Projecte llegit
Títol: Precise Orbital Tracking of GEOSAR Missions using Interferometry
Director/a: NICOLÁS ÁLVAREZ, JORGE
Departament: TSC
Títol: Precise Orbital Tracking of GEOSAR Missions using Interferometry
Data inici oferta: 30-01-2020 Data finalització oferta: 30-09-2020
Estudis d'assignació del projecte:
DG ENG AERO/SIS TEL
| Tipus: Individual | |
| Lloc de realització: |
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| Segon director/a (UPC): BROQUETAS IBARS, ANTONI | |
| Paraules clau: | |
| Interferometry, Precise Orbit Determination, GEOSAR | |
| Descripció del contingut i pla d'activitats: | |
| Background: Low Earth Orbit Synthetic Aperture Radars (LEOSAR) present a main drawback regarding their revisit time of several days or weeks. At most, they can only provide an image of the same area of the planet per week. To mitigate this limitation, Geosynchronous Synthetic Aperture Radars (GEOSAR) missions will be able to provide permanent monitoring over wide areas of the planet.
We are working in the context of an on-going GEOSAR mission. The European Space Agency (ESA) has selected Hydroterra to compete as the tenth Earth Explorer. Hydroterra will help scientists unravel the details of the daily water cycle. In that way, in the event of a natural disaster, they would be able to predict the development of floods and emergency services will be able to safely evacuate the citizens before the water rise. GEOSAR presents a main challenge: it requires unprecedented orbit determination precision. We have to demonstrate that we can get this precision before launching any spacecraft. We have designed and built a ground interferometer in the UPC-D3 building in order to track non-cooperative geostationary telecommunication satellites. Goal: The project consists of retrieving the geostationary satellite orbits from the acquired interferometric observables and test the effects of different orbit observables such as GNSS, laser ranging, etc. By means of estimation techniques such as Least Squares and Extended Kalman Filter, the interferometric observables are fitted to an orbital model which has to accurately reproduce the geostationary environment. |
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| Overview (resum en anglès): | |
| A major limitation of current low-Earth orbit synthetic aperture radars (LEOSAR) is related to their review time of several days or weeks. We cannot provide continuous surveillance over the same area of the planet. The introduction of the Geosynchronous Synthetic Aperture Radar (GEOSAR) is intended to provide permanent observation over a wide area of the planet. The determination of the orbit of a GEOSAR is one of the main challenges of the mission. Currently, an interferometer has been built on the campus of the Polytechnic University of Catalonia that obtains observables on current satellites in geosynchronous orbit.
Regarding the methodology of this work, we have carried out a study of the interferometer system from which we determine the orbit of a satellite, based on the actual data determined. Currently, new studies are emerging that achieve a considerable improvement by using swarms of satellites in GEO orbit. This is why we are also studying the possibility of determining the orbits of three different satellites using a single interferometer. Prior to the determinations we have carried out several simulations with the aim of contrasting their results with the real ones. Summarizing the main results of this research, we see that from the theoretical study we can appreciate the benefits of the interferometer system and also detect possible modifications to improve its performance. Using as reference the real data collection, we have been able to carry out orbit determinations obtaining favourable results. The conclusions drawn throughout the study, lead us to affirm that interferometry demonstrates its future potential and its validity based on the tests performed. Today, the favourable results of this technique are of great importance, given the advent of GEOSAR missions. |
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