Projecte llegit
Títol: Digital Control and Optimization of an Interferometric Orbit Observation System for GEOSAR Missions
Director/a: NICOLÁS ÁLVAREZ, JORGE
Departament: TSC
Títol: Digital Control and Optimization of an Interferometric Orbit Observation System for GEOSAR Missions
Data inici oferta: 04-02-2020 Data finalització oferta: 04-10-2020
Estudis d'assignació del projecte:
GR ENG SIST AEROESP
| Tipus: Individual | |
| Lloc de realització: |
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| Segon director/a (UPC): BROQUETAS IBARS, ANTONI | |
| Paraules clau: | |
| Interferometry, orbit determination, automatic gain control, Hydroterra, GEOSAR, Earth observation, ESA | |
| 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 developing a set of digital control procedures in order to optimize the operation of the ground-based interferometer. The system is programmed in terms of frequency tuning and channel gain. The implementation of these procedures will allow us to efficiently track different satellites as well as optimizing the signal processing depending on the channel. This work will have a direct influence in the outcome of the orbit determination precision. |
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| Overview (resum en anglès): | |
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A major limitation of current Low Earth Orbit Synthetic Aperture Radar (LEOSAR) missions comes with the revisit times of days or weeks. They have proven to be an effective way of imaging the Earth. However, they cannot provide continuous monitoring over wide areas of the planet. Geosynchronous Synthetic Aperture Radar (GEOSAR) missions aim at solving this problem. To operate properly, they need unprecedented levels of orbit determination precision. To this end, interferometry stands out, since it is able to provide orbit observables from current GEO satellites, that serve as illuminators of opportunity.\\ This work is performed in the context of an on-going ESA mission, named Hydroterra. Its objective is to help scientists unravel the mysteries of the daily water cycle. It could also help in preventing massive casualties in the case of short period catastrophes, like land subsidence or floods.\\ An automatic gain control (AGC) subsystem is devised to improve the free path losses that will appear in a future interferometer with a bigger baseline. Its addition will increase the Signal to Noise Ratio (SNR) that the slave antennae will emit. Thus, allowing for higher sensitivities and better precision levels.\\ The methodology used for the testing and validation of the AGC is presented along with the experimental results obtained. The system is capable of supporting significant degradations of the signal and still recover the original information.\\ The observations obtained from the currently working interferometer are presented and discussed. \\ |
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