{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:37:26Z","timestamp":1760150246341,"version":"build-2065373602"},"reference-count":35,"publisher":"MDPI AG","issue":"20","license":[{"start":{"date-parts":[[2023,10,17]],"date-time":"2023-10-17T00:00:00Z","timestamp":1697500800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001665","name":"French Research Agency","doi-asserted-by":"publisher","award":["ANR-18-CE22-0020"],"award-info":[{"award-number":["ANR-18-CE22-0020"]}],"id":[{"id":"10.13039\/501100001665","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper investigates the performance of a wide variety of radar imaging modes, such as nadir-looking B-scan, or side-looking synthetic aperture radar tomographic acquisitions, performed in both back- and forward-scattering geometries, for the inspection and characterization of roadways. Nadir-looking B-scan corresponds to a low-complexity mode exploiting the direct return from the response, whereas side-looking configurations allow the utilization of angular and polarimetric diversity in order to analyze advanced features. The main objective of this paper is to evaluate the ability of each configuration, independently of aspects related to operational implementation, to discriminate and localize shallow underground defects in the wearing course of roadways, and to estimate key geophysical parameters, such as roughness and dielectric permittivity. Campaign measurements are conducted using short-range radar stepped-frequency continuous-waveform (SFCW) devices operated in the C and X bands, at the pavement fatigue carousel of Universit\u00e9 Gustave Eiffel, over debonded areas with artificial defects. The results indicate the great potential of the newly proposed forward-scattering tomographic configuration for detecting slight defects and characterizing roadways. Case studies, performed in the presence of narrow horizontal heterogeneities which cannot be detected using classical B-scan, show that both the coherent integration along an aperture using the back-projection algorithm, and the exploitation of scattering mechanisms specific to the forward-looking bistatic geometry, allows anomalous echoes to be detected and further characterized, confirming the efficacy of radar imaging techniques in such applications.<\/jats:p>","DOI":"10.3390\/s23208522","type":"journal-article","created":{"date-parts":[[2023,10,17]],"date-time":"2023-10-17T08:25:09Z","timestamp":1697531109000},"page":"8522","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Comparison of Imaging Radar Configurations for Roadway Inspection and Characterization"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4571-363X","authenticated-orcid":false,"given":"Mengda","family":"Wu","sequence":"first","affiliation":[{"name":"IETR (Institut d\u2019\u00c9lectronique et des Technologies du num\u00e9Rique), UMR CNRS 6164, University of Rennes, 35000 Rennes, France"},{"name":"ISAE-SUPAERO (Institut Sup\u00e9rieur de l\u2019A\u00e9ronautique et de l\u2019Espace), University of Toulouse, 31400 Toulouse, France"}]},{"given":"Laurent","family":"Ferro-Famil","sequence":"additional","affiliation":[{"name":"ISAE-SUPAERO (Institut Sup\u00e9rieur de l\u2019A\u00e9ronautique et de l\u2019Espace), University of Toulouse, 31400 Toulouse, France"},{"name":"CESBIO (Centre d\u2019Etudes Spatiales de la Biosph\u00e8re), University of Toulouse, 31400 Toulouse, France"}]},{"given":"Frederic","family":"Boutet","sequence":"additional","affiliation":[{"name":"IETR (Institut d\u2019\u00c9lectronique et des Technologies du num\u00e9Rique), UMR CNRS 6164, University of Rennes, 35000 Rennes, France"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1461-2003","authenticated-orcid":false,"given":"Yide","family":"Wang","sequence":"additional","affiliation":[{"name":"IETR (Institut d\u2019\u00c9lectronique et des Technologies du num\u00e9Rique), UMR CNRS 6164, Nantes Universit\u00e9, F-44000 Nantes, France"}]}],"member":"1968","published-online":{"date-parts":[[2023,10,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Barriera, M., Pouget, S., Lebental, B., and Van Rompu, J. 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