A New Method of Precise Jason-2 Altimeter Calibration Using a Microwave Transponder

Hausleitner, W.; Moser, Florian; Desjonqueres, J. D.; Boy, F.; Picot, Nicolas; Weingrill, J.; Mertikas, Stelios P.; Daskalakis, A.

doi:10.1080/01490419.2012.718239

Cited by 17 publications

(14 citation statements)

References 20 publications

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“…The PFAC infrastructure has been involved in calibrations in the past with another and older transponders in Gavdos Island for Envisat [59] and Jason-2 [60]. In this work, calibration results have…”

Section: Transponder Calibration Resultsmentioning

confidence: 99%

Fifteen Years of Cal/Val Service to Reference Altimetry Missions: Calibration of Satellite Altimetry at the Permanent Facilities in Gavdos and Crete, Greece

et al. 2018

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Satellite altimetry provides exceptional means for absolute and undisputable monitoring of changes in sea level and inland waters (rivers and lakes), over regional to global scales, with accuracy and with respect to the center of mass of the Earth. Altimetry system’s responses have to be continuously monitored for their quality, biases, errors, drifts, etc. with calibration. Absolute calibration of altimeters is achieved by external and independent to satellite facilities on the ground. This is the mainstay for a continuous, homogenous, and reliable monitoring of the earth and its oceans. This paper describes the development of the Permanent Facility for Altimetry Calibration in Gavdos/Crete, Greece, as of 2001 along with its infrastructure and instrumentation. Calibration results are presented for the reference missions of Jason-1, Jason-2, and Jason-3. Then, this work continues with the determination of relative calibrations with respect to reference missions for Sentinel-3A, HY-2A, and SARAL/AltiKa. Calibration results are also given for Jason-2 and Jason-3 altimeters using the transponder at the CDN1 Cal/Val site on the mountains of Crete, with simultaneous comparisons against sea-surface calibration and during their tandem mission. Finally, the paper presents procedures for estimating uncertainties for altimeter calibration to meet the Fiducial Reference Measurement standards.

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Section: Transponder Calibration Resultsmentioning

confidence: 99%

Fifteen Years of Cal/Val Service to Reference Altimetry Missions: Calibration of Satellite Altimetry at the Permanent Facilities in Gavdos and Crete, Greece

et al. 2018

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“…Absolute range calibration of altimeters using transponders have been carried out for Envisat [14], Jason-2 [15], CryoSat-2 [16], and Jason-3 [17]. Sentinel-3A transponder calibration results have been presented in [17,18] using the transponder operating at the CDN1 Cal/Val site in West Crete.…”

Section: Transponder Calibrationmentioning

confidence: 99%

Absolute Calibration of the European Sentinel-3A Surface Topography Mission over the Permanent Facility for Altimetry Calibration in west Crete, Greece

et al. 2018

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This work presents calibration results for the altimeter of Sentinel-3A Surface Topography Mission as determined at the Permanent Facility for Altimetry Calibration in west Crete, Greece. The facility has been providing calibration services for more than 15 years for all past (i.e., Envisat, Jason-1, Jason-2, SARAL/AltiKa, HY-2A) and current (i.e., Sentinel-3A, Sentinel-3B, Jason-3) satellite altimeters. The groundtrack of the Pass No.14 of Sentinel-3A ascends west of the Gavdos island and continues north to the transponder site on the mountains of west Crete. This pass has been calibrated using three independent techniques activated at various sites in the region: (1) the transponder approach for its range bias, (2) the sea-surface method for the estimation of altimeter bias for its sea-surface heights, and (c) the cross-over analysis for inspecting height observations with respect to Jason-3. The other Pass No.335 of Sentinel-3A descends from southwest of Crete to south and intersects the Gavdos calibration site. Additionally, calibration values for this descending pass are presented, applying sea-surface calibration and crossover analysis. An uncertainty analysis for the altimeter biases derived by the transponder and by sea-surface calibrations is also introduced following the new standard of Fiducial Reference Measurements.

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“…The transponder, as an in-orbit radar altimeter calibration approach, can also be used to estimate the time tag bias of the altimeter. The transponder can be taken as a point target, and its responding signal is free from the error sources introduced by sea surface dynamics, e.g., sea state bias, ocean waves, atmospheric loading, currents, and tides [10]. Therefore, it is feasible to utilize the transponder as an independent approach to estimate the altimeter's time tag bias.…”

Section: Introductionmentioning

confidence: 99%

HY-2A Altimeter Time Tag Bias Estimation Using Reconstructive Transponder

Wan

Guo

Zhao

et al. 2015

IEEE Geosci. Remote Sensing Lett.

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Independent clocks provide time tags for the precision orbit determination (POD) equipment and the radar altimeter onboard the HY-2A satellite, and a bias between POD data' time tag and corresponding range observation's time tag from the HY-2A altimeter exists. The time tag bias contributes a bias in the sea surface height observation due to the nonzero time rate of change of the HY-2A altimeter's height. A transponder for in-orbit radar altimeter calibration provides an approach to estimate the time tag bias. The altimeter receives the responding signals from the transponder and generates ranges. Pertinent reference ranges are obtained from the POD data and the transponder's coordinate. Using the ranges from the radar altimeter and the reference ranges, the time tag bias between the POD data and the altimeter observations can be estimated. During an in situ HY-2A altimeter calibration campaign using a reconstructive transponder from August 9, 2012, to July 20, 2014, 17 estimations of the altimeter's time tag bias were obtained. The preliminary results are presented in this letter.

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A New Method of Precise Jason-2 Altimeter Calibration Using a Microwave Transponder

Cited by 17 publications

References 20 publications

Fifteen Years of Cal/Val Service to Reference Altimetry Missions: Calibration of Satellite Altimetry at the Permanent Facilities in Gavdos and Crete, Greece

Fifteen Years of Cal/Val Service to Reference Altimetry Missions: Calibration of Satellite Altimetry at the Permanent Facilities in Gavdos and Crete, Greece

Absolute Calibration of the European Sentinel-3A Surface Topography Mission over the Permanent Facility for Altimetry Calibration in west Crete, Greece

HY-2A Altimeter Time Tag Bias Estimation Using Reconstructive Transponder

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