The Design And Realizition Of Maritime Satellite Telephone Terminal Based On GSPS

The main application scenarios of satellite phones are deserts,mountains,and oceans where the population is sparse and ordinary base stations are not easy to set up.Because it relies on satellites as a relay,the price is usually higher,but the signal and voice quality is relatively poor.Even so,its role in certain fields(such as military,cultural communication,ocean going,expedition,etc.)cannot be replaced by other conventional communications.This thesis studies and implements a "Maritime Satellite Phone Terminal Based on Global Satellite Phone Service(GSPS)",which is mainly used in ocean scenarios.Due to the ship’s changing course and fluctuating sea level,the satellite telephone antenna also has some requirements: target tracking angular velocity:≥1°/s,antenna rotation angular velocity: ≥60°/s;real-time satellite capture and seamless switching of ephemeris.Firstly,this thesis introduces the development of maritime satellite communication system and the market situation of maritime satellite telephone terminal.Then,the core design idea of this thesis is elaborated: in hardware,modular design is adopted to facilitate deployment on board and after-sales maintenance;in software,the robustness,stability and isolation of software communication are ensured by establishing communication protocol and introducing embedded operating system.The key work of this thesis is to solve many problems and challenges faced by maritime satellite telephone terminals through specific hardware and software design.Firstly,the satellite telephone is divided into two parts: the main unit in the cabin and the antenna control unit outside the cabin through modular design,which effectively solves the problem of antenna blocking in the cabin and increases the signal-to-noise ratio of the antenna signal;secondly,the data transmission and power supply with the antenna control unit outside the cabin are realized by using the shielded twisted pair cable with strong anti-interference ability through the Power supply Over Ethernet(POE),It effectively suppresses the interference to other electromagnetic equipment on the same ship,as well as the interference introduced from other equipment;thirdly,it introduces embedded operating system and graphics library,which provides a more friendly human-computer interface and richer functions than similar products at home and abroad;fourthly,it adopts the transmission of digital signal between the main engine unit and the antenna control unit outside the cabin,which is better than the analog voice signal The signal has stronger anti-interference ability,so it has better voice quality.Fifth,the extravehicular antenna unit is based on the ring-focus antenna,and the feed corrugated horn is the core,and a set of high-gain,high signal-noise ratio antennas and antenna feed systems are designed.Finally,the antenna and antenna feed system were simulated and demonstrated;the whole terminal was tested and verified as well as electromagnetic compatibility tests.Through the design and implementation of this thesis,it can meet all the requirements of marine satellite communication system for ship station.At the same time,it provides a maritime satellite telephone terminal with all-weather,real-time,high voice quality and friendly human-computer interface.