Robust SVA method for every sampling rate condition

Sci. China Technol. Sci.

et al. 2010

The existing spatially variant apodizations (SVAs) either cannot depress the sidelobes effectively or reduce the energy of the mainlobe. To improve this, a modified SVA (MSVA) is put forward in this paper, which expands the traditional filter from 3-taps to 5-taps and sets relevant parameters according to different sampling rates to get the excellent result that satisfies constrained optimization theory. A method for synthetic aperture radar (SAR) sidelobe control based on MSVA is presented, which applies MSVA to range compression and azimuth compression to control sidelobes. This method which is available for any Nyquist sampling rate can both depress the sidelobes effectively and keep the energy of the mainlobe and the resolution of the image. The method can reduce sidelobe levels more effectively than classical amplitude weighting while maintaining the image resolution, as demonstrated by the result of the experiment. synthetic aperture radar, sidelobe suppression, resolution, SVA Citation: Ni C, Wang Y F, Xu X H, et al. A SAR sidelobe suppression algorithm based on modified spatially variant apodization.

Section: Sva and Its Improvementmentioning

confidence: 99%

Section: Sva and Its Improvementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A SAR sidelobe suppression algorithm based on modified spatially variant apodization

Sci. China Technol. Sci.

et al. 2010

“…It is able to control sidelobes of SAR images effectively by applying sequential nonlinear operations to complex-valued SAR imagery [20]. This method is originally proposed with requirement that the data should be sampled at an integer multiple of Nyquist frequency, but now it can be used to suppress sidelobes in any case of Nyquist sampling rates [21].…”

Section: Introductionmentioning

confidence: 99%

A stable realization of apodization filtering applied to noise SAR and SAR range sidelobe suppression

EURASIP J. Adv. Signal Process.

et al. 2012

Pulse response of radar system always suffers from high sidelobe level resulting in resolution degradation. Investigated here is a sidelobe suppression method based on apodization filtering technique for range responses of synthetic aperture radar (SAR) and noise SAR systems. The core of apodization filtering is finding an appropriate filtering vector in time domain. Compared with original apodization filtering, the proposed method could be realized stably because it could get correct filtering vector efficiently. This method contains three important steps: constructing coefficient matrix and desired response vector; performing ill-posed analysis; and solving equation to find filtering vector. In these steps, convolution kernel method is adopted to construct coefficient matrix; spectral condition is introduced as an indicating function for ill-posed analysis; and total variation method is used to resolve ill-posed equation for getting filtering vector. Elaborate theoretical derivation is presented to demonstrate the feasibility of this method. In order to test its effect, simulation experiments are implemented. Simulation results show that there is a great suppression of range sidelobes after processed by this method. With increasing filter length, the performance of filtered output is improved but time cost is increasing correspondingly. Furthermore, the proposed method is also effective with noise disturbance.

“…This method can suppress sidelobes effectively while maintaining fine resolution, but there are some residual sidelobes. Carlos Castillo-Rubio presented a robust SVA (RSVA) algorithm [14] based on GSVA, which extends the filter from 3-taps to 5-taps and is able to suppress sidelobes effectively in any case of Nyquist sampling rates. However, this method sometimes loses the mainlobe energy.…”

Section: Introductionmentioning

confidence: 99%

A super-resolution algorithm for synthetic aperture radar based on modified spatially variant apodization

Sci. China Phys. Mech. Astron.

et al. 2010

The existing spatially variant apodizations (SVAs) either cannot depress the sidelobes effectively or reduce the energy of the mainlobe. To improve this, a modified SVA (MSVA) is put forward in this paper, which expands the traditional filter from 3-taps to 5-taps and sets relevant parameters according to different sampling rates to get the excellent result that satisfies constrained optimization theory. A modified super-SVA is also presented, which compares the result after the iteration with the original signal and makes the one whose amplitude is smaller as the initial value of the next iteration. This method can eliminate the sidelobes produced by the intermediate operation, so that the following bandwidth extrapolation is more available. Super-MSVA is presented based on the modified SVA and modified super-SVA, which is suitable for any Nyquist sampling rate, can extrapolate the signal bandwidth many times through iteration with a commensurate improvement in resolution, as demonstrated by the result of the experiment. synthetic aperture radar, sidelobe suppression, super-resolution, SVA