Foreword to the special issue on advances in ground-penetrating radar research and applications

THIS Special Issue in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (IEEE JSTARS) on ground-penetrating radar research and applications is edited as an extension of the 16th International Conference on Ground Penetrating Radar (GPR 2016), held at the Department of Land Surveying and Geo-informatics, The Hong Kong Polytechnic University, Hong Kong, from June 13 to June 16, 2016. The topics covered by GPR 2016 included the following: 1) novel developments of GPR systems and antennas; 2) advanced data and image processing algorithms, data modeling approaches; 3) inversion method for quantitative reconstruction of material properties; 4) geology, sedimentology, mining and glaciology, environmental and agricultural science and engineering; 5) civil engineering applications, such as underground utility, infrastructures, buildings, geo-technics, and landmine detection; 6) archaeology and cultural heritage; 7) planetary exploration and synthetic aperture radar; and 8) validation and security applications. In total, 121 conference papers, 4–6 pages each, were published in the Proceedings of the 16th International Conference on Ground Penetrating Radar collected in the IEEE Xplore Digital Library. A special tribute was arranged to late Derald G. Smith in an oral session (geology, sedimentology, stratigraphy, mining, glaciology, hydrology) on his visionary in the application of GPR in earth science applications. Authors were invited to extend their papers to full-length journal papers in this Special Issue of IEEE JSTARS, which was also open to external contributions. In total, nine papers were accepted for publication. The nine papers are briefly summarized.