Fig. 1. Schematic of light source scanning on slit object plane

Fig. 2. Schematic of image quality measurement based on virtual knife edge method

Fig. 3. The optical layout of R channel of NGPS

Fig. 4. Energy distribution of oversampled and under-sampled image at center wavelength 677.5 nm of R channel

Fig. 5. Simulation results of ESF and LSF for point light source with incident focal ratio of f/16 at the center wavelength 677.5 nm

Fig. 6. Overall structure of NGPS and light source scanning system

Fig. 7. The dispersion spectrum of CCD plane located in the center of image plane and oversampled image at 693 nm of the center holes array

Fig. 8. The ESF and LSF of the center hole edge at 693 nm measured by straight edge method

Fig. 9. The ESF and LSF of 25 μm pin hole at 693 nm measured by virtual knife edge method

Fig. 10. The LSF of 117 μm square hole at 689 nm， 693 nm and 701 nm measured directly by oversampling

Fig. 11. The ESF and LSF of 117 μm square hole at 689 nm， 693 nm and 701 nm measured by virtual knife edge method