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The influence of the azimuth angle and water surface roughness determined by wind speeds on the SAR imaging of a metallic bridge over water was simulated after the identification of the double- and triple-bounced radar returns. Different bounced returns were caused by interactions of the bridge surface and water surface. In the simulation, the radar wavelength was L-band. The azimuth angle was between...
A novel digital beamforming (DBF) algorithm for spaceborne synthetic aperture radar (SAR) system based on sparse direction-of-arrive (DOA) estimation is presented, which can solve the beam mispointing caused by the terrain height. Compared to the traditional subspace-based algorithms, the approach has no strict requirement for the number of snapshots. Finally, the simulated results validate the proposed...
An approach to estimate tree height of coniferous forest in mountainous areas at plateau was developed using a combined function. One pair of dual Pol- InSAR images acquired on 20 June 2007 and 5 August 2007 by Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (ALOS-PALSAR) sensor over Zoige plateau, northwestern Sichuan, China was used to evaluate the approach. The derived...
A Moon-based synthetic aperture radar (SAR) system can provide large-scale, long-term, and constant earth observation (EO). Nevertheless, several problems should be solved before implementation. The problems include the ultra-small range of antenna viewing angles, the largest cell size of SAR allowed without the consideration of range cell migration and the related antenna size, and the decorrelation...
Compressive sensing theory can recover the original signal from little observation data, by means of the non-adaptive measurement far below Nyquist sampling and the optimization method. Due to the number of track is limited and the uneven distribution of tracks, the traditional method is difficult to image effectively in the practical application, while the compressive sensing theory by tomoSAR three-dimensional...
A novel algorithm to estimate moving target velocity for a spaceborne high resolution and wide swath (HRWS) synthetic aperture radar (SAR)/ground moving target indication (GMTI) system is presented. To retain the power of the moving target, one needs to know the velocity of the moving target before clutter suppression and spectrum reconstruction. According to the relationship between the velocity...
This live demonstration presents a first-in-kind fully integrated Ku-band Synthetic Aperture Radar (SAR) transceiver chip in 65-nm CMOS that fits for micro-UAVs. The transmitter presents 13.3-dBm output power and 1.48 GHz chirp bandwidth centering at 15 GHz. The receiver front-end attains 23.5-dB gain, −33-dBm IPldB and 5.6-to-6.3dB noise figure. The receiver analog baseband achieves 0.68-to-9.8-MHz...
Synthetic aperture radar (SAR) that complements optical imagers with capabilities to acquire imagery during night and inclement weather is indispensable for remote sensing, traffic mapping, etc. Recent unmanned aerial vehicles (UAVs) have been miniaturized to <1m3, providing an inexpensive and flexible platform for SAR imaging applications. Besides, there is increasing demand on the high resolution...
Using the polarization as a scale, we compensated for the azimuth scale effect on the building identification in urban areas. With the increase of polarization dimension (from a single polarization, dual-polarization, to polarimetric data with the rotation of azimuth angle) or change of polarization scale, the azimuth scale effect was gradually resolved.
Detailed information about a building and its surrounding is generally contained in hi-resolution synthetic aperture radar (SAR) data. An approach to extract the information and to identify the building with linear features from a single hi-resolution SAR image has been developed. With the strong radar backscattering and shape feature of a building in SAR image, external markers were derived by an...
A normalized function was proposed as the framework to study the heterogeneity of urban radar targets. The function consisted of three types of scales, the physical size of a target, heterogeneity in dielectric constant, and target geometry. The azimuth direction or azimuth scale, one component of the target geometry was exampled to investigate the influence of azimuth orientations of buildings on...
Azimuth ambiguities in SAR image are very common phenomena. The ambiguities are visually identifiable due to their high intensities in low radar backscatter background of sea environment. The ambiguities can be mistaken as ships and cause false alarms in ship detection. Therefore, for maritime applications (i.e. ship target detection), it is important to analyze the characteristic of azimuth ambiguities...
SAR image from sea can constantly contain ships and their ambiguities in azimuth and range directions. For maritime applications, the ambiguities are visible due to their strong intensities in a low backscattering background of sea environment. Thus, the ambiguities can be often mistaken as ships and cause false alarms. Many approaches have been proposed for reducing the azimuth ambiguities in single...
In this work we present an approximate technique for high-frequency EM scattering and ISAR image modeling of targets on deck, where major scattering mechanisms from both the isolated target body and the multipath interaction between the target and the deck are included. The target body is geometrically modeled using facets and wedges. Physical optics (PO) method is used to calculate the facet scattering,...
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