Synthetic aperture radar possesses the capability to provide two-dimensional imaging for remote sensing and earth observation regardless of weather conditions. The high-resolution SAR image is always desired. However, the data volume of echo signals is huge while the on-board storage or communication bandwidth to ground station is limited. Instead of transmitting raw signals, transmitting region of interest of images can be efficient. Consequently, processing for real-time and high-resolution SAR imaging is essential, either for spaceborne SAR or for airborne SAR . In 2021, Synthetic Aperture Standards Committee (SASC) was approved by IEEE Standards Association for establishing technical standards to enhance its applications.