The modulation technologies of L1 signal in GPS/Galileo system have reached many achievements. The chaotic-BOC modulation showed the new usage of signal modulation in Galileo satellite communication. The Lü system (LS) chaos sequence has perfect chaotic characteristic in three -dimension discrete dynamic systems; especially the three-dimension data can be three orthogonal components. From the acquisition and positioning of L1 signal, the chaotic-BOC modulation technology was a right way to choose. The positioning way need the three parameters of the satellite at least here just use the three-dimension chaos system which could be used the three received signals demodulated to get the synchronized signals. These three parts used the Lü system chaotic sequence to solve the spread spectrum communication. Some simulation figure and data illustrated the chaotic system performance which approached to the original PN in GPS/Galileo system. As L1 signal is for civil application and open service, the chaotic way was significant for the future use.