Doppler Centroid Estimation Ambiguity For Synthetic Aperture Radars

Chang, Ching‐Wen; Curlander, John C.

doi:10.1109/igarss.1989.577932

Cited by 22 publications

(5 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These pairs are used for atmospheric separation and post-stage inversion. Figure 8 shows the velocity field of Nanjing City and its surrounding area (Chang and Curlander 1989;Bozzano et al 2010;Solari et al 2016).…”

Section: Spatio-temporal Baseline Analysismentioning

confidence: 99%

Study of subsidence monitoring in Nanjing City with small-baseline InSAR approach

Qiu

Jiang

Zhou

et al. 2019

Geomatics, Natural Hazards and Risk

View full text Add to dashboard Cite

The surface subsidence in Nanjing has become increasingly apparent because of the influence of geological conditions and the rapid progress of urbanization. Here, the theory of synthetic aperture radar interferometry is analysed, and a method based on the short baseline subset (SBAS) technology is proposed. The method can overcome time and baseline decorrelation and other factors, and it can extract points with high coherence from interferograms have short spatio-temporal baselines when the atmospheric delay phase and the noise phase in the frequency domain are used to differentiate the corresponding characteristics. The slow deformation ratio of the monitoring area over long periods can also be calculated by this method. In this study, the 16 advanced land observing satellite (ALOS) data acquired from 2007 to 2011 in Nanjing are processed by the SBAS technology and compared with levelling result. This work emphasizes that the SBAS technology could derive the cumulative deformations of surfaces and deformation fields accurately.

show abstract

Section: Spatio-temporal Baseline Analysismentioning

confidence: 99%

Study of subsidence monitoring in Nanjing City with small-baseline InSAR approach

Qiu

Jiang

Zhou

et al. 2019

Geomatics, Natural Hazards and Risk

View full text Add to dashboard Cite

show abstract

“…The beam view vector must be rotated using two transformations. First, the view vector is rotated clockwise around the positive axis by the pitch angle , using the Euler transformation matrix [25] 6 nose UP (increases Doppler) (12) Then, the view vector is rotated clockwise around the positive axis by the yaw angle using the transformation nose LEFT (increases Doppler) (13) so that the unit view vector becomes (14) in Frame 0. 7 Finally, this satellite-centered frame is translated to the parallel, earth-centered Frame 1…”

Section: Step 1: Rotate Beam By the Satellite Pitch And Yaw (To Frame 1)mentioning

confidence: 99%

A spatially selective approach to Doppler estimation for frame-based satellite SAR processing

Cumming

2004

IEEE Trans. Geosci. Remote Sensing

View full text Add to dashboard Cite

Abstract-When Doppler centroid estimators are applied to satellite synthetic aperture radar (SAR) data, biased estimates are often obtained because of anomalies in the received data. Typical anomalies include areas of low SNR, strong discrete targets, and radiometric discontinuities. In this paper, a new method of Doppler centroid estimation is presented that takes advantage of principles such as spatial diversity, estimator quality checks, geometric models, and the fitting of a "global" estimate over a wide area of a SAR scene. In the proposed scheme, Doppler estimates are made over small blocks of data covering a whole frame, so that all parts of the scene are potentially represented. The quality of each block estimate is examined using data statistics or estimator quality measures. Poor estimates are rejected, and the remaining estimates are used to fit a surface model of the Doppler centroid versus the range and azimuth extent of the scene. A physical model that relates the satellite's orbit, attitude, and beam-pointing-direction to the Doppler centroid is used to get realistic surface fits and to reduce the complexity (dimensionality) of the estimation problem. The method is tested with RADARSAT-1 and Shuttle Radar Topography Mission X-band SAR (SRTM/X-SAR) spaceborne data and is found to work well with scenes that do have radiometric anomalies, and in scenes where attitude adjustments cause the Doppler to change rapidly.Index Terms-Geometry models, global surface fit, quality metrics, satellite synthetic aperture radar (SAR) Doppler centroid estimation.

show abstract

“…However, because the azimuth spectrum is periodically repeated with the radar PRF f P , only the f DB , the mapped value of f D in the main period, can be estimated with traditional clutter-lock methods [1,2]. Therefore, when |f D |>f P / 2, the Doppler centroid ambiguity occurs and subsequently leads to the deterioration in image quality [3].…”

Section: Introductionmentioning

confidence: 99%

PRF-ambiguity resolution for SAR by contrast minimization in range-Doppler domain

Peng

2007

Front. Electr. Electron. Eng. China

View full text Add to dashboard Cite

An algorithm was developed to accurately estimate the Doppler centroid, which is needed for highquality synthetic aperture radar (SAR) image formation by resolving the SAR pulse repetition frequency (PRF) ambiguity. The algorithm uses the SAR range migration to resolve the PRF-ambiguity by searching for a PRF-ambiguity number that minimizes the intensity contrast in the rangeDoppler domain. Experimental results show that the approach, compared with traditional methods for resolving the SAR PRF ambiguity, is more suitable for both high contrast scenes such as urban areas and low contrast scenes such as mountains. Moreover, the approach is more computationally efficient for there are no time-consuming correlations or fast Fourier transform (FFT) operations needed in the range-Doppler domain and only part of the range cells are used in the calculation.

show abstract

Doppler Centroid Estimation Ambiguity For Synthetic Aperture Radars

Cited by 22 publications

References 3 publications

Study of subsidence monitoring in Nanjing City with small-baseline InSAR approach

Study of subsidence monitoring in Nanjing City with small-baseline InSAR approach

A spatially selective approach to Doppler estimation for frame-based satellite SAR processing

PRF-ambiguity resolution for SAR by contrast minimization in range-Doppler domain

Contact Info

Product

Resources

About