A High Resolution TDI CCD Camera for Microsatellite (HRCM)
- Paper ID
IAF-02-B.3.08
- author
- company
Tsinghua Space Center, Tsinghua University
- country
China
- year
2002
- abstract
A 1m pixel resolution and lightweighted TDI CCD (Time Delay Integration Charge Coupled Devices) camera for microsatellite is proposed in this paper. And the choice of optical system configuration is mainly discussed. In the scheme selected the on-axis TMA (Three Mirror Anastigmat) is applied for the system design, and it consists of a interval image and real exit pupil to be convenient for rejecting stray light of the system. In the system there is a small size fold mirror for folding the system outer size. Moreover the subpixel imaging scheme is presented to increase the imaging resolution from Nyquist frequence to double it. In the scheme the SiC (Silicon Carbide) and C-C (Carbon Compound) materials are used for mirrors and part of mechanical structure correspondingly. Compact optical design and subpixel imaging technique and light weight materials limit the mass of the system less than 20kg. The optical design results are illustrated besides, and the mechanical structure and optical alignment precept are discussed in the paper. And the MTF (Modulation Transfer Function) of the global system is estimated also. Design results are that FOV is 2°, the focal length is 3000mm, the relative aperture is 1/11, and the detector size is 12288x128 elements by 8.75pm per pixel.