Modeling And Simulation Of A SysML Based Beidou Receiver

In recent years, the functionality of electronic system is getting richer, as the same time, its complexity is also rising. Various design tools and methods for complex systems have emerged. The satellite navigation system is also a complex electronic system with many disciplines. With the continuous development and perfection of Beidou satellite navigation system, it is very important to find an effective design method to accelerate its industrialization and application. Based on this and combined with the application of microstrip antenna, this paper takes the receiver of the Beidou navigation system as the research object, introduces the idea of model-based system engineering, uses IBM Rational Rhapsody as the modeling tool, uses System modeling language, does some exploration and research of the Beidou receiver system for the analysis and architectural design. Based on the methodology of model-based system engineering, this paper uses SysML to build the system model of Beidou receiver in Rhapsody.The work of this paper mainly reflected as follows:First, the visualization of the model as the center, driving the entire Beidou receiver system design process. Based on the analysis of the system requirements of Beidou receiver, so divide the Beidou receiver into three modules: antenna, RF front end and baseband processing subsystem.Secondly,using the static view of the Beidou receiver system to describe its structure and functional components, so as to the three modules for their detailed design and carding. The main design parameters of the antenna module are constrained.Defining the type and main parameters of the devices contained in the RF front end, as well as the internal module diagram to describe the connection between the devices.Based on these views and parameters, use the ADS to simulate the RF link gain requirements, and distribute it rationally. Divide the baseband processing subsystem into four modules: capture, tracking, telemetry and positioning calculation. According to the working principle of each module, topology of their static model view.At the same time, establish the dynamic interaction view between the modules of the baseband processing subsystem and the activity diagram of the internal data processing flow of each module, to describe the logic function of the baseband processing subsystem.Thirdly, according to the interactive logic and control flow described in these views, code the corresponding program of each module in MATLAB. That used to achieve the Beidou navigation signal capture processing, track processing, message demodulation and location solution, and ultimately to achieve positioning function. In this paper, based on the parallel code acquisition algorithm, study the parallel code search acquisition that combined with non-coherent accumulation, to improve the sensitivity of signal acquisition and give the comparison result.Finally, through the integration of each module, the collected off-line IF data files are analyzed and output, and the corresponding results of each module of the baseband processing subsystem are output. Using the graphical results show that the function of the Beidou receiver.