A Fast PS Sequence Selection Algorithm for GNSS-Based InBSAR

Global navigation satellite system-based bistatic synthetic aperture radar interferometry (GNSS-based InBSAR) enables near-real-time 3-D deformation monitoring by combining interferometric phases from different satellites at varying time points. However, the low resolution and low signal-to-noise ratio (SNR) compromise the reliability of persistent scatterer (PS) association in time-series imagery, introducing the reuse of PSs. To achieve this, it demands PS selection algorithms with both high computational efficiency and precision. In this letter, a fast PS sequence selection algorithm is proposed for GNSS-based InBSAR. First, pre PS sequences are screened based on sequence length, SNR, position offset, and amplitude dispersion to ensure interferometric phase stability under low-SNR conditions. Second, a criterion is set to select the ”best” sequence, facilitating the rapid removal of duplicate PSs. Finally, the computational load is quantitatively characterized, demonstrating O(n²) efficiency. Validation of the proposed algorithm is carried out using BeiDou satellite measured data, achieving 2-h-interval 3-D deformation measurements.