{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:07:52Z","timestamp":1760242072042,"version":"build-2065373602"},"reference-count":23,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2018,12,21]],"date-time":"2018-12-21T00:00:00Z","timestamp":1545350400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004543","name":"China Scholarship Council","doi-asserted-by":"publisher","award":["201706025038"],"award-info":[{"award-number":["201706025038"]}],"id":[{"id":"10.13039\/501100004543","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Geosynchronous synthetic aperture radar (GEO SAR) has the potential for conducting long-term observation of target zones, which is essential for remote sensing applications such as disaster monitoring and vegetation measurements. The squint imaging mode is crucial for long-term observation using GEO SAR. However, this type of SAR imaging is problematic because the squint mode introduces a nonzero range cell walk, which increases the prevalence of invalid data in echoes and intensifies the coupling between the azimuth and range. Therefore, this paper proposes a novel squint mode GEO SAR imaging method based on the correction of the bulk range walk of received signals. Adjusting the starting time of the receiving window significantly reduces the redundancy in echoes. Then, first-order filtering, range cell migration correction, range compression, partial dechirp, and azimuth compression are used to obtain the imaging result. Simulation results for the GEO SAR imaging of Wenchuan County in China demonstrate that the proposed algorithm can achieve a resolution of 5 m within a 30 \u00d7 30 km swath over 48% of the orbital period.<\/jats:p>","DOI":"10.3390\/rs11010017","type":"journal-article","created":{"date-parts":[[2018,12,21]],"date-time":"2018-12-21T12:14:49Z","timestamp":1545394489000},"page":"17","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Squint Mode GEO SAR Imaging Using Bulk Range Walk Correction on Received Signals"],"prefix":"10.3390","volume":"11","author":[{"given":"Jiwen","family":"Geng","sequence":"first","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100191, China"}]},{"given":"Ze","family":"Yu","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100191, China"}]},{"given":"Chunsheng","family":"Li","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100191, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2968-2888","authenticated-orcid":false,"given":"Wei","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Electronic &amp; Electrical Engineering, University of Sheffield, Sheffield S1 4ET, UK"}]}],"member":"1968","published-online":{"date-parts":[[2018,12,21]]},"reference":[{"key":"ref_1","unstructured":"Tomiyasu, K. (1978, January 9\u201313). Synthetic aperture radar in geosynchronous orbit. Proceedings of the 1978 Antennas and Propagation Society International Symposium, Washington, DC, USA."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"324","DOI":"10.1109\/TGRS.1983.350561","article-title":"Synthetic Aperture Radar Imaging from an Inclined Geosynchronous Orbit","volume":"GE-21","author":"Tomiyasu","year":"1983","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","unstructured":"(2003, April 18). Global Earthquake Satellite System: A 20-Year Plan to Enable Earthquake Prediction, JPL Document, NASA and JPL, Tech. Rep. JPL 400-1069, Available online: https:\/\/solidearth.jpl.nasa.gov\/GESS\/3123_GESS_Rep_2003.pdf."},{"key":"ref_4","unstructured":"Madsen, S.N., Edelstein, W., DiDomenico, L.D., and LaBrecque, J. (2001, January 9\u201313). A geosynchronous synthetic aperture radar; for tectonic mapping, disaster management and measurements of vegetation and soil moisture. Proceedings of the IGARSS 2001, Sydney, Australia."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3999","DOI":"10.1109\/JSTARS.2015.2418814","article-title":"Modeling and Processing of Two-Dimensional Spatial-Variant Geosynchronous SAR Data","volume":"8","author":"Li","year":"2015","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Li, Z., Li, C., Yu, Z., Zhou, J., and Chen, J. (2011, January 24\u201329). Back projection algorithm for high resolution GEO-SAR image formation. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium, Vancouver, BC, Canada.","DOI":"10.1109\/IGARSS.2011.6048967"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"760","DOI":"10.1109\/TAES.2003.1238734","article-title":"Synthetic-aperture radar processing using fast factorized back-projection","volume":"39","author":"Ulander","year":"2003","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"194","DOI":"10.1109\/7.78293","article-title":"SAR data focusing using seismic migration techniques","volume":"27","author":"Cafforio","year":"1991","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"786","DOI":"10.1109\/36.298008","article-title":"Precision SAR processing using chirp scaling","volume":"32","author":"Raney","year":"1994","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"854","DOI":"10.1109\/7.489529","article-title":"A new two-dimensional squint mode SAR processor","volume":"32","author":"Franceschetti","year":"1996","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1049\/el.2011.1892","article-title":"Chirp scaling algorithm for GEO SAR based on fourth-order range equation","volume":"48","author":"Bao","year":"2012","journal-title":"Electron. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"481","DOI":"10.2528\/PIER12092603","article-title":"An Improved Nonlinear Chirp Scaling Algorithm Based on Curved Trajectory in Geosynchronous SAR","volume":"135","author":"Hu","year":"2013","journal-title":"Prog. Electromagn. Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"19","DOI":"10.2528\/PIER13071206","article-title":"A Refined Two-Dimensional Nonlinear Chirp Scaling Algorithm for Geosynchronous Earth Orbit SAR","volume":"143","author":"Zeng","year":"2013","journal-title":"Prog. Electromagn. Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"4868","DOI":"10.1109\/TGRS.2013.2285721","article-title":"A 2-D Space-Variant Chirp Scaling Algorithm Based on the RCM Equalization and Subband Synthesis to Process Geosynchronous SAR Data","volume":"52","author":"Sun","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1109\/LGRS.2016.2599224","article-title":"A TSVD-NCS Algorithm in Range-Doppler Domain for Geosynchronous Synthetic Aperture Radar","volume":"13","author":"Chen","year":"2016","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Yu, Z., Lin, P., Xiao, P., Kang, L., and Li, C. (2016). Correcting spatial variance of RCM for geo sar imaging based on time-frequency scaling. Sensors, 16.","DOI":"10.3390\/s16071091"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1119","DOI":"10.1109\/JSTARS.2015.2497000","article-title":"A Modified Frequency Domain Algorithm Based on Optimal Azimuth Quadratic Factor Compensation for Geosynchronous SAR Imaging","volume":"9","author":"Ding","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"5724","DOI":"10.1109\/JSTARS.2017.2765353","article-title":"A 2-D Nonlinear Chirp Scaling Algorithm for High Squint GEO SAR Imaging Based on Optimal Azimuth Polynomial Compensation","volume":"10","author":"Zhang","year":"2017","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Motohka, T., Kankaku, Y., Suzuki, S., and Shimada, M. (2017, January 23\u201328). Status of the advanced land observing satellite-2 (ALOS-2) and its follow-on L-band SAR mission. Proceedings of the IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Fort Worth, TX, USA.","DOI":"10.1109\/IGARSS.2017.8127482"},{"key":"ref_20","unstructured":"Cumming, I.G., and Wong, F.H. (2004). Digital Signal Processing of Synthetic Aperture Radar Data, Artech House."},{"key":"ref_21","unstructured":"Geng, J., Yu, Z., Lin, P., Xiao, P., and Li, C. (2018, January 4\u20137). Fourth-order chirp scaling imaging algorithm for Geosynchronous Synthetic Aperture Radar. Proceedings of the EUSAR 2018, 12th European Conference on Synthetic Aperture Radar, Aachen, Germany."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1109\/7.481254","article-title":"A chirp scaling approach for processing squint mode SAR data","volume":"32","author":"Davidson","year":"1996","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_23","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\/11\/1\/17\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:35:37Z","timestamp":1760196937000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/11\/1\/17"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,12,21]]},"references-count":23,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2019,1]]}},"alternative-id":["rs11010017"],"URL":"https:\/\/doi.org\/10.3390\/rs11010017","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2018,12,21]]}}}