Research And Design Of The Key Technology In GALILEO Receiver System

Galileo is Europe's own satellite wireless navigation system. Minister of each country's ministry of communications in European Union formally subscribed the agreement and started to build on March 2002. It is forecasted to be launched into use in 2008, which is the terminative sign of American GPS system's being the champion in the world. Our country subscribed the technological cooperation agreement of China's participation into the Galileo scheming on October 2004. China agreed to invest a total of 200 million euros, which signed a huge pace of national spaceflight project walk up to Europe in international cooperation field. Under this developing background of international navigation system, the research of Galileo receiver system has much importance.The paper begins with the structure and composing of Galileo system. The signal structure and service mode are introduced, spread spectrum communication theory-communication basis of system and positioning principle are discussed, and the factors that influence positioning precision are analyzed. In spread spectrum communication, the key technology of receiver system is to realize the fast capture and credible track of spread spectrum signal. On the basis of Galileo system's characteristic and consulting a large quantity of datum concerning satellite navigation and spread spectrum receiver both at home and abroad, the text presents a parallel fast acquisition mode called FFT-based algorithm and expatiates it theoretically and through mathematical discursion; With unknown frequency and phase of carrier, the Galileo receiver adopt noncoherent early-late tracking loop (DDLL) and digital Costas loop (DPLL) to realize credible track of PN code and carrier. The paper traverses the math model of DDLL loop and discussed the performance in linear and non-linear situation in detail. The math model and linear characteristic of DPLL loop are presented and the stable condition is achieved.The multi-path effect in Galileo receiver and loop track error caused by multi-path effect are discussed, two methods of eliminating multi-path effect are presented. Finally, the structure frame of single-channel signal processing module is given, the circuit design of DCO module of PN code and carrier is realized; the...