This paper presents the design of a system for geo-location of persons in distress in high-sea areas by means of a constellation of 48 nano-satellites (Cubesats). The CAESAR constellation is designed to orbit in Low Earth Orbits (LEO) in a Walker Delta Pattern constellation at an altitude of 710 km and an inclination of 45?. The system geo-locates a user by means of a TDOA algorithm refined by an Extended Kalman Filter used to estimate the user's true location from the TDOA initial location, thus allowing the use of only 2 satellites in a formation rather than 3 as required by independent TDOA algorithms. The constellation's characteristics, geo-location algorithm and formation control, allows the location of a user in less than 15 minutes from the moment of signal transmission and with a location error smaller than 1 km. A detailed design of the mission-related attributes of the constellation as well as the satellites' hardware design is presented in this paper. Also, a programmatic design, including WBS, cost estimation, reliability and risk analyses is presented hereinafter.
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