Print SHAN Qing-xiao, CHEN Jian-yun, ZHONG Xiao-peng, YANG Jun
(Mechatronic and Automation School, National University of Defense Technology, Changsha 410073, China)
Abstract: A timing method based on simulated GPS RF signal is proposed for the GPS timing device. By using this method the device can be synchronized with external time without any change making of the original device. At first, the orbit model of GPS satellite is set up and the navigation message is simulated. Then the observation data can be calculated based on the position of device. The navigation data is modulated to the GPS pseudo random code. The pseudo range can be obtained from the observation data and the signal delay is taken into consideration. At last the simulated GPS signal is obtained through orthogonal RF modulation. The established prototype can realize the above simulation procedure and the experiment showed that the timing precision of 10 ns can be obtained by using this method.
Key words: GPS timing; RF signal simulation; time transfer