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In geosynchronous (GEO) synthetic aperture radar (SAR), the high orbit height and the long integration time would lead to the significant round-trip delay time and the curved flight path, thus the traditional range model with ‘stop-go’ assumption will be ineffective. In this Paper, based on the analysis of instantaneous Doppler frequency of GEO SAR, an equivalent midpoint mathematical model is proposed...
The on-going European Space Agency (ESA) Sentinel-1 mission has introduced an important change in the management of SAR data, freely opening the archives of the generated Level-0 and Level-1 products to the scientific community.
Simultaneous synthetic aperture radar (SAR) imaging and ground moving target indication (GMTI) is of great importance in remote sensing applications, but it is difficult to be implemented for existing methods due to the cross-interferences between stationary targets/clutter and moving targets. Generally, the imaged moving targets may be displaced in azimuth according to their radial velocities and...
This study proposed a novel method to analyze slick-free and oil covered sea surface backscattering in the special case of Deepwater Horizon (DWH) oil spill accident based on combination of tilted Bragg scattering and volume scattering components. The DWH accident represents a particular and challenging case due to the very large amount of leaked oil that came from the bottom of the ocean. The proposed...
In this paper, a new scheme is presented for ground moving target indication for multichannel synthetic aperture radar (SAR) systems using the asymmetric distribution of the spatial spectrum. Two feature images are generated via accumulating energy intensities of the positive and the negative spatial spectrum, respectively. In the two images, the stationary backgrounds have the same intensity while...
It is still a challenge to obtain the collapsed building distribution from post-disaster polarimetric synthetic aperture radar (SAR) data. This paper proposed a novel approach for extracting the spatial distribution of collapsed buildings using post-disaster RADARSAT-2 SAR data. In this method, non-building areas are removed by using eigen-values λ2 + λ3. Then, the modified Freeman decomposition which...
This paper is focused on investigations of the improved detection of icebergs in open water using spectral analysis of polarimetric SAR data. The objectives of this study are to analyze the behavior of ice objects in open water using the sublook cross-correlation magnitude (SCM). It is shown that there is an improvement of iceberg-sea contrast when the SCM is used instead of multilook intensities...
Comparing to the original backprojection (BP) algorithm, the fast factorized backprojection algorithm accelerates enormously by dividing the synthetic aperture into many small pieces and finishes the BP integral in many stages. Numerous two-dimensional (2-D) image interpolation operations are utilized to raise accuracy. In this letter, a new factorized backprojection algorithm is proposed where no...
The technique of multiple apertures in azimuth enables a wide swath synthetic aperture radar (SAR) with high azimuth resolution. In a traditional multi-channel SAR system, a reconstruction algorithm is built to recover the ambiguous Doppler spectrum caused by non-uniform sampling. However, if the system pulse repetition frequency (PRF) is near some specific values, singular points exist in the reconstruction...
Faced with an increasingly complex electromagnetic environment of space, Synthetic Aperture Radar (SAR) is susceptible to the influence of the Radio Frequency Interference (RFI) signals, thus seriously affecting the SAR image interpretation. This is even worse for the low-frequency-band SAR systems (P-band for example) which are disturbed by a lot of television broadcasting signals. Based on the model...
In this letter, an improved kernel density estimation (KDE) constant false alarm rate (CFAR) method is proposed for ship detection in single polarization synthetic aperture radar (SAR) images. The proposed method consists of a target enhancement filter, an adaptive KDE bandwidth estimation method and an improved KDE-CFAR. The gravity-based target enhancement filter is utilized to remove the inhomogeneity...
Technology for marine vessel monitoring and analysis combining Synthetic Aperture Radar (SAR) and Automatic Identification System (AIS) is presented in this paper. Detection results in SAR image are validated and analyzed with corresponding AIS information. In order to evaluate the performance of the techniques, nine ERS-2 SAR images covering the year 2007 and corresponding AIS polls are used. The...
To overcome the contradiction between wide unambiguous swath and high azimuth resolution in synthetic aperture radar (SAR) system, a multi-channel reconstruction method is investigated to unambiguously recover the azimuth signal even for nonuniform spatial samplings. This reconstruction method is derived from matrix inversion method under least square principle. By taking the system additive noise...
A new wavenumber domain mapping method for the highly squinted beam steering synthetic aperture radar (BS-SAR) is analysed. After the mapping operation, the two dimensional (2-D) spectrums have a broadside form which can be regarded as an equivalent broadside SAR. Furthermore, a novel 2-D two-step approach is introduced to avoid spectral aliasing and skewing caused by the beam steering and the high...
This paper presents the potential of differential synthetic aperture radar (SAR) interferometry to detect the gaps of the displacement rate between the buildings and the land surface. We assumed that the information about building surface displacement can be extracted from single look SAR images whereas the information about land surface deformation can be extracted from multi look SAR images. The...
Change detection is an important issue in many applications. In this study, we propose a new change detector for multi-temporal polarimetric synthetic aperture radar (SAR) images. The new detector is based on the optimization of polarimetric contrast minimization. The optimized solution of the contrast model is also given. Experiments are performed on two RADARSAT-2 data sets and results show agreement...
One key problem in forward-looking synthetic aperture radar (SAR) imaging is that symmetrical targets along the flight path have the same Doppler history, this paper proposes a new forward-looking SAR imaging by the use of frequency diverse array (FDA) antenna. Different from conventional phased-array and multiple-input multiple-output (MIMO) antennas, which provide angle-dependent only transmit beampattern,...
In this paper, the analytic expression of synthetic aperture radar (SAR) image spectrum in the polar grid system is derived based on the wavenumber analysis. By revealing the relationship between wavenumber variable and image spectrum in the polar system, we can better understand the mechanism of fast factorized BP (FFBP) processing. Moreover, the form of phase error in spectral domain can be possibly...
This paper proposed a modified Water Cloud Model (MWCM) for rice variable estimation during the whole growth season with eight RADARSAT-2 quad-pol SAR images. The improvements achieved with the MWCM include considering the heterogeneity of water content of the rice canopy in different directions and different phenologies, and applying the scattering components from an improved polarimetric decomposition...
In this paper, we propose a sparse optimization method to suppress the masking effect of noise synthetic aperture radar (SAR) imaging. The transmitted noise waveforms have large fluctuations in the spectrum, which results in high-level sidelobes in the range direction. Weak targets can be masked by the sidelobes of strong targets when traditional matched filtering (MF) is applied. Inspired by the...
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