Title :
Azimuth Phase Center Adaptation on Transmit for High-Resolution Wide-Swath SAR Imaging
Author :
Gebert, Nicolas ; Krieger, Gerhard
Author_Institution :
German Aerosp. Center, Microwaves & Radar Inst., Wessling, Germany
Abstract :
Synthetic aperture radar (SAR) systems with multiple receive channels allow for high-resolution wide-swath imaging thus overcoming a fundamental limitation of conventional single-aperture SAR. By using multiple apertures in azimuth, additional samples are received for each transmitted pulse. This allows for a reduced pulse repetition frequency (PRF) thereby enabling a wider swath. However, a nonoptimum PRF is associated with a nonuniform sample spacing in azimuth and needs to be compensated by a multichannel reconstruction algorithm. For strong deviations from the optimum PRF, the inverse character of such an algorithm might result in a degraded performance. This can be overcome by an innovative advanced transmit antenna architecture which allows for a pulse-to-pulse shift of the phase center. Such an antenna enables the adaptive adjustment of the system´s phase center positions to the respective PRF, thereby ensuring constant performance over a clearly extended PRF range. In particular, in combination with conventional multichannel processing strategies, this technique represents the next step toward a fully active multiple-input multiple-output (MIMO) SAR and has a great potential for future systems.
Keywords :
MIMO systems; array signal processing; geophysical signal processing; radar antennas; radar signal processing; remote sensing by radar; signal reconstruction; synthetic aperture radar; azimuth phase center adaptation; high-resolution wide-swath SAR imaging; multichannel reconstruction algorithm; multiple receive channels; multiple-input multiple-output SAR; reduced pulse repetition frequency; synthetic aperture radar; transmit antenna architecture; Digital beamforming (DBF) on receive; high-resolution wide-swath synthetic aperture radar (SAR); optimized multichannel azimuth processing; phase center adaptation;
Journal_Title :
Geoscience and Remote Sensing Letters, IEEE
DOI :
10.1109/LGRS.2009.2025245