GPS功能必须具备GPS终端、传输网络和监控平台三个要素；这三个要素缺一不可；通过这三个要素，可以提供车辆防盗、反劫、行驶路线监控及呼叫指挥等功能。用-GPS function must have the GPS terminal, transmission network and monitoring platform three elements these three elements are indispensable through these three elements, ca