Author Affiliations
1Chongqing Key Laboratory of Manufacturing Equipment Mechanism Design and Control, School of Mechanical Engineering, Chongqing Technology and Business University, Chongqing 400067, China2No. 32037 Unit of PLA, Yaoan, Yunnan 675300, Chinashow less
Fig. 1. Principle of MCAO system based on sodium LGSs. (a) Schematic diagram for two-layer turbulent tomography by MCAO system with three sodium LGSs constellation; (b) transformation of coordinates between footprint and meta-pupil, where is for meta-pupil coordinates and is for footprint coordinates
Fig. 2. Gray map of projection matrix for three sodium LGSs constellation
Fig. 3. Simulated results of wavefront reconstruction with two layers of atmospheric turbulence and three sodium LGSs through tomography. Upper row for ground layer turbulence and lower row for high layer turbulence. (a), (d) Initial distorted wavefront; (b), (e) reconstructed wavefront through tomography; (c), (f) residual error
Fig. 4. SR map obtained by MCAO system with three sodium LGSs, with yellow pentagrams representing sodium LGSs
Fig. 5. Performance evolution of 500 frames for MCAO system with three sodium LGSs during 1 s
Fig. 6. Constellations of sodium LGSs with different numbers and located at different positions. (a) 3+1; (b) 4; (c) 4+1; (d) 5; (e) 5+1; (f) 6
Fig. 7. SR maps obtained by MCAO systems for sodium LGS constellations with different numbers and configurations, with yellow pentagrams representing sodium LGSs. (a) 3+1; (b) 4; (c) 4+1; (d) 5; (e) 5+1; (f) 6
Fig. 8. Mean values of SR and STD obtained by MCAO systems for sodium LGS constellations with different numbers and configurations
Fig. 9. Influence of zenith angle of sodium LGSs on performance of MCAO system
Fig. 10. Influence of zenith angle of sodium LGSs on uniformity of MCAO system
Type | Variable | Value | Description |
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Atmosphere | r0 /cm | 8 | Fried parameter(@550 nm) | Fsampling /Hz | 500 | Sampling frequency | Hi /km | 0, 8 | Turbulent layer altitude | Si | 0.7, 0.3 | Turbulent layer relative strength | Telescope | D /m | 10 | Diameter of telescope | /(′) | 1 | Field of view | | H band | Observation band | /(°) | 0 | Zenith angle of telescope | Sodium LGS | HLGS /km | 90 | Altitude of LGSs | n | 3 | Number of LGSs | RLGS /(″) | 41.459 | Zenith angle of each LGS | Azimuth angle /(°) | 0, 120, 240 | Azimuth angle of each LGS | /nm | 589.159 | Wavelength of sodium LGS | M | 0 | Magnitude of LGS | WFS | d /m | 0.4 | Diameter of sub-aperture of WFS | Sub-aperture resolution /pixel | 10×10 | Number of pixel in each sub-aperture | Zernike order | 105 | Order for Zernike polynomials decomposition | K | 25×25 | Sub-aperture number of WFS |
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Table 1. Main parameters for simulation