Recent developments in space technology and real-time processing capabilities have significantly enhanced the imaging techniques of Synthetic Aperture Radar (SAR) satellites. SAR satellites, equipped with active imaging modes, employ electromagnetic signals transmitted and collected via antennas to produce high-resolution images using the Doppler shift principle. However, challenges persist due to the high velocity of satellite overpass and limitations in the satellite-to-ground transmission link, leading to delays in transmitting SAR echo and imaging data to ground stations. With the growing demand for real-time data products among satellite data users, traditional methods of imaging designated areas, transferring data within the visible arc to domestic stations, and ground processing are no longer sufficient to meet these needs. Therefore, addressing the issue of real-time onboard processing and direct transmission of critical target information is of paramount importance. To resolve this, satellites are now equipped with real-time processors that utilize advanced and specifically optimized algorithms to effectively extract key target information from SAR images. While ensuring the accuracy of target detection, this approach also guarantees the timeliness of critical target information acquisition, resulting in readily usable data images for ground applications. This paper discusses the technological breakthroughs in SAR satellite on-orbit imaging and the implementation of real-time onboard processing, highlighting its impact on data timeliness and reliability.