PERANCANGAN DAN IMPLEMENTASI BAND PASS FILTER PADA SYNTETHIC APERTURE RADAR DENGAN FREKUENSI 1,27 GHz

Synthetic Aperture Radar (SAR) merupakan salah satu teknologi radar yang digunakan untuk aplikasi penginderaan permukaan bumi (remote sensing). Sistem SAR ini bekerja pada frekuensi 1265-1275 MHz dengan frekuensi tengah 1270 MHz. Noise perangkat dan interferensi selalu ada dalam system komunikasi termasuk dalam sistem SAR. Untuk dapat bekerja dengan baik maka dibutuhkannya band pass filter untuk bisa meloloskan frekuensi tersebut.Untuk mendapatkan hasil tersebut, filter ini harus memiliki tingkat akurasi slope yang tajam dann mem iliki bandwidth 10 MHz . Pada perancangan band pass filter menggunakan metode Hairpin - Line dan simulasinya software CST Studio Suite .H asil pengukuran dari filter yang direalisasikan menunjukkan frekuensi 1.27 GHz dan selektivitas yang baik . Namun nilai Re turn Loss masih cukup besar yaitu - 9.33 dB dan Insertion Loss minimal sebesar - 13.51 dB. Dengan adanya perangkat filter ini, s ehingga dapat mendukung perancangan Synthetic Aperture Radar di laboratorium riset RADAR Telkom University

Innovative Adaptive Techniques for Multi Channel Spaceborne SAR Systems

Synthetic Aperture Radar (SAR) is a well-known technology which allows to coherently combine multiple returns from (typically) ground-based targets from a moving radar mounted either on an airborne or on a space-borne vehicle. The relative motion between the targets on ground and the platform causes a Doppler effect, which is exploited to discriminate along-track positions of targets themselves. In addition, as most of conventional radar, a pulsed wide-band waveform is transmitted periodically, thus allowing even a radar discrimination capability in the range direction (i.e. in distance). For side-looking acquisition geometries, the along-track and the range directions are almost orthogonal, so that the two dimensional target discrimination capabiliy results in the possibility to produce images of the illuminated area on ground. A side-looking geometry consists in the radar antenna to be, either mechanically or electronically, oriented perpendicular to the observed area. Nowadays technology allows discrimination capability (also referred to as resolution) in both alongtrack and range directions in the order of few tenths of centimeters. Since the SAR is a microwave active sensor, this technology assure the possibility to produce images of the terrain independently of the sunlight illumination and/or weather conditions. This makes the SAR a very useful instrument for monitoring and mapping both the natural and the artificial activities over the Earth’s surface. Among all the limitations of a single-channel SAR system, this work focuses over some of them which are briefly listed below: a) the performance achievable in terms of resolution are usually paid in terms of system complexity, dimension, mass and cost; b) since the SAR is a coherent active sensor, it is vulnerable to both intentionally and unintentionally radio-frequency interferences which might limit normal system operability; c) since the Doppler effect it is used to discriminate targets (assumed to be stationary) on the ground, this causes an intrinsic ambiguity in the interpretation of backscattered returns from moving targets. These drawbacks can be easily overcome by resorting to a Multi-cannel SAR (M-SAR) system

Innovative Adaptive Techniques for Multi Channel Spaceborne SAR Systems

Synthetic Aperture Radar (SAR) is a well-known technology which allows to coherently combine multiple returns from (typically) ground-based targets from a moving radar mounted either on an airborne or on a space-borne vehicle. The relative motion between the targets on ground and the platform causes a Doppler effect, which is exploited to discriminate along-track positions of targets themselves. In addition, as most of conventional radar, a pulsed wide-band waveform is transmitted periodically, thus allowing even a radar discrimination capability in the range direction (i.e. in distance). For side-looking acquisition geometries, the along-track and the range directions are almost orthogonal, so that the two dimensional target discrimination capabiliy results in the possibility to produce images of the illuminated area on ground. A side-looking geometry consists in the radar antenna to be, either mechanically or electronically, oriented perpendicular to the observed area. Nowadays technology allows discrimination capability (also referred to as resolution) in both alongtrack and range directions in the order of few tenths of centimeters. Since the SAR is a microwave active sensor, this technology assure the possibility to produce images of the terrain independently of the sunlight illumination and/or weather conditions. This makes the SAR a very useful instrument for monitoring and mapping both the natural and the artificial activities over the Earth’s surface. Among all the limitations of a single-channel SAR system, this work focuses over some of them which are briefly listed below: a) the performance achievable in terms of resolution are usually paid in terms of system complexity, dimension, mass and cost; b) since the SAR is a coherent active sensor, it is vulnerable to both intentionally and unintentionally radio-frequency interferences which might limit normal system operability; c) since the Doppler effect it is used to discriminate targets (assumed to be stationary) on the ground, this causes an intrinsic ambiguity in the interpretation of backscattered returns from moving targets. These drawbacks can be easily overcome by resorting to a Multi-cannel SAR (M-SAR) system

EVALUASI POLARISASI CITRA SAR (SYHTHETIC APERTURE RADAR) UNTUK KLASIFIKASI OBYEK TUTUPAN LAHAN

Penggunaan pengindraan jauh sensor aktif SAR (Synthetic Aperture Radar) masih kurang dimanfaatkan sebagai upaya pengganti pengindraan jauh optis untuk pemetaan tutupan lahan, padahal citra optis masih memiliki tutupan awan yang menjadi kendala besar dalam pemantauan obyek tutupan lahan. Keunggulan Citra SAR Sentinel-1A adalah dapat menembus awan serta tidak berpengaruh pada keadaan cuaca. Dengan memanfaatkan teknologi polarisasi, citra SAR dapat membentuk komposit RGB yang berbeda, dalam penelitian ini digunakan komposit VV+VH,VH,VV/VH yaitu R dengan polarisasi VV+VH, G dengan polarisasi VH dan B dengan polarisasi VV/VH, menghasilkan tampilan citra SAR yang dapat diinterpretasi obyek tutupan lahannya. Ini dilakukan untuk mengevaluasi seberapa besar teknologi polarisasi SAR membantu dalam pemetaan obyek tutupan lahan. Hasil dari interpretasi tersebut dapat diidentifikasikan enam obyek tutupan lahan yang terdiri dari bangunan (permukiman desa, kota, dan gedung), sawah, hutan, semak, semak belukar dan lahan terbuka, hasil tersebut masih belum mampu untuk pemetaan tutupan lahan secara mendetil karena masih minimnya tutupan lahan yang dapat diinterpretasi pada komposit polarisasi tersebut. Tahapan Klasifikasi dilakukan dengan menggunakan dua metode yaitu maximum likelihood dan Support Vector Machine (SVM). Hasil akurasi keseluruhan confusion matrix dari klasifikasi maximum likelihood adalah 78,95% sedangkan klasifikasi Support Vector Machine (SVM) adalah 87,37%. Secara akurasi keselurahan dapat disimpulkan bahwa metode Support Vector Machine (SVM) lebih baik digunakan dalam klasifikasi citra SA

PERANCANGAN DAN REALISASI ANTENA MIKROSTRIP ARRAY PATCH SEGITIGA SAMA SISI UNTUK S-BAND TRANSMITER SATELIT MIKRO

ABSTRAKSI: Perkembangan teknologi antariksa yang begitu pesat berperan serta pada perkembangan teknologi komunikasi satelit. Sebagai salah satu bentuk wahana pembelajaran, Telkom University mengembangkan riset teknologi satelit mikro yang digunakan untuk payload Syntetic Aperture Radar (SAR). SAR merupakan instrument aktif gelombang mikro yang menggunakan prinsip kerja radar (radio detection and ranging) yang digunakan untuk memproduksi citra beresolusi tinggi dari permukaan bumi dalam segala kondisi. Data image tersebut dikirim melalui antena S-Band Transmitter ke stasiun bumi. Antena mikrostrip adalah sebuah jenis antena ringan dengan volume yang kecil yang cocok dengan kebutuhan S-Band transmitter satelit mikro dilihat dari segi ketersediaan ruang yang terbatas. Konfigurasinya yang sederhana mempermudah proses perakitan dan penyesuaian dengan kondisi satelit mikro itu sendiri. Selain itu, antena mikrostrip juga mendukung jenis polarisasi sirkular yang akan berguna dalam mengatasi efek rotasi Faraday akibat putaran ion yang ada di atmosfer serta pola radiasi unidireksional untuk keperluan komunikasi point to point dengan stasiun bumi. Untuk mengatasi gain dan bandwidth rendah yang secara teoretis dimiliki, dalam tugas akhir ini dirancang antena mikrostrip secara array dengan menggunakan teknik catu proximity coupled. Guna mencapai polarisasi sirkular penelitian ini juga mengusulkan desain catuan dengan sub-feed orthogonal. Hasil perancangan disimulasikan dengan bantuan perangkat lunak bantu berbasis Method of Moment (MoM) dengan menggunakan bahan substrat epoxy FR-4 dengan nilai µ = 4.3. Hasil pengukuran menunjukkan performansi antenna dengan frekuensi tengah 2.35 GHz mendapatkan bandwidth impedansi 230 MHz untuk target return loss ≤ -10 dB, bandwidth axial ratio mencapai 32 MHz guna memenuhi prasyarat polarisasi sirkular, dan gain rata-rata 5.27 dBic. Sementara pola radiasi unidireksional dengan nilai HPBW azimuth 63,8 0 dan HPBW elevasi 89 0 . rKATA KUNCI: satelit mikro, S-Band Transmitter, antena mikrostrip, antena array, proximity coupledABSTRACT: The rapid development of space technology affects the development of satellite communication technology. As learning mission, Telkom University developed technology research satellite microsatellite which used for payload Syntetic Aperture Radar (SAR). SAR is an active microwave instrument which has radar (radio detection and ranging) working principle to produce high resolution images of the surface of the earth in all conditions. The image data sent over by the S-Band transmitter to the ground station. Microstrip antenna is a lightweight antenna types with small volumes that match the needs of the microsatellite’s S-Band transmitter in terms of limited space availability. Simple configuration simplify the assembly process and the adjustment to the conditions of microsatellite itself. In addition, the microstrip antenna also supports the type of circular polarization that would be useful in overcoming the effects of Faraday rotation due to the rotation of ions present in the atmosphere as well as unidirectional radiation pattern for both point to point communications with the ground station. To cope with the low gain and bandwidth that is theoretically owned, in this thesis is designed as a microstrip antenna array using the proximity technique coupled supply. In order to achieve circular polarization of this study also proposes the design of a feed ration with sub-orthogonal. The results of the design is simulated with the help of assistive software-based Method of Moment (MoM) using epoxy substrate material FR-4 with a value of μr = 4.3. The measurement results show the performance of the antenna with the center frequency of 2:35 GHz gain bandwidth of 230 MHz for the target impedance return loss ≤ - 10 dB axial ratio bandwidth up to 32 MHz in order to fulfill the prerequisites of circular polarization, and the average gain dBic 5:27. While unidirectional radiation pattern with a value of 63.8 0 azimuth HPBW and HPBW elevation 89 0 KEYWORD: microsatellite, S-Band transmitter, microstrip antenna, array antenna, proximity couple

Integration of micro-gravity and geodetic data to constrain shallow system mass changes at Krafla Volcano, N Iceland

New and previously published micro-gravity data are combined with InSAR data, precise levelling and GPS measurements to produce a model for the processes operating at Krafla volcano, 20 years after its most recent eruption. The data have been divided into two periods: from 1990 to 1995 and from 1996 to 2003 and show that the rate of deflation at Krafla is decaying exponentially. The net micro-gravity change at the centre of the caldera is shown, using the measured Free Air Gradient, to be -85 μGal for the first and -100 μGal for the second period. After consideration of the effects of water extraction by the geothermal power station within the caldera, the net gravity decreases are -73 ± 17 μGal for the first and -65 ± 17 μGal for the second period. These decreases are interpreted in terms of magma drainage. Following a Mogi point source model we calculate the mass decrease to be ~2 x 1010 kg/yr reflecting a drainage rate of ~0.23 m3/s, similar to the ~0.13 m3/s drainage rate previously found at Askja volcano, N-Iceland. Based on the evidence for deeper magma reservoirs and the similarity between the two volcanic systems, we suggest a pressure-link between Askja and Krafla at deeper levels (at the lower crust or the crust-mantle boundary). After the Krafla fires, co-rifting pressure decrease of a deep source at Krafla stimulated the subsequent inflow of magma, eventually affecting conditions along the plate boundary in N-Iceland, as far away as Askja. We anticipate that the pressure of the deeper reservoir at Krafla will reach a critical value and eventually magma will rise from there to the shallow magma chamber, possibly initiating a new rifting episode. We have demonstrated that by examining micro-gravity and geodetic data, our knowledge of active volcanic systems can be significantly improved

A Sensitivity Study of L-Band Synthetic Aperture Radar Measurements to the Internal Variations and Evolving Nature of Oil Slicks

This thesis focuses on the use of multi-polarization synthetic aperture radar (SAR) for characterization of marine oil spills. In particular, the potential of detecting internal zones within oil slicks in SAR scenes are investigated by a direct within-slick segmentation scheme, along with a sensitivity study of SAR measurements to the evolving nature of oil slicks. A simple, k-means clustering algorithm, along with a Gaussian Mixture Model are separately applied, giving rise to a comparative study of the internal class structures obtained by both strategies. As no optical imagery is available for verification, the within-slick segmentations are evaluated with respect to the behavior of a set of selected polarimetric features, the prevailing wind conditions and weathering processes. In addition, a fake zone detection scheme is established to help determine if the class structures obtained potentially reflect actual internal variations within the slicks. Further, the evolving nature of oil slicks is studied based on the temporal development of a set of selected geometric region descriptors. Two data sets are available for the investigation presented in this thesis, both captured by a full-polarization L-band airborne SAR system with high spatial- and temporal resolution. The results obtained with respect to the zone detection scheme developed supports the hypothesis of the existence of detectable zones within oil spills in SAR scenes. Additionally, the method established for studying the evolving nature of oil slicks is found convenient for accessing the general behavior of the slicks, and simplifies interpretation

KEMUNGKINAN KETERDAPATAN ENDAPAN EMAS PRIMER DI KABUPATEN BOMBANA, SULAWESI TENGGARA

Maraknya penambangan emas rakyat di wilayah Kabupaten Bombana, Propinsi Sulawesi Tenggara mendatangkan persoalan besar bagi pemerintah daerah setempat dan sekaligus menjadi fenomena geologis yang menarik. Pada Januari 2009, penambang tradisional yang turut mendulang emas mencapai sekitar 63.000 orang. Selain di endapan sungai, emas sekunder juga ditemukan pada Formasi Langkowala, yang berumur Miosen. Formasi Langkowala terdiri atas Anggota Batupasir dan Anggota Konglomerat, keduanya saling menjemari. Formasi ini menyebar luas di Dataran Langkowala. Sungai yang mengalir pada dataran ini berhulu pada Pegunungan Mendoke dan Pegunungan Rumbia. Keduanya dibentuk oleh batuan malihan dan batuan sedimen malih. Interpretasi hasil inderaan jauh dilakukan pada citra Landsat dan IFSAR digabungkan dengan DEM untuk indentifikasi adanya bentukan morfologi yang memungkinkan terbentuknya emas primer. Beberapa kenampakan melingkar dan kerucut dapat dilihat dari citra IFSAR dan satelit Landsat. Kenampakan itu diduga sebagai intrusi dan pusat erupsi gunung api, akan tetapi tidak dijumpai kenampakan serupa pada Pegunungan Rumbia

Deep Learning Hydrodynamic Forecasting for Flooded Region Assessment in Near-Real-Time (DL Hydro-FRAN)

Hydrodynamic flood modeling improves hydrologic and hydraulic prediction of storm events. However, the computationally intensive numerical solutions required for high-resolution hydrodynamics have historically prevented their implementation in near-real-time flood forecasting. This study examines whether several Deep Neural Network (DNN) architectures are suitable for optimizing hydrodynamic flood models. Several pluvial flooding events were simulated in a low-relief high-resolution urban environment using a 2D HEC-RAS hydrodynamic model. These simulations were assembled into a training set for the DNNs, which were then used to forecast flooding depths and velocities. The DNNs' forecasts were compared to the hydrodynamic flood models, and showed good agreement, with a median RMSE of around 2 mm for cell flooding depths in the study area. The DNNs also improved forecast computation time significantly, with the DNNs providing forecasts between 34.2 and 72.4 times faster than conventional hydrodynamic models. The study area showed little change between HEC-RAS' Full Momentum Equations and Diffusion Equations, however, important numerical stability considerations were discovered that impact equation selection and DNN architecture configuration. Overall, the results from this study show that DNNs can greatly optimize hydrodynamic flood modeling, and enable near-real-time hydrodynamic flood forecasting.Comment: 21 pages, 8 figure