{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T16:07:14Z","timestamp":1784736434566,"version":"3.55.0"},"reference-count":32,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2023,7,27]],"date-time":"2023-07-27T00:00:00Z","timestamp":1690416000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"publisher","award":["2022M720444"],"award-info":[{"award-number":["2022M720444"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"publisher","award":["11833001"],"award-info":[{"award-number":["11833001"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"publisher","award":["61931002"],"award-info":[{"award-number":["61931002"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Key Program of National Natural Science Foundation of China","award":["2022M720444"],"award-info":[{"award-number":["2022M720444"]}]},{"name":"Key Program of National Natural Science Foundation of China","award":["11833001"],"award-info":[{"award-number":["11833001"]}]},{"name":"Key Program of National Natural Science Foundation of China","award":["61931002"],"award-info":[{"award-number":["61931002"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The transmitter and receiver of unmanned aerial vehicle (UAV) bistatic synthetic aperture radar (Bi-SAR) are respectively carried on different UAV platforms, which has the advantages of flexible movement and strong concealment, and has broad application prospects in remote sensing fields. However, the range cell migration (RCM) and azimuth non-linear phase (ANP) of UAV Bi-SAR are seriously spatially variant along the range and azimuth directions, while the UAV Bi-SAR has a short operating range, complex trajectory and wide azimuth beam. Aiming at the problem that the RCM and ANP of UAV Bi-SAR in spotlight mode are difficult to correct and equalize due to the severe two-dimensional (2D) spatial variation, an RCM correction (RCMC) and ANP equalization (ANPE) method based on Doppler domain blocking is proposed. First, the azimuth spatial variance of RCM is eliminated by Doppler blocking, and the range spatial variant RCMC is realized by RNCS. Second, by combining Doppler blocking with azimuth nonlinear chirp scaling (ANCS), this method can adapt to ANPE with larger width and more severe spatial variation. At last, the criteria of Doppler blocking are given in detail, and the effectiveness of the proposed method is verified by UAV Bi-SAR real data and computer simulation.<\/jats:p>","DOI":"10.3390\/rs15153734","type":"journal-article","created":{"date-parts":[[2023,7,28]],"date-time":"2023-07-28T02:08:00Z","timestamp":1690510080000},"page":"3734","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["An Improved UAV Bi-SAR Imaging Algorithm with Two-Dimensional Spatial Variant Range Cell Migration Correction and Azimuth Non-Linear Phase Equalization"],"prefix":"10.3390","volume":"15","author":[{"given":"Junjie","family":"Yan","sequence":"first","affiliation":[{"name":"School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linghao","family":"Li","sequence":"additional","affiliation":[{"name":"School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Han","family":"Li","sequence":"additional","affiliation":[{"name":"School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meng","family":"Ke","sequence":"additional","affiliation":[{"name":"School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinnong","family":"Ma","sequence":"additional","affiliation":[{"name":"School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinshuai","family":"Sun","sequence":"additional","affiliation":[{"name":"School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,7,27]]},"reference":[{"key":"ref_1","unstructured":"Auterman, J.L. (1984, January 13\u201314). Phase stability requirements for bistatic SAR. Proceedings of the IEEE National Radar Conference, Atlanta, GE, USA."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"5238618","DOI":"10.1109\/TGRS.2022.3221859","article-title":"First Demonstration of Single-Pass Distributed SAR Tomographic Imaging With a P-Band UAV SAR Prototype","volume":"60","author":"Wang","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1049\/ip-rsn:20045091","article-title":"Bistatic SAR image formation","volume":"153","author":"Yates","year":"2006","journal-title":"IEE Proc.-Radar Sonar Navig."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1049\/ip-rsn:19981731","article-title":"Improved azimuthal resolution of forward looking SAR by sophisticated antenna illumination function design","volume":"145","author":"Loehner","year":"1998","journal-title":"IEE Proc.-Radar Sonar Navig."},{"key":"ref_5","unstructured":"Wu, J., Yang, J., Yang, H., and Huang, Y. (2009, January 19\u201324). Optimal geometry configuration of bistatic forward-looking SAR. Proceedings of the 2009 IEEE International Conference on Acoustics, Speech and Signal Processing, Taipei, China."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1049\/ip-rsn:20045111","article-title":"Spaceborne bi-and multistatic SAR: Potential and challenges","volume":"153","author":"Krieger","year":"2006","journal-title":"IEE Proc.-Radar Sonar Navig."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Cumming, I., and Bennett, J. (1979, January 2\u20134). Digital processing of Seasat SAR data. Proceedings of the ICASSP\u201979\u2014IEEE International Conference on Acoustics, Speech, and Signal Processing, Washington, DC, USA.","DOI":"10.1109\/ICASSP.1979.1170630"},{"key":"ref_8","first-page":"5208915","article-title":"Efficient Fast Time-Domain Processing Framework for Airborne Bistatic SAR Continuous Imaging Integrated With Data-Driven Motion Compensation","volume":"60","author":"Xu","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_9","first-page":"5225916","article-title":"A Novel CFFBP Algorithm With Noninterpolation Image Merging for Bistatic Forward-Looking SAR Focusing","volume":"60","author":"Li","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1494","DOI":"10.1109\/JSTARS.2016.2639580","article-title":"Fast factorized backprojection algorithm for one-stationary bistatic spotlight circular SAR image formation","volume":"10","author":"Xie","year":"2017","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Xie, H., Shi, S., Li, F., An, D., Xiao, H., Xie, C., Fang, Q., Wang, G., Wang, L., and Wang, F. (2017, January 14\u201316). Fast time domain approach for bistatic forward-looking SAR imaging based on subaperture processing and local beamforming. Proceedings of the 2017 2nd International Conference on Frontiers of Sensors Technologies (ICFST), Shenzhen, China.","DOI":"10.1109\/ICFST.2017.8210511"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Feng, D., Xie, H., An, D., and Huang, X. (2015, January 14\u201316). Fast factorized back projection algorithm for spotlight bistatic forward-looking low frequency UWB SAR. Proceedings of the IET International Radar Conference 2015, Hangzhou, China.","DOI":"10.1109\/IRS.2015.7226274"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"8627","DOI":"10.1109\/TGRS.2019.2921917","article-title":"A fast time-domain SAR imaging and corresponding autofocus method based on hybrid coordinate system","volume":"57","author":"Liang","year":"2019","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"610","DOI":"10.1109\/LGRS.2008.2000971","article-title":"The polar format imaging algorithm based on double chirp-Z transforms","volume":"5","author":"Tang","year":"2008","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1433","DOI":"10.1109\/TAES.2008.4667720","article-title":"Polar format agorithm using chirp scaling for spotlight SAR image formation","volume":"44","author":"Zhu","year":"2008","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1147","DOI":"10.1109\/TAES.2004.1386870","article-title":"Polar format algorithm for bistatic SAR","volume":"40","author":"Rigling","year":"2004","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1109\/LGRS.2020.2984909","article-title":"Azimuth migration-corrected phase gradient autofocus for bistatic SAR polar format imaging","volume":"18","author":"Miao","year":"2020","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_18","first-page":"1382","article-title":"Polar format algorithm wavefront curvature compensation under arbitrary radar flight path","volume":"Volume 2","author":"Mao","year":"2011","journal-title":"Proceedings of the 2011 IEEE CIE International Conference on Radar"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3311","DOI":"10.1109\/JSEN.2018.2809508","article-title":"A space-variant phase filtering imaging algorithm for missile-borne BiSAR with arbitrary configuration and curved track","volume":"18","author":"Deng","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Hu, C., Zeng, T., Long, T., and Yang, C. (2006, January 16\u201319). Forward-looking bistatic SAR range migration alogrithm. Proceedings of the 2006 CIE International Conference on Radar, Shanghai, China.","DOI":"10.1109\/ICR.2006.343436"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Wu, J., Huang, Y., Xiong, J., and Yang, J. (2007, January 17\u201320). Range Migration Algorithm in Bistatic SAR Based on Squint Mode. Proceedings of the 2007 IEEE Radar Conferenc, Waltham, MA, USA.","DOI":"10.1109\/RADAR.2007.374283"},{"key":"ref_22","first-page":"5203916","article-title":"Focusing Translational-Variant Bistatic Forward- Looking SAR Data Using the Modified Omega-K Algorithm","volume":"60","author":"Li","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"294","DOI":"10.1109\/TGRS.2019.2936255","article-title":"Focusing the L-Band Spaceborne Bistatic SAR Mission Data Using a Modified RD Algorithm","volume":"58","author":"Li","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2493","DOI":"10.1109\/TGRS.2008.917599","article-title":"Focusing bistatic SAR data using the nonlinear chirp scaling algorithm","volume":"46","author":"Wong","year":"2008","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_25","unstructured":"Xiaolan, Q., Donghui, H., and Chibiao, D. (2007, January 5\u20139). Non-linear chirp scaling algorithm for one-stationary bistatic SAR. Proceedings of the 2007 1st Asian and Pacific Conference on Synthetic Aperture Radar, Huangshan, China."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"6718","DOI":"10.1109\/TGRS.2015.2447393","article-title":"Subaperture approach based on azimuth-dependent range cell migration correction and azimuth focusing parameter equalization for maneuvering high-squint-mode SAR","volume":"53","author":"Zeng","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4160","DOI":"10.1109\/TGRS.2019.2961562","article-title":"Focusing of Bistatic SAR with Curved Trajectory Based on Extended Azimuth Nonlinear Chirp Scaling","volume":"58","author":"Wang","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"5240814","DOI":"10.1109\/TGRS.2022.3228803","article-title":"Focusing High-Maneuverability Bistatic Forward-Looking SAR Using Extended Azimuth Nonlinear Chirp Scaling Algorithm","volume":"60","author":"Song","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_29","first-page":"4007105","article-title":"Focusing Nonparallel-Track Bistatic SAR Data Using Modified Frequency Extended Nonlinear Chirp Scaling","volume":"19","author":"Li","year":"2022","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1109\/LGRS.2013.2250904","article-title":"Focusing bistatic forward-looking SAR with stationary transmitter based on keystone transform and nonlinear chirp scaling","volume":"11","author":"Wu","year":"2013","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Zeng, T., Wang, Z., Liu, F., and Wang, C. (2020). An improved frequency-domain image formation algorithm for mini-UAV-based forward-looking spotlight BiSAR systems. Remote Sens., 12.","DOI":"10.3390\/rs12172680"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1109\/LGRS.2006.885862","article-title":"A Two-Dimensional Spectrum for Bistatic SAR Processing Using Series Reversion","volume":"4","author":"Neo","year":"2007","journal-title":"IEEE Geosci. Remote Sens. Lett."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/15\/3734\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T20:20:29Z","timestamp":1760127629000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/15\/15\/3734"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,7,27]]},"references-count":32,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2023,8]]}},"alternative-id":["rs15153734"],"URL":"https:\/\/doi.org\/10.3390\/rs15153734","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,7,27]]}}}