Research On Ultra-tight SINS/GPS Integrated Navigation System

The Strap-down Inertial Navigation System (SINS) and Global Positioning System (GPS) are highly complementary to each other. The full fusing SINS with GPS can meet the high accuracy, high continuity and high reliability navigation requirements. Ultra-tight integration changes the structure of traditional GPS tracking loops. It can enhance receiver's signal processing and anti-jamming capability. In this paper, this level of coupling is referred to as ultra-tight integration and the related technology are researched. The main works include:1. The theory of SINS has been introduced briefly, and the gyroscopes, accelerometers, as well as the carrier's trajectory and attitude have been simulated. At last, the high-dynamic GPS IF signal has been generated by Matlab software.2. The traditional FFT parallel acquisition algorithm is used to accomplish the code phase and Doppler frequency estimation. In order to effectively reduce the average acquisition time and improve capture performance, velocity information from SINS is used to remove the Doppler frequency.3. The main sources of the thermal noise and the impact of dynamics in the Phase Lock loops (PLL) and Delay lock loops (DLL) are analyzed, and they have a conflict on the design of PLL. In order to remove the impact of Doppler shift in high dynamics, reduce thermal noise and improve tracking performance, the structure of SINS-aided GPS receiver tracking loop was designed.4. With GPS and SINS error equation, the position, velocity integration and the pseudo-range, pseudo-range rate integration are established respectively. According to the result of simulation, we can conclude: The pseudo-range, pseudo-range rate model can accomplish the high accuracy navigation.