Caribbean Green Team 2019

Elsa Ames, Tyler Klein, Nate Krinsky, Aji Sjamsu, Jonathan Traester

Doppler Shift Navigation

While the accuracy and reliability of GPS navigation systems makes them ideal for commercial use, GPS systems require four visible satellites and can be easily jammed, rendering them useless in remote locations and military applications. If the location and transmission frequency of one visible satellite is known, it is possible to obtain a position fix by tracking the Doppler shift of the satellite transmission. Doppler shift navigation has been explored in the past (eg. the Transit system), but initial developments were never expanded upon. We utilized recent developments in small, cheap, and easily accessible Software-Defined Radios to develop a signals of opportunity based navigation system. We accomplished this by recording a known satellite transmission using an SDR, tracking the Doppler shift of the signal, and using numerical optimization, along with the measurements, to obtain a position fix. The project required significant research on satellite constellations, software defined radios, carrier recovery, and numerical optimization.

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Caribbean Green Team Project Poster