Spaceborne synthetic aperture radar (SAR) motion compensation using autofocus | ||||
| Journal of Engineering Science and Military Technologies | ||||
| Article 5, Volume 8, Issue 1, March 2024, Page 61-68 PDF (1.6 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejmtc.2023.213167.1258 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
Ahmed Salah ELBohy   1; Ashraf Khaled Helmy2; Ahmed S Mashaly1; Ahmed A Azouz1
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| 1Avionics Department, Military Technical College | ||||
| 2National Authority for Remote Sensing and Space | ||||
| Abstract | ||||
| A common tool for remote sensing is Synthetic Aperture Radar (SAR). It is a very confident compared to other forms of remote sensing since it has the advantages of operating with high efficiency in all weather and throughout the day. In ideal circumstances, the SAR platform travels along a straight path at constant height and velocity. However, the eccentric orbit of satellites does not support this idea leading to decrease the quality of the focused image. This paper suggests a Phase Gradient Autofocus (PGA) solution to be applied to Sentinel-1 data addressing the SAR image-focus problem where space-variant motion defects could not be disregarded, taking the biggest advantages of using satellite SAR having access to actual data, such as Sentinel 1 level-0 and level-1 real data obtained from the European Space Agency Copernicus website, a free access hub for level-0 and level-1 data types. Furthermore, two distinct measures are employed in the endorsement process. First, measuring the contrast and entropy of the formatted image. Second, four high power reflecting points in the scene area has been visually inspected moreover assessing their amplitude response.The suggested approach that employs PGA optimizes the image quality by attaining improved entropy and contrast when compared to the original Sentinel-1 images. | ||||
| Keywords | ||||
| Chirp scaling algorithm (CSA); image quality; phase gradient autofocus (PGA); sentinel-1; synthetic aperture radar (SAR) | ||||
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