HAUT - Galileo Reference High Accuracy Service (HAS) User Algorithm and User Terminal

Along with the growing interest and widespread use of GNSS, there is an increased request for achieving higher accuracy.

In particular, the so-called Precise Point Positioning (PPP)-which translates into an accuracy at the level of few decimetres can be achieved only through the application of “corrections” to the navigation message data which are normally broadcast by GNSS space segment.

As a pioneering service offered by Galileo, the Galileo High Accuracy Service (HAS) is an open access and free of charge service based on the provision of precise orbit and clock corrections, as well as biases, disseminated for both the Galileo and GPS constellations.

HAS aims at unleashing PPP by a global, worldwide coverage, given that its data are transmitted directly by the Galileo space segment In order to support PPP in harsh environments, HAS also distributes its information via Internet terrestrial links.

The Contractor was Spaceopal, with its partners ANavS, DLR, Iguassu,IABG.

They designed first the HAS-UA to be adopted to achieve a Precise Point Positioning (PPP) based on Galileo HAS.

Then, was developed the HAS-UT, an equipment hosting the reference User Algorithm, produced in 6 quite solid H/W units and delivered to EUSPA at the Acceptance Review milestone of the Project.

Challenge and technical solution

The HAS-UT implements PPP operating in several working modes,which include:

• single constellation (Galileo);
• multi-constellation (Galileo + GPS).

It has the capability of exploiting all the HAS corrections delivered in Initial Service- SL1, which means operating up do triple- Frequency for Galileo (e.g.: El/E5a/E6), combined or not with dual-frequency for GPS (L1/L2C).

The HAS-UT can be configured to retrieve Galileo HAS corrections either from Galileo E6-B or internet link corrections over NTRIP in RTCM3 format.