{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:19:26Z","timestamp":1760242766733,"version":"build-2065373602"},"reference-count":30,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2016,5,12]],"date-time":"2016-05-12T00:00:00Z","timestamp":1463011200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"ESTEC","award":["ESTEC Contract 4000103923"],"award-info":[{"award-number":["ESTEC Contract 4000103923"]}]},{"DOI":"10.13039\/501100010198","name":"MINECO","doi-asserted-by":"publisher","award":["AYA2011-29183-C02-01"],"award-info":[{"award-number":["AYA2011-29183-C02-01"]}],"id":[{"id":"10.13039\/501100010198","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Imaging"],"abstract":"<jats:p>The Synthetic Aperture Interferometric Radiometer Performance Simulator (SAIRPS) has been a three-year project sponsored by the European Space Agency (ESA) to develop a completely generic end-to-end performance simulator of arbitrary synthetic aperture interferometric radiometers. In a companion manuscript (Part I), the Radiative Transfer Module used to generate synthetic fully polarimetric brightness temperatures from 1 to 100 GHz, including land and ocean covers, as well as the atmosphere, is described in detail. In this manuscript (Part II), the instrument model, the calibration procedure, and the imaging algorithms are described. The instrument model includes the simulation of the array topology in terms of the number of antenna elements, the time-dependent position and orientation, and the arbitrary receivers\u2019 topology which can be modified from a very generic one by connecting and disconnecting subsystems. All the parameters can be, one by one, defined either by mathematical functions or by input data files, including the frequency and temperature dependence. Generic calibration algorithms including an external point source, the flat target transformation, and the two-level correlated noise injection are described. Finally, different image reconstruction algorithms suitable for arbitrary array topologies have also been implemented and tested. Simulation results have been validated and selected results are presented.<\/jats:p>","DOI":"10.3390\/jimaging2020018","type":"journal-article","created":{"date-parts":[[2016,5,12]],"date-time":"2016-05-12T10:18:45Z","timestamp":1463048325000},"page":"18","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Microwave Imaging Radiometers by Aperture Synthesis Performance Simulator (Part 2): Instrument Modeling, Calibration, and Image Reconstruction Algorithms"],"prefix":"10.3390","volume":"2","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9514-4992","authenticated-orcid":false,"given":"Adriano","family":"Camps","sequence":"first","affiliation":[{"name":"Universitat Polit\u00e8cnica de Catalunya UPC-BarcelonaTech (UPC) &amp; Institut d\u2019Estudis Espacials de Catalunya\/Centre de Tecnologies de l\u2019Espai-UPC, Campus Nord, Building D4, Office 016, E-08034 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0031-0802","authenticated-orcid":false,"given":"Hyuk","family":"Park","sequence":"additional","affiliation":[{"name":"Universitat Polit\u00e8cnica de Catalunya UPC-BarcelonaTech (UPC) &amp; Institut d\u2019Estudis Espacials de Catalunya\/Centre de Tecnologies de l\u2019Espai-UPC, Campus Nord, Building D4, Office 016, E-08034 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yujin","family":"Kang","sequence":"additional","affiliation":[{"name":"Universitat Polit\u00e8cnica de Catalunya UPC-BarcelonaTech (UPC) &amp; Institut d\u2019Estudis Espacials de Catalunya\/Centre de Tecnologies de l\u2019Espai-UPC, Campus Nord, Building D4, Office 016, E-08034 Barcelona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jorge","family":"Bandeiras","sequence":"additional","affiliation":[{"name":"DEIMOS Engenharia SA, Av. Dom Jo\u00e3o II 2, 1998-023 Lisboa, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jose","family":"Barbosa","sequence":"additional","affiliation":[{"name":"DEIMOS Engenharia SA, Av. Dom Jo\u00e3o II 2, 1998-023 Lisboa, Portugal"},{"name":"Research and Development in Aerospace-RDA GmbH, Rigiplatz 5, 8006 Z\u00fcrich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paula","family":"Vieira","sequence":"additional","affiliation":[{"name":"DEIMOS Engenharia SA, Av. Dom Jo\u00e3o II 2, 1998-023 Lisboa, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ana","family":"Fria\u00e7as","sequence":"additional","affiliation":[{"name":"DEIMOS Engenharia SA, Av. Dom Jo\u00e3o II 2, 1998-023 Lisboa, Portugal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Salvatore","family":"D\u2019Addio","sequence":"additional","affiliation":[{"name":"European Space Agency-European Space and Technology Center ESA-ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,5,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1677","DOI":"10.1109\/TGRS.2004.830641","article-title":"The visibility function in interferometric aperture synthesis radiometry","volume":"42","author":"Corbella","year":"2004","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1109\/LGRS.2005.846885","article-title":"Polarimetric formulation of the visibility function equation including cross-polar antenna patterns","volume":"2","author":"Camps","year":"2005","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"657","DOI":"10.1029\/96RS03198","article-title":"Impact of Antenna Errors on the Radiometric Accuracy of Large Aperture Synthesis radiometers. Study Applied to MIRAS","volume":"32","author":"Camps","year":"1997","journal-title":"Radio Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1543","DOI":"10.1029\/98RS02813","article-title":"Mutual Coupling Effects on Antenna Radiation Pattern: An Experimental Study Applied to Interferometric Radiometers","volume":"33","author":"Camps","year":"1998","journal-title":"Radio Sci."},{"key":"ref_5","unstructured":"Pozar, D.M. (2011). Microwave Engineering, John Wiley and Sons, Inc.. [4th ed.]."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2004","DOI":"10.1109\/22.168757","article-title":"Wave techniques for noise modelling and measurement","volume":"40","author":"Wedge","year":"1992","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1049\/el:19970526","article-title":"Threshold and Timing Errors of 1 bit\/2 level Digital Correlators in Earth Observation Synthetic Aperture Radiometry","volume":"33","author":"Camps","year":"1997","journal-title":"Electron. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"775","DOI":"10.1029\/RS008i008p00775","article-title":"Digital-correlation techniques in radio science","volume":"8","author":"Hagen","year":"1973","journal-title":"Radio Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1109\/81.847872","article-title":"Phase noise in oscillators: A unifying theory and numerical methods for characterization","volume":"47","author":"Demir","year":"2000","journal-title":"IEEE Trans. Circuit Syst. Fundam. Theory Appl."},{"key":"ref_10","unstructured":"Kobayashi, H., Morimura, M., Kobayashi, K., and Onaya, Y. (1999, January 28\u201330). Aperture jitter effects in wideband ADC systems. Proceedings of the 38th SICE Annual Conference, Iwate, Japan."},{"key":"ref_11","unstructured":"Maxim, I.C. Application Note 3359, 10 December 2004, Clock (CLK) Jitter and Phase Noise Conversion. Available online: http:\/\/www.maxim-ic.com\/app-notes\/index.mvp\/id\/3359."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"6066","DOI":"10.3390\/s110606066","article-title":"A General Analysis of the Impact of Digitization in Microwave Correlation Radiometers","volume":"11","author":"Camps","year":"2011","journal-title":"Sensors"},{"key":"ref_13","unstructured":"Ulaby, F., Moore, R., and Fung, A.K. (1981). Microwave Remote Sensing, Artech House. [1st ed.]."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1032","DOI":"10.1029\/2002RS002695","article-title":"Fringe-washing function calibration in aperture synthesis microwave radiometry","volume":"38","author":"Butora","year":"2003","journal-title":"Radio Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1000","DOI":"10.1109\/36.508417","article-title":"On-board phase and modulus calibration of large aperture synthesis radiometers: Study applied to MIRAS","volume":"34","author":"Torres","year":"1996","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2679","DOI":"10.1109\/TGRS.2006.874246","article-title":"Denormalization of Visibilities for In-Orbit Calibration of Interferometric Radiometers","volume":"44","author":"Torres","year":"2006","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"5183","DOI":"10.1080\/0143116031000070337","article-title":"Redundant Space Calibration of Hexagonal and Y-Shaped Beamforming Radars and Interferometric Radiometers","volume":"24","author":"Camps","year":"2003","journal-title":"Int. J. Remote Sens."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"613","DOI":"10.1109\/TGRS.2008.916259","article-title":"The Flat Target Transformation","volume":"46","author":"Suess","year":"2008","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_19","unstructured":"Camps, A. (1996). Application of Interferometric Radiometry to Earth Observation. [Ph.D. Thesis, Universitat Politecnica de Catalunya]."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"67","DOI":"10.2528\/PIER97041500","article-title":"Extension of the CLEAN Technique to the Microwave Imaging of Continuous Thermal Sources by Means of Aperture Synthesis Radiometers","volume":"18","author":"Camps","year":"1998","journal-title":"Prog. Electromagn. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1109\/TGRS.2007.907603","article-title":"Improved Image Reconstruction Algorithms for Aperture Synthesis Radiometers","volume":"46","author":"Camps","year":"2008","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1459","DOI":"10.1029\/98RS00829","article-title":"Angular Resolution of two-dimensional hexagonally sampled interferometric radiometers","volume":"33","author":"Camps","year":"1998","journal-title":"Radio Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1109\/36.551946","article-title":"The Processing of Hexagonally Sampled Signals with Standard Rectangular Techniques: Application to 2D Large Aperture Synthesis Interferometric Radiometers","volume":"35","author":"Camps","year":"1997","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"560","DOI":"10.1109\/TSP.2002.807005","article-title":"Non-uniform fast Fourier transforms using min-max interpolation","volume":"51","author":"Fessler","year":"2003","journal-title":"IEEE Trans. Signal Process."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"793","DOI":"10.1109\/LGRS.2008.2005915","article-title":"Angular and Radiometric Resolution of Y-Shaped Non-uniform Synthetic Aperture Radiometers for Earth Observation","volume":"5","author":"Camps","year":"2008","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1109\/LGRS.2008.2012123","article-title":"NUFFT-Based Iterative Reconstruction Algorithm for Synthetic Aperture Imaging Radiometers","volume":"6","author":"Zhou","year":"2009","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1109\/36.210465","article-title":"Calibration of a synthetic aperture radiometer","volume":"31","author":"Tanner","year":"1993","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1109\/LGRS.2006.890553","article-title":"First 2-D Interferometric Radiometer Imaging of the Earth from an Aircraft","volume":"4","author":"Kainulainen","year":"2007","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1649","DOI":"10.1109\/TGRS.2004.830940","article-title":"A resolving matrix approach for synthetic aperture imaging radiometers","volume":"42","author":"Anterrieu","year":"2004","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_30","first-page":"417","article-title":"Aperture synthesis with non-regular distribution of interferometer baselines","volume":"15","year":"1974","journal-title":"Astron. Astrophys. Suppl. Ser."}],"container-title":["Journal of Imaging"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2313-433X\/2\/2\/18\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:23:43Z","timestamp":1760210623000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2313-433X\/2\/2\/18"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,5,12]]},"references-count":30,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2016,6]]}},"alternative-id":["jimaging2020018"],"URL":"https:\/\/doi.org\/10.3390\/jimaging2020018","relation":{},"ISSN":["2313-433X"],"issn-type":[{"type":"electronic","value":"2313-433X"}],"subject":[],"published":{"date-parts":[[2016,5,12]]}}}