Self-Powered End-to-End Wireless Sensor Network for Geophysical Explorations

The underground layers of the Earth contain immense resources that require geophysical surveys. This article presents an end-to-end, self-powered wireless sensor network (WSN) for geophysical surveys. The WSN conducts geophysical surveys in an energy-efficient, portable manner. It includes a sensing element, advanced electronics, data processing and digitization, and wireless transmission with networking capabilities between sensing nodes. The system is equipped with a power management module with solar-powered charging capabilities, allowing for at least six days of effective operation on a few hours' worth of charge. The electronic circuitry performing amplification and filtering provides cut-off frequencies of 8.2-108 Hz, and the sensor node exhibits a sampling frequency of 600 SPS. Furthermore, the system implements power modes (active/sleep) to reduce power consumption, with a nominal power usage of only 650 mW at its maximum. The WSN comprises a multihop implementation with smart routing to ensure power-efficient and reliable data transmission. In addition, message encryption is implemented for enhanced wireless security. A field test was conducted to validate the proposed geophysical data acquisition system. Geophysical signals were detected and wirelessly transmitted over a 200 m² area employing a network of six nodes to a storage unit, where they were successfully reconstructed and remained stored for later processing and analysis.