is obtained by the following formula: Where c is the speed of light.

5. The method according to claim 1, characterized in that The phase compensation method is used to complete beamforming within the subarray, including: Suppose a sub-matrix contains n array elements: X1, X2, …, X n ; Taking the center point O of the sub-array as the reference, the kth array element X of the sub-array k The phase difference between the receiving and transmitting signals and the center point O is the phase compensation value ΔΦ(X k ); Based on the phase compensation value of the sub-array, the beamforming of all array elements in the sub-array is completed.

6. The method according to claim 5, characterized in that The step of completing beamforming of all array elements in the subarray based on the phase compensation value of the subarray includes: The beamforming signal within the subarray is obtained by the following formula: Among them, S 子阵 (t) is the beam synthesis signal of the subarray, S k (t) is the transmit and receive signal of the kth array element in the sub-array.

7. The method according to claim 1, characterized in that The method of completing beam synthesis of the spherical array antenna according to the delay compensation method between the sub-arrays in the activation area includes: The time delay compensation method is used between the sub-arrays in the activation area, that is, the spatial delay of each sub-array receiving and transmitting signal is compensated to the same value. It is geometrically equivalent to virtualizing each sub-array in the activation area on a plane perpendicular to the receiving and transmitting signals, and then completing the beam synthesis of the array.

8. The method according to claim 7, characterized in that The beam synthesis of the array is completed, including: The coordinates of the beam pointing point on the array surface corresponding to the activation area of ​​the spherical array antenna are (x0, y0, z0), and the activation area contains m sub-arrays: Z1, Z2, …, Z h ,…,Z m ; Take the subarray Z h The center point coordinates (x h ,y h ,z h ) is the submatrix Z h The coordinates of the subarray Z are based on the beam pointing point. h The delay difference between the receiving and transmitting signals and the beam pointing point is the delay compensation value Δτ h Based on the delay compensation value of each sub-array receiving and transmitting signal, the beam synthesis of all sub-arrays on the array surface is completed.

9. The method according to claim 8, characterized in that The method of completing beamforming of all sub-arrays on the array plane based on the delay compensation value of each sub-array receiving and transmitting signal includes: The beam synthesis of all sub-arrays on the array is completed by the following formula: Among them, S 合成 (t) is the composite signal of all sub-arrays in the activation area, S 子阵h (t) is the transmit and receive signal of the hth subarray in the activation area.

10. The method according to any one of claims 1 to 9, characterized in that: In a subarray, the maximum distance between array elements is set as the subarray length. The activation area of ​​the digital beam spherical phased array antenna is a cone formed by taking the center of the spherical array as the vertex, the beam pointing as the central axis, and the angle with the central axis as the activation area angle. That is, an area is divided on the antenna array surface, namely the activation area; wherein the activation area angle is the angle between the incoming wave direction of the subarray on the boundary of the activation area and the normal line of the subarray.

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