Validation of a Combined GNSS Correction and NMA L-Band Service Against Spoofing.

This paper presents a spoofing validation strategy and real-world results using Fugro's AtomiChron L-band mobile-satellite service (MSS). AtomiChron combines correction data for precise point positioning (PPP) applications and navigation message authentication (NMA) for all four GNSS to preserve their integrity and potentially detect spoofing attacks. A commercial multi-GNSS signal generator carries out real-world multi-GNSS signals' position and time spoofing. The devices under test are professional multi-GNSS receivers, partly equipped with the AtomiChron NMA and Galileo OSNMA service and Galileo public regulated service (PRS) for comparison. The results show that NMA, in general, is a valuable add-on for spoofing detection, especially if NMA is not only provided for Galileo as in OSNMA. Still, the latency to detect spoofing is in the area of tens of seconds. Therefore, a combination of different metrics, incl. NMA is strongly recommended for a GNSS receiver's spoofing protection.