Research And Implementation Of WSN Location Algorithm Based On RSSI

Wireless Sensor Networks(WSN)is an intelligent network information system that integrates functions of information collection,processing,communication and transmission.It is widely applied in military,commercial and civil fields.The location information of the nodes plays a supporting role in the construction of the WSN,so that the WSN can provide location-related services.In the positioning algorithm of WSN,the positioning algorithm can be divided into ranging-based and ranging-free according to whether or not ranging.Among them,the algorithm ranging-free has a great advantage in the complexity and scalability of the algorithm,but most of them are only suitable for places with low positioning accuracy requirements.The classical centroid algorithm highlights its advantages of low complexity and high scalability,but it also has the problem of low positioning accuracy.To reduce the error,it is necessary to increase the cost to increase the distribution density of anchor nodes.The ranging technology can improve the positioning accuracy.In many ranging technologies,the RSSI(Received Signal Strength Indication)ranging technology does not require additional equipment and can improve positioning accuracy.Therefore,some researchers have combining traditional centroid algorithm with RSSI ranging technique,a weighted centroid localization algorithm was proposed.RSSI-based weighted centroid positioning algorithm improves the positioning accuracy of the centroid positioning algorithm,but in practical environment applications,the RSSI value will be affected by the environment instability,and the location error will be too large due to the low number of anchor nodes at the network boundary.In order to reduce these errors,uses the ranging model,median weighted filtering and establishment of ranging error correction library to reduce the impact of environmental factors;also through the iterative idea,iterative error correction and the establishment of algorithm error correction library to improve the boundary positioning accuracy.The RSSI-based boundary weighted centroid localization algorithm is abbreviated as BIWC.The main work is as follows:In the ranging phase of the BIWC positioning algorithm,study the range model of RSSI,analyze the influence of different environments on the attenuation parameters and RF parameters in the model.For the problem that the parameters in the model are highly dependent on the environment,the logarithm range model is used to measure the test environment to obtain the optimal parameters,and then use the median value weighted filtering method to process the ranging results obtained by the ranging model,filter out the erratic signals for improve the anti-jamming performance of the algorithm.Finally,in order to solve different problems in different areas of the environment,the measure of partition correction for error is proposed to improve the accuracy of ranging.The ranging error correction library is established by using the distance measurement information to more accurately correct the ranging results in different areas and reduce the impact of the environment on the algorithm,accurate ranging information lays the foundation for the following positioning stage.In the positioning phase of the BIWC positioning algorithm,uses iterative idea to solve the problem of border location inaccuracy caused by the insufficient number of anchor nodes in the original algorithm.Transform the localized blind nodes into secondary anchor nodes,solve the positioning problem caused by the lack of anchor nodes,and the secondary anchor nodes can cause iterative error,increase the weight parameters of the secondary anchor nodes for reduce secondary anchor nodes weight in the calculation process to reduce iterative errors.Finally,a location error correction library is added by get a set of errors in every area of the environment to correct the positioning calculation result,thereby further improving the adaptability of the BIWC algorithm to a complex environment and improving its positioning accuracy.Finally,in order to realize the BIWC algorithm and test the improvement effect of the algorithm,a BIWC-based positioning system was designed.After the design of the related node hardware in the system,the software of the node was designed according to the implementation process of the algorithm,and the upper computer monitoring software was designed.The test results show that the BIWC algorithm is more adaptive to complex environments and can reduce the positioning error caused by the lack of anchor nodes.