Design And Implementation Of Real-time Data Stream Software Based On Ntrip

As a data-intensive application, data stream has been widely accepted and widely used in financial services, network monitoring, telecom data management, Sensor detection and other fields. In the data flow model, data is large, rapid and time-varying and data streams arrive continuously. One import direction of data stream model researches is how to realize the real-time processing of the data. This paper mainly studied how to realize the real-time processing of RTK data and achieved the processing and the storage system of data stream model.First, we analyzed the functional requirements of the data processing system and the characteristics of RTK data stream based on which we proposed the solution of using Ntrip system to realize the data processing and mainly achieved server and processing center of Ntrip system. The server is responsible for receiving, analyzing and storage of data flow and the processing center implements the forwarding function of data flow.Then, we detailed the design and implementation of each function module of the system, including data stream reception module, data flow analysis module, data flow storage module and data forwarding module. To provide data for others, the data stream reception module is the basis of the system. As the core of the system, the data flow analysis module provides parsed data for the data flow storage module and offers data in RTCM format for the data flow forwarding module.The data reception module is implemented of the asynchronous mechanism using which to guarantee the real-time data reception. We realized the data processing through the callback function of asynchronous operation For data flow analysis module, we divides the analysis into data packets extraction stage and message parsing stage according to the characteristics of the data stream. The first stage is used to extract the data stream into data packets. We realized appropriate extraction algorithms for several encoding formats. And the message parsing stage realized t he parsing of data depending on the message type. We defined a unified interface for easy expansion of the system functionality. The data flow storage module realized the storage of original data and the storage of message data in RINEX format. In order to facilitate retrieval and management, we formulated rules for file naming and storage. The data forwarding module is a server program that listens the requests of Ntrip server and the client and distinguish the request message. For server request, the module receives the data stream after verification while for the client request it forwards specified data stream directly.Finally, we designed test cases for data flow analysis module, data flow storage module and data flow forwarding module and conducted the test validation. The result show these modules function correctly and the content of this paper can realize the real-time processing, storage and forwarding of RTK data commendably.