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Based on linear array 3D imaging, this paper introduces a keystone algorithm combined with the arc array SAR 2D imaging method and proposes a modified 3D imaging algorithm based on keystone transformation. The first step is to discuss the target azimuth angle, retain the far-field approximation method of the first-order term, analyze the influence of the forward motion of the platform on the along-track position, and realize the two-dimensional focusing of the target slant range\u2013azimuth direction. The second step is to redefine a new azimuth angle variable in the slant-range along-track imaging and use the keystone-based processing algorithm in the range frequency domain to eliminate the coupling term generated by the array angle and the slant-range time. The corrected data are used to perform along-track pulse compression to obtain the focused image of the target and realize the three-dimensional imaging of the target. Finally, in this article, the spatial resolution of the AA-SAR system in the forward-looking state is analyzed in detail, and the change in the spatial resolution of the system and the effectiveness of the algorithm are verified through simulation.<\/jats:p>","DOI":"10.3390\/s23052674","type":"journal-article","created":{"date-parts":[[2023,3,1]],"date-time":"2023-03-01T02:02:56Z","timestamp":1677636176000},"page":"2674","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["A Modified Keystone-Based Forward-Looking Arc Array Synthetic Aperture Radar 3D Imaging Method"],"prefix":"10.3390","volume":"23","author":[{"given":"Xiaofan","family":"Zhu","sequence":"first","affiliation":[{"name":"College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, China"},{"name":"Inner Mongolia Key Laboratory of Radar Technology and Application, Hohhot 010051, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7720-1183","authenticated-orcid":false,"given":"Pingping","family":"Huang","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, China"},{"name":"Inner Mongolia Key Laboratory of Radar Technology and Application, Hohhot 010051, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8045-8817","authenticated-orcid":false,"given":"Wei","family":"Xu","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, China"},{"name":"Inner Mongolia Key Laboratory of Radar Technology and Application, Hohhot 010051, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9071-9470","authenticated-orcid":false,"given":"Weixian","family":"Tan","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, China"},{"name":"Inner Mongolia Key Laboratory of Radar Technology and Application, Hohhot 010051, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yaolong","family":"Qi","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, China"},{"name":"Inner Mongolia Key Laboratory of Radar Technology and Application, Hohhot 010051, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,28]]},"reference":[{"key":"ref_1","unstructured":"Bennett, J.R., Cumming, I.G., and Deane, R.A. 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