Analyze and design of signal generator for regional radio navigation system

The navigation signal generator is an essential device in radio navigation and position system. The technique scheme of regional radio navigation system is briefly presented, and the signal generator of the navigation system is analyzed and designed in detail. Adopting the direct digital synthesis (DDS) to generate the pseudo random code clock which has high precision and high stability, and using the special function of DDS chip AD9854 to realize BPSK modulation, meanwhile the CPLD device is introduced to design the spread spectrum PN code generator and the spread spectrum modulator. The paper focuses on some key techniques of the time synchronization for each terrestrial navigation station is discussed. The results from the practical measurement indicate that the signal generator has high precision and nice stability; moreover BPSK modulation realizes the carrier suppression with good concealment and strong anti-jamming ability.