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Design Of WSN Location System Based On RSSI Ranging

Posted on:2011-03-22Degree:MasterType:Thesis
Country:ChinaCandidate:W J LiuFull Text:PDF
GTID:2178330332460699Subject:Microelectronics and Solid State Electronics
Abstract/Summary:PDF Full Text Request
With the rapid development of MEMS, wireless communication, embedded system and sensor technology, the wireless sensor network that integrates above technologies has became a research focus. Wireless sensor network has considerable applications in many fields, such as military defense, medical monitoring, smart home, environmental monitoring and traffic control.In many applications, the location where the event occurs is the important information that the wireless sensor network node should obtain. Hence, the wireless sensor network positioning technology is of great significance to the application of wireless sensor network.In this thesis, we first studied the positioning technology and designed a wireless sensor network positioning system based on RSSI ranging. Adopting STM32F103CB microprocessor and CC2500 RF chip to design a low cost and low power wireless sensor network node, we realized the networking of multi-node and the wireless transmission of data. We then conducted the ranging experiment by studying the wireless signal attenuation model in the actual environment. Here, the linear least square method was employed to compensate the range error. At last, according to the ranging result, we employed the maximum likelihood estimate algorithm to locate the blind node in the network. We designed the application program of center node, reference node and blind node, as well as the host-computer location demo interface. RS232 serial communication interface was employed to realize the communication between wireless sensor network and host-computer. By means of sending appropriate commands to host-computer, the system designed in this paper could realize the environmental parameters setting, the query or update of reference nodes coordinate, positioning of blind nodes and other functions.In summary, the system that employed RSSI nodes ranging technology without adding additional hardware, could meet the requirements of low cost and low power of wireless sensor network. Besides, many I/O interfaces were reserved in designation of hardware, which can be used for extension of the sensor to make it convenient for various situations'application. The nodes networking employed peer-to-peer form that was convenient for the extension of the network size. The positioning results obtained by the actual environment showed that the positioning accuracy was up to 11.2%, totally met the positioning requirements.
Keywords/Search Tags:WSN Location, RSSI Ranging, Maximum Likelihood Estimate Algorithm, STM32
PDF Full Text Request
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