The Design And Realization Of Wireless Sensor Network Positioning System

The Localization Technique has been more and more focused on as a WSN(Wireless Sensor Networks) key support technique. WSN localization algorithm theory research has achieved many more fruits, and algorithm research has been mature. In different point of view, localization algorithm can be divided into many kinds: centralized, distributed, infrastructure-based, range-based and range-free localization algorithm. The researchers indeed provide many resolutions for the fault of these algorithms. However, many problems can be found if these algorithms are applied into the physical WSN. This paper will analyze these factors which influence the localization algorithm based on the existed localization algorithm and localization system in the round, and put forward the corresponding resolutions, and summarize the principles which localization systems must be followed.Based on these principles and resolutions, we choose the localization algorithm DV-Hop corresponding to the experiment surrounding, and make further research on RSSI(Radio Signal Strength Indicator) as an assistant localization technique, and resolve these problems: system instability and localization precision worse, nodes overlapped seriously, and so on. To build RSSI ranging model, we have collected a mass of RSSI ranging data from the experiment environment, and used reasonable statistic and correction methods; then, based on the built RSSI model, pc demo system displays the node position in a graphic way, and intelligently concludes these data which collect from node localization system, analyzes the ranging error and localization precision in the current environment. It is proved by experiment that improved localization system obtains a steady, reliable and high precision effect in a little-increased computation and communication spending instance. In a regular topology, improved localization system can achieve a 20% below precision; in general, the localization precision is about 32%, therefore, this system can be applied into WSN.To develop the localization system efficiency, we will also introduce TOSSIM simulator and GDB debug tools. The usage of TOSSIM simulator and GDB debug tool are very helpful and efficient for WSN application development. According these debug methods, localization system can not be developed on the Mica2 platform, only simulate the system on the pc platform.