The Design And Implementation Of Communication System Based On Inmarsat And GPS

Nowadays, cellular communication is one of the most popular of communication. Yet the usual way of communication through cellular system would be unaccessible in certain environment since there’re specific environment requirement for setting up of cells, like in the desert, the sea and the air. Based on geostationary Inmarsart satellites, Inmarsat communication covers most of global area, despite of various topographic conditions. This thesis is to design and implement satellite communication and location system based on Inmarsat communication module and GPS location module.Requirements for satellite communication system vary and change frequently, which raise the cost to develop different requirement for customers in perspective of development time and maintenance. Lua script is new solution for customer configuration. User can realize their special requirement just through Lua scripts, which is more human friendly and understandable. On the other hand, script issues won’t affect host program, which are the main features the whole system. Thus using Lua script makes the system more stable.In this thesis, satellite and location system architecture are designed in layers. Whole system is divided into four layers, which are script configuration layer, application layer, GPS and Inmarsat module management layer and ThreadX platform abstraction layer from top to bottom. Lua script configuration layer allows the user to realize communication and location logics and parameter settings through Lua script. Application layer provide interface for Lua scripts, including geofence, auto report and odometer computation. GPS and Inmarsat module management layer drives GPS and Inmarsat module and offer significant services to upper layer, which includes turn on and off GPS/Inmarsat module, get GPS location information, send and receive Inmarsat messages. At the bottom, ThreadX platform abstraction layer provide platform interfaces such as file system interface, GPIO and general serial communication APIs, based on ThreadX real-time operation system.As the last part, stability is significant for embedded system, which makes overall unit tests a key part in embedded system development. For a system contains hundreds of serial interface commands, manual test waste too much time and energy. Thus in this thesis automatic unit test including automatic script generator and Gtest become important way to solve the test problem. Based on automatic tests and performance analysis, this thesis verifies realization of satellite and location system requirements.