Query: How many satellites does the BeiDou-1 have?
Context: The first BeiDou system, officially called the BeiDou Satellite Navigation Experimental System (simplified Chinese: 北斗卫星导航试验系统; traditional Chinese: 北斗衛星導航試驗系統; pinyin: Běidǒu wèixīng dǎoháng shìyàn xìtǒng) and also known as BeiDou-1, consists of three satellites and offers limited coverage and applications. It has been offering navigation services, mainly for customers in China and neighboring regions, since 2000.