Implementation of a Testbed for GNSS-R Payload Performance Evaluation

Abstract

The functional performance of space-borne instruments must be validated on ground before and after satellite integration. The effects of Radio-Frequency Interference are also becoming more important, even in protected bands for Earth Observation (EO). In this work, a GNSS and GNSS-R signal simulator is developed as part of a testbed of GNSS receivers and GNSS-R payloads' performance in high dynamics, and to study the effects of RFI in the GNSS-R observables. This work describes the different concepts and key enabling techniques that have been developed to support this project.

Airborne GNSS-R: A Key Enabling Technology for Environmental Monitoring

“…Using the same procedure as described in [46], the specular reflection point of the GPS signals is obtained [47] by an iterative algorithm which uses the WGS84 ellipsoid and the positions of the transmitter and receiver. For each airborne receiver, a number of specular points corresponding to the GPS satellites in view at that moment in time were calculated.…”

“…Previous studies regarding RFI effects on GNSS-R measurements [56,57] conclude that pre-and post-correlation methods need to be implemented for RFI detection and mitigation in the receiver in order to retrieve accurate measurements. The use of a test bed [46] to characterize the effect of RFI on the GNSS-R instrument and to develop countermeasures is increasingly important before and during campaigns, as the problem of RFI remains unsolved and is continuously affecting active missions with passive sensors [58,59].…”

Analysis on the Feasability of Airborne GNSS-R Receivers for Weather Nowcasting and Target Detection

“…Using the same procedure found in [10], the specular point of the reflection of the GPS signal on the Earth's surface before being captured by the tentative down-looking antenna of each plane is obtained. Thus, for each plane in the world and for each 10-second window in several months of data, 5-12 specular points (belonging to the different GPS satellites in view) were calculated with a precision under 10 meters, as seen in Fig.…”