Projecte llegit
Títol: Improvement of End-to-end Simulator for spaceborne GNSS-R Instrument
Director/a: PARK, HYUK
Departament: FIS
Títol: Improvement of End-to-end Simulator for spaceborne GNSS-R Instrument
Data inici oferta: 24-01-2019 Data finalització oferta: 24-09-2019
Estudis d'assignació del projecte:
GR ENG SIST AEROESP
| Tipus: Individual | |
| Lloc de realització: EETAC | |
| Paraules clau: | |
| Satellite Remote Sensing, Simulator, TDS-1 | |
| Descripció del contingut i pla d'activitats: | |
| Recently, many studies are being conducted to expand the GNSS-R
technique for the Earth observation using the spaceborne measured data of the UK TDS-1 and NASA CYGNSS missions. For ocean applications, many studies have been reported, e.g., measuring the sea surface roughness, wind speed, and sea surface height. Land applications are also explored to measure land geophysical parameters. From ground and airborne experiments, it has been reported that the GNSS-R technique is capable of providing the information of soil moisture, vegetation thickness, and biomass. From spaceborne experiments, several studies have been conducted, and they have shown the feasibility of land geophysical parameter retrievals such as soil moisture from the spaceborne DDM. Although those studies have demonstrated the feasibility of spaceborne GNSS-R to measure some land geophysical parameters, and in particular soil moisture, the quality of estimated sensitivity is not very good due to several effects linked to the observation geometry and the instrument. For example, the elevation angles, the antenna pattern, the thermal noise level vary the DDM. Topography and surface roughness of the reflected area also affect the GNSS-R measurements. Therefore, further studies of all these effects are needed to demonstrate the feasibility of spaceborne GNSS-R land applications. This work analyzes the impacts of some parameters to the DDM from spaceborne GNSS-R. Using the developed end-to-end (E2E) simulator, DDMs are generated varying the input parameters, such as elevation angle, soil moisture, and topography of the glistening zone. The variation of the DDM peaks is investigated according to the parameter variation. |
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| Overview (resum en anglès): | |
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The GNSS-R technique has been in development for many years, and it has presented an opportunity to make measurements of soil characteristics. The applications it has are enormous, from measuring the ocean winds, to check the soil moisture or surface roughness, even checking the layout of a big ice bodies. The GARCA simulator will be used to know to what extent what it is known about models and also ground and airborne experiments on GNSS-R applications for soil moisture and vegetation biomass is still applicable from space. Its purpose is also to try to discover if there is any additional phenomenon that should be modelled and which geo-physical characteristics affect our measurements. In order to validate the GARCA simulator its results must be compared to actual and real data and for that, the TDS-1 project has been selected. The TechDemoSat-1 GNSS-Reflectometry Ground Processing Project is a project sponsored by the ESA to have a series of technology satellites aiming to provide rapid and affordable means of testing up to date space hardware directly in orbit. This project uses the TDS-1 L1b data obtained directly from the Merrbys website, and also the GARCA simulator to make all the validations. The structure of this project starts with an introduction to GNSS-R, how it works and its applications. Then an introduction to the TDS-1 project in both a hardware point of view and a data-focused point of view. Finally the last chapter will focus on the GARCA simulator and the validation of a series of simulations that have been performed to test different aspects of such program. |
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