However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the ION. Personal use of this publication is permitted. In a parallel programme, an instrument, GPSOS, is developed for the NPOESS satellites with IPO (NOAA, NASA & DOD) as customer. GRAS-2 GNSS Receiver for Atmospheric Sounding GRAS-2, the next generation Radio Occultation instruments from RUAG Space, will provide Radio Occultation data from all MetOp-SG satellites until 2050. Setting occultation: as the LEO moves behind the earth we obtain a profile of bending angles, a, as a function of impact parameter. Personal use of this publication is permitted. A high performance radio occultation receiver, GRAS, is being developed at Saab Ericsson Space for the ESA Metop satellites for Eumetsat. GPS RO geometry GPS transmitter a LEO receiver eg, GRAS Tangent point 20,200km 800km The motion of LEO results in sounding progressively lower regions of the atmosphere. Processing of GRAS/METOP radio occultation data recorded in closed-loop and raw-sampling modes Atmospheric Measurement Techniques 10. T1 - Ground Based Radio Occultation Measurements Using the GRAS Receiver

Gras receiver radio occultation