IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (Jan 2021)

In-Orbit External Calibration Method for Synthetic Aperture Radiometer

  • Jiakun Wang,
  • Yinan Li,
  • Wenxin Chen,
  • Pengju Jin,
  • Hailiang Lu,
  • Xiaojiao Yang,
  • Guangnan Song,
  • Pengfei Li,
  • Hao Li,
  • Rongchuan Lv

DOI
https://doi.org/10.1109/JSTARS.2021.3066488
Journal volume & issue
Vol. 14
pp. 3763 – 3773

Abstract

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The effective calibration of systematic errors is a precondition for high-quality images from a synthetic aperture radiometer system. The receiving channel errors can be relatively well calibrated, but antenna errors cannot be calibrated effectively in-orbit. This article proposes an in-orbit external antenna error calibration method for synthetic aperture radiometers using external calibration point sources on the ground. Simulation and experimental results demonstrate the accuracy and feasibility of the method. The layout of on-ground calibration point sources was then explored. Our results indicate that is sufficient to adjust the power of the calibration point sources when SNR is 30 dB, and that the calibration requirements can initially be met with three calibration point sources. If better calibration effect is required, eight calibration point sources are sufficient. Nonrepeated and uniform azimuth angle schemes appear to be the optimal layout for operating the proposed method, but adjustments can be made as necessary to suit the situation at hand. Finally, a feasible implementation scheme was established. The proposed method has certain reference value in terms of image quality improvement and practical engineering applications.

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