Optimal Antenna Pairing of A Miniaturized Radar Array for Smart Sensing of Soil Carbon Content

The foundation of soil carbon management is the measurement of soil carbon content, which potentially enables many carbon-negative or carbon-neutral technologies for fighting climate change and improving soil health for greater crop yield. Several researchers used a non-intrusive method to quantify soil organic carbon content using ground penetrating radar (GPR) with a fixed sensor configuration. The sensor we used in this study, however, is compactly comprised of an array of 18 radar transmitter (TX) and receiver (RX) pairs. It is necessary to propose an assessment of sensing performance which can avoid possible failure in identifying the correct soil carbon spatial-temporal changes. In this paper, we provide a comprehensive assessment of the evaluation of non-intrusive methods for sensing soil carbon content when a radar array is used. Specifically, our proposed evaluation score utilizes explicit physical knowledge as a data-driven metric to find the optimal antenna pair combination for our radar array sensor under different sensing tasks and environments. We evaluated our soil carbon sensing score (SCSS) using the data collected from real-world soil sample experiments. The results show that the optimal antenna pair has the greatest sensing ability to measure soil carbon content in a variety of sensing environments and sensing distances, with a 36% increase in classification accuracy.