Design And Implementation Of RSSI Based Indoor Localization Algorithm

With the rapid development of wireless sensor network technology, indoor positioning technology has been widely used in many fields. The key point of indoor positioning technology is positioning algorithm. An excellent positioning algorithm should be able to eliminate the influence of confounding factors on the positioning results, calculate the position of the test nodes accurately and timely. This paper is based on the RSSI localization technology to do the research and make improvements.This paper with the goal of improving the positioning accuracy, improve the localization methods in range finding, filtering and calculative process. Firstly, in the aspect of establishing range model, based on the traditional logarithmic model, take the relationship between the shaking RSSI signals and the distance into account, an improved logarithmic model is proposed. It can dynamically correct the environmental parameters; can improve the ranging accuracy to some extent, lay a good foundation for positioning calculations. Secondly, in the aspect of filtering, make the median as reference value the weighted filtering algorithm is proposed. This method not only has the better filtering effect, but also can exclude the error introduced by external disturbance factors. Then we do the research on the triangular positioning algorithm, and find that a certain proportion of data cannot obtain their positioning results. Thus, combined with fuzzy mathematics knowledge, this paper uses close degree positioning method for trilateral localization method to make supplement. Finally, specific to the program application of our positioning system, one scheme based on RSSI variation trends is proposed. This scheme is suitable for narrow tunnel with frequently changed environments. Although the accuracy of our positioning algorithm is a little worse, it has simple requirement to hardware and has less affected by environment. Therefore, the algorithm that proposed in this paper is suitable for indoor complex conditions and the system with less demanding positioning accuracy.In this paper, the above theory is experimentally verified. The experimental data in this paper are measured under the actual environment and according to the actual needs to add some anti-interference errors by human. The experimental results show that, compared to the traditional positioning algorithm, the method that proposed in this paper has made full consideration of the actual application environment possibly exist interference and further improved it, the RSSI-based indoor node positioning accuracy is effectively improved.