EO·Atlas
GRAS (GNSS Receiver for Atmospheric Sounding)
European dual-frequency GNSS radio occultation receiver flown on MetOp-A, MetOp-B, and MetOp-C for atmospheric temperature, humidity, pressure, and ionospheric sounding. GRAS tracks GPS signals through atmospheric limb occultations and has operational heritage across the EUMETSAT Polar System first-generation MetOp series.
GRAS is a dual-frequency GNSS radio occultation receiver flown on MetOp-A, MetOp-B, and MetOp-C for atmospheric temperature, humidity, pressure, and ionospheric sounding [1][2]. It tracks GPS L1 and L2 limb-occultation signals at 1.57542 GHz and 1.2276 GHz, using passive GNSS L-band measurements rather than an imaging swath [3]. The instrument supports the EUMETSAT Polar System MetOp series, giving users a long operational record for radio occultation data continuity across the three MetOp platforms [2]. The instrument originated with Saab Ericsson Space and is recorded under RUAG Space AB in current MetOp documentation, so procurement or heritage analysis should treat those names as successive supplier identities rather than separate payload designs [1][2].
Pricing not publicly listed by operator
Supply chain position
- GNSS radio occultationvia MetOp-B
ESA and EUMETSAT identify GRAS as the GNSS radio occultation receiver on MetOp-A, MetOp-B, and MetOp-C.
None on record.
- [1]ESA About GRASagency doc2026-06-14
- [2]EUMETSAT Metop instrumentsoperator engineering2026-06-14
- [3]WMO OSCAR instrument record for GRASagency doc2026-06-14
How to cite this page
Plain text
GRAS (GNSS Receiver for Atmospheric Sounding). EO-Atlas, SpectraWorks B.V. https://eo-atlas.org/products/sensor/gras (CC BY 4.0)
BibTeX
@misc{eoatlas:products:sensor:gras,
title = {GRAS (GNSS Receiver for Atmospheric Sounding)},
author = {{EO-Atlas}},
publisher = {SpectraWorks B.V.},
note = {CC BY 4.0},
url = {https://eo-atlas.org/products/sensor/gras}
}