Passive receiving device based on non-uniform array and dynamic light beam forming method

Abstract

The application provides a passive receiving device based on a non-equidistant array and a dynamic optical beam forming method, and relates to the technical field of microwave photon reconnaissance. The device comprises an antenna array, a signal transmission line, a wavelength division multiplexing device, an optical splitter, a tunable laser and a control center. Each column of passive antennas is connected with the input end of the corresponding signal transmission line, and the output end of the signal transmission line is in communication connection with the input end of the wavelength division multiplexing device. The output end of the wavelength division multiplexing device is in communication connection with the input end of the optical splitter through a first dispersion optical fiber. Each signal transmission line is in communication connection with the output end of the tunable laser, and the input end of the tunable laser is in communication connection with the control center. The control center is used for controlling the tunable laser to output a carrier signal with a target wavelength to the corresponding signal transmission line. The application adjusts the phases of the optical signals received by the non-equidistant passive antennas to be consistent by using the characteristics of fiber dispersion.

Description

Technical Field

[0001] This invention relates to the field of microwave photonic reconnaissance technology, specifically to a passive receiving device based on a non-equally spaced array and a dynamic optical beamforming method. Background Technology

[0002] Passive array receiving antennas have been widely used as a safe and effective means of space reconnaissance.

[0003] However, existing passive array receiving antennas are mainly equally spaced, meaning that the spacing between each column of antennas in a passive array receiving antenna is equal. Data shows that non-equally spaced arrays are effective in suppressing sidelobe amplitude; however, ensuring that the received optical signal phase is consistent at non-equally spaced antenna arrays remains a pressing technical problem to be solved. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a passive receiving device and a dynamic optical beamforming method based on a non-equally spaced array, solving the problem of ensuring that the phase of the optical signal received at the non-equally spaced antenna array is consistent.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A passive receiving device based on a non-equally spaced array includes an antenna array, a signal transmission line, a wavelength division multiplexing device, an optical splitter, a tunable laser, and a control center. The antenna array includes several rows of passive antennas arranged in sequence with non-equal spacing.

[0009] Each column of passive antennas is connected to the input end of a corresponding signal transmission line, and the output end of the signal transmission line is communicatively connected to the input end of the wavelength division multiplexing device.

[0010] The output of the wavelength division multiplexing device is connected to the input of the optical splitter via a first dispersive optical fiber.

[0011] Each of the signal transmission lines is communicatively connected to the output of the tunable laser, and the input of the tunable laser is communicatively connected to the control center.

[0012] The control center is used to control the tunable laser to output a carrier signal of the target wavelength to the corresponding signal transmission line.

[0013] Preferably, the signal transmission line includes a low-noise amplifier and an electro-optic converter connected in sequence;

[0014] The signal input terminal of the low-noise amplifier is communicatively connected to the passive antenna of the corresponding column; the signal output terminal of the low-noise amplifier is communicatively connected to the signal input terminal of the electro-optic converter.

[0015] The other signal input terminal of the electro-optic converter is communicatively connected to the output terminal of the corresponding tunable laser.

[0016] The signal output terminal of the electro-optic converter is communicatively connected to the input terminal of the wavelength division multiplexing device.

[0017] Preferably, the output of the optical splitter is connected to the signal receiving end of the control center through several second dispersive optical fibers, and there is a length difference between each second dispersive optical fiber.

[0018] Preferably, the lengths of each second dispersion fiber are arranged in an arithmetic sequence.

[0019] Preferably, the angle between the normal direction of the antenna array and the horizontal plane is in the range of [0°, 90°].

[0020] A dynamic optical beamforming method for non-equidistant arrays, applied to the passive receiving device described above, includes:

[0021] S1. Obtain the reference wavelength and reference coordinates corresponding to the passive antennas in the reference column of the antenna array;

[0022] S2. For other columns of passive antennas in the antenna array, based on the spacing difference between the current column of passive antennas and the reference column of passive antennas, and in combination with the antenna spacing difference, the reference wavelength, the length of the first dispersive fiber and the fiber dispersion coefficient, the target wavelength corresponding to the current column of passive antennas is obtained.

[0023] S3. Use the reference wavelength and each of the target wavelengths as the wavelengths of the carrier signals output by the tunable laser to the corresponding signal transmission lines, and use the target wavelengths to receive the incoming wave signals.

[0024] Preferably, the step of calculating the antenna spacing difference between the current column passive antenna and the reference column passive antenna includes:

[0025] Obtain the position coordinates of each column of passive antennas, and combine them with the reference coordinates of the reference column of passive antennas to calculate the distance of the current column of passive antennas relative to the reference column of passive antennas.

[0026] Preferably, the calculation process for the target wavelength includes:

[0027] Using formula The target wavelength is calculated, where λ iλi is the wavelength of the passive antenna in the i-th column; λ0 is the reference wavelength corresponding to the passive antenna in the reference column; Δd i is the spacing difference between the passive antenna in the i-th column and the passive antenna in the reference column; L is the length of the first dispersive fiber, and D is the fiber dispersion coefficient of the first dispersive fiber.

[0028] (III) Beneficial Effects

[0029] This invention provides a passive receiving device and a dynamic optical beamforming method based on a non-equally spaced array. Compared with the prior art, it has the following advantages:

[0030] This invention utilizes the characteristic of optical fiber dispersion to transmit optical signals of different wavelengths through dispersive optical fiber, thereby adjusting the phase of the optical signals received by passive antennas that are not evenly spaced to be consistent, so as to achieve zero phase difference between passive antennas. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A schematic diagram of a passive receiving device based on a non-equally spaced array provided in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of an antenna array provided in an embodiment of the present invention;

[0034] Figure 3 A three-dimensional schematic diagram of an antenna array provided in an embodiment of the present invention;

[0035] Figure 4 for Figure 3 Side view of the antenna array in the image;

[0036] Figure 5 This is a flowchart illustrating a dynamic optical beamforming method for non-equidistant arrays provided in an embodiment of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] This application provides a passive receiving device and a dynamic optical beamforming method based on a non-equally spaced array to achieve phase consistency of the optical signals received at the non-equally spaced passive receiving antenna.

[0039] Example 1:

[0040] like Figure 1 As shown, this embodiment of the invention provides a passive receiving device based on a non-equally spaced array, including an antenna array, a signal transmission line, a wavelength division multiplexing device, an optical splitter, a tunable laser, and a control center.

[0041] This invention defines an antenna array comprising several columns of passive antennas arranged sequentially with non-equidistant spacing. For example, see [link to example]. Figure 1 , Figure 1 The antenna array is arranged in a rectangular pattern and includes n columns of passive antennas, with each column containing more than one passive antenna.

[0042] like Figure 2 As shown, Figure 2 A schematic diagram of a special antenna array is disclosed. A row of passive antennas is generally referred to as a "channel," each corresponding to... Figure 2 Antenna 1, antenna 2, antenna 3, and antenna n are mentioned in this embodiment. Furthermore, the signal transmission lines corresponding to each column of passive antennas in this embodiment are identical.

[0043] Taking one of the passive antennas as an example, such as Figure 1 As shown,

[0044] The passive antennas in this column are connected to the input of the signal transmission line, which in turn is communicatively connected to the output of the optical splitter. The signal transmission line includes a low-noise amplifier module, an electro-optical conversion module, and a wavelength division multiplexing (WDM) device connected in sequence. For example, antenna 1, acting as the first passive antenna, transmits its signal to the low-noise amplifier module, which then transmits it to the electro-optical conversion module. The electro-optical conversion module uses the light from the tunable laser as a carrier signal, converts the signal from the low-noise amplifier module into an optical signal, modulates it onto the carrier signal, and then sends it to the WDM device. The WDM device combines the signals from antenna 1 to antenna n and transmits them to the optical splitter via the first dispersive fiber.

[0045] The optical splitter then branches the modulated signal into m second-dispersion optical fibers, which are then sent to various photodetectors and digital-to-analog converters, and finally to the control center. In practical applications, the lengths of the m second-dispersion optical fibers are not equal. For example, the lengths of the m second-dispersion optical fibers are arranged sequentially, and the lengths of adjacent second-dispersion optical fibers form an arithmetic sequence.

[0046] Furthermore, such as Figure 3 As shown, Figure 3 A three-dimensional schematic diagram of an antenna array is disclosed, wherein the X, Y, and Z directions are orthogonal, the plane formed by the X and Y directions is a horizontal plane, and the Z direction is a vertical direction. Figure 4 As shown, Figure 4 A side view of this type of antenna array is disclosed. In this embodiment of the invention, a column of passive antennas refers to an antenna array whose normal direction has a certain angle α ∈ [0°, 90°] with the horizontal plane, such as 10°, 30°, 52°, 66°, 80°, and 90°. Passive antennas located in the same vertical plane (a vertical plane parallel to the XZ plane) constitute a column. Each passive antenna in the same column is spread out along the direction of the angle α with the X direction on a plane perpendicular to the Y axis. The passive antennas in each column are spread out along the Y direction at a certain interval.

[0047] Example 2:

[0048] This invention provides a dynamic optical beamforming method for non-equally spaced arrays. Specifically, the method is applied to the passive receiving device as described in Embodiment 1.

[0049] like Figure 5 As shown, the method includes:

[0050] S1. Obtain the reference wavelength and reference coordinates corresponding to the passive antennas in the reference column of the antenna array.

[0051] Continuing with the example in Example 1, here we can... Figure 3 The column of passive antennas corresponding to antenna 1 in the array is designated as the reference column of passive antennas, and its corresponding coordinates are used as the reference coordinates. In other words, the reference passive antenna array can contain multiple passive antennas with the same azimuth and elevation angles, differing only in height in the vertical direction. Conversely, multiple passive antennas in the reference array correspond to the same reference coordinates. Similarly, the coordinates of the other columns of passive antennas in the antenna array are all the same.

[0052] S2. For other columns of passive antennas in the antenna array, based on the spacing difference between the current column of passive antennas and the reference column of passive antennas, and in combination with the antenna spacing difference, the reference wavelength, the length of the first dispersive fiber and the fiber dispersion coefficient, the target wavelength corresponding to the current column of passive antennas is obtained.

[0053] The steps for calculating the antenna spacing difference between the current column passive antenna and the reference column passive antenna in this process include:

[0054] Obtain the position coordinates of each column of passive antennas, and combine them with the reference coordinates of the reference column of passive antennas to calculate the distance of the current column of passive antennas relative to the reference column of passive antennas.

[0055] Based on this, this step specifically utilizes the formula The target wavelength is calculated, where λ i λi is the wavelength of the passive antenna in the i-th column; λ0 is the reference wavelength corresponding to the passive antenna in the reference column; Δd i is the spacing difference between the passive antenna in the i-th column and the passive antenna in the reference column; L is the length of the first dispersive fiber, and D is the fiber dispersion coefficient of the first dispersive fiber.

[0056] After the target wavelength corresponding to the i-th column of passive antennas is calculated, this embodiment of the invention takes the next column of passive antennas, i.e. the (i+1)-th column of passive antennas, as the current column of passive antennas and returns to execute step S2. This process is repeated until the target wavelength corresponding to each column of passive antennas is obtained.

[0057] S3. Use the reference wavelength and each of the target wavelengths as the wavelengths of the carrier signals output by the tunable laser to the corresponding signal transmission lines, and use the target wavelengths to receive the incoming wave signals.

[0058] In this step, a tunable laser is used to send the carrier wave of the target wavelength to the corresponding electro-optic converter. The electro-optic converter modulates the signal 1 corresponding to antenna 1 according to the reference wavelength (which can be regarded as the target wavelength 1), the signal 2 corresponding to antenna 2 according to the target wavelength 2, the signal n corresponding to antenna n according to the target wavelength n, and so on. Then, it performs modulation and electro-optic conversion to obtain n modulated optical signals, and then sends the n modulated optical signals to the wavelength division multiplexing equipment.

[0059] The wavelength division multiplexing (WDM) equipment receives signals from various paths with a phase difference. This phase difference corresponds to the spacing between each row of passive antennas relative to a reference passive antenna. The WDM equipment combines n signals (signal 1 - signal n) into one signal group 0. Then, signal group 0 is transmitted to the optical splitter via the first dispersive fiber 103. At this point, the length of the first dispersive fiber is fixed, and the time difference between signals of different wavelengths passing through the first dispersive fiber can compensate for the time difference caused by the spacing difference between each row of antennas. Therefore, the phase difference between the signals in signal group 0 received by the optical splitter is zero.

[0060] This invention utilizes the dispersion property of optical fibers to transmit optical signals of different wavelengths through dispersive optical fibers. This allows the phase of the optical signals received by unequally spaced passive antennas to be adjusted to be consistent, achieving zero phase difference between the passive antennas. In other words, this invention uses dispersive optical fibers to achieve the function of a phase shifter.

[0061] The optical splitter copies signal group 0 m times, and then transmits each copy through m second-dispersion optical fibers via photodetectors (PDs) to the corresponding digital-to-analog converters (ADs). For example, signal group 1 is sent to AD1, signal group 2 to AD2, signal group 3 to AD3, ..., signal group m to AD1. m And so on. Among them:

[0062] The length of the second dispersive fiber corresponding to the digital-to-analog converter AD1 is L1;

[0063] The length of the second dispersive fiber corresponding to the digital-to-analog converter AD2 is L2;

[0064] The length of the second dispersive fiber corresponding to the digital-to-analog converter AD3 is L3;

[0065] ...

[0066] Digital-to-analog converter (AD) m-1 The corresponding second-dispersion fiber has a length of L. m-1 ;

[0067] Digital-to-analog converter (AD) m The corresponding second-dispersion fiber has a length of L. m .

[0068] Then L2-L1=T; L3-L2=T;…;L m -L m-1 =T, in other words, L1, L2, L3, L m-1 L m The signal groups 0, which are in an arithmetic sequence, are transmitted by second-dispersion optical fibers of different lengths. This allows for equal phase differences between the different signal groups, resulting in beams 1 to m with different directions. Each digital-to-analog converter then sends the received signals to the control center for signal processing.

[0069] It is necessary to point out that in some cases, if the antenna position in the embodiment of the present invention is changed by the antenna position adjustment mechanism, in order not to affect the phase consistency of the optical signal received at the non-equally spaced passive receiving antennas, it is necessary to return to the above S1 step to recalculate the target wavelength of each column of passive antennas, and then receive the incoming wave signal based on the target wavelength. After each adjustment, the adjustment displacement of each passive antenna in the same column is the same, but it is not necessary to limit whether it is one column or multiple columns that are adjusted. That is, the embodiment of the present invention supports the use of different non-equal spacing for receiving incoming wave signals, which greatly improves the adaptability of the antenna array to incoming wave signals.

[0070] In summary, compared with existing technologies, it has the following beneficial effects:

[0071] 1. This invention utilizes the characteristic of optical fiber dispersion to transmit optical signals of different wavelengths through dispersive optical fiber, thereby adjusting the phase of the optical signals received by passive antennas that are not evenly spaced to be consistent, so as to achieve zero phase difference between passive antennas.

[0072] 2. The embodiments of the present invention support the use of different non-equidistant spacing for receiving incoming wave signals, which greatly improves the adaptability of the antenna array to incoming wave signals.

[0073] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A passive receiving device based on a non-equally spaced array, characterized in that, It includes an antenna array, signal transmission lines, wavelength division multiplexing equipment, optical splitter, tunable laser and control center, wherein the antenna array includes several rows of passive antennas arranged in sequence with non-equidistant spacing; Each column of passive antennas is connected to the input end of a corresponding signal transmission line, and the output end of the signal transmission line is communicatively connected to the input end of the wavelength division multiplexing device. The output of the wavelength division multiplexing device is connected to the input of the optical splitter via a first dispersive optical fiber. Each of the signal transmission lines is communicatively connected to the output of the tunable laser, and the input of the tunable laser is communicatively connected to the control center. The control center is used to control the tunable laser to output a carrier signal of the target wavelength to the corresponding signal transmission line; wherein, the process of acquiring the target wavelength includes: Obtain the reference wavelength and reference coordinates corresponding to the passive antennas in the reference column of the antenna array; for the passive antennas in other columns of the antenna array, based on the spacing difference between the current column of passive antennas and the reference column of passive antennas, and in combination with the spacing difference, the reference wavelength, the length of the first dispersive fiber and the fiber dispersion coefficient, obtain the target wavelength corresponding to the current column of passive antennas.

2. The passive receiving device as described in claim 1, characterized in that, The signal transmission line includes a low-noise amplifier and an electro-optic converter connected in sequence. The signal input terminal of the low-noise amplifier is communicatively connected to the passive antenna of the corresponding column; the signal output terminal of the low-noise amplifier is communicatively connected to the signal input terminal of the electro-optic converter. The other signal input terminal of the electro-optic converter is communicatively connected to the output terminal of the corresponding tunable laser. The signal output terminal of the electro-optic converter is communicatively connected to the input terminal of the wavelength division multiplexing device.

3. The passive receiving device as described in claim 1, characterized in that, The output of the optical splitter is connected to the signal receiving end of the control center through several second-dispersion optical fibers, and there is a length difference between each second-dispersion optical fiber.

4. The passive receiving device as described in claim 3, characterized in that, The lengths of each second dispersion fiber are arranged in an arithmetic sequence.

5. The passive receiving device as described in claim 1, characterized in that, The angle between the normal direction of the antenna array and the horizontal plane is in the range of [0°, 90°].

6. A method for dynamic optical beamforming for non-equidistant arrays, characterized in that, The passive receiving device as described in any one of claims 1 to 5 includes: S1. Obtain the reference wavelength and reference coordinates corresponding to the passive antennas in the reference column of the antenna array; S2. For other columns of passive antennas in the antenna array, based on the spacing difference between the current column of passive antennas and the reference column of passive antennas, and in combination with the spacing difference, the reference wavelength, the length of the first dispersive fiber and the fiber dispersion coefficient, the target wavelength corresponding to the current column of passive antennas is obtained. S3. Use the reference wavelength and each of the target wavelengths as the wavelengths of the carrier signals output by the tunable laser to the corresponding signal transmission lines, and use the target wavelengths to receive the incoming wave signals.

7. The dynamic optical beamforming method as described in claim 6, characterized in that, The steps for calculating the spacing difference between the current column passive antenna and the reference column passive antenna include: Obtain the position coordinates of each column of passive antennas, and combine them with the reference coordinates of the reference column of passive antennas to calculate the distance of the current column of passive antennas relative to the reference column of passive antennas.

8. The dynamic optical beamforming method as described in claim 6, characterized in that, The calculation process for the target wavelength includes: Using formula The target wavelength is calculated, where, For the first The wavelength of the passive antenna; The reference wavelength is the one corresponding to the passive antenna of the reference column. For the first The spacing difference between the passive antenna column and the reference passive antenna column; The length of the first dispersion fiber, denoted as the fiber dispersion coefficient of the first dispersion fiber.

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