Accurate Topsoil Thickness Detection using SFCW Radar

Topsoil is essential for agriculture, storing nutrients and water necessary for plant growth, but is susceptible to erosion from rainfall and human activities, reducing its thickness and productivity. Unlike conventional methods, this research utilizes Stepped Frequency Continuous Wave (SFCW) Radar as a non-destructive method to estimate topsoil thickness with high resolution without damaging the soil structure. This research investigates the effect of soil dielectric properties such as conductivity on the radar signal and the impact of signal-to-noise ratio (SNR) on measurement accuracy. Simulation results show that higher SNR values result in more accurate estimates, with moderate conductivity values providing better accuracy than very low or high values. For example, at a soil thickness of 20 cm, the thickness estimate at a conductivity value (σ) of 0.1 S/m, the accuracy is 99.5%, but it decreases to 88.7% at σ = 1 S/m. Similarly, at a thickness of 40 cm, the estimate at σ = 0.1 S/m, the accuracy is 99.8%, but it decreases to 88.93% at σ = 1 S/m. In addition, with a topsoil thickness of 20 cm, the estimated thickness at SNR = 13 dB is 19.85 cm with an accuracy of 99.25%, and at a thickness of 40 cm, the estimate is 40.46 cm with an accuracy of 98.85%, with an overall average accuracy of 99.043% at SNR = 13 dB.