CHEN Hua①②③ GUO Wei①② YANG Shuangbao①② XU Ke①② XU Xiyu①② SHI Lingwei①② WANG Lei①②
①(Key Laboratory of Microwave Remote Sensing, Chinese Academy of Sciences, Beijing 100190, China) ②(Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190, China) ③(University of Chinese Academy of Sciences, Beijing 100049, China)
Abstract：The key invoation technology of Synthetic Aperture Radar ALtimeter (SARAL) are Doppler-beam sharppen and delay/doppler range compensation. The combination of these two technologies makes it has high along-track resolution and high precision in height measurement. On the basis of 2 m sea wave height and 2 km ground grid, the accuracy of sea surface height measured by SARAL will reach 2 cm. In order to verify the accuracy of SARAL, based on a thorough study of the SARAL height measurement principle and traditional radar altimeter calibration method, a calibration method for SARAL based on Global Navigation Satellite System (GNSS) buoy calibration is developed. The method uses temporal and spatial consistency matching and multi- baseline joint solution to improve the accuracy of sea surface height measurement, then it is applied to the first airborne test of SARAL and the first airborne flight experiment data processing. By analyzing the results of airborne flight experiment data, at the same time of validation SARAL measurement precision, the feasibility of the SARAL calibration method is preliminarily verified.
JENSEN J R and RANYE R K. Delay/Doppler radar altimeter: Better measurement precision[C]. IEEE International Geoscience and Remote Sensing Symposium, Seattle, 1998, 4: 2011-2013.
[2]
PHALIPPOU L and ENJOLRAS V. Re-tracking of SAR altimeter ocean power-waveforms and related accuracies of the retrieved sea surface height, significant wave height and wind speed[C]. IEEE International Geoscience and Remote Sensing Symposium, Barcelona, 2007: 3533-3536.
[3]
LEUSCHEN C J and RANEY R K. Initial results of data collected by the APL D2P radar altimeter overland and sea ice[J]. Johns Hopkins APL Technical Digest, 2005, 26(2): 114-122.
[4]
LENTZ H, BORISCH W, BRAUN H M, et al. An airborne radar altimeter with very high spatial resolution[C]. Proceedings of the Advanced RF Sensors for Earth Observation 2006 (ASRI), Workshop on RF and Microwave Systems, Instruments & Sub-Systems, ESA7ESTEC, Noordwijk, The Netherlands, 2006: 156-164.
[5]
YANG Shuangbao. The mean echo model and data process of SAR altimeter[C]. IEEE International Geoscience and Remote Sensing Symposium, Vancouver, 2011: 2077-2080.
[6]
HALIMI A, MAILHES C, TOURNERET J, et al. A semi- analytical model for delay/Doppler altimetry and its estimation algorithm[J]. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(7): 4248-4258.
[7]
RANEY R K, SMITH W H F, and SANDWELLC T D. A high-resolution gravimetric and bathymetric mission[C]. Space 2004 Conference and Exposition, San Diego, 2004: 1525-1529.
[8]
GALIN N, WINGHAM D J, CULLEN R, et al. Calibration of the CryoSat-2 interferometer and measurement of across- track ocean slope[J]. IEEE Transactions on Geoscience and Remote Sensing, 2013, 51(1): 57-72.
[9]
HAINES B J, DESAI S D, BORN G H, et al. The harvest experiment: Calibration of the climate data record from TOPEX/POSEIDON, Jason-1 and the ocean surface topography mission[J]. Marine Geodesy, 2010, 33(S1): 91-113.
[10]
WATSON C, WHITE N, CHURCH J, et al. Absolute calibration in Bass Strait, Australia: TOPEX, Jason-1 and OSTM/Jason-2[J]. Marine Geodesy, 2011, 34(3): 242-260.
[11]
BONNEFOND P, EXERTIER P, LAURAIN O, et al. Absolute calibration of Jason -1 and Jason-2 altimeters in Corsica during the formation flight phase[J]. Marine Geodesy, 2010, 33(S1): 80-90.
[12]
MERTIKAS S, IOANNIDES R, TZIAVOS I, et al. Statistical models and latest results in the determination of the absolute bias for the radar altimeters of Jason satellites using the Gavdos facility[J]. Marine Geodesy, 2010, 33(S1): 114-149.
[13]
WINGHAM D J, PHALIPPOU L, MAVEOCORDATOS C, et al. The mean echo and echo cross product from a beamforming interferometric altimeter and their application to elevation measurement[J]. IEEE Transactions on Geoscience and Remote Sensing, 2004, 42(10): 2305-2323.
YE Pei, XU Ke, and XU Xiyu. Study on denoising the instrumental errors of the sea surface heigtht series derived from buoys[J]. Remote Sensing Technology and Application, 2015, 30(4): 661-666. doi: 10.11873/j.issn.1004-0323.2015. 40661.
LIU Peng, XU Ke, WANG Lei, et al. Precision comparison and airborne experiment validation between SAR altimeter and conventional altimeter[J]. Journal of Electronics & Information Technology, 2016, 38(10): 2495-2501. doi: 10.11999/JEIT151354.
[16]
SHI Lingwei, XU Ke , LIU Peng, et al. Height precision of SAR altimeter and conventional radar altimeter based on flight experimental data[J]. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2016, 9(6): 2676-2686.
