The Polarimetric L-Band Imaging Synthetic Aperture Radar (PLIS): Description, Calibration, and Cross-Validation

Liujun Zhu, Jeffrey P. Walker, Nan Ye, Christoph Rüdiger, Jorg M. Hacker, Rocco Panciera, Mihai A. Tanase, Xiaoling Wu, Douglas A. Gray, Nick Stacy, Alvin Goh, Heath Yardley, Jim Mead

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)


    The polarimetric L-band imaging synthetic aperture radar (PLIS) is a high spatial resolution (better than 6 m) airborne synthetic aperture radar system that has been dedicated to scientific research into civilian applications since 2010. The weight of PLIS is ∼38 kg, allowing it to be installed aboard small low-cost aircraft, with two antennas used to measure the full backscatter matrix for a swath between 15° and 50° on each side of the flight direction. Calibration based on a total of 96 calibration points and a homogeneous forest during the two recent soil moisture active passive experiments (SMAPEx-4 and 5) showed an overall radiometric accuracy of 0.58 dB (root-mean-square error) over trihedral passive radar calibrators. Independent evaluation based on polarimetric active radar calibrators showed an amplitude imbalance of 0.17 dB with a standard deviation of 0.15 dB and a phase imbalance of 3.87° with a standard deviation of 2.86°. Two calibrated phased-array L-Band synthetic aperture radar-2 (PALSAR-2) images with different observation modes (ScanSAR and Stripmap) were compared with the calibrated PLIS images. The agreement between PALSAR-2 Stripmap and PLIS had a root mean square difference of 1.27 dB and a correlation coefficient of 0.87. Further comparisons over different landcover types confirmed that homogeneous forest and grassland areas constitute optimal targets for cross-validation and/or calibration.

    Original languageEnglish
    Pages (from-to)4513-4525
    Number of pages13
    JournalIEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
    Issue number11
    Publication statusPublished - Nov 2018


    • Calibration and validation
    • cross-calibration
    • phased-array L-Band synthetic aperture radar-2 (PALSAR-2)
    • polarimetric L-band imaging SAR (PLIS)
    • synthetic aperture radar (SAR)


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