A survey on inline soil pollution measurement and mapping technologies

This paper reviews recent advancements in underground positioning and monitoring, particularly for soil pollution detection and mapping. Unlike conventional indoor and outdoor systems, underground environments pose unique challenges. Robotic platforms, including the Moon/Mars Underground Mole (MMUM) and bioinspired Mole-bot, utilize drills, augers, and additive layering for soil exploration, with some featuring autonomous control for efficient data collection. The review also examines real-time soil monitoring techniques, such as electrochemical sensors for pollutant detection and spectroscopic methods like Laser-Induced Breakdown Spectroscopy (LIBS) and Near-Infrared Reflectance Spectroscopy (NIRS). These approaches, when combined, enhance large-scale soil analysis for environmental and agricultural applications. Additionally, underground positioning remains complex due to electromagnetic interference and GPS unavailability. Techniques like Ground Penetrating Radar (GPR), ultra-wideband (UWB), ZigBee, and magnetic field-based localization provide potential solutions but face limitations such as signal attenuation. Continued research is essential for improving the accuracy and efficiency of these methods in subsurface applications, from pollution monitoring to resource exploration.