说明：  是2014-5-19版最新产品程序。在USART2中断程序中获取GPS/北斗定位（时间，经纬度和高度）及可用卫星数和信号强度数据。并确立以北斗优先的原则，只要北斗定位有效，就用单北斗运行，不用GPS。使用和X芯星通UN220 III N模块。
(Get GPS/Beidou (time, latitude, longitude and altitude) in USART2 interrupt program and the number of available satellites and signal strength data. And to establish the principle of priority to the Big Dipper, as long as the Beidou positioning effectively, run with a single Compass, not GPS. Use and UN220 III N module.)