HASlib: An Open-Source Decoder for the Galileo High Accuracy Service

Abstract

The upcoming Galileo High Accuracy Service (HAS) will provide decimeter-level Precise Point Positioning (PPP) corrections free of charge. The HAS corrections are High-Parity Vertical Reed–Solomon encoded on the Galileo E6 navigation data in a format reminiscent of but not identical to many State Space Representation (SSR) formats. In this paper we present the HASlib which is an open-source library intended to facilitate the use of the HAS in R&D purposes. HASlib decodes the E6 navigation data frames and outputs the corrections in RTCM 3 or IGS SSR formats, as configured by the user. This makes it possible to use HAS with existing GNSS receivers and PPP engines that do not natively support the HAS formats. In the first release, BINEX and Septentrio SBF are supported as input formats. HASlib is written in Python language and its design is modular, which implies that support for other input or output formats is straightforward to implement. This paper describes the architecture and main features of the library. Furthermore, proof-of-concept results are presented to show that the library can be run in real time on a miniature desktop computer and that the output is compatible with the open-source PPP-Wizard package for PPP computation.