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System Design and Image Enhancement for SAR Satellite Constellations
- Author(s)
- 김경록
- Advisor
- 김재현
- Department
- 일반대학원 전자공학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2022-02
- Language
- eng
- Keyword
- SAR; image application; newspace; satellite constellation; system design
- Alternative Abstract
- With the remarkable advances in space technologies, small satellite and synthetic aperture radar (SAR) are innovated for satellite communication and remote sensing at low Earth orbit. In small satellite, the payload, such as SAR and other sensors, should be designed the small size and the light weight while preserving functional aspects. Thus, the small satellites have relatively limited function than large satellites. The SAR constellations, which is a group of small satellites, collect the global data during the mission and downlink the enormous data to the ground station within a few minutes. The ground stations which are distributed over a world-wide should process the downlinked SAR data for providing various services, e.g. SAR images, global disaster monitoring, object detection. Therefore, this dissertation proposes optimization of SAR system and image applications for spaceborne SAR constellations. First, the system design with multi direct digital synthesizer using polynomial regression is proposed for high-quality and small signal generator in X-band SAR system. The proposed scheme is able to generate stable wideband waveform using less system clock than conventional method. The size of developed hardware is reduced containing digital part as well as analog part. Second, the adaptive selection algorithm considering the queue-backlog of ground station is proposed to maximize time-average SAR image quality in data-burst SAR constellations. The algorithm selects the time-average optimal filter under consideration of queue state. As the selected result, the satellite SAR data is processed to the corresponding images for providing to the users such as institute, military, academic and general user. Lastly, the optimization of image processing method is designed to utilize spaceborne SAR constellations. The proposed algorithm maximizes object detection accuracy while providing stabilized service in the ground station. To achieve this goal, the area of interest and the quality requirements are defined in terms of users. In conclusion, this dissertation enables that small SAR can have the improved image application with the intelligent ground stations in satellite constellations.
- Fulltext
- Appears in Collections:
- Graduate School of Ajou University > Department of Electronic Engineering > 4. Theses(Ph.D)
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