Implementation of a GNSS-R payload based on software defined radio for the 3CAT-2 mission

Abstract

©2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The 3CAT-2 nanosatellite aims at demonstrating global navigation satellite system reflectometry (GNSS-R) techniques for spaceborne applications in the small form of a six-unit CubeSat. There are many challenges involved from a size, processing, and power perspectives. The proposed solution for the payload uses a software-defined radio (SDR) connected to a nadir looking array of dual-band and dual-frequency and dual-polarization antennas to capture the reflected GNSS signals and to a zenith looking patch antenna to capture the direct ones. The SDR is controlled by the payload computer, which retrieves the binary samples and processes the raw data to obtain delay-doppler maps (DDMs) via various techniques. DDMs are then compressed using the fully adaptive prediction error coder algorithm, producing an output more suitable for the limited downlink capabilities of these small platforms.Peer Reviewe