# An Efficient On-Chip Data Storage and Exchange Engine for Spaceborne SAR System
## 1 Introduction  
Based on the synthetic aperture principle and making use of the Doppler information generated by the relative motion of the radar platform and the target being detected, spaceborne synthetic aperture radar (SAR) is a high-resolution microwave imaging technology [1; 2; 3; 4]. It has a variety of characteristics, such as all-time, all-weather, high-resolution large width, and has a certain degree of surface penetration, offering it a unique advantage in applications such as disaster monitoring, marine monitoring, resource surveying, mapping and military [5; 6; 7; 8; 9]. Recent publications provide an overview of the application of satellite remote sensing technology to natural hazards such as earthquakes, volcanoes, floods, land-slides, and coastal flooding [10; 11; 12]. The first spaceborne synthetic aperture radar oceanographic satellite, Seasat-1, was launched by the United States in June 1978, successfully ushering in a new age of spaceEarth observation [13]. Since then, spaceborne SAR imaging has attracted the attention of many countries and has become a highly competitive and rapidly developing technology field. In recent years, it has also become a significant method of Earth observation. For example, on 7 April 2022, China successfully launched the Gaofen-3 03 satellite is a C-band SAR satellite, which mainly acquires reliable and stable high-resolution SAR images to provide operational application data support for China's marine development, land environmental resource monitoring and emergency disaster prevention and mitigation [14]. The European Space Agency (ESA) launched the SAOCOM-1B satellite in 2020 as part of the SAOCOM-1 SAR satellite mission, which also includes the previously launched SAOCOM-1A satellite. The mission's objective is to acquire data with high-quality radiometric and geometric accuracy while offering frequent revisits to support specific operational needs. Moreover, it aims to deliver timely information to aid natural and human-caused disaster management, such as regional floods, volcanic eruptions, earthquakes, and landslides [15]. In 2018, ICEYE launched two ICEYE satellites, the first two satellites in the company's planned satellite constellation, and since 2018 the company has launched 16 satellites and plans to launch more than 10 satellites in 2022 and beyond, forming a world-unprecedented SAR constellation networking system that can provide revisits at several hours level and up to 0.25 m ultra-high resolution [16]. Future spaceborne Synthetic Aperture Radar (SAR) technology will likely advance in several areas, including miniaturization, multi-band, multi-mode, high-resolution capabilities, and ultra-wide imaging. The traditional method for processing SAR data involves the satellite storing the raw data and then downlinking it to ground equipment for further processing. This approach is referred to as the \"satellite data downlink and ground processing\" method. As the amount of acquired data geometrically increases, this processing method has low timeliness, which makes it difficult to meet the needs of high-timeliness tasks such as maritime target surveillance, key regional situation changes, earthquake and landslide disaster assessment [17]. In recent years, due to the large-scale development of chip manufacturing technology, researchers have begun to explore real-time processing technology for space-level chips with strong processing capabilities. The utilization of on-orbit processing technology can significantly alleviate the pressure of data transmission between satellites and ground stations, enhance the efficiency of information acquisition, and facilitate prompt decision-making. In 2010, the Netherlands National Aerospace Laboratory (NLR) developed the processor for the on-board payload data processing (OPDP) architecture.