Galileo OS NMA authentication services under test

4 August 2021

Galileo OS NMA authentication services under test


Since November 28th 2020, the navigation authentication data has been transmitted through the Galileo Open Service (OS) signal.  This is the first open service GNSS signal ever to provide authentication service, namely Open Service Navigation Message Authentication (OSNMA). We are participating in the evaluation that is taking currently ongoing and are capable of evaluating the authentication service that is being provided. The main tool employed to process the authentication data is the Matlab based SiSiTau v2.0 tool, which uses the bits transmitted by the satellite to authenticate the transmitted navigation data messages. We used two main methods to retrieve the navigation data bits:

  1. Connecting to the receiving antenna, a USRP or another radio frequency front-end, and then processing the stored IF samples with the inhouse MuSNAT software receiver.
  2. Connecting to the receiving antenna, a Septentrio PolaRx5 receiver, which is capable of outputting directly the navigation data bits.

During the recording phase two different antennas have been used. The first one is a rooftop antenna located in building 61, allowing to evaluate the authentication performance for a static receiver. The second one is a rotating antenna located in building 62, which allows to emulate a pedestrian dynamic scenario.