(1) Module working voltage: the working voltage of the terminal comes from the on-board battery, which is usually 12V or 24V, and the module voltage should be less than the power supply voltage;

（2）通讯方式：可采用无线网络和短信息方式通讯；（3）终端在线率：为了确保终端与监控数据交流的实时性，终端应保持高在线率；

(2) Communication mode: wireless network and short message communication can be used; (3) terminal online rate: in order to ensure the real-time data exchange between the terminal and the monitoring center, the terminal should maintain a high online rate;

（4）丢包率：丢包率是指测试中，所丢失数据包数量占所发送数据包的比率，为了降低数据丢包率，在设计中可以考虑，发生无线传输模块不能连接网络，导致终端不能登录系统的情况时，待无线传输模块脱离盲区后，将数据补传服务器；

(4) Packet loss rate: the packet loss rate refers to the ratio of the number of lost packets to the transmitted packets in the test. In order to reduce the packet loss rate, it can be considered in the design that when the wireless transmission module cannot connect to the network and the terminal cannot log in to the system, the data will be transmitted to the server after the wireless transmission module is out of the blind zone;

（5）定位精确度：车辆监控调度系统的电子地图精度数量级是米，我国二级道路的标准宽度为 30~60m，如果要对车辆进行准确的监控，定位精度需控制在30m 以内，否则，当两条道路的距离过近时，就可能出现定位错误，即正在某条公路上行驶的车辆被定为在道路外或其它道路上。

(5) Positioning accuracy: the order of magnitude of the electronic map accuracy of the vehicle monitoring and dispatching system is meters. The standard width of the secondary road in China is 30 ~ 60m. If the vehicle is to be accurately monitored, the positioning accuracy should be controlled within 30m Otherwise, when the distance between the two roads is too close, positioning error may occur, that is, the vehicle driving on a certain road is determined to be outside the road or on other roads.