Projecte llegit
Títol: Interferometric Baseline Extension for Precise Orbit Determination of Geostationary Satellites
Director/a: NICOLÁS ÁLVAREZ, JORGE
Departament: TSC
Títol: Interferometric Baseline Extension for Precise Orbit Determination of Geostationary Satellites
Data inici oferta: 28-01-2021 Data finalització oferta: 28-09-2021
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, remote sensing, GEOSAR, electronics, hardware | |
| 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. 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. The group has developed a ground interferometer prototype in the UPC-D3 building in order to track non-cooperative geostationary telecommunication satellites. The first experimental demonstration has shown promising results.
The student will work in the context of some on-going space missions: - The European Space Agency (ESA) selected Hydroterra on its call for the tenth Earth Explorer mission. Hydroterra will help scientists unravel the details of the daily water cycle. 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. - NASA Jet Propulsion Laboratory (JPL) has a keen interest in the presented technique and has contacted us to join their team in an emerging snow remote sensing mission. Goal: The project consists of retrieving geosynchronous satellite orbits from experimental interferometric measurements. The student will work with an Extended Kalman Filter module programmed with Python in order to estimate the satellite trajectory. They will work with different datasets of observables: we either perform the tracking of a single satellite or three satellites at a time. The student will also work in the compensation of errors caused by atmospheric perturbations. They will analyze the data of a meteorological station and correlate them with the orbit observations. |
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| Overview (resum en anglès): | |
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GEOSAR (Geosynchronous Synthetic Aperture Radar) mission satellites allow continuous monitoring of large areas of the planet. Unlike those located in lower orbits (LEOSAR), which have a revisit time of days and the area they cover of the globe is limited. However, geostationary orbit satellites, which are the subject of study in this work, face the challenge of knowing their position with unprecedented precision. This cannot be defined using the same techniques as LEOSAR, such as the ones based on Doppler effect or global navigation satellite systems, because of their negligible relative motion with the Earth and being farther away than GNSS constellations. Different alternatives are studied to know the benefits and drawbacks of each one, besides proposing our own solution for orbital determination by means of interferometry. This work is part of the development of a ground-based interferometer by the TSC (Signal Theory and Communications) department, which started in the context of a GEOSAR mission: Hydroterra. This was selected to compete by ESA in the 10th Earth Explorer. Prior to this project, the design, manufacture and implementation of a compact baseline interferometer (~10 m) has already been achieved. It is currently operating on the roof of the UPC-D3 building, where a second version with an extended baseline (~100 m), offering higher order precision. To do so, the designs of the interferometer in operation are duplicated, improved and adapted to the new requirements. Specifically, the requirements for the power supply system, the reference module, the front-end module and the baseband are studied and resulted. Moreover, a repetition system inclusion is needed. Finally, a suitable cabinet is selected in which to integrate the system. Its interior layout and roof installation are designed. With the system in operation, results are obtained under known conditions to verify its performance. |
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