Projecte llegit
Títol: Active Signal Repeater for Interferometric Precise Orbit Determination
Director/a: NICOLÁS ÁLVAREZ, JORGE
Departament: TSC
Títol: Active Signal Repeater for Interferometric Precise Orbit Determination
Data inici oferta: 02-02-2021 Data finalització oferta: 02-10-2021
Estudis d'assignació del projecte:
GR ENG SIS TELECOMUN- GR ENG SIST AEROESP
- GR ENG TELEMÀTICA
| Tipus: Individual | |
| Lloc de realització: |
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| Segon director/a (UPC): BROQUETAS IBARS, ANTONI | |
| Paraules clau: | |
| interferometry, precise orbit determination, remote sensing, radar, geosynchronous satellites | |
| Descripció del contingut i pla d'activitats: | |
| 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 remote sensing missions: The European Space Agency (ESA) has 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 increasing the baseline of the current ground interferometer in order to decrease the uncertainty of the orbit observables. The student will have to develop a radio link that receives the satellite signal and repeats it towards the receiver with a reliable SNR. This will contribute to the precise orbit determination of remote sensing satellites in geosynchronous orbits. |
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| Overview (resum en anglès): | |
| The European Space Agency (ESA) is considering, among others, the GCLASS/ Hydroterra mission to be the tenth mission to use a Synthetic Aperture Radar to carry through several studies of the Earth surface. The aim of the mission is to observe and understand the processes that carries out the water cycle in the Earth with the purpose of rising up the security level among citizens. Furthermore, it could also be implemented with Earth surface catastrophes as for example earthquakes or volcanoes. For executing the project, a group of investigators from Universitat Polit `ecnica de Catalunya is working on the concept of orbital determination of a satellite in the GEO orbit. In order to do so, an interferometer has been designed and fabricated in the D3 Campus Nord building in the UPC. The main purpose is to receive the signal from the ASTRA 19.2E geostationary satellite constellation located at about 36000 kilometres in the distance. For achieving it, the mission is based on the GEOSAR concept. A geosynchronous synthetic aperture radar is a radar located in the GEO orbit and that will be the main responsible of providing the necessary images for carrying out the studies of the different phenomena that occur in the Earth surface. These kind of radars have a large number of benefits. There is a main point that must be highlighted: its short revisit time, which means that they have the capacity of providing a continuous vision of a concrete area of the planet. In any case, they also present a major drawback which will play the leading role on this interferometric project: GEOSAR requires a very precise orbit determination process. In order to achieve it, it is proposed to enlarge the separation between the receiver antennas, called baseline, as a way of minimizing the observation uncertainty of the orbit. This will be accomplished by the build-up of a interferometer along different university buildings. The previously mentioned interferometer, will be based on an antenna array separated approximately 100 m between each other. Thus, so that a signal reception can be captured with enough quality to be processed, it will be necessary the build-up of a repeater module that assures a certain signal level. In this project, it will be specifically studied the way of achieving a repetition and amplification of the received signal by the terrestrial parabolic antenna, due to the large amount of losses that the signal suffers along the path, so that it can be processed and analysed for eventually getting the most precise approach as possible of the GEO orbit, where these satellites are located. |
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