| Global navigation satellite system can provide continuously, high-precision three-dimensional position, velocity and time at any time based on timing, distance surveying and space rendezvous. However, its performance may be subjected to the environment impact including the signal interference and dynamic factors. Since inertial navigation system is regarded as a reliable way for obtaining navigation information, INS/GNSS integrated navigation system based on their complementary nature has been constantly under development and improvement. In recent years, in order to satisfy the performance requirements of anti-jamming and high dynamic adaptation for satellite navigation, the ultra-tightly coupled INS/GNSS technology has been proposed and developed gradually. Therefore, it is rather important and significant in studying and analyzing such key issues: architecture design, integration models and coupling mechanism.This paper mainly focuses on the research on baseband signal processing including signal acquisition and tracking algorithms for Beidou software receiver. Then, the ultra-tight integration architecture and models, coupling mechanism and anti-jamming performance test and analysis in high dynamic environment have been studied. Furthermore, an adaptive robust ultra-tightly coupled algorithm has been proposed to solve the disturbance impact for navigation solutions. Finally, the ultra-tight receiver and ultra-tightly coupled test system has been developed and designed based on FPGA and DSP. The main work includes the following aspects:Firstly, the architecture and the signal acquisition and tracking algorithms for the Beidou software receiver have been studied. Based on analysis of the characteristics of GPS and Beidou signals modulation, a simultaneous multiple satellite signal acquisition algorithm based on parallel phase search method is proposed. Furthermore, the validity and reliability of the acquisition results are enhanced using the coherent accumulation approach. Then, the computation efficiency and test performance are compared between different acquisition algorithms for software receivers.Secondly, the theory of signal tracking and demodulation has been studied. The intrinsic relationships between the phase and frequencies measurements of loop signals and receiver states have been analyzed. Moreover, the model and the principle of vector tracking loop have been designed and analyzed. Then, with analysis of the computation load for each module in the signal processing, a multiple channels’ signal vector tracking algorithm based on fast correlation operations has been proposed. In addition, the parameters optimization method based on robust estimation has further been studied. Finally, the comparison between the scalar and vector tracking algorithms has been given to demonstrate the tracking capacity in high dynamic and weak signal environment.Thirdly, the vector tracking algorithm only exploits the receiver states to generate the replica signal, which may lead to the loose lock of loops in a high dynamic environment. To solve this problem, the ultra-tight GNSS/INS integration has been studied. Based on the analysis of the architecture, model and scheme for the typical ultra-tightly coupled GPS/INS system, the core features and the intrinsic relevance between phase and frequency biases of replica signals and INS states are analyzed to represent the deep fusion of INS and the tracking loop. Meanwhile, an ultra-tight integration algorithm based on the vector loops pre-filters has been proposed and the commands for replica signals generation with INS information have been given. Finally, semi-physical simulation tests are carried out to demonstrate the stress adaptation performance and anti-jam capability in the high dynamic and jamming environments.Besides, a small perturbation appeared in the ultra-tightly coupled navigation solutions when high jamming was encountered. In this situation, to decrease the influence of the disturbance and high dynamic to the ultra-tightly coupled system, an adaptive robust ultra-tightly coupled algorithm based on the optimization factor has been proposed further. Finally, the performance tests of the proposed approach in a large maneuvering and signal jamming environment have been shown and analyzed, compared with multiple ultra-tightly coupled GNSS/INS algorithms.Finally, the hardware system of ultra-tight receiver has been developed and the ultra-tightly coupled test system has been designed, which both are implemented using FPGA and DSP. And the signal processing modules have been studied in both FPGA and DSP, such as local carrier generation module, local code generation module, correlation module and bit synchronization/frame synchronization module in FPGA, which has collaboration with DSP that deals with ephemeris parameters demodulation, local signal control and integrated navigation computation. Finally, the real data has been used to demonstrate the performance of pre-filters and the controlled tracking loops for ultra-tightly coupled INS/GNSS system.The research work in this dissertation lays a technology requirement for ultra-tightly coupled INS/GNSS integration, the thorough and systematic research on Beidou receiver baseband signal processing and ultra-tight integration theory have been carried out, which provide theory foundation and technology support for ultra-tightly coupled hardware system development.
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