View Instrument

Instrument Type: GPS Receiver, Operational Mode: , Collection Type: TBD, Other Information: GRAS will not view the Earth system with a vertical scan but will instead look tangentially through the Earth's atmosphere. The instrument will measure the time delay of the refracted GPS radio signals as the ray (signal path) skirts the Earth's atmosphere on its way from the transmitting GPS satellite to MetOp. By precisely computing position and velocity of MetOp and the GPS satellite, the measured time delay can be converted to the bending angle of the ray path, which again can be converted to values of temperature, pressure and water vapor content in the atmosphere. The resulting quantities will be functions of height above sea level (from ground level up to approximately 80 km), an atmospheric profile.