Intelligent Magnetic Sensing System for Low Power WSN Localization Immersed in Liquid-Filled Industrial Containers

Wireless sensor networks (WSN) have become an important research domain and have been deployed in many applications, e.g., military, ambient intelligence, medical, and industrial tasks. The location of wireless sensor nodes is a crucial aspect to understand the context of the measured values in industrial processes. Numerous existing technologies, e.g., based on radio frequency (RF), light, and acoustic waves, have been developed and adapted for requirements of localization in WSN. However, physical constraints of the application environment and each localization technology lead to different aptness. In particular, for liquid media in industrial containers, determining the location of every sensor nodes becomes very challenging. In this paper, a localization concept based on intelligent magnetic sensing system using triaxial anisotropic magnetoresistive (AMR) sensor with appropriate switched coils combined with a centralized localization algorithm based on iterative non-linear mapping (NLM) is presented. Here, our system is extended by low power and fast localization based on triangulation for feasible local position computation. The experimental results, both in the air as well as in liquid filled stainless steel container, delivered in the average an absolute localization error in the order of 6 cm for both NLM and triangulation. In future work, we will scale our approach to industrial container size required for beer brewing industry and increase the accuracy and speed by timely electronics and calibration.