GRIPP: an Open-Source and Portable Software Defined Radio Oriented GNSS/SBAS Receiver

Global Navigation Satellite Systems (GNSS) and Satellite-Based Augmentation Systems (SBAS) are today widely used in various domains, from automotive applications to safety of life. Due to their rapid evolutions, constantly aiming to improve the accuracy and robustness of the PVT (Position, Velocity and Time) solutions offered, a constant wave of applications conception, development and updates is experienced.

In the light of this, opening the access to the PVT algorithms is needed. It can ease not only the development of such applications by navigation engineers, but also introduce GNSS and SBAS technology in a ludic way to students and general audience. As usage of industrial mass-markets and professional receivers is limited by their non accessible proprietary algorithms, the use of open-source solutions, like GNSS-SDR or FGI-GSRx, has to be encouraged. r.

The development of the GRIPP (GNSS/SBAS Receiver, Independent and Portable PVT) equipment aims to satisfy these goals. This system (Figure 1) is composed of:

- a Raspberry Pi, acting as a PVT solutions computer and datastore,
- a Pocket SDR device and associated open-source software. This SDR (Software Defined Radio) is specifically designed to retrieve GNSS RAW data,
- a dual or triple-band L-band antenna.

This system, compatible with Galileo E1, E5 and E6 and GPS L1, L2 and L5 frequency bands, hosts an open-source software based on the Pocket SDR one. This software aims to store several hours of RAW navigation messages and compute its own PVT solutions through a configurable algorithm. This one, in development, can segregate live or recorded signals received depending on the constellation and/or satellites in view.