{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T17:14:38Z","timestamp":1771521278033,"version":"3.50.1"},"reference-count":31,"publisher":"MDPI AG","issue":"20","license":[{"start":{"date-parts":[[2022,10,21]],"date-time":"2022-10-21T00:00:00Z","timestamp":1666310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>This paper presents the design and processing of the SAR acquisition technique named frequency scanning (f-SCAN), aimed to obtain high sensitivity to targets with low backscattering and to improve the signal-to-noise ratio (SNR) in wide-swath systems. The f-SCAN is an interesting alternative to the scanning on receive method (SCORE), which needs multiple phase centres achieved using the digital beam forming (DBF) technique. f-SCAN requires less hardware complexity than SCORE; at the same time, it improves the sidelobes and ambiguities\u2019 suppression. The elements used in f-SCAN to generate the pencil beam are the true time delay lines (TTDLs) and the phase shifters (PSs). The general methodology to design an f-SCAN spaceborne SAR high-resolution wide-swath (HRWS) system is introduced; emphasis is put on the mathematical definition of the timing parameters and on a novel method of using TTDLs to achieve the full spanning of wide swaths. The processing of f-SCAN data is also considered: we introduce a novel algorithm to limit the data volume and to guarantee an almost invariant slant range impulse response function (IRF) by removing spectral distortions. Eventually, new definitions, specific for f-SCAN, of the well-known SAR performance parameters, are provided. Simulation results and performances are presented. The advantages and disadvantages with respect to SCORE are discussed using the design of a real case system.<\/jats:p>","DOI":"10.3390\/rs14205283","type":"journal-article","created":{"date-parts":[[2022,10,24]],"date-time":"2022-10-24T10:09:23Z","timestamp":1666606163000},"page":"5283","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Design of f-SCAN Acquisition Mode for Synthetic Aperture Radar"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7126-0040","authenticated-orcid":false,"given":"Pietro","family":"Guccione","sequence":"first","affiliation":[{"name":"Aresys SRL, 20132 Milan, Italy"},{"name":"Department of Electrical Information Engineering, Politecnico di Bari, 70126 Bari, Italy"}]},{"given":"Daniele","family":"Mapelli","sequence":"additional","affiliation":[{"name":"Aresys SRL, 20132 Milan, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4227-1565","authenticated-orcid":false,"given":"Davide","family":"Giudici","sequence":"additional","affiliation":[{"name":"Aresys SRL, 20132 Milan, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1761-598X","authenticated-orcid":false,"given":"Adriano Rosario","family":"Persico","sequence":"additional","affiliation":[{"name":"Aresys SRL, 20132 Milan, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2022,10,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1109\/MGRS.2013.2248301","article-title":"A tutorial on synthetic aperture radar","volume":"1","author":"Moreira","year":"2013","journal-title":"IEEE Geosci. Remote Sens. Mag."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1735","DOI":"10.1109\/TGRS.2003.815662","article-title":"Digital beamforming in SAR systems","volume":"41","author":"Younis","year":"2003","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"260","DOI":"10.1109\/LGRS.2004.832700","article-title":"Unambiguous SAR signal reconstruction from nonuniform displaced phase center sampling","volume":"1","author":"Krieger","year":"2004","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_4","unstructured":"Suess, M., Grafmueller, B., and Zahn, R. (2001, January 9\u201313). A novel high resolution, wide swath SAR system. Scanning the Present and Resolving the Future. Proceedings of the IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217), Sydney, Australia."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1109\/36.823926","article-title":"The \u201cMyth\u201d of the minimum SAR antenna area constraint","volume":"38","author":"Freeman","year":"2000","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_6","unstructured":"John, C. (1992). Curlander, R.N.M. Synthetic Aperture Radar: Systems and Signal Processing, Wiley."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Davidson, M.W.J., and Furnell, R. (2021, January 11\u201316). ROSE-L: Copernicus L-Band Sar Mission. Proceedings of the 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, Brussels, Belgium.","DOI":"10.1109\/IGARSS47720.2021.9554018"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Geudtner, D., Tossaint, M., Davidson, M., and Torres, R. (2021, January 11\u201316). Copernicus Sentinel-1 Next Generation Mission. Proceedings of the 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, Brussels, Belgium.","DOI":"10.1109\/IGARSS47720.2021.9554226"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1109\/TGRS.2012.2201947","article-title":"First Spaceborne Demonstration of Digital Beamforming for Azimuth Ambiguity Suppression","volume":"51","author":"Kim","year":"2013","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2994","DOI":"10.1109\/TGRS.2010.2041356","article-title":"Multichannel Azimuth Processing in ScanSAR and TOPS Mode Operation","volume":"48","author":"Gebert","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TGRS.2021.3062973","article-title":"Compact and Free-Floating Satellite MIMO SAR Formations","volume":"60","author":"Giudici","year":"2022","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Guccione, P., Monti Guarnieri, A., Rocca, F., Giudici, D., and Gebert, N. (2020). Along-Track Multistatic Synthetic Aperture Radar Formations of Minisatellites. Remote Sens., 12.","DOI":"10.3390\/rs12010124"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Tan, W., Xu, W., Huang, P., Huang, Z., Qi, Y., and Han, K. (2017). Investigation of Azimuth Multichannel Reconstruction for Moving Targets in High Resolution Wide Swath SAR. Sensors, 17.","DOI":"10.3390\/s17061270"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Freeman, A., Krieger, G., Rosen, P., Younis, M., Johnson, W.T.K., Huber, S., Jordan, R., and Moreira, A. (2009, January 4\u20138). SweepSAR: Beam-forming on receive using a reflector-phased array feed combination for spaceborne SAR. Proceedings of the 2009 IEEE Radar Conference, Pasadena, CA, USA.","DOI":"10.1109\/RADAR.2009.4977140"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"564","DOI":"10.1109\/TAES.2009.5089542","article-title":"Digital Beamforming on Receive: Techniques and Optimization Strategies for High-Resolution Wide-Swath SAR Imaging","volume":"45","author":"Gebert","year":"2009","journal-title":"IEEE Trans. Aerosp. Electron. Syst."},{"key":"ref_16","unstructured":"Mailloux, R. (2017). Phased Array Antenna Handbook, Artech House. [3rd ed.]."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Roemer, C. (2017, January 23\u201328). Introduction to a new wide area sar mode using the F-SCAN principle. Proceedings of the 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Fort Worth, TX, USA.","DOI":"10.1109\/IGARSS.2017.8127840"},{"key":"ref_18","unstructured":"Roemer, C., Gierlich, R., Marquez-Martinez, J., and Notter, M. (2018, January 4\u20137). Frequency Scanning applied to Wide Area SAR Imaging. Proceedings of the 12th European Conference on Synthetic Aperture Radar (EUSAR 2018), Aachen, Germany."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3619","DOI":"10.1109\/TGRS.2019.2958863","article-title":"On the Frequency Dispersion in DBF SAR and Digital Scalloped Beamforming","volume":"58","author":"Zhao","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_20","first-page":"1","article-title":"Performance Demonstration of Dispersive SCORE: Digital Scalloped Beamforming With X-Band and C-Band DBF-SARs","volume":"19","author":"Chen","year":"2022","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Xu, W., Yu, Q., Fang, C., Huang, P., Tan, W., and Qi, Y. (2021). Onboard Digital Beamformer with Multi-Frequency and Multi-Group Time Delays for High-Resolution Wide-Swath SAR. Remote Sens., 13.","DOI":"10.3390\/rs13214354"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1109\/LGRS.2018.2867723","article-title":"Multifrequency Subpulse SAR: Exploiting Chirp Bandwidth for an Increased Coverage","volume":"16","author":"Bordoni","year":"2019","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"275","DOI":"10.2528\/PIER12071811","article-title":"Frequency Scanning Based Radar System","volume":"132","author":"Alvarez","year":"2012","journal-title":"Prog. Electromagn. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1155\/2017\/5717641","article-title":"Pulse Dispersion in Phased Arrays","volume":"2017","author":"Haupt","year":"2017","journal-title":"Int. J. Antennas Propag."},{"key":"ref_25","unstructured":"Scheiber, R., Martone, M., and Gollin, N. (April, January 29). Chirp Selection and Data Compression for Spaceborne Wide-Swath SAR in FScan-Mode. Proceedings of the 13th European Conference on Synthetic Aperture Radar (EUSAR 2021), Online."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"6434","DOI":"10.1109\/TGRS.2020.2976864","article-title":"Signal Modeling and Analysis for Elevation Frequency Scanning HRWS SAR","volume":"58","author":"Nan","year":"2020","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"855","DOI":"10.1109\/36.298013","article-title":"The wavenumber shift in SAR interferometry","volume":"32","author":"Gatelli","year":"1994","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2352","DOI":"10.1109\/TGRS.2006.873853","article-title":"TOPSAR: Terrain Observation by Progressive Scans","volume":"44","year":"2006","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_29","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_30","unstructured":"Calabrese, D., and Episcopo, R. (2014, January 3\u20135). Derivation of the SAR Noise Equivalent Sigma Nought. Proceedings of the 10th European Conference on Synthetic Aperture Radar (EUSAR 2014), Berlin, Germany."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1436","DOI":"10.1109\/LGRS.2015.2406815","article-title":"On the Pulse Extension Loss in Digital Beamforming SAR","volume":"12","author":"Younis","year":"2015","journal-title":"IEEE Geosci. Remote Sens. 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