The Designe And Implementation Of National Maritime Search And Rescue Support System

Aiming at the shortcomings of China's maritime search and rescue emergency drift predicting process,such as cumbersome procedures,slow response speed,and the calculation range that cannot cover the whole sea area,etc,the paper has designed and developed National Maritime Search And Rescue Support System(NAMSAR),Integrate dynamic environment data and drift prediction computing resources from multiple units including NMFC,EMFC,SMFC and so on,provides automated drift forecasting services for "Remote drift prediction request delivery——Drift prediction calculation on server-Results presentation——Presentation generation" for the country.The platform is designed and developed based on a service-oriented SOA architecture,which is divided into five layers including access layer,application interface layer,application management layer,application service layer and data foundation layer.It provides three types of clients including desktop,web and android mobile versions.Achieving some functions including Expert case predictions,Common case predictions,Team case predictions and visualization of marine dynamic environment data for expert users and ordinary users.The main key technologies for the platform are as follows:(1)Integration Technology of Distributed Maritime Drift Prediction Service System Based on SOA ArchitectureThe platform server divides the drift prediction and environment field visualization into multiple service units which connects to each other through the protocol,and uses the Web Service technology to encapsulate the service unit into a standard interface.On the basis of modular bottom service,the platform creates high level services by different combinations and realizes a coarse-grained and low-coupling architecture style with advantages of good scalability and easy maintenance.(2)Asynchronous Multi-thread Synchronization Technology for Massive Dynamic Environment DataThe platform establishes an adaptive data transmission mechanism based on Socket and FTP,using the underlying TCP/IP protocol to communicate with the file synchronization message by Socket guarantying the stability of data transmission.The platform improved the efficiency of data transmission by asynchronous multi-thread technology,Achieving simultaneous interconnection between data synchronization server and multiple clients by multithreading,and avoiding thread blocking by asynchronous when the network is unstable,achieving the efficient synchronization of massive dynamic environment data.The platform has been operational since October 2016.It has provided search and rescue support services for more than 20 units such as the National Maritime Search and Rescue Center,Shandong Maritime Search and Rescue Center,Tianjin Maritime Search and Rescue Center,etc.,and provides services of English version for ASEAN countries such as Indonesia and Malaysia.The platform provided drift prediction services more than 100 times and completed the synchronization task of 5TB dynamic environment data in 2017.The successful application of the platform has greatly improved the technical ability of marine search and rescue emergency protection service of our nation.