High-precision satellite clock bias (SCB) prediction is essential for real-time remote sensing, real-time precise point positioning (RT-PPP), Earth observation, and spaceborne geodetic applications of Global Navigation Satellite Systems (GNSS). However, real-time services are frequently interrupted in data-scarce environments such as communication outages, which severely restrict the continuity and reliability of high-precision applications. To address this issue, a multi-scale decomposition-fus