SSTI
The SSTI (Satellite to Satellite Tracking Instrument)is a state-of-the-art GPS receiver that has been designed to operate in a low-Earth orbit environment. The objective is to provide the SST-hl (Satellite-to-Satellite Tracking - high/low) contribution to the gravity field recovery, by the simultaneous tracking of up to 12 GPS satellite signals. In addition, SSTI provides data for precise orbit determination; it is also used for real-time on-board navigation and attitude-reference-frame determination. The SSTI instrument is based on the Lagrange architecture, a flight-proven device of Laben, Milan, Italy, a unit of Thales Alenia Space, Italy