Waveform contamination identification and accurate sea surface height extraction algorithm for high-frequency fully-focused SAR in severely interfered coastal regions

doi:10.11947/j.AGCS.2025.20240103

Abstract

Abstract:

In coastal regions, particularly within 3 km from the coast, the accurate estimation of sea surface height (SSH) has remained a significant challenge for satellite altimetry techniques. This study investigates the fully-focused SAR (FFSAR) altimetry technique and proposes a SSH estimation algorithm based on contamination rejection and range compensation. Tide gauge data are introduced as independent observations to validate the altimetry performance of FFSAR in severe interfered coastal areas under different along-track sampling rates (20, 80, 200, and 600 Hz). The experiment results show that: ① In the highly contaminated region within 3 km from the coast, increasing the FFSAR sampling rate from 20 Hz to 200 Hz significantly improves data availability and accuracy. ② The standard deviations of the altimetry results obtained using the proposed algorithm against the validation data are reduced from 0.36 (TGWD)、0.31 (EEMSHAVEN)、0.68 (DENHELDER) and 0.17 m (IJMON) to 0.22、0.22、0.48 and 0.14 m, respectively, corresponding to an improvement of over 20%. ③ At the 200 Hz sampling rate, the altimetry results from the proposed algorithm show better consistency with the validation data compared to the MWaPP and PP-OCOG algorithms.

Key words: SAR altimetry, FFSAR, coastal area, signal contamination, SSH extraction

CLC Number:

P229

Hongkai SHI, Xiufeng HE, Yihao WU, Xiangtian ZHENG, Minfeng SONG. Waveform contamination identification and accurate sea surface height extraction algorithm for high-frequency fully-focused SAR in severely interfered coastal regions[J]. Acta Geodaetica et Cartographica Sinica, 2025, 54(2): 272-285.

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采样率/Hz	TGW2/m	AWG/m
20	0.136	0.115
80	0.141	0.117
200	0.139	0.118
600	0.160	0.145

采样率/Hz	TGWD/m	EEMSHAEN/m	DENHELDER/m	IJMON/m
20	0.36	0.31	0.68	0.17
80	0.35	0.27	0.56	0.18
200	0.22	0.22	0.48	0.14
600	0.27	0.26	0.51	0.15

测高结果/Hz	Max/m	Min/m	Mean/m	SD/m
20	0.74	-0.82	0.05	0.36
80	0.85	-0.70	0.10	0.35
200	0.43	-0.36	0.04	0.22
600	0.51	-0.41	0.05	0.27

测高结果	TGWD	EEMSHAVEN	DENHELDER	IJMON
200 Hz PP-OCOG	0.57	0.76	1.33	0.20
200 Hz MWaPP	0.56	0.73	1.28	0.13
200 Hz FFSAR_RNG	0.22	0.22	0.48	0.14