Deviations of the aircraft trajectory and instabilities of the aircraft orientation lead to non-uniform illumination of the ground by the antenna beam and, as a result, to radiometric errors in radar images obtained with airborne synthetic aperture radars (SAR). The clutter-lock technique is commonly used to avoid the radiometric errors. However, this approach leads to strong geometric distortions in SAR images in the case of fast and significant instabilities of antenna orientation. Here we propose a multi-look radiometric correction technique which can be used instead of the clutter-lock. The proposed approach has been tested by using a Ku-band airborne SAR system installed onboard a light-weight aircraft.
Category: Research
Range-Doppler Algorithm with Extended Number of Looks
Instabilities of the antenna beam orientation lead to radiometric errors in SAR images. This is one of the most difficult problems for the application of the range-Doppler algorithm, which implies a straight-line flight with a constant orientation. In the paper, we propose a radiometric correction approach for compensation of such instabilities.
Multi-Look Stripmap SAR Processing Algorithm with Built-In Correction of Geometric Distortions
SAR systems installed on small aircrafts suffer from trajectory deviations and instabilities of antenna orientation. These kinds of motion errors lead to significant geometric distortions in SAR images. In the paper, we describe a time-domain multi-look stripmap SAR processing algorithm with built-in correction of geometric distortions. In the algorithm, the azimuth reference functions and range migration curves are specially designed to produce SAR images directly on a correct rectangular grid on the ground plane. The proposed technique has been successfully tested by using a Ku-band airborne SAR system.
Correction of Radiometric Errors by Multi-Look Processing with Extended Number of Looks.
The application of the clutter-lock technique in case of fast and significant instabilities of the antenna orientation leads to strong geometric distortions in SAR images. In the paper we propose a radiometric correction approach which could be used with SAR processing algorithms without clutter-lock.
Multi-Look SAR Processing with Build-In Geometric Correction
Synthetic aperture radar (SAR) systems onboard small aircrafts suffer from trajectory deviations and instabilities of antenna orientation. These kinds of motion errors lead to significant geometric distortions in SAR images. In order to correct the distortions, we propose a time-domain multi-look stripmap SAR processing algorithm with built-in geometric correction. In the algorithm, the azimuth reference functions and range migration curves are designed to produce SAR images directly on a correct rectangular grid on the ground plane. The proposed technique has been successfully tested by using a Ku-band airborne SAR system installed onboard light-weight aircraft.
Improving SAR Images: Built-In Geometric and Multi-Look Radiometric Corrections
Abstract—SAR systems installed on small aircrafts and UAVs suffer from trajectory deviations and instabilities of antenna orientation. These kinds of motion errors lead to significant geometric distortions and radiometric errors in SAR images. In the paper, we describe a time-domain multi-look stripmap SAR processing algorithm with built-in geometric and multi-look radiometric corrections. Geometric correction is performed due to azimuth reference functions and range migration curves specially designed to produce SAR images directly on a rectangular grid on the ground plane. Radiometric correction is based on multi-look processing with extended number of looks. The proposed techniques have been successfully tested with a Ku-band SAR system installed on a light-weight aircraft.
Multi-Look SAR Processing with Built-In Geometric Correction
In the paper a time-domain multi-look stripmap SAR processing algorithm with built-in geometric correction is considered. In the algorithm, the azimuth reference functions and range migration curves are designed to produce SAR images directly on a correct rectangular grid on the ground plane.
Correction of Radiometric Errors by Multi-Look Processing with Extended Number of Looks
The application of the clutter-lock technique in case of fast and significant instabilities of the antenna orientation leads to strong geometric distortions in SAR images. In the paper we propose a radiometric correction approach which could be used with SAR processing algorithms without clutter-lock.
