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Projecte llegit

Títol: ERASMUS TFG CARLOS ACEBES: Opportunistic Navigation with Iridium Next LEO Satellites

Estudiants que han llegit aquest projecte:

Director/a: ROBERT SANXIS, FRANCESC JOSEP

Departament: EEL

Títol: ERASMUS TFG CARLOS ACEBES: Opportunistic Navigation with Iridium Next LEO Satellites

Data inici oferta: 16-07-2020     Data finalització oferta: 31-07-2020


Estudis d'assignació del projecte:
    DG ENG AERO/SIS TEL
Tipus: Individual
 
Lloc de realització: ERASMUS
 
        Supervisor/a extern: Prof. Zak M. Kassas
        Institució/Empresa: University of California, Irvine (UCI).
 
Paraules clau:
Doppler Positioning, Signals of Opportunity, Low Earth Orbit (LEO) Satellite Navigation, Phase-Locked Loop (PLL), Extended Kalman Filter (EKF)
 
Descripció del contingut i pla d'activitats:
 
Overview (resum en anglès):
The concept of opportunistic navigation arises from the future demands that autonomous vehicles will require in order to navigate in a reliable and accurate way in GNSS-challenged environments. Specifically, GNSS signals are not robust enough against intentional jamming attacks and they are unencrypted, making them accessible by hackers and completely spoofable.

Some alternatives that have been identified as timely sources of positioning are signals of opportunity, which cluster a broad spectrum including broadband LEO (Low Earth Orbits) satellite signals, AM/FM radio signals, Wi-Fi signals and even cellular LTE/4G signals, and which can be exploited for navigation although they were not transmitted for this purpose.

Particularly, LEO satellite signals have inherent attributes that make them even more desirable for opportunistic navigation. First, their received signal power is around 30dB higher than GNSS signals since they are located approximately twenty times closer to the Earth’s surface. Second, they will be abundant in the following years since private companies are planning to aggregately launch thousands of broadband Internet satellites into LEO. Third, they will be diverse in frequency and direction since each broadband provider will deploy its satellites into unique constellations.

Unfortunately, there are several challenges with using LEO satellite signals for navigation as it is discussed throughout this document. For instance, there is a need of having specifically designed receivers that can extract navigation observables from LEO satellites and, furthermore, the internal clocks of LEO satellites are not as precisely synchronized as GNSS satellite clocks, requiring the receiver to account for extra timing shifts.

In this way, the present thesis addresses the problem of navigating opportunistically with Iridium Next LEO satellite signals by proposing a complete receiver architecture that allows to make Doppler measurements to satellite signals in order to obtain a PNT (Positioning, Navigation and Timing) solution.

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