Visitors look at a model simulated the Beidou Satellite Navigation System displayed by the China Aerospace Science and Technology Corporation, during the 9th China International Aviation and Aerospace Exhibition in Zhuhai, south China's Guangdong province, Nov. 13, 2012. Some 650 manufactures at home and abroad attended the six-day airshow kicked off on Tuesday, which was expected to receive 400,000 visitors. [Photo/Xinhua]