An antenna array and phase resolution method adapted to high-precision angle measurement with ultra-wide field of view

Abstract

The present invention discloses an antenna array and a phase resolution method adapted to high-precision angle measurement with an ultra-wide field of view, belonging to the technical field of antenna measurement. A plurality of antennas are arranged on three circular arrays with different radii, forming three independent and symmetric measurement baselines. The difference between the radii of the two smaller circular arrays is less than half of the wavelength of the incident wave, and the sum of the diameters of the two smaller circular arrays is greater than the diameter of the largest circular array. Based on the above antenna array, the present invention proposes a phase resolution method to achieve angle measurement in a wide field of view and greatly simplifies the phase ambiguity resolution operation.

Description

Technical Field

[0001] The present invention relates to an antenna array and a phase resolution method suitable for high-precision angle measurement with an ultra-wide field of view, belonging to the technical field of antenna measurement. Background Art

[0002] The integrated long-range microwave rendezvous radar is an important device for realizing rendezvous and docking in the research mission of the new-generation manned spacecraft, providing real-time relative distance, speed, azimuth angle, and pitch angle information for the rapid autonomous rendezvous and docking of the two spacecrafts; the angle measurement requirement during the rendezvous and docking process of the new spacecraft mission is continuous, reliable, high-precision, and ultra-wide field of view angle measurement.

[0003] The current common angular measurement antenna layouts are divided into implementation methods such as L-shaped arrays, cross-shaped arrays, and circular arrays. Relatively speaking, circular arrays are more suitable for ultra-wide field of view angle measurement. The current circular array antenna layouts are mostly uniform circular array interferometer designs, that is, the antennas are evenly distributed on the same circular plane. In order to meet the requirements of high-precision angle measurement, the baseline length between the circular array antenna elements will be greater than the incident half-wavelength, resulting in a phase ambiguity problem. Currently, the phase ambiguity resolution operations for uniform circular array interferometers mostly enumerate all phase differences with different ambiguity degrees, construct a phase difference sample library, solve the phase ambiguity through correlation operations, or use short baseline multiple virtual transformations, and then gradually implement long baseline phase ambiguity resolution operations. The ambiguity resolution operation process is relatively complex. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: overcoming the deficiencies of the prior art, the present invention proposes an antenna array and a phase resolution method suitable for high-precision angle measurement with an ultra-wide field of view. Through the design of the antenna layout method and the resolution method, wide field of view angle measurement is realized, and the phase ambiguity resolution operation is simplified.

[0005] The technical solution of the present invention is:

[0006] An antenna array suitable for high-precision angle measurement with an ultra-wide field of view, in which several antennas are arranged on three circular arrays with different radii, forming three independent and symmetric measurement baselines. The difference between the radii of the two smaller circular arrays is less than the half-wavelength of the incident wave, and the sum of the diameters of the two smaller circular arrays is greater than the diameter of the largest circular array.

[0007] Preferably, 12 angle measurement antennas are distributed on three circular arrays:

[0008] 6 angle measurement antennas are respectively located at the 6 vertices of the inscribed regular hexagon of the circular array V1 with the largest radius;

[0009] 3 angle measurement antennas are respectively located at 3 adjacent vertices of the inscribed regular hexagon of the circular array V2 with the smallest radius;

[0010] Three angle-measuring antennas are distributed at three vertices of the inscribed regular hexagon of the third circular array V3, and these three vertices are on the other side of the three vertices where the angle-measuring antennas of the circular array V2 are placed;

[0011] The angle-measuring antennas on the circular arrays V2 and V3 are both located on the symmetry axes of the inscribed regular hexagon of the circular array V1.

[0012] Preferably, the multiple of the difference between the sum of the diameters of the two smaller circular arrays and the diameter of the largest circular array relative to the radius difference of the two smaller circular arrays, and the multiple of the radius difference between the largest circular array and the second smallest circular array relative to the difference between the sum of the diameters of the two smaller circular arrays and the diameter of the largest circular array are equal.

[0013] Preferably, the multiple of the difference between the sum of the diameters of the two smaller circular arrays and the diameter of the largest circular array relative to the radius difference of the two smaller circular arrays, and the multiple of the diameter of the largest circular array relative to the radius difference between the largest circular array and the second smallest circular array are equal.

[0014] Preferably, each angle-measuring antenna on the measurement baseline is controlled by an independent switch.

[0015] Using the antenna array for high-precision angle measurement adapting to ultra-wide field of view described in claim 1, an antenna array phase resolution method is realized, including:

[0016] Performing phase ambiguity resolution operations on three measurement baselines respectively to obtain the unambiguous longest baseline phase difference;

[0017] Using the phase differences of any two unambiguous longest baselines to construct an analytical function to calculate the incident angle of the array surface;

[0018] Based on the incident angle of the array surface, calculating the azimuth angle and elevation angle of the array surface.

[0019] Preferably, using the virtual baseline without phase ambiguity to guide the longest baseline to realize the phase ambiguity resolution of the measurement baseline.

[0020] Preferably, performing phase ambiguity resolution operations on three measurement baselines respectively, including:

[0021] 1) Using the virtual baseline 1 (AiBi - CiDi) to resolve the ambiguity of the virtual baseline 2 (BiCi - (AiBi + CiDi)) to obtain the unambiguous phase difference phase_inv2 of the virtual baseline 2:

[0022] L_inv1 = L_AiBi - L_CiDi

[0023] L_inv2 = L_BiCi - (L_AiBi + L_CiDi)

[0024] phase_inv1_1 = (phaseAi - phaseBi) - (phaseCi - phaseDi)

[0025]

[0026]

[0027]

[0028] 2) Use the virtual baseline 2 to resolve the ambiguity of the real baseline CiDi, and obtain the unambiguous phase difference phase_CiDi of the real baseline CiDi:

[0029]

[0030]

[0031] 3) Use the real baseline CiDi to resolve the ambiguity of the longest baseline AiDi, and obtain the unambiguous phase difference phase_AiDi of the longest baseline AiDi:

[0032]

[0033]

[0034] In the formula, i takes values of 1, 2, 3, and each time a value is taken for the above calculations, and finally the unambiguous phase difference phase_AiDi is obtained; L_AiBi is the baseline length of AiBi, L_CiDi is the baseline length of CiDi, L_BiCi is the baseline length of BiCi, L_AiDi is the baseline length of AiDi, L_inv1 and L_inv2 are the lengths of the virtual baseline 1 and the virtual baseline 2 respectively; phase_inv21, phase_CiDi_2, and phase_AiDi_2 are the estimated values of the current baseline difference obtained by calculation, phase_inv2_1 is the measured value of the phase difference of the virtual baseline 2, phaseAi, phaseBi, phaseCi, and phaseDi are the phase values of Ai, Bi, Ci, and Di respectively, and round is the rounding operation; among them, the angle-measuring antennas located on the largest circular array are denoted as A1, A2, A3, D1, D2, D3, the angle-measuring antennas located on the smallest circular array are denoted as B1, B2, B3, the angle-measuring antennas located on the second largest circular array are C1, C2, C3, A1, B1, C1, D1 are on the same straight line, A2, B2, C2, D2 are on the same straight line, and A3, B3, C3, D3 are on the same straight line.

[0035] Preferably, the array surface angle calculation includes:

[0036] (1) A baseline group is formed by using two non-ambiguous longest baselines. The sum and difference operations are performed on the non-ambiguous phase differences of the longest baselines to obtain the sum value sum_phase and the difference value sub_phase;

[0037] (2) Construct an analytical function:

[0038]

[0039] In the formula, j is the imaginary unit, r is the maximum radius of the circular array, λ is the wavelength of the incident wave, and α and β are the incident angles of the antenna array plane;

[0040] (3) Use the analytical function to calculate the incident angles α and β of the array plane:

[0041]

[0042] In the formula, arg(f) represents taking the argument of the complex number f, and |f| represents taking the magnitude of the complex number f.

[0043] Preferably, the calculation of the azimuth angle and elevation angle of the array plane includes:

[0044] Use the array plane angles α and β to solve the relationship between the azimuth angle and elevation angle as follows:

[0045]

[0046] The beneficial effects of the present invention compared with the prior art are:

[0047] (1) The antennas are arranged on circular arrays with three different radii, forming three independent and symmetric angle-measuring baselines. By designing the baseline lengths between the antennas, a non-ambiguous virtual baseline is constructed, and the angle measurement is gradually guided to the longest baseline, simplifying the phase ambiguity resolution operation;

[0048] (2) With the design of three independent baselines, each baseline is controlled by a separate switch, and the three baselines are independently controlled. When performing the angle resolution, two of the baselines are selected to complete the angle measurement operation, which can avoid the situation where the angle measurement function fails due to the abnormality of one baseline, ensuring the high reliability of the measurement.

[0049] (3) In the phase ambiguity resolution operation of the present invention, the phase ambiguity number of the guided baseline is directly calculated by using the baseline ratio of the guiding baseline and the guided baseline. Only three times of guiding are performed, and each guiding only includes multiplication operation and rounding operation. Compared with the exhaustive method, which needs to exhaust 2K (K is the baseline length / wavelength) possible situations and perform a correlation operation on the phase differences obtained by calculating the 2K ambiguity numbers and the phase differences measured to obtain the ambiguity number with the smallest error to determine the non-ambiguous phase difference, the operation amount and complexity are greatly reduced.

[0050] (4) Compared with the L array, the circular array has a wider angular measurement field of view. Using the antenna layout of the present invention, when the radius of the circular array is 14 times the incident wavelength, angular measurement of ±80°×±80° (approximate full-field angular measurement) can be achieved, and the angular measurement accuracy is better than 0.15° within the full field, with high measurement accuracy. Description of the Drawings

[0051] Figure 1 Schematic diagram of the antenna array surface layout of the embodiment of the present invention;

[0052] Figure 2 Coordinate system diagram of the antenna array surface of the embodiment of the present invention;

[0053] Figure 3 Comparison diagram of the ambiguity resolution algorithm and the exhaustive method of the embodiment of the present invention. Detailed Implementation Manner

[0054] The present invention will be described in detail below with reference to the drawings and specific embodiments as follows:

[0055] An antenna array adapted to ultra-wide field of view and high-precision angular measurement, as Figure 1 shown, includes 12 angular measurement antennas, and the 12 angular measurement antennas are distributed on three hexagonal circular arrays with the same center and different radii;

[0056] 6 angular measurement antennas A1, A2, D3, D1, D2, A3 are sequentially located at the 6 vertices of the hexagonal circular array V1 with the largest radius in a clockwise order;

[0057] 3 angular measurement antennas B1, B2, B3 are respectively located at 3 adjacent vertices of the hexagonal circular array V2 with the smallest radius. Among them, B1 is located on the measurement baseline A1D1, at the vertex close to A1; B2 is located on the measurement baseline A2D2;

[0058] 3 angular measurement antennas C1, C2, C3 are distributed at 3 vertices of the third hexagonal circular array V3, and these 3 vertices are on the other side of the 3 vertices where the angular measurement antennas are placed on the hexagonal circular array with the smallest radius; C1 is located on the connection line A1D1.

[0059] This antenna array forms three measurement baselines: the angular measurement antennas A1, B1, C1, D1 form measurement baseline 1, the angular measurement antennas A2, B2, C2, D2 form measurement baseline 2, and the angular measurement antennas A3, B3, C3, D3 form measurement baseline 3; the included angle between the three baselines is 60°; and each baseline is controlled by an independent switch, and the three baselines are symmetrically designed.

[0060] For the convenience of phase ambiguity resolution operation, the lengths of the antenna measurement baselines are designed to meet the following conditions (the three baselines are symmetrically designed, and the A1D1 baseline is described as an example):

[0061] The designed virtual baseline 1 is a baseline without phase ambiguity, and the baseline length A1B1 - C1D1 is less than half of the wavelength of the incident wave; the longest baseline A1D1 (with a baseline length greater than half of the wavelength and having phase ambiguity) is used for angle calculation.

[0062] The baseline ratio T is defined as the length of the guided baseline / the length of the guiding baseline. The baseline ratio T is related to the probability of phase ambiguity resolution. As the baseline ratio T increases, the probability of phase ambiguity resolution will decrease. That is, under the same ambiguity resolution requirements, the larger the baseline ratio T, the higher the measurement accuracy requirement for the antenna phase difference. Therefore, the shortest baseline cannot be directly used to guide the longest baseline for ambiguity resolution operations, but a step-by-step guiding method should be adopted.

[0063] Define the relevant variables used in the calculated values as follows:

[0064]

[0065] The phase calculation method disclosed in the present invention includes:

[0066] 1. Phase ambiguity resolution operation: The present invention uses the virtual baseline without phase ambiguity to gradually guide the longest baseline for phase ambiguity resolution operations. Specifically, virtual baseline 1 (AiBi - CiDi) is used to guide virtual baseline 2 (BiCi - (AiBi + CiDi)), virtual baseline 2 is used to guide baseline CiDi, and baseline CiDi is used to guide the longest baseline A1D1;

[0067] Perform phase ambiguity resolution operations on the three measurement baselines respectively to obtain the unambiguous phase differences of the longest baselines phase_A1D1, phase_A2D2, and phase_A3D3; The phase ambiguity resolution operation for each measurement baseline is:

[0068] (1) Use virtual baseline inv1 to resolve the ambiguity of virtual baseline inv2 to obtain the unambiguous phase difference:

[0069] L_inv1 = L_AiBi - L_CiDi

[0070] L_inv2 = L_BiCi - (L_AiBi + L_CiDi)

[0071] phase_inv1_1 = (phaseAi - phaseBi) - (phaseCi - phaseDi)

[0072]

[0073]

[0074]

[0075] (2) Use the virtual baseline inv2 to resolve the ambiguity of the real baseline CiDi:

[0076]

[0077]

[0078] (3) Use the real baseline CiDi to resolve the ambiguity of the longest baseline AiDi:

[0079]

[0080]

[0081] In the formula, i takes values 1, 2, 3; L_AiBi is the baseline length of AiBi, L_CiDi is the baseline length of CiDi, L_BiCi is the baseline length of BiCi, L_CiDi is the baseline length of AiDi, L_inv1 and L_inv2 are the lengths of the virtual baselines inv1 and inv2 respectively; phase_inv21, phase_CiDi_2, and phase_AiDi_2 are the estimated values of the current baseline differences calculated, phase_inv2_1 is the measured value of the phase difference of the virtual baseline 2, phase_inv2, phase_CiDi, and phase_AiDi are the unambiguous phase differences obtained by solving, phaseAi, phaseBi, phaseCi, and phaseDi are the phase values of Ai, Bi, Ci, and Di respectively, and round is the rounding operation.

[0082] 2. Array plane angle calculation

[0083] After ambiguity resolution, the unambiguous phase differences of the longest baselines phase_A1D1, phase_A2D2, and phase_A3D3 are obtained. Use two groups of baselines to jointly calculate the incident angles (α, β) of the array plane. The definition of the array plane coordinate system is as Figure 2 shown.

[0084] (1) Use two unambiguous longest baselines to form a baseline group, perform sum and difference operations on the baseline group to obtain the sum value (sum_phase) and the difference value (sub_phase);

[0085] (2) Construct an analytical function:

[0086]

[0087] In the formula, j is the imaginary unit, r is the maximum radius of the circular array, λ is the wavelength of the incident wave, α and β are the incident angles of the antenna array plane;

[0088] (3) Calculate the incident angles (α, β) of the array surface using analytical functions

[0089]

[0090] In the formula, arg(f) represents taking the argument of the complex number f, and |f| represents taking the magnitude of the complex number f.

[0091] 3. Calculate the azimuth and elevation angles using the array surface angles

[0092] According to the definitions of the azimuth and elevation angles, the relationships between the azimuth and elevation angles are solved using the array surface angles as follows:

[0093]

[0094] As Figure 3 shown, for the ambiguity resolution operation of this algorithm, the baseline ratio of the guiding baseline and the guided baseline is directly used to calculate the phase ambiguity number of the guided baseline. It only goes through three times of guiding, and each guiding only includes multiplication operations and rounding operations. Compared with the exhaustive method, the exhaustive method needs to exhaust 2K (K is the baseline length / wavelength, in this design, K = 28) possible cases, and perform a correlation operation on the phase differences obtained by calculating the 2K ambiguity numbers and the measured phase differences to obtain the ambiguity number with the minimum error to determine the unambiguous phase difference, greatly reducing the amount of calculation and complexity.

[0095] The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. An antenna array adapted to high-precision angle measurement with an ultra-wide field of view, characterized in that, a number of antennas are arranged on three circular arrays with different radii, forming three independent and symmetric measurement baselines. The difference between the radii of the two smaller circular arrays is less than half the wavelength of the incident wave, and the sum of the diameters of the two smaller circular arrays is greater than the diameter of the largest circular array; 12 angle-measuring antennas are distributed on the three circular arrays: 6 angle-measuring antennas are respectively located at the 6 vertices of the inscribed regular hexagon of the circular array V1 with the largest radius; 3 angle-measuring antennas are respectively located at 3 adjacent vertices of the inscribed regular hexagon of the circular array V2 with the smallest radius; 3 angle-measuring antennas are distributed at 3 vertices of the inscribed regular hexagon of the third circular array V3, and these 3 vertices are on the other side of the 3 vertices where the angle-measuring antennas are placed on the circular array V2; The angle-measuring antennas on the circular arrays V2 and V3 are all located on the symmetry axes of the inscribed regular hexagon of the circular array V1.

2. The antenna array adapted to high-precision angle measurement with an ultra-wide field of view according to claim 1, characterized in that, the multiple of the difference between the sum of the diameters of the two smaller circular arrays and the diameter of the largest circular array relative to the difference between the radii of the two smaller circular arrays, and the multiple of the difference between the radius of the largest circular array and the second smallest circular array relative to the difference between the sum of the diameters of the two smaller circular arrays and the diameter of the largest circular array are equal.

3. The antenna array adapted to high-precision angle measurement with an ultra-wide field of view according to claim 1, characterized in that, the multiple of the difference between the sum of the diameters of the two smaller circular arrays and the diameter of the largest circular array relative to the difference between the radii of the two smaller circular arrays, and the multiple of the diameter of the largest circular array relative to the difference between the radius of the largest circular array and the second smallest circular array are equal.

4. The antenna array adapted to high-precision angle measurement with an ultra-wide field of view according to any one of claims 1-3, characterized in that, the angle-measuring antennas on each measurement baseline are controlled by an independent switch.

5. A phase resolution method for an antenna array adapted to high-precision angle measurement with an ultra-wide field of view, using the antenna array adapted to high-precision angle measurement with an ultra-wide field of view according to claim 1, characterized in that, including: performing phase ambiguity resolution operations on the three measurement baselines respectively to obtain the unambiguous phase difference of the longest baseline; using the phase differences of any two unambiguous longest baselines to construct an analytical function to calculate the incident angle of the array plane; calculating the azimuth angle and elevation angle of the array plane based on the incident angle of the array plane.

6. The phase resolution method for an antenna array adapted to high-precision angle measurement with an ultra-wide field of view according to claim 5, characterized in that, using the virtual baseline without phase ambiguity to guide the longest baseline to achieve phase ambiguity resolution of the measurement baseline.

7. The phase resolution method for an antenna array adapted to high-precision angle measurement with an ultra-wide field of view according to claim 6, characterized in that, performing phase ambiguity resolution operations on the three measurement baselines respectively, including: 1) Using virtual baseline 1 to resolve the ambiguity of virtual baseline 2, where virtual baseline 1 is AiBi - CiDi and virtual baseline 2 is BiCi - (AiBi + CiDi), to obtain the unambiguous phase difference phase_inv2 of virtual baseline 2: L_inv1 = L_AiBi - L_CiDi L_inv2 = L_BiCi - (L_AiBi + L_CiDi) phase_inv1_1 = (phaseAi - phaseBi) - (phaseCi - phaseDi) 2) Use the virtual baseline 2 to resolve the ambiguity of the real baseline CiDi, and obtain the unambiguous phase difference phase_CiDi of the real baseline CiDi: 3) Use the real baseline CiDi to resolve the ambiguity of the longest baseline AiDi, and obtain the unambiguous phase difference phase_AiDi of the longest baseline AiDi: In the formula, i takes values of 1, 2, and 3, and each time a value is taken for the above calculations, and finally the unambiguous phase difference phase_AiDi is obtained; L_AiBi is the baseline length of AiBi, L_CiDi is the baseline length of CiDi, L_BiCi is the baseline length of BiCi, L_AiDi is the baseline length of AiDi, L_inv1 and L_inv2 are the lengths of virtual baseline 1 and virtual baseline 2 respectively; phase_inv21, phase_CiDi_2, and phase_AiDi_2 are the estimated values of the current baseline difference obtained by calculation, phase_inv2_1 is the measured value of the phase difference of virtual baseline 2, phaseAi, phaseBi, phaseCi, and phaseDi are the phase values of Ai, Bi, Ci, and Di respectively, and round is the rounding operation; among them, the angle-measuring antennas located on the largest circular array are denoted as A1, A2, A3, D1, D2, D3, the angle-measuring antennas located on the smallest circular array are denoted as B1, B2, B3, the angle-measuring antennas located on the second largest circular array are C1, C2, C3, and A1, B1, C1, D1 are on the same straight line, A2, B2, C2, D2 are on the same straight line, and A3, B3, C3, D3 are on the same straight line.

8. An antenna array phase resolution method for adapting to ultra-wide field of view high-precision angle measurement according to claim 5, characterized in that the array surface angle resolution includes: (1) Use two unambiguous longest baselines to form a baseline group, and perform sum and difference operations on the unambiguous phase differences of the longest baselines to obtain the sum value sum_phase and the difference value sub_phase; (2) Construct an analytical function: where \(j\) is the imaginary unit, \(r\) is the maximum radius of the circular array, \(\lambda\) is the wavelength of the incident wave, and \(\alpha\) and \(\beta\) are the incident angles of the antenna array plane; (3) Use the analytical function to calculate the array surface incident angles α, β: In the formula, arg(f) represents taking the argument of the complex number f, and |f| represents taking the magnitude of the complex f.

9. An antenna array phase resolution method for adapting to ultra-wide field of view high-precision angle measurement according to claim 5, characterized in that the array surface azimuth and elevation angle resolution includes: Solve the azimuth and elevation angle relationships by using the array surface angles α, β as follows:

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