Frequency-Based Analysis of Matching Accuracy Between Satellite Radio Frequency and AIS Data for Ship Identification

Vessels can deactivate their Automatic Identification System (AIS) to operate undetected and potentially engage in illegal activities. To address this, satellite-based radio frequency (RF) data are increasingly being used for identifying such vessels. This study evaluates the matching accuracy among RF and AIS data based on the frequency and distance. RF data were acquired on 22 September, 25 September, and 7 December 2023. According to the frequency range, the dataset was separated into frequency-1 (3.024–3.077 GHz) and frequency-2 (9.3734–9.4249 GHz). Six distance thresholds (2 km, 3 km, 6 km, 8 km, 13 km, and 18 km) were employed for the matching process. The results depicted that the average matching rates were 95%, 92%, and 92% for the RF dataset on 22 September, 25 September, and 7 December, respectively. Additionally, the results revealed that the matching rates decreased with distance, e.g., for the RF dataset on 22 September, the average highest matching rate (47%) was found at a 2 km distance and the minimum matching rate (0.9%) was observed at an 18 km distance. Furthermore, the analysis delineated that frequency-2 consistently exceeded frequency-1, particularly at longer distances, showing a more stable trend in matching accuracy.