Wide-Area Localization System Based on LoRa Mesh

The positioning task of the Internet of Things (IoT) for outdoor environment requires that the node devices meet the requirements of low power consumption, long endurance and low cost, and that the positioning system can achieve high-precision positioning and wide-area coverage. Traditional IoT positioning technology cannot balance the cost, energy consumption and positioning performance well. Based on LoRa technology, LoRaWAPS, a low-cost, low-power and outdoor positioning system with multi-anchor wireless Mesh networking and multi-dimensional data fusion is designed in this chapter. To meet the need of positioning system, a low-power consumption and high-reliability LoRa Mesh protocol is proposed. Aiming at the problem that the accuracy of LoRa ranging is easily affected by the non-line-of-sight path propagation of signals, a distance estimation algorithm based on the fusion of time of flight (ToF) and received signal strength indicator (RSSI) multi-sampling data is proposed. Furthermore, a position estimation algorithm is designed to minimize a posteriori RSSI error for multi-anchor cooperative estimation scenarios. Based on the LoRa Mesh protocol, and the ranging and positioning algorithm, the prototype of LoRaWAPS is built and tested in the campus environment. The experimental results show that the proposed system can provide good location service for campus area. The peak power consumption of a single device in the system is less than 120 mW and the cost is less than $10, which can meet the outdoor positioning requirements of low-power and low-cost.