Compensating the PTR and LPF Features of the HY-2A Satellite Altimeter Utilizing Look-Up Tables

Xu, Xiangde; Xu, Ke; Wang, Zhenzhan; Liu, Heguang; Wang, Lei

doi:10.1109/jstars.2014.2364026

Cited by 11 publications

(2 citation statements)

References 27 publications

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“…We believe that this is not caused by the lookup table optimization algorithm, but by the error introduced by approximating the actual sinc(•) point target response function with a Gaussian function in the parabolic cylinder model. It should be noted that this approximation strategy is not only present in the parabolic cylinder model, but also adopted by many SAR processing models, indicating that it is a common issue [29]. Figure 8 shows the influence of Significant Wave Height (SWH) and off-nadir angle on the shape of the backscattering model.…”

Section: Parabolic Cylinder Model and Its Accelerated Version Algorithmmentioning

confidence: 99%

Coastal Waveform Retracking for Synthetic Aperture Altimeters Using a Multiple Optimization Parabolic Cylinder Algorithm

Zheng,

Xu,

et al. 2023

Remote Sensing

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The importance of monitoring sea level in coastal zones becomes more and more obvious in the era of global climate change, because, in coastal zones, although satellite altimetry is an ideal tool in measuring sea level over open ocean, but its accuracy often decreases significantly at coast due to land contamination. Although the accuracy of waveform processing algorithms for synthetic aperture altimeters has been improved in the last decade, the computational speed is still not fast enough to meet the requirements of real-time processing, and the accuracy cannot meet the needs of nearshore areas within 1 km from the coast. To improve the efficiency and accuracy in the coastal zone, this study proposed an innovative waveform retracking scheme for the coastal zone based on a multiple optimization parabolic cylinder algorithm (MOPCA) integrated with machine learning algorithms such as recurrent neural network and Bayesian estimation. The algorithm was validated using 153-pass repeat cycle data from Sentinel-6 over Qianliyan Island and Hong Kong–Wanshan Archipelago. The computational speed of the proposed algorithm was four to five times faster than the current operational synthetic aperture radar (SAR) retracking algorithm, and its accuracy within 0–20 km from the island was comparable to the most popular SAMOSA+ algorithm, better than the official data product provided by Sentinel-6. Especially, the proposed algorithm demonstrates remarkable stability in the sense of proceeding speed. It maintains consistent performance, even when dealing with intricate wave patterns within a proximity of 1 km from the coast. The results showed that the proposed scheme greatly improved the quality of coastal altimetry waveform retracking.

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Section: Parabolic Cylinder Model and Its Accelerated Version Algorithmmentioning

confidence: 99%

Coastal Waveform Retracking for Synthetic Aperture Altimeters Using a Multiple Optimization Parabolic Cylinder Algorithm

Zheng,

Xu,

et al. 2023

Remote Sensing

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“…where T is the onboard tracking range, E is the retracked offset (with time dimension), "c/2 (c being the light velocity)" is the scaling factor from time to range, D is the Doppler correction, M is the instrument imperfection bias [38,39], and 0.180 is a bias (in meters) due to wrong altimeter antenna reference point [40].…”

Section: Altimetry Data Processingmentioning

confidence: 99%

Coastal Altimetry: A Promising Technology for the Coastal Oceanography Community

Xu¹,

Ke²,

Xu³

et al. 2020

Estuaries and Coastal Zones - Dynamics and Response to Environmental Changes

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Satellite altimetry has been one of the most important implements for physical oceanographers. The conventional altimeter is best performed over open ocean surface, yet there are many attempts to exploit the potential of altimetry in coastal zone in the last decade. To achieve a high performance for coastal altimetry is a multi-fold effort: the more sophisticated instrument concepts, the smarter onboard trackers, the more expert data editing criteria, the more specific retracking algorithms, the more advanced error correction methods, etc. In this chapter, each of the above aspects is described in detail, and some representative works in the altimetry community are reviewed. Particularly, the coastal altimetry offshore Hong Kong is addressed as a case study to demonstrate the potential of the new technology. In the conclusive session, some prospects for the coastal oceanography community are presented.

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Calibration compaigns of the HY-2A satellite altimeter significant wave height by a GNSS buoy

Shen

2015

2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

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Compensating the PTR and LPF Features of the HY-2A Satellite Altimeter Utilizing Look-Up Tables

Cited by 11 publications

References 27 publications

Coastal Waveform Retracking for Synthetic Aperture Altimeters Using a Multiple Optimization Parabolic Cylinder Algorithm

Coastal Waveform Retracking for Synthetic Aperture Altimeters Using a Multiple Optimization Parabolic Cylinder Algorithm

Coastal Altimetry: A Promising Technology for the Coastal Oceanography Community

Calibration compaigns of the HY-2A satellite altimeter significant wave height by a GNSS buoy

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