It is composed of the spacecraft bus, supplied by CNES, and two payload modules, the nadir payload module and the KaRIn payload module. Medium-accuracy Orbit Ephemeris (MOE) providing position and velocity vectors of satellite center of mass. 2016; Wang et al. Tracking data from onboard Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) instrument. Discrete measurements at nadir for each half orbit, along the ground track. However, the specific wavelength at which the nadir altimeter can be used for the SWOT validation (hereinafter nadir scale) has not been thoroughly evaluated. - Networks from CNES X-band stations to X-band network center Observations from SWOT can be used to better understand ocean currents and processes happening at spatial scales on the order of 15-150 km, something that has not been done before. This is the main objective of this study, namely, to make a quantitative assessment of the wavelengths (nadir scale) longer than which the onboard nadir altimeter can be used as a validation reference. Figure 38: RW speed evolution at low altitude (image credit: CNES), Figure 39: Solar arrays position for low altitude reentry (image credit: CNES). For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).


Figure 19: Overview of AOCS modes (image credit: TAS, CNES). Alternatives are to use moorings for continuous sampling, combined with fast underway CTDs (instruments that measure electrical conductivity, temperature, and depth), gliders, or profiling floats.

Learn more about what will make SWOT a transformational satellite mission by visiting the Science Team page. SWOT will include a Ka-band Radar Interferometer (KaRIn) that will send and receive radar pulses to antennas mounted on booms attached to the spacecraft. *** Floodplain map made from multi-temporal water elevations.

The nadir track does not collocate with the KaRIn swaths . To learn more about the mission, go to SWOT Mission page. A pass is half an orbit/revolution that starts and ends at the poles. Otomatis kita membutuhkan strategi yang baik dalam mewujudkan tercapainya semua tujuan tersebut. If swath data (i.e., green overlay) impacts the ability to see map details, temporarily "Hide Tracks" using the radio button. The fact that the payload has to be taken into account before the mission, during the mission and after the mission! 2019, unpublished manuscript). - during the mission, as the quality of the products depends on two major criteria: a very high dynamical stability and a very good knowledge of the attitude. Developed in cooperation with iXSea, the state-of-the-art Astrix® products provide the highest performances on the market. 2019). SWOT measurements are not impeded by clouds, so the synoptic maps of sea surface height provided by SWOT will track fine-scale circulation features at daily intervals (twice daily at crossovers) during this fast-sampling phase.

This has been done over different surfaces: Forest area, water surfaces from river, lake, marshes and ponds, bare soils and agricultural areas with different kinds of crops. Figure 14: The flight system configurations (image credit: CNES, NASA/JPL), 360 Mbit/s high rate between KaRIn and the SSR, 5m total observatory height and 23 m span. Figure 30: Photo of the ASTRIX®200 unit (image credit: Airbus DS), Figure 31: Implementation of the 3 OH STR (Optical Head Star Tracker), image credit: CNES, TAS. - CNES will provide the SWOT spacecraft bus, the KaRIn instrument's RFU (Radio Frequency Unit), the dual frequency Ku/C-band Nadir Altimeter, the DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) receiver package, satellite command and control, and data processing infrastructure. During the flights, the project used a dedicated calibration area where corner reflectors were installed. The error (the dashed line) is significantly lower than the model truth for the long wavelengths (>56 km), but becomes larger than the truth for the smaller wavelengths, which is understandable as the signals with shorter wavelengths usually decorrelate faster. Moreover, SWOT's detailed information on ocean circulation will improve understanding of the ocean environment including motion of life-sustaining nutrients and harmful pollutants. The particularity of this experiment is the line of sight geometry, with very steep incident angles, along with a SAR/XTI (SAR/Cross Track Interferometry) configuration. [2018] The SWOT mission is a partnership between two communities, physical oceanography and hydrology, to share high vertical accuracy and high spatial resolution topography data produced by payload configuration, whose principal instrument is the Ka-band Radar Interferometer (KaRIn) for making swath measurement of the elevation of land surface water and ocean surface … A High-Resolution Look at the World's Oceans. It is derived from the mass memory developed by STEEL ELECTRONIC for CNES as part of the Myriade Evolutions program, but with considerably improved data throughput and storage capacity. 3) Data calibration: The project flew over regions of interest and applied calibration coefficients estimated at previous steps. A major challenge and opportunity offered by SWOT's fine-scale sea surface height (SSH) observations are to study the interaction of these balanced ocean motions (driven by Earth's rotation, wind, and buoyancy effects) with the internal tides and internal gravity waves that stir and circulate water beneath the ocean's surface. (2018). Figure 53 (middle) is presenting the coherence figure; those areas with folded signals are well observable with some characteristic fringes. The global statistics on nadir scale remain unclear but are important for the mission’s calibration and validation (CalVal). SWOT will measure ocean surface topography and land surface water elevation with great accuracy, using interferometry to achieve two-dimensional mapping. Several sources of errors limit the accuracy of the final height: • Random errors, most notably the measurement noise of the interferometric phase difference. s%20Presented/SWOT_OSU_Rodriguez.pdf, 16) Lee-Lueng Fu, Douglas Alsdorf, Erensto Rodriguez, Rosemary Morrow, Nelly Mognard, Juliette Lambin, Parag Vaze, Thierry Lafon, "The SWOT (Surface Water and Ocean Topography) Mission: Spaceborne Radar Interferometry for Oceanographic and Hydrological Applications," March, 2009, URL: http://swot.jpl.nasa.gov/publicationFiles/oceanobs09_swot.pdf, 17) Michael Durand, Lee-Lueng Fu, Dennis P. Lettenmaier, Douglas, E. Alsdorf, Ernesto Rodriguez, Daniel Esteban-Fernandez, "The Surface Water and Ocean Topography Mission: Observing Terrestrial Surface Water and Oceanic Submesoscale Eddies," Proceedings of the IEEE, Vol.

The last verification concerns the STR (Star Tracker): firstly, the fields of view shall not be affected by the solar arrays orientation and secondly they have to be not blinded by the Earth (especially at low altitude) or by the Sun. We thank Dimitris Menemenlis and Chris Hill for making the llc4320 available and Chris Henze and Bron Nelson for allowing us to analyze the large amount of model output on the Pleiades, a supercomputer at the NASA Ames Research Center.

HR data will have terrestrial corrections applied. The large daily volume of ~7 Tbit requires ~ 20 downlinks/day. Figure 50: Vaccarès area of interest. The ground segment architecture integrates all of the functions required to completely support mission operations. It is an international partnership involving the French space agency, CNES, and CSA (Canadian Space Agency). The gyro will be integrated at the heart of the KaRIn (Ka-band Radar Interferometer) instrument. Although SWOT's 2D radar interferometric technique will reduce the measurement error by more than an order of magnitude compared to today's 1D along-track altimetry missions, SWOT's actual spatial resolution will vary spatially and temporally, depending on the relative strength of ocean signals and the magnitude of measurement errors. Also shown as the solid black line is the expected spectral continuation. In hydrology, the key objectives are to develop river discharge models, the effects of layover, and the wetland data product definition. To resolve that, an HR mask will be used.

Available with latency of < 2 days. HR measurements will not be taken everywhere, due to bandwidth issues of downlinking the data. Figure 2 shows three examples of the SSH spectrum and the error spectrum at low and high latitudes.

The surface water spatial resolution of 50 m impacts the onboard data handling and data downlink requirements due to the large associated data volume (+ 7 TBit/day) and the raw data rate of KaRIn of 360 Mbit/s. Hydrologists will use the data to calculate the rate of water gained or lost in lakes, reservoirs, and wetlands as well as discharge variations in rivers, globally. One can determine the height measurement from the two equations stated in Figure 7. The areas not covered by the mask will be preprocessed to a Low Rate (LR) with low spatial resolution. Several scene types were covered, including ocean (Mediterranean), a coastal area (Piemanson), a lagoon (Vaccarès) and a hydrology site (the Rhône river south of Arles). This animation shows the various stages of boom deployment for the interferometer antennas.

The SWOT measurement concept is illustrated in Figure 5. One validation and five measurement flights (2011) have been realized in the frame of this campaign, with an altitude around 3000 m. The project focused on the 0 to 5° incident angles range flying over different types of surfaces.

As a result, the error-to-signal ratio due to the spatial separation is larger in low latitudes and consequently the nadir scale is large, ~100 km in the equatorial Pacific. SWOT will observe rivers wider than 100 m and lakes with a surface area of 15 acres or more (i.e., an outline of 250 m x 250 m or 820 ft x 820 ft).
Since the SWOT measurement performance and the oceanic fine-scale signals vary geographically and seasonally, our understanding of the oceanic variability at 15- to 150-km scales would greatly benefit from in situ observations made at different locations during the 90-day fast-sampling phase.

However, using a gimbal generates vibrations that would degrade the accuracy of one of SWOT's instruments,KARIN (Ka-band Radar Interferometer). Similarly, the three frequency microwave radiometer is of Jason series heritage. The Surface Water and Ocean Topography (SWOT) is a new satellite mission highlighted in the 2007 decadal survey as the next-generation radar altimeter following the success of the decades-long nadir-looking altimeter (Durand et al. In order to disentangle the substantial contributions of high-frequency motions (such as internal waves) to SSH, we need to observe the 2D in situ dynamic height on hourly timescales. 1).