Extended common-image-point gathers (CIP) constructed by wide-azimuth TI waveequation migration contain all the necessary information for angle decomposition as a function of the reflection and azimuth angles at selected locations in the subsurface. The aperture and azimuth angles are derived from the extended images using analytic relations between the spaceand time-lag extensions using inform...

A directional wideband measurement campaign was performed in urban macrocells at 2 GHz using a channel sounder and a 8-sensor linear antenna array at the base station. Directions of arrival at the Base Station (BS) were estimated by beamforming using the antenna array. Directions of arrival at the Mobile Station (MS) were estimated by beamforming using parts of the measurement route. Global par...

In this study, an attempt has been made to define the geometry of sensor and source position to best relate plant biophysical parameters with bidirectional reflectance of wheat varieties varying in canopy architecture and to validate the performance of PROSAIL radiative transfer model. A field experiment was conducted with two wheat cultivars varying in canopy geometry and phenology. The bidire...

Following two months of very successful commissioning and the first science observations on the GBT (see the following articles), operation was suspended in early April, one month earlier than planned, to work on the azimuth track. As described in previous NRAO Newsletters, the azimuth track wear strips, on which the azimuth wheels roll, were shifting slightly in a circumferential direction as ...

This paper presents a dual-band planar antenna array for ISM band applications (2.4 GHz and 2.45 GHz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estimation. An adaptive beamforming algorithm is applied for a planar antenna array, which is able to steer its main beam and nulls in azimuth and elevation planes over a wide frequency...

Geosynchronous Orbit Synthetic Aperture Radar (GEO SAR) has recently received increasing attention due to its ability of performing staring observations of ground targets. However, GEO SAR staring observation has an ultra-long integration time that conventional frequency domain algorithms cannot handle because of the inaccurately assumed slant range model and existing azimuth aliasing. To overc...

In this paper we propose a novel methodology to estimate the true velocity of fast moving targets using a single synthetic aperture radar sensor without increasing the Pulse Repetition Frequency. The basic reasoning is that, although the returned echoes may be aliased in the azimuth direction, its phase is informative with respect to the moving target trajectory parameters. We will use this kno...

Current spaceborne SAR missions steer the satellite to follow an orbital tube in order to guarantee interferometric compatibility between data takes. In this contribution it is shown that the size of the orbital tube can impact the interferometric performance in terms of azimuth spectral decorrelation and azimuth coregistration requirements under high Doppler centroids, which can be specially c...

In this paper, a modified azimuth nonlinear chirp scaling (NLCS) algorithm is derived for high-squint bistatic synthetic aperture radar (BiSAR) imaging to solve its inherent difficult issues, including the large range cell migration (RCM), azimuth-dependent Doppler parameters, and sensibility of higher order terms. First, using Lagrange inversion theorem, an accurate spectrum suitable processin...

We consider a multiple-input-multiple-output radar system and derive a theoretical framework for the recoverability of targets in the azimuth-range domain and the azimuth-range-Doppler domain via sparse approximation algorithms. Using tools developed in the area of compressive sensing, we prove bounds on the number of detectable targets and the achievable resolution in the presence of additive ...