Prioritizing Beijing Subway Intervals for Field Review Using PS-InSAR and SBAS-InSAR

Railway and metro inspection planning requires an ordered set of engineering intervals for follow-up investigation. This study combines persistent scatterer interferometric synthetic aperture radar (PS-InSAR) and small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) to prioritize intervals by joint relative prominence and assess ranking uncertainty. The Shilihe–Bagou corridor of Beijing Subway Line 10 was analyzed using 48 ascending Sentinel-1A scenes from 2021 to 2024. Rates were centered on each product’s corridor median and aggregated into paired route bins. The smaller method-specific percentile rank defined joint prominence, while paired block bootstrap quantified rank variability. PS-only and SBAS-only rankings shared only two of their first five intervals. The joint same-direction shortlist comprised the two Huoqiying–Bagou units, Changchunqiao–Huoqiying, Cishousi–Chedaogou, and Lianhuaqiao–Gongzhufen. Spatial and representation tests retained four or five baseline members, and all three boundary-allocation tests retained all five. The main Huoqiying–Bagou interval had a baseline 95% rank interval of 1–3 and, together with Changchunqiao–Huoqiying, remained selected throughout the tested spatial settings. The short open-cut Huoqiying–Bagou unit remained prominent but changed to opposite relative directions under the 200 m grid. These results distinguish persistent priorities for targeted field review from intervals requiring closer examination of spatial sampling and cross-method differences.