Albert Garcia-Mondéjar

isardSAT

Coasts are continually changing and remote sensing from satellites has the potential to both map and monitor coastal change at multiple scales. Unlike optical technology, synthetic aperture radar (SAR) is uninfluenced by darkness, clouds, and rain, potentially offering a higher revision period to map shoreline position and change, but this can only...

The two-dimensional frequency-based omega-K method is known to be a suitable algorithm for Fully-Focused SAR (FF-SAR) radar altimeter processors, as its computational efficiency is much higher than equivalent time-based alternatives without much performance degradation. In this paper we provide a closed-form description of a two-dimensional frequen...

A trihedral corner reflector has been used to evaluate the capability of passive reflectors to calibrate radar altimeters such as the Poseidon-4 altimeter on board Sentinel-6A. The reflector location, placed on the top of a mountain ridge and about 4-km off-nadir of the Sentinel-6A subsatellite track, allows capturing echoed signals with a Signal-t...

Presentation of the approach and validation of a Coastal Processor, over different Areas around the globe and using 4 different altimetry missions. A refinement of the algorithms has been conducted in the last years, in order to make it robust, reliable, fast, and easy to implement.

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and mo...

CryoSat-2 is the first satellite mission carrying a high pulse repetition frequency radar altimeter with interferometric capability on board. Across track interferometry allows the angle to the point of closest approach to be determined by combining echoes received by two antennas and knowledge of their orientation. Accurate information of the plat...

The Sentinel-3 Mission Performance Centre (S3MPC) is tasked by the European Space Agency (ESA) to monitor the health of the Copernicus Sentinel-3 satellites and ensure a high data quality to the users. This paper deals exclusively with the effort devoted to the altimeter and microwave radiometer, both components of the Surface Topography Mission (S...

Swath mode processing of CryoSat-2 Synthetic Aperture Radar Interferometric (SARIn) mode has been used to monitor elevation of areas with complex topography such as over ice sheet and ice cap margins. Swath processing relies on an accurate measure of the angle of arrival of the measured echo and, therefore, requires custom strategies in order to re...

Sentinel-3 is the Earth observation satellite mission designed to ensure the long-term collection and operational delivery of high-quality measurements of, among others, the sea surface topography. Post-launch calibration and validation of the satellite measurements is a prerequisite to achieve the desired level of accuracy and ensure the return of...

The SHAPE Processor implements all of the steps necessary to derive rivers and lakes water levels and discharge from Delay-Doppler Altimetry and perform their validation against in situ data. The processor uses FBR CryoSat-2 and L1A Sentinel-3A data as input and also various ancillary data (proc. param., water masks, L2 corrections, etc.), to produ...

This article explores the modification and inclusion of different algorithms within an in-house Delay-Doppler processor (DDP) chain in order to understand their potentiality and the related impact in terms of geophysical retrievals’ precision, when operating the synthetic aperture radar (SAR) mode of CryoSat-2 mission over open ocean. To do so, a f...

Transponders are commonly used to calibrate absolute range from conventional altimeter waveforms because of their characteristic point target radar reflection. The waveforms corresponding to the transponder distinguish themselves from the other waveforms resulting from natural targets, in power and shape. ESA deployed a transponder available for th...

Over the past 20 years, satellite radar altimetry has shown its ability to revolutionise our understanding of the ocean and climate. Previously, these advances were largely limited to ice-free regions, neglecting large portions of the Polar Regions. Launched in 2010, the European Space Agency’s (ESA) polar-orbiting CryoSat satellite was specificall...

For more than 25 years, satellite radar altimetry has provided continuous information on the state of the cryosphere and on its contribution to global sea-level rise. The technique typically delivers maps of ice-sheet elevation and elevation change with 3–10 km spatial resolution and seasonal to monthly temporal resolution. Here we show how the int...

During the last decade the radar altimetry has entered its golden age as demonstrated by the different number of missions (Jason-3, CryoSat-2, SARAL/Altika, Sentinel-3) currently operating and the forthcoming Sentinel-6. The latter is an operational oceanography programme of two satellites that will ensure continuity to the Jason series of operatio...

Satellite altimetry has been used extensively in the past few decades to observe changes affecting large and remote regions covered by land ice such as the Greenland and Antarctic ice sheets. Glaciers and ice caps have been studied less extensively due to the limitation of altimetry over complex topography. However, their role in current sea-level...

During the last decade the radar altimetry has entered in its golden age as demonstrated by the different number of missions (Jason-3, CryoSat-2, SARAL/Altika, Sentinel-3a) currently operating and continuity missions planned for the near future (Sentinel-3b, Sentinel-6). The relatively new operational SAR mode in CryoSat-2 and Sentinel-3 missions,...

This poster presents the range and datation results using the Crete transponder for the first 23 cycles. This work is been carried out within the Sentinel-3 Mission Performance Center activity S3MPC.

The CryoSat mission is designed to determine fluctuations in the mass of the Earth’s land and the marine ice fields. Its primary payload is a radar altimeter that operates in different modes optimised depending on the kind of surface: Low resolution mode (LRM), SAR mode (SAR) and SAR interferometric mode (SARin). This radar is named SIRAL: Syntheti...

the core of this presentation intends to show the potential capabilities of the ACDC method when integrate in the CryoSat-2 and Sentinel-3 processing baselines, comparing the retrieved geophysical parameters with the conventional SAR processing baselines for both missions over FBR CryoSat-2 data on several tracks over open-ocean. Taking into accoun...

This comparative study is based on the validation of the different in-house developed DDP processing approaches through the inversion of the geophysical parameters (SSH, SWH and sigma0), exploiting an in- house implementation of the Chris et al 2015 analytical SAR retracker. This analytical retracker is adapted hand- in-hand to the L1B processing i...

SIRAL Range, Datation and Interferometric Phase results from 2010-2016 using data over the Svalbard Transponder.

The lake-level change is one of the important indicators for the water balance of the Qinghai-Tibetan Plateau (QTP). In this region lake level is directly affected by the temperature both upstream and in the surroundings. In addition, other factors like: precipitation, evaporation, glaciers, perennial snow cover and permafrost do have an impact as...

The universal altimetry toolbox, BRAT (Broadview Radar Altimetry Toolbox), already capable of dealing with past and current altimetry missions’ data, incorporates now the capability of reading the upcoming Sentinel-3 L1 and L2 products. ESA promotes and supplies this new feature, supporting users of the future Sentinel-3 SAR Altimetry Mission.

Over the past 20 years, satellite radar altimetry has shown its ability to revolutionize our understanding of the ocean and climate. These advances were mainly limited to ice-free regions, leaving aside large portions of Polar Regions. Launched in 2010, the polar-orbiting CryoSat Satellite was designed to measure the changes in the thickness of pol...

A new method of forming the synthetic aperture radar altimeter multilook backscattered power waveform is proposed for application over water. The method compensates the waveform for both variations in amplitude and dilation in range, which are caused by the geometry of the observation and the signal processing chain of the instrument. Using Cryosat...

SAR Altimetry algorithm improvements applied to the Sentinel-6/Jason-CS mission

CryoSat's Synthetic Interferometric Radar Altimeter (SIRAL) [1] is a Ku-band pulsewidth limited radar altimeter that trans-mits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for De-lay/Doppler processing [2]. Moreover SIRAL takes advan-tage of two antennas mounted across-track for interferom...