Development and characterization of active pixel sensors for space applications

Abstract

Since 1993, research concerning CMOS APS (Active Pixel Sensors) has been intensively carried out, in order to offer an alternative to CCDs as an image sensor, particularly in space applications. Many laboratories have demonstrated the feasibility of these new devices and the high level of performances that can be achieved. Nowadays, the first generation of commercial devices becomes available for consumer electronics, and start to be used in many applications such as surveillance micro-cameras, video- conferencing, digital-still cameras. The latest designs have shown that APS is getting closer to the CCD in terms of performance level in scientific applications. APS device offers high potentialities for space applications (low power, low cost, high integration level), and fast improvements will make this sensors available for spacecraft: star tracker, planetary imaging functions, fine guidance sensor... A summary of APS benefits for space applications will be presented in this paper. Recently developed APS image sensors (128 X 128 and 256 X 256 pixels) designed by the Conception d'Imageurs Matriciels Integres (CIMI) group of SUPAERO and jointly tested by CIMI and Matra Marconi Space will be presented. The results demonstrate that standard CMOS process is well suited for image sensors implementation. The trade-off regarding the pixel detector choice (photoMos vs photodiode) will be discussed. Finally, future trends and perspectives for APS applications in space activities will be presented.