Reserch Of Key Technologies Of Elert Massage Transmition Based On Beidou System

With the climate of global changing in these years, and the special geographical location of China, the lots of disasters occurred, for example as freezing rain, snow, earthquakes and other natural disasters. The part of emergencies of China pays attentions to use alert information to prevent peoples from disasters. Currently, there are many conventional means of communication, such as SMS, telephone, fax, etc., which can be used to transmit early warning information, and which has its specific scope of use and constraints. There are some problems of the conventional means such as time-poor and information covered with blind spots problems. Therefore, researching a mean to transmit alert message is required with all coverage, timely and efficientThe key technology of alert message transmission based on Beidou satellite is the main content of this paper. The key technologies contain the use of broadcast mode of Beidou system to transmit early warning information timely; the packet protocols for long alert message transmitting; the code rules of area for sending and receiving alert message accurately; using application layer redundancy coding scheme to resolve the accurate of transmission.We design interrelated protocols and simulate. We construct the module of alert transmit system based on Beidou satellite system corresponding the research of this paper. And the actual test verified the feasibility of the research of this paper.The alert message transmit system based on Beidou satellite can solve the remote rural areas, mountains, sea area, where the conventional communicate network can't cover, to resolve "the last one mile"problem of the alert message transmission, which gives a new method of alert information transmission.