人们早就利用天上的星星来指路了。比如,北斗星总在地球正北方的上空,晚上赶路的人靠它来辨别方向,就不会走错路。而海上航行的舰船也利用天上的星座来航行。不过,科技的发展使得天上的卫星能主动给人指路了,不仅随时告诉你行走的方向、距离,而且还准确告诉你位置和离目的地的距离,这就是现代卫星导航定位系统。 People have long used the stars in the sky to point their fingers. For example, the Big Dipper is always over the earth just north of the night hurry to identify the direction by which people will not go the wrong way. Vessels at sea also use the constellation of heaven to navigate. However, the development of science and technology makes the satellite in the sky can take the initiative to give directions, not only tell you the direction of walking at any time, distance, but also accurately tell you the location and distance from the destination, this is the modern satellite navigation and positioning system.