Application of the multiple PRF technique to resolve Doppler centroid estimation ambiguity for spaceborne SAR

Chang, Ching‐Wen; Curlander, John C.

doi:10.1109/36.175329

Cited by 63 publications

(22 citation statements)

References 14 publications

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“…Frame 1 in Figure 3 is a subimage for the comparison between a conventional SAR image and the corresponding estimated NRCS image. The first step is estimating the Doppler centroid f0 for each range cell [11,[15][16][17][18][19], and then shifting the Doppler spectrum centroid of the single-look complex image to zero. Note that ocean currents can lead to an additional local shift of the Doppler centroid [20][21][22].…”

Section: Example 1: Qualitative Analysis For the Estimation Methods Inmentioning

confidence: 99%

Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images

et al. 2017

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Abstract:The image intensities of low-backscattering areas in synthetic aperture radar (SAR) images are often seriously contaminated by the system noise floor and azimuthal ambiguity signal from adjacent high-backscattering areas. Hence, the image intensity of low-backscattering areas does not correctly reflect the backscattering intensity, which causes confusion in subsequent image processing or interpretation. In this paper, a method is proposed to estimate the normalized radar cross-section (NRCS) of low-backscattering area by utilizing the differences between noise, azimuthal ambiguity, and signal in the Doppler frequency domain of single-look SAR images; the aim is to eliminate the effect of system noise and azimuthal ambiguity. Analysis shows that, for a spaceborne SAR with a noise equivalent sigma zero (NESZ) of −25 dB and a single-look pixel of 8 m × 5 m, the NRCS-estimation precision of this method can reach −38 dB at a resolution of 96 m × 100 m. Three examples are given to validate the advantages of this method in estimating the low NRCS and the filtering of the azimuthal ambiguity.

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Section: Example 1: Qualitative Analysis For the Estimation Methods Inmentioning

confidence: 99%

Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images

et al. 2017

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“…In solving for the Doppler ambiguity number, several algorithms have been used, such as the look displacement [2], multiple PRF [3], wavelength diversity (WDA) [4], multilook cross correlation (MLCC) [5], and multilook beat frequency (MLBF) algorithms [5]. However, the accuracy and robustness of the Doppler ambiguity number estimate still need improvement to satisfy current high-quality SAR processing requirements.…”

mentioning

confidence: 99%

Adding Sensitivity to the MLBF Doppler Centroid Estimator

Cumming

2007

IEEE Trans. Geosci. Remote Sensing

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“…Among the mentioned three algorithms, WDA and MLCC are suitable for low-contrast scene, and MLBF is propitious to high-contrast scene. Multiple PRF [4][5][6] avoids Doppler ambiguity based on a set of PRFs, whose disadvantages lie in the complexity of system design. Therefore, this method is employed mostly in ScanSAR mode.…”

Section: Introductionmentioning

confidence: 99%

Parameter estimation and imaging of moving targets in bistatic synthetic aperture radar

Huang

Yang

et al. 2016

J. Appl. Remote Sens

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, "Parameter estimation and imaging of moving targets in bistatic synthetic aperture radar," J. Appl. Remote Sens. 10(1), 015018 (2016), doi: 10.1117/1. JRS.10.015018. Abstract. In high-resolution bistatic synthetic aperture radar (SAR) systems, parameter estimation is essential to moving target imaging quality. However, precise parameters are difficult to obtain without priori information due to the relative along-track and across-track velocities between the moving target and platforms that change with time. A parameter estimation and imaging approach for moving targets is proposed. First, slant range and relative velocities expression are deduced based on the geometry of bistatic SAR model with one stationary configuration. Then, range curvature term are compensated skillfully by fitting the range-compressed curve in two-dimensional time domain, meanwhile, the initial estimated range walk slope can be achieved. Finally, precise Doppler centroid is estimated through searching for the maximum contrast with folding search algorithm, which is giving consideration to both searching precision and computational complexity. Thus, the proposed algorithm provides an effective way for parameter estimation and imaging of moving target without prior information and interpolation operation. Experimental results show the effectiveness of the proposed method. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 UnportedLicense. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Application of the multiple PRF technique to resolve Doppler centroid estimation ambiguity for spaceborne SAR

Cited by 63 publications

References 14 publications

Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images

Doppler Spectrum-Based NRCS Estimation Method for Low-Scattering Areas in Ocean SAR Images

Adding Sensitivity to the MLBF Doppler Centroid Estimator

Parameter estimation and imaging of moving targets in bistatic synthetic aperture radar

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