The Research On Techniques Of Dignal Generation And Processing For High Dynamic GNSS System

GNSS satellite navigation system is of great significance to the development of national aeronautics and astronautics. Its development not only shows the level of science and technology of a country, but also because GNSS satellite navigation has important applications in aerospace, surveying and transportation, GNSS navigation technology brings huge economic benefits.This subject is aimed at the GNSS high-dynamic navigation system of various modules in-depth study and related design and implementation.Including the design and implementation of GNSS satellite signal regeneration module, the design and implementation of high dynamic receiver motion scene simulation module,the design and implementation of carrier tracking loop algorithm for GNSS carrier receiver that can adapt to high dynamic environment, and the application of Kalman filter .The contents of this paper and the corresponding results are as follows:(1) Introduce the background and development prospect of GNSS navigation satellite system, and discuss the research significance of the subject.(2) The basic principle and working flow of the software of GNSS high dynamic signal and motion scene simulator are discussed, and then the improvement and optimization are made. Based on a JPL high dynamic scene proposed by the American Jet Dynamics Laboratory, a variety of scenarios suitable for multi-mode high dynamic receiver development and testing were designed and successfully applied.(3) GNSS product development, in order to reduce development costs, shorten the development cycle, usually require a signal source system in the simulation of navigation satellite signal generation. In this paper, a regenerative signal source system is designed. The data source is not PC simulation, but real signal. Will be on the day signal demodulation processing, regeneration can be used for experimental development of the signal, more accurate and real-time.(4) carrier receiver in a high dynamic movement, will have a larger carrier Doppler frequency shift, serious even lead to carrier tracking loop lost lock. In order to enable the receiver to track the high dynamic signal stably, this paper designs a short-term cyclic queue algorithm, which can quickly update the high dynamic parameters in the loop to ensure that the loop can keep tracking without loss of lock. Finally, the experiment is carried out and the expected results are obtained.(5) The short-term cyclic queue algorithm does not effectively solve the problem of random noise rejection or suppression in the loop, so this paper proposes a Kalman filter with better processing dynamic noise. On the basis of studying the theory of Kalman filtering process,the Kalman state matrix and the measurement matrix are constructed, and the filter divergence problem is discussed and solved. Finally,the simulation test iscarried out and the experimental results are obtained.