Abstract:To guarantee the launching of the rocket in zero window, this article designs a software method based on IRIG-B code for testing and launching (hereinafter referred to B code for short) for rocket, to ensure the system process synchronized from 10 minute before the ignition to ignition. We can use the receiving time of B code got by UDP network to update the local B code time through redundancy algorithm. With the newest local B code time and the default set fire time, we can calculate the countdown to execute the process automatically.