Design and implementation of camera CCD readout for a remote sensing LEO satellite

This paper presents the design and implementation of CCD readout circuits for a remote sensing satellite camera in visible band. CCD even and odd pixels are read out independently during image acquisition. The readout board receives control parameters of CCD and A/D such as CCD integration time and required gains of each analogue to digital convertor (A/D) of CCD even and odd channels. A/D gain should be programmed to provide equal amplitudes in 2 CCD channels (odd and even channels) in same conditions. After adjusting the CCD and A/D parameters the image is captured. The required deriving signals for CCD and A/D are generated in CCD readout board. Analogue output of CCD is amplified and then converted to the digital one. In order to decrease the system volume and weight and increase system capability, the timing and control signals are generated via FPGA. Correlated double sampling (CDS) process is performed on CCD output image data to increase the signal to noise ratio. Moreover, in this paper detail design of CCD readout implementation are presented and appropriate electrical elements are selected. Finally, schematic of constructed board of CCD readout circuits is presented.