In-Orbit Calibration and Validation of HY-2B Altimeter using an Improved Transponder

Wang, Caiyun; Guo, Wei; Liu, Peng; Wang, Te; Cui, Hongbin

doi:10.1109/igarss39084.2020.9324657

Cited by 2 publications

(3 citation statements)

References 3 publications

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“…As shown in Figure 1a, the frequency point at the maximum peak represents the echo signal. As well as Wang et al's subsequent calibration work on HY-2B [14,15], studies were conducted with the altimeter in search mode.…”

Section: Introductionmentioning

confidence: 99%

A Signal Matching Method of In-Orbit Calibration of Altimeter in Tracking Mode Based on Transponder

Fang,

Guo,

Wang

et al. 2024

Remote Sensing

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In this paper, a matching method for altimeter and transponder signals in Sub-optimal Maximum Likelihood Estimate (SMLE) tracking mode is proposed. In the in-orbit calibration of the altimeter in SMLE tracking mode using the reconstructive transponder, it is necessary to separate the forwarding signal from the ground echo signal. At the same time, the fluctuations in the received signal of the altimeter, which are caused by the forwarding signal of the transponder, can be eliminated. The transponder generates a bias when measuring the arrival time of the transmitting signal from the altimeter and embeds this bias in both the transponder-recorded data and the altimeter-recorded data. Therefore, the two sets of data have one-to-one correspondence, and they are superimposed using the sliding sum method. Moreover, the distance between the altimeter and the transponder is a parabolic geometric relationship, and the outliers are eliminated by the fitting error minimization decision, and the transponder signal is separated from the ground echo. The final altimeter transmitting–receiving signal path is obtained. Furthermore, the principles underlying this method can be used for any transponder that can adjust the response signal delay during calibration.

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Section: Introductionmentioning

confidence: 99%

A Signal Matching Method of In-Orbit Calibration of Altimeter in Tracking Mode Based on Transponder

Fang,

Guo,

Wang

et al. 2024

Remote Sensing

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“…It can provide flexible echo forms, precise time delay, and better Signal to Noise Ratio (SNR), being an ideal simulator for the altimeter function test before its launch. Based on the RSS, an improved transponder was developed early in 2019, and employed in two calibration campaigns, April 2019 and October 2020, at different sites [12], [13].…”

Section: Introductionmentioning

confidence: 99%

“…For HY-2B, an improved transponder was designed and utilized in two calibration campaigns. The altimeter instrument delay is obtained, and the range calibration precision is better than 1cm [12].…”

Section: Introductionmentioning

confidence: 99%

In-Orbit Calibration and Validation of HY-2B Altimeter Using an Improved Transponder

Wang

Lin

et al. 2021

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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HY-2B (Haiyang) is the follow-on mission to HY-2A, the Chinese first sea satellite for oceanography, launched in Oct 2018. The main payloads onboard are similar to HY-2A. For the altimeter, an in-orbit calibration mode was designed to achieve higher calibration precision. An improved transponder was built and deployed for the calibration campaign. The purpose of the paper is to describe the in-orbit calibration and validation of HY-2B altimeter based on an improved transponder. A signal-rebuilt transponder was developed and employed in HY-2A altimeter calibration. It played an important role in quantitative analysis of HY-2A altimeter data products. For HY-2B altimeter, a newly-designed calibration mode was added, and an improved transponder was built. It has some advantages over the previous one in the rebuilt signal forms and modulation ways. Two calibration campaigns were carried out, in April 2019 and October 2020 at different sites. In the two campaigns, the precision of the altimeter range calibration is obtained less than 1 cm. For further validation and assessment to the result, a comparison between HY-2B and Jason-3 was performed in term of SSH (Sea Surface Height) on the tens of cross track points in the open ocean. The comparison result shows high degree of accuracy and stability of HY-2B altimeter instrument. In China's next five-year plan (2021-2025), many more transponders and related calibration facilities would be installed in the ocean calibration fields, serving a variety of different satellite altimetry missions.

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In-Orbit Calibration and Validation of HY-2B Altimeter using an Improved Transponder

Cited by 2 publications

References 3 publications

A Signal Matching Method of In-Orbit Calibration of Altimeter in Tracking Mode Based on Transponder

A Signal Matching Method of In-Orbit Calibration of Altimeter in Tracking Mode Based on Transponder

In-Orbit Calibration and Validation of HY-2B Altimeter Using an Improved Transponder

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