Radar apertur sintetis: Perbedaan antara revisi

'''Radar apertur sintetis''' atau '''Synthetic-aperture radar''' ('''SAR''') adalah bentuk [[radar]] yang digunakan untuk membuat [[gambar]] [[dua dimensi]] atau rekonstruksi objek [[tiga dimensi]], seperti [[lanskap]]. SAR menggunakan gerakan [[antena]] radar di atas [[wilayah]] target untuk memberikan [[resolusi]] spasial yang lebih baik daripada radar pemindai berkas konvensional. SAR biasanya dipasang pada platform yang bergerak, seperti [[pesawat terbang]], uav drone atau [[pesawat ruang angkasa]], dan memiliki asal-usul dalam bentuk radar udara tampak samping / side looking airborne radar (SLAR) yang canggih. Jarak tempuh perangkat SAR di atas target dalam waktu yang dibutuhkan sinyal radar untuk kembali ke antena menciptakan bukaan antena sintetis yang besar (ukuran antena). Biasanya, semakin besar aperture, semakin tinggi resolusi gambar, terlepas dari apakah aperture itu fisik (antena besar) atau sintetis (antena bergerak)- ini memungkinkan SAR untuk membuat gambar resolusi tinggi dengan antena fisik yang relatif kecil. Selain itu, SAR memiliki sifat memiliki apertur yang lebih besar untuk objek yang lebih jauh, memungkinkan resolusi spasial yang konsisten pada rentang jarak pandang.<ref>"Introduction to Airborne RADAR", G. W. Stimson, Chapter 1 (13 pp).</ref><ref name=":2">Tomographic SAR. Gianfranco Fornaro. National Research Council (CNR). Institute for Electromagnetic Sensing of the Environment (IREA) Via Diocleziano, 328,I-80124 Napoli, ITALY</ref><ref>Oliver, C. and Quegan, S. Understanding Synthetic Aperture Radar Images. Artech House, Boston, 1998.</ref><ref name=":3">Synthetic Aperture Radar Imaging Using Spectral Estimation Techniques. Shivakumar Ramakrishnan, Vincent Demarcus, Jerome Le Ny, Neal Patwari, Joel Gussy. University of Michigan.</ref><ref>{{Cite web | url=https://sciengsustainability.blogspot.com/2017/02/bridge-monitoring-with-satellite-data.html |title = Science Engineering & Sustainability: Bridge monitoring with satellite data SAR}}</ref><ref name=":4">{{Cite journal|last1=Moreira|first1=Alberto|last2=Prats-Iraola|first2=Pau|last3=Younis|first3=Marwan|last4=Krieger|first4=Gerhard|last5=Hajnsek|first5=Irena|last6=P. Papathanassiou|first6=Konstantinos|title=A tutorial on synthetic aperture radar|journal= IEEE Geoscience and Remote Sensing Magazine|volume=1|year= 2013|issue=1|pages=6–43|doi=10.1109/MGRS.2013.2248301|s2cid=7487291|url=https://elib.dlr.de/82313/1/SAR-Tutorial-March-2013.pdf}}</ref><ref>{{Cite journal|last1=R. Bamler|last2=P. Hartl|title=Synthetic aperture radar interferometry|journal=Inv. Probl.|volume=14|number=4|pages=R1–R54|date=August 1998|doi=10.1088/0266-5611/14/4/001|bibcode=1998InvPr..14R...1B}}</ref><ref name=":9">{{Cite book |doi = 10.1016/B978-0-12-396500-4.00020-X|chapter = SAR Interferometry and Tomography: Theory and Applications|title =Communications and Radar Signal Processing|volume = 2|pages = 1043–1117|series = Academic Press Library in Signal Processing|year = 2014|last1 = Fornaro|first1 = Gianfranco|last2 = Pascazio|first2 = Vito|isbn = 9780123965004}}</ref><ref>{{Cite book |doi = 10.1109/IGARSS.2015.7326425|chapter = Three-dimensional and higher-order imaging with tomographic SAR: Techniques, applications, issues|title = 2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)|pages = 2915–2918|year = 2015|last1 = Reigber|first1 = Andreas|last2 = Lombardini|first2 = Fabrizio|last3 = Viviani|first3 = Federico|last4 = Nannini|first4 = Matteo|last5 = Martinez Del Hoyo|first5 = Antonio|isbn = 978-1-4799-7929-5|s2cid = 9589219}}</ref><ref>Massachusetts Institute of Technology, [http://ocw.mit.edu/resources/res-ll-003-build-a-small-radar-system-capable-of-sensing-range-doppler-and-synthetic-aperture-radar-imaging-january-iap-2011/lecture-notes/MITRES_LL_003IAP11_lec04.pdf Synthetic Aperture Radar (SAR) Imaging using the MIT IAP 2011 Laptop Based Radar], Presented at the 2011 MIT Independent Activities Period, 24 January 2011.</ref><ref>University of Illinois at Urbana-Champaign, [http://www.jpier.org/PIER/pier.php?paper=13112203 AZIMUTH STACKING ALGORITHM FOR SYNTHETIC APERTURE RADAR IMAGING], By Z. Li, T. Jin, J. Wu, J. Wang, and Q. H. Liu.</ref>

 

Untuk membuat citra SAR, pulsa gelombang radio yang berurutan ditransmisikan untuk "menerangi" pemandangan target, dan gema setiap denyut diterima dan direkam. Pulsa tersebut ditransmisikan dan gema diterima menggunakan antena pembentuk berkas tunggal, dengan panjang gelombang satu meter hingga beberapa milimeter. Saat perangkat SAR di dalam pesawat atau pesawat ruang angkasa bergerak, lokasi antena relatif terhadap target berubah seiring waktu. Pemrosesan sinyal dari pantulan radar yang direkam secara berurutan memungkinkan penggabungan rekaman dari berbagai posisi antena ini. Proses ini membentuk bukaan antena sintetis dan memungkinkan pembuatan gambar dengan resolusi lebih tinggi daripada yang mungkin dilakukan dengan antena fisik tertentu.<ref>NASA, [https://ntrs.nasa.gov/search.jsp?R=19950017534 An improved algorithm for retrieval of snow wetness using C-band AIRSAR], 25 October 1993.</ref><ref>[http://www2.ece.ohio-state.edu/~ertine/Ertin2014b.pdf Three Dimensional Imaging of Vehicles], from Sparse Apertures in Urban Environment, Emre Ertin, Department of Electrical and Computer Engineering, The Ohio State University.</ref><ref>Xiaoxiang Zhu, "Spectral Estimation for Synthetic Aperture Radar Tomography", Earth Oriented Space Science and Technology – ESPACE, 19 September 2008.</ref><ref>{{Cite journal|last=D. Rodriguez|title=A computational Kronecker-core array algebra SAR raw data generation modeling system|journal=Signals, Systems and Computers, 2001. Conference Record of the Thirty-Fifth Asilomar Conference on Year: 2001|volume=1}}</ref><ref name=":13">{{Cite journal|last=T. Gough|first=Peter|title=A Fast Spectral Estimation Algorithm Based on the FFT|journal= IEEE Transactions on Signal Processing|volume= 42| issue = 6 |date= June 1994|pages=1317–1322|bibcode=1994ITSP...42.1317G|doi=10.1109/78.286949}}</ref><ref name=":10">{{Cite journal |last1=Datcu |first1=Mihai |last2=Popescu |first2=Anca |last3=Gavat |first3=Inge |title= Complex SAR image characterization using space variant spectral analysis |journal=2008 IEEE Radar Conference |year=2008}}</ref><ref>{{Cite journal |last=J. Capo4 |title= High resolution frequency wave-number spectrum analysis |journal= Proceedings of the IEEE|volume=57 |issue= 8 |pages= 1408–1418 |date= August 1969 |doi= 10.1109/PROC.1969.7278 }}</ref><ref name=":5">{{Cite journal|last1=A. Jakobsson|last2=S. L. Marple|last3=P. Stoica|title=Computationally efficient two-dimensional Capon spectrum analysis|journal= IEEE Transactions on Signal Processing|volume=48|year=2000|issue=9|pages=2651–2661|doi=10.1109/78.863072|bibcode=2000ITSP...48.2651J|citeseerx=10.1.1.41.7}}</ref><ref>{{Cite journal|last1=I. Yildirim|last2=N. S. Tezel|last3=I. Erer|last4=B. Yazgan|title=A comparison of non-parametric spectral estimators for SAR imaging|journal=Recent Advances in Space Technologies, 2003. RAST '03. International Conference On. Proceedings of Year: 2003}}</ref>

 

 

== Referensi ==