Author Affiliations
1 National Astronomical Observatories, Nanjing Institute of Astronomical Optics & Technology, Chinese Academy of Sciences, Nanjing, Jiangsu 210042, China;2 Key Laboratory of Astronomical Optics & Technology, Chinese Academy of Sciences, Nanjing, Jiangsu 210042, China;3 University of Chinese Academy of Sciences, Beijing 100049, Chinashow less
Fig. 1. Principle diagram of NRM-GS algorithm. (a) Original wavefront; (b) I (ξ,η); (c) wavefront after mask; (d) INRM(ξ,η); (e) fMT of INRM(ξ,η); (f) principle of NRM-GS algorithm
Fig. 2. Flow chart of data processing based on NRM-GS algorithm
Fig. 3. Iteration processes for NRM-GS algorithm with and without phase constraints or ordinary GS algorithm. (a) S curves; (b) ERMS curves
Fig. 4. Recovery of astigmatism aberration. (a) Original wavefront; (d) wavefront after mask; (b)(e) recovered wavefronts by NRM-GS algorithm and GS algorithm; (c)(f) recovered residual wavefronts by NRM-GS algorithm and GS algorithm
Fig. 5. Iteration processes for NRM-GS algorithms with and without phase constraints or ordinary GS algorithm. (a) S curves; (b) ERMS curves
Fig. 6. Recovery of randomly combined wavefront (first 15 terms). (a) Original wavefront; (d) wavefront after mask; (b)(e) recovered wavefronts by NRM-GS algorithm and GS algorithm; (c)(f) recovered residual wavefronts by NRM-GS algorithm and GS algorithm
Fig. 7. Comparison of Zernike polynomial coefficients (first 15 items) of original wavefront with those by NRM-GS algorithm and GS algorithm
Fig. 8. Recovery results of co-phase errors on synthetic aperture telescope. (a) Original wavefront; (b) recovered wavefront by NRM-GS algorithm; (c) recovered residual wavefront by NRM-GS algorithm; (d) wavefront after mask; (e) recovered wavefront by GS algorithm; (f) recovered residual wavefront by GS algorithm
Fig. 9. Iteration processes for NRM-GS algorithms with and without phase constraints or ordinary GS algorithm when co-phase errors on synthetic aperture telescope are detected. (a) S curves; (b) ERMS curves of residual wavefronts on three sub-telescopes
Sub-aperture | Original phase | Initial phase | Initial phase error | |
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NRM-GS piston component | GS random initial phase | NRM-GS piston component | GS random initial phase |
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1 | 0.1789λ | 0.1787λ | 0.1261λ | -0.0002λ | 0.0526λ | 2 | 0.0439λ | 0.0437λ | 0.1197λ | -0.0002λ | -0.0757λ | 3 | 0.2589λ | 0.2587λ | 0.1248λ | -0.0002λ | -0.1341λ | 4 | -0.0870λ | -0.0872λ | 0.1265λ | -0.0002λ | -0.2135λ | 5 | -0.3021λ | -0.3023λ | 0.0278λ | -0.0002λ | -0.3229λ |
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Table 1. Original wavefront phases, initial phases of NRM-GS and ordinary GS algorithms and their errors for six-sub-aperture centers
Single order Zernike term | NRM-GS algorithm | GS algorithm | |
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Residual wavefront ERMS | Number of iteration | Residual wavefront ERMS | Number of iteration |
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3 | 0.0040λ | 91 | 0.1523λ | 105 | 5 | 0.0031λ | 112 | 0.1167λ | 191 | 9 | 0.0145λ | 125 | 0.1096λ | 212 | 11 | 0.0056λ | 97 | 0.1244λ | 129 | 12 | 0.0080λ | 109 | 0.1241λ | 136 | 13 | 0.0123λ | 103 | 0.1248λ | 117 | Average | 0.0079λ | | 0.1253λ | |
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Table 2. Six groups of recovery results of single order Zernike polynomial by NRM-GS algorithm and GS algorithm
Sub-aperture | Original phase | Initial phase | Initial phase error | |
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NRM-GS piston component | GS random initial phase | NRM-GS piston component | GS random initial phase |
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1 | -0.164λ | -0.1521λ | 0.1051λ | -0.0119λ | -0.2791λ | 2 | -0.1284λ | -0.1086λ | 0.091λ | -0.0198λ | -0.2194λ | 3 | 0.0907λ | 0.0861λ | 0.1259λ | 0.0046λ | -0.0352λ | 4 | 0.1995λ | 0.1924λ | 0.1245λ | 0.0071λ | 0.075λ | 5 | -0.1301λ | -0.1212λ | 0.0051λ | -0.0089λ | -0.1361λ | 6 | 0.0887λ | 0.1027λ | 0.1244λ | -0.014λ | -0.0357λ |
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Table 3. Original wavefront phases, initial phases and their errors for six-sub-aperture centers
Number of terms of Zernike polynominals | RMS of original wavefront ϕ0 | NRM-GS | GS | |
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Residual wavefront ERMS | Number of iterations | Residual wavefront ERMS | Number of iterations |
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1(first 15 terms) | 0.1156λ | 0.0088λ | 95 | 0.1241λ | 98 | 2(first 20 terms) | 0.1919λ | 0.0140λ | 112 | 0.1027λ | 127 | 3(first 25 terms) | 0.1048λ | 0.0240λ | 108 | 0.1556λ | 145 | 4(first 30 terms) | 0.1301λ | 0.0099λ | 99 | 0.1342λ | 165 | 5(first 37 terms) | 0.0800λ | 0.0141λ | 110 | 0.1258λ | 128 |
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Table 4. Five groups of recovery results of randomly combined wavefronts by NRM-GS algorithm and GS algorithm
Sub-telescope | Piston error | Tip error | Tilt error |
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123 | 0.0000λ0.2000λ0.0500λ | 0.2000λ0.1254λ0.0752λ | 0.0752λ0.0627λ0.1254λ |
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Table 5. Added co-phase errors on each sub-telescope
Sub-aperture | Original phase | Initial phase | Initial phase error | |
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NRM-GS piston component | GS random initial phase | NRM-GS piston component | GS random initial phase |
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1 | 0.0000λ | 0.0000λ | 0.0235λ | 0.0000λ | -0.0235λ | 2 | 0.0112λ | 0.0011λ | 0.0453λ | 0.0101λ | -0.0341λ | 3 | 0.3734λ | 0.3707λ | 0.1305λ | 0.0027λ | 0.2132λ | 4 | 0.0384λ | 0.0289λ | 0.0973λ | 0.0095λ | -0.0589λ | 5 | 0.0461λ | 0.0378λ | 0.0542λ | 0.0083λ | -0.0081λ |
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Table 6. Original wavefront phases, initial phases and their errors
Co-phase error | Maximum ERMS | Minimum ERMS | Average ERMS | Average number of iteration | | | |
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NRM-GS | GS | NRM-GS | GS | NRM-GS | GS | NRM-GS | GS |
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Piston(10 groups) | 0.0078λ | 0.0741λ | 0.0045λ | 0.0424λ | 0.0056λ | 0.0533λ | 37 | 43 | Tip/tilt(10 groups) | 0.0100λ | 0.1327λ | 0.0037λ | 0.1240λ | 0.0071λ | 0.1267λ | 38 | 49 | Piston, tip/tilt (10 groups) | 0.0064λ | 0.0860λ | 0.0022λ | 0.0423λ | 0.0045λ | 0.0651λ | 40 | 47 |
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Table 7. Recovery results of multigroup co-phase errors