A global positioning scheme which consists of the local positioning method, the simple correction algorithm, the three-dimensional transformation algorithm and position prediction algorithm in blind areas is proposed to obtain real-time global positioning information for the miners.The remainder of the paper is organized as follows. In Section 2, we describe the architecture and deployment scenario of MPPS. In Section 3, the data models of global positioning systems are studied. In Section 4, we introduce the global positioning scheme. In Section 5, we analyze the prototype system and experimental results. A brief overview of related work is introduced in Section 6. Finally, we conclude the paper.2.
?The System Architecture and Deployment Scenario2.1.
The System ArchitectureAs shown in Figure 1, the MPPS architecture is divided into three layers: the field monitoring layer, the upper supervision layer, and the remote supervision layer. The field monitoring layer includes the mobile nodes, the reference nodes, the gateways and the base stations. The communication between the mobile node, the reference node and the gateway is wireless. The mobile nodes continuously receive the reference nodes’ location and RSSI within a one hop coverage area, calculate their own locations based on a locating algorithm, and send them to the gateway through multi-hop routing. The gateway then sends the original location information to the base station through RS-485 bus.
The base station collects the location information of all miners on its own level and sends it to the upper computer after packaging through the controller area network (Controller Area Network: CAN) bus.
Figure 1.Architecture of MPPS.The upper supervision layer includes the upper computer, which is equipped with a CAN bus card in addition to a local area network (Local Area Network: LAN) card. The upper computer can communicate with the base station through the CAN card. The upper computer continuously receives the packets from the base station through the CAN interface, and then processes and visualizes these data packets. Based on the client/server model, the remote Drug_discovery supervision level can also be divided into three layers, namely the database server Brefeldin_A layer, web server layer, and browser layer.
The database server and web server are connected with the upper computer through the LAN bus complying with the TCP/IP protocol. The remote monitoring computers are connected with the web server through the Internet, and are used to monitor a variety of statistical information of MPPS through a browser.2.2. The Deployment ScenarioThe tunnel network partition for a real coal mine [18] is shown in Figure 2.