Black ice, a thin and nearly invisible ice layer on roads and pavements, poses a significant danger to drivers and pedestrians during winter due to its transparency. We propose an efficient black ice detection system and technique utilizing Global Positioning System (GPS)-reflected signals. This system consists of a GPS antenna and receiver configured to measure the power of GPS L1 band signal strength. The GPS receiver system was designed to measure the signal power of the Right-Handed Circular Polarization (RHCP) and Left-Handed Circular Polarization (LHCP) from direct and reflected signals using two GPS antennas. Field experiments for GPS LHCP and RHCP reflection measurements were conducted at two distinct sites. We present a Normalized Polarized Reflection Index (NPRI) as a methodological approach for determining the presence of black ice on road surfaces. The field experiments at both sites successfully detected black ice on asphalt roads, indicated by NPRI values greater than 0.1 for elevation angles between 45o and 55o. Our findings demonstrate the potential of the proposed GPS-based system as a cost-effective and scalable solution for large-scale black ice detection, significantly enhancing road safety in cold climates. The scientific significance of this study lies in its novel application of GPS reflection signals for environmental monitoring, offering a new approach that can be integrated into existing GPS infrastructure to detect widespread black ice in real-time.

1. Introduction
2. Data
3. Methods
4. Results
    4.1. Theoretical NPRI curves
    4.2. Measurement of GPS
    4.3. Interpretation of NPRI
5. Discussion
6. Summary and Conclusions
Acknowledgments
References

• Young-Joo Kwon(Moon Soul Graduate School of Future Strategy, Korea Advanced Institute of Science and Technoogy, Daejeon 34141, Republic of Korea)
• Hyun-Ju Ban(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Sumin Ryu(Satellite Application Division, Korea Aerospace Research Institute, Daejeon 34133, Republic of Korea)
• Suna Jo(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Han-Sol Ryu(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Yerin Kim(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Jeong-Eun Park(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Yun-Jeong Choi(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Kyung-Hoon Han(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Yeonjun Kim(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea)
• Sungwook Hong(Department of Environment, Energy, and Geoinfomatics, Sejong University, Seoul 05006, Republic of Korea) Corresponding author