CN-121995625-A - Multi-target collaborative optimization design method of space gravitational wave telescope and space gravitational wave telescope

CN121995625ACN 121995625 ACN121995625 ACN 121995625ACN-121995625-A

Abstract

The invention discloses a multi-target collaborative optimization design method of a space gravitational wave telescope and the space gravitational wave telescope, which solve the technical problems that the existing space gravitational wave telescope design method is difficult to consider wavefront quality, TTL noise suppression, backward stray light control and engineering adjustment feasibility, and the core is that TTL noise is used as a direct optimization target parallel to wavefront errors, and a minimum Prewitt gradient weighting combined optimization algorithm is utilized to design the space gravitational wave telescope with high robustness to angular shake and platform micro-vibration.

Inventors

REN ZHIGUANG
LI XUYANG
YUAN HAO
WANG WEI
CHAI WENYI
WU MENGYUAN
YI HONGWEI

Assignees

中国科学院西安光学精密机械研究所

Dates

Publication Date: 20260508
Application Date: 20260408

Claims (10)

1. The multi-target collaborative optimization design method of the space gravitational wave telescope is characterized by comprising the following steps of: S1, constructing an initial structure of a space gravitational wave telescope and acquiring initial structural parameters, wherein the initial structure comprises a main mirror (1), a secondary mirror (2), a third mirror (4), a fourth mirror (5) and an aperture diaphragm (6), a far-field emission end laser signal is incident to the main mirror (1), sequentially passes through the main mirror (1) and the secondary mirror (2) to be imaged at an intermediate image plane (3), and sequentially passes through the third mirror (4) and the fourth mirror (5) to be reflected and then is emitted to the aperture diaphragm (6) in parallel; The structural parameters comprise a reflecting surface type, a vertex curvature radius, a quadric surface coefficient and a distance between the reflecting surface type, the vertex curvature radius, the quadric surface coefficient and the secondary mirror (2) of the primary mirror (1), a distance between the reflecting surface type, the vertex curvature radius, the quadric surface coefficient and the intermediate image surface (3) of the secondary mirror (2), an inclination angle of the intermediate image surface (3) and a distance between the intermediate image surface and the third reflecting mirror (4), a reflecting surface type, an inclination angle, an inclination type and a distance between the reflecting surface type, the inclination angle and the fourth reflecting mirror (5) of the third reflecting mirror (4), and a distance between the reflecting surface type, the inclination angle and the aperture diaphragm (6) of the fourth reflecting mirror (5); s2, determining the numerical value and the spatial distribution characteristics of TTL noise of an initial structure in a full aperture and a full view field by adopting a minimum Prewitt gradient weighting combined optimization algorithm; S3, constructing an error control function based on multi-objective cooperation according to the numerical value and the spatial distribution characteristics of TTL noise; S4, taking the error control function as an evaluation function, inputting the initial structural parameter into the optical design software, and inputting the error control function into a macro program for optimizing the optical parameter; S5, based on the optimized structural parameters, analyzing whether each tolerance of the initial structure meets a preset tolerance, if not, returning to the step S4 after adjusting the weight factor of the error control function, and if so, executing the step S6; S6, analyzing whether all stray light of the initial structure meets preset indexes or not based on the optimized structural parameters, if not, adjusting the weight factors of the error control function, and returning to the step S4, and if so, using the optimized structural parameters as design parameters of the space gravitational wave telescope to finish the design of the space gravitational wave telescope.
2. The multi-objective collaborative optimization design method of the space gravitational wave telescope according to claim 1, wherein step S2 is specifically as follows: s2.1, dividing the full view field of the initial structure into m multiplied by n view field grids, and sampling point coordinates of the current view field grid Initializing to , , wherein, , ; S2.2, calculating a full aperture optical path distribution matrix of a predefined central view field; S2.3, calculating the optical path of the current view field grid at the exit pupil position; s2.4, sequentially calculating optical paths of different apertures of the initial structure at the exit pupil position based on the optical path of the current view field grid at the exit pupil position to obtain a full aperture optical path distribution matrix of the initial structure at the exit pupil position under the current view field grid; s2.5, calculating a deviation matrix of a full-aperture optical path distribution matrix of the current view field grid and a full-aperture optical path distribution matrix of the central view field; s2.6, calculating the numerical value and the spatial distribution characteristic of TTL noise at the sampling point position of the current field grid according to the deviation matrix; s2.7, order Judging Whether or not it is true, if so, according to , Determining the current view field grid again, returning to the step S2.3, and if not, executing the step S2.8; S2.8, order Judging Whether or not it is true, if so, according to , Determining the current view field grid again, returning to the step S2.3, if not, obtaining the numerical value and the spatial distribution characteristic of TTL noise at the sampling point positions of m multiplied by n view field grids, and executing the step S2.9; S2.9, determining the numerical value and the spatial distribution characteristic of the TTL noise of the initial structure in the full aperture and the full view field according to the numerical value and the spatial distribution characteristic of the TTL noise at the sampling point positions of the m multiplied by n view field grids.
3. The multi-objective collaborative optimization design method for a space gravitational wave telescope according to claim 2, characterized in that: in step S3, the error control function based on multi-objective synergy is constructed as follows: ; in the formula, As a function of the control of the error, For the wavefront error of the spatial gravitational wave telescope at the exit pupil position, Is that Weight factors of (2); For the numerical size and spatial distribution characteristics of TTL noise in the full aperture of the effective field of view at the exit pupil location, Is that Weight factors of (2); For the errors caused by the guarantee of the structural parameters, Is that Weight factors of (2); represented in the full field of view Sampling point coordinates of an internally divided field of view grid , Representing coordinates of sampling points Is a trace of the area of (a).
4. The multi-objective collaborative optimization design method for a space gravitational wave telescope according to claim 3, wherein the method comprises the following steps: in step S1, when the initial structure of the space gravitational wave telescope is constructed, a mathematical relationship model of the inclination angle of the third reflecting mirror (4) and the inclination angle of the fourth reflecting mirror (5) is established through geometrical optical analysis: ; in the formula, Is the parallelism error of the incident light ray at the entrance pupil position and the emergent light ray at the exit pupil position of the space gravitational wave telescope, and the value of the parallelism error satisfies the following condition , Is the inclination angle of the middle image plane (3), Is the inclination angle of the third reflecting mirror (4), Is the inclination angle of the fourth reflecting mirror (5); In step S1, when the initial structure of the space gravitational wave telescope is constructed, the following conditions should be satisfied when the inclination angles of the third reflecting mirror (4) and the fourth reflecting mirror (5) are set: 。
5. The multi-objective collaborative optimization design method for a space gravitational wave telescope according to claim 4, wherein the method comprises the following steps: In step S1, an initial structure of the space gravitational wave telescope is constructed by adopting a mirror image splicing strategy.
6. A space gravitational wave telescope is characterized in that the space gravitational wave telescope is obtained by adopting the multi-target collaborative optimization design method of any one of claims 1-5, and comprises a primary mirror (1), a secondary mirror (2), a third reflecting mirror (4), a fourth reflecting mirror (5) and an aperture diaphragm (6), a far-field emission end laser signal is incident to the primary mirror (1), is imaged at an intermediate image plane (3) through the primary mirror (1) and the secondary mirror (2) in sequence, is reflected through the third reflecting mirror (4) and the fourth reflecting mirror (5) in sequence, and is emitted to the aperture diaphragm (6) in parallel.
7. The space gravitational wave telescope of claim 6, wherein: The reflecting surface of the primary mirror (1) is quadric, the radius of curvature of the vertex is-1298.56 +/-20 mm, the coefficient range of the quadric is-1+/-0.22, and the distance range between the secondary mirror and the primary mirror (2) is-625.78 +/-12 mm; The reflecting surface of the secondary mirror (2) is hyperboloid, the radius of curvature of the vertex is-49.105 +/-5 mm, the coefficient range of the quadric is-1.187 +/-0.22, and the distance range between the secondary mirror and the intermediate image surface (3) is 547.87 +/-10 mm; the distance between the intermediate image plane (3) and the third reflecting mirror (4) is 251+/-10 mm, and the inclination angle is-0.75+/-0.45 degrees; the type of the reflecting surface of the third reflecting mirror (4) is a 2-order free curved surface, and the distance between the third reflecting mirror and the fourth reflecting mirror (5) is-92.48+/-12 mm; The type of the reflecting surface of the fourth reflecting mirror (5) is a plane, and the distance between the fourth reflecting mirror and the aperture diaphragm (6) is 270+/-9 mm.
8. The space gravitational wave telescope of claim 7, wherein: the inclination angle of the third reflecting mirror (4) satisfies The tilt type is eccentric bending; The inclination angle of the fourth reflecting mirror (5) satisfies The tilt type is eccentric bending.
9. The space gravitational wave telescope of claim 8, wherein: The reflecting surface type of the main mirror (1) is a quadric surface, the vertex curvature radius is-1298.56 mm, the quadric surface coefficient is-1, the distance between the reflecting surface type of the main mirror and the secondary mirror (2) is-625.78 mm, the reflecting surface type of the secondary mirror (2) is a hyperboloid, the vertex curvature radius is-49.105 mm, the quadric surface coefficient is-1.187, the distance between the reflecting surface type of the secondary mirror and the intermediate image surface (3) is 547.87mm, the inclination angle of the intermediate image surface (3) is-0.75 degrees, the distance between the reflecting surface type of the intermediate image surface and the third mirror (4) is 251mm, the reflecting surface type of the third mirror (4) is a 2-order free-form surface, the inclination angle is 12.5 degrees, the inclination type is eccentric bending, the distance between the reflecting surface type of the third mirror and the fourth mirror (5) is-92.48 mm, the inclination angle is-12.125 degrees, and the distance between the reflecting surface type of the reflecting surface of the fourth mirror (5) and the aperture diaphragm (6) is 270mm.
10. A receiving end of a remote laser communication system is characterized in that the receiving end is obtained by adopting the multi-target collaborative optimization design method of the space gravitational wave telescope according to any one of claims 1-5, and comprises a primary mirror (1), a secondary mirror (2), a third mirror (4), a fourth mirror (5) and an aperture diaphragm (6), a far-field transmitting end laser signal is incident to the primary mirror (1), is imaged at an intermediate image plane (3) through the primary mirror (1) and the secondary mirror (2) in sequence, is reflected by the third mirror (4) and the fourth mirror (5) in sequence, and is emitted to the aperture diaphragm (6) in parallel.

Description

Multi-target collaborative optimization design method of space gravitational wave telescope and space gravitational wave telescope Technical Field The invention relates to a space gravitational wave telescope, in particular to a multi-target collaborative optimization design method of a space gravitational wave telescope and the space gravitational wave telescope designed by the design method. Background The optical performance requirements of a space gravitational wave telescope are essentially different from those of a traditional astronomical telescope. In order to ensure the inter-satellite laser interferometry accuracy, the method not only requires higher wavefront quality to ensure the wavefront accuracy after ultra-long distance propagation, but also requires ultra-high optical path stability and ultra-low stray light level. The jitter and wavefront error coupling generated by the satellite platform where the test mass block is located, and TTL (time to length) noise introduced by the non-uniformity of the wavefront distortion distribution at the entrance pupil are key factors for restricting the optical path stability. The principle of the method is that the emergent wave front approaches to a single curvature spherical wave by minimizing the residual wave aberration of an optical system, so that the difference of wave fronts in all directions in the visual axis jitter range is reduced, and the aim of suppressing TTL noise is fulfilled. However, this conventional method has the following inherent drawbacks: 1) The realization difficulty of high-precision processing and surface ultra-smooth processing is greatly improved due to the high-order complex surface shape introduced for extremely optimizing the wavefront error, and when the surface roughness is difficult to reach 5A or even 2.5A, the backward scattering caused by the surface defect can not be effectively inhibited, so that the problem that the requirements of low TTL noise and low backward stray light distribution are difficult to be met is solved. 2) The extremely high wavefront quality requirement makes the space gravitation wave telescope extremely sensitive to the adjustment tolerance, the design method based on complex surface shape combination has the advantages of more adjustment dimension, small tolerance and difficulty in realization due to the fact that the capability of the existing process is easily exceeded, the all-microcrystalline glass hydroxyl catalytic bonding process used in the adjustment process has irreversibility, and once solidification lacks a later adjustment compensation space, the almost harsh requirement is provided for the initial adjustment tolerance, and the failure risk is increased due to the excessively high adjustment error, so that the problem that the requirements of low TTL noise and high adjustment tolerance are difficult to be simultaneously achieved is solved. 3) The traditional design often needs to make a difficult trade-off between complex free-form surfaces and ultra-smooth processing, i.e. back scattering suppression, and is difficult to simultaneously meet the severe background noise index of scientific measurement. In order to avoid the sensitivity of high-order complex surface shapes and tolerances, a simple spherical or low-order aspheric design is often adopted, and the design mode is at the expense of system compactness, so that the axial size and the whole volume of the space gravitational wave telescope are obviously increased, and in space application, the space gravitational wave telescope is directly converted into more serious thermal control challenges and lower structural natural frequency, thereby being unfavorable for realizing ultrahigh optical path stability. Disclosure of Invention The invention aims to solve the technical problems that the existing space gravitational wave telescope design method is difficult to consider wavefront quality, TTL noise suppression, backward stray light control and engineering adjustment feasibility, and provides a multi-target collaborative optimization design method of a space gravitational wave telescope and the space gravitational wave telescope. In order to achieve the above purpose, the technical solution provided by the present invention is: the multi-target collaborative optimization design method of the space gravitational wave telescope is characterized by comprising the following steps of: S1, constructing an initial structure of a space gravitational wave telescope and acquiring initial structural parameters, wherein the initial structure comprises a primary mirror, a secondary mirror, a third reflecting mirror, a fourth reflecting mirror and an aperture diaphragm, a far-field emission end laser signal is incident to the primary mirror, sequentially imaged at an intermediate image plane through the primary mirror and the secondary mirror, sequentially reflected by the third reflecting mirror and the fourth reflecting mirror, and then