参考下这个设计
http://tiaozhanbei.net/project/6536/#:~:text=GPS%E8%87%AA%E5%8A%A8%E5%AF%BC%E8%88%AA%E6%8E%A2%E4%BC%A0%E8%BE%93%E5%88%B0%E8%AE%A1%E7%AE%97%E6%9C%BA%E4%B8%8A%E3%80%82
