title: SNR and Standard Deviation of cGNSS-R and iGNSS-R Scatterometric Measurements.
abstract: This work addresses the accuracy of the Global Navigation Satellite Systems (GNSS)-Reflectometry (GNSS-R) scatterometric measurements considering the presence of both coherent and incoherent scattered components, for both conventional GNSS-R (cGNSS-R) and interferometric GNSS-R (iGNSS-R) techniques. The coherent component is present for some type of surfaces, and it has been neglected until now because it vanishes for the sea surface scattering case. Taking into account the presence of both scattering components, the estimated Signal-to-Noise Ratio (SNR) for both techniques is computed based on the detectability criterion, as it is done in conventional GNSS applications. The non-coherent averaging operation is considered from a general point of view, taking into account that thermal noise contributions can be reduced by an extra factor of 0.88 dB when using partially overlapped or partially correlated samples. After the SNRs are derived, the received waveform's peak variability is computed, which determines the system's capability to measure geophysical parameters. This theoretical derivations are applied to the United Kingdom (UK) TechDemoSat-1 (UK TDS-1) and to the future GNSS REflectometry, Radio Occultation and Scatterometry on board the International Space Station (ISS) (GEROS-ISS) scenarios, in order to estimate the expected scatterometric performance of both missions.
authors.affiliation: Department of Signal Theory and Communications, Universitat Politécnica de Catalunya-BarcelonaTech (UPC), 08034 Barcelona, Spain. alberto.alonso.arroyo@tsc.upc.edu.|Earth System Research Laboratory (ERSL), National Oceanic and Atmospheric Administration (NOAA), Boulder, CO 80305-3337, USA. alberto.alonso.arroyo@tsc.upc.edu.
authors.forename: Alberto
authors.initials: A
authors.lastname: Alonso-Arroyo
authors.affiliation: Department of Signal Theory and Communications, Universitat Politécnica de Catalunya-BarcelonaTech (UPC), 08034 Barcelona, Spain. jorge.querol@tsc.upc.edu.
authors.forename: Jorge
authors.initials: J
authors.lastname: Querol
authors.affiliation: Department of Signal Theory and Communications, Universitat Politécnica de Catalunya-BarcelonaTech (UPC), 08034 Barcelona, Spain. carlos.lopez@tsc.upc.edu.
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopez-Martinez
authors.affiliation: Earth System Research Laboratory (ERSL), National Oceanic and Atmospheric Administration (NOAA), Boulder, CO 80305-3337, USA. valery.zavorotny@noaa.gov.
authors.forename: Valery U
authors.initials: VU
authors.lastname: Zavorotny
authors.affiliation: Department of Signal Theory and Communications, Universitat Politécnica de Catalunya-BarcelonaTech (UPC), 08034 Barcelona, Spain. park.hyuk@tsc.upc.edu.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Park
authors.affiliation: Department of Signal Theory and Communications, Universitat Politécnica de Catalunya-BarcelonaTech (UPC), 08034 Barcelona, Spain. daniel.pascual@tsc.upc.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pascual
authors.affiliation: Department of Signal Theory and Communications, Universitat Politécnica de Catalunya-BarcelonaTech (UPC), 08034 Barcelona, Spain. onrubia@tsc.upc.edu.
authors.forename: Raul
authors.initials: R
authors.lastname: Onrubia
authors.affiliation: Department of Signal Theory and Communications, Universitat Politécnica de Catalunya-BarcelonaTech (UPC), 08034 Barcelona, Spain. alberto.alonso@noaa.gov.
authors.forename: Adriano
authors.initials: A
authors.lastname: Camps
keywords: GNSS-R; GNSS-Scatterometry; SNR; cGNSS-R; iGNSS-R