AGRICULTURE
OSNMA: A step toward multi-layered GNSS security
Given their low power level at the receiver antenna, GNSS signals are susceptible to any in-band interference.
The public structure of civilian GNSS signals exposes them to counterfeit signals and spoofing attacks, where users can be misled about their timing and/or position information. To make matters worse, advances in software-based technologies have made spoofing easier, intensifying concerns about GNSS security as a critical ongoing issue.
Signal protection is the front line of the battle for GNSS security, which involves cryptographic techniques to safeguard GNSS signals from being used by unauthorised users or manipulated by counterfeit transmitters.
This article spotlights GNSS security enhancement through cryptologic protection tailored for a prototype OEM7 receiver using the newly developed Galileo E1-B Open Service Navigation Message Authentication (OSNMA).
While OSNMA delivers a dependable level of service availability in open-sky and suburban areas, its performance degrades in dense environments, where the reception of signals and data decoding are interrupted more frequently.
What you will learn
Written by Ali Pirsiavash, GNSS resilience researcher, Ali Broumandan, resilient GNSS lead, and Sandy Kennedy, VP innovation at Hexagon’s Autonomy & Positioning division, this article describes the Galileo E1-B OSNMA service developed by the European Union to enhance GNSS security. Test scenarios using a prototype receiver in various urban environments are presented to look at the functionality and availability of OSNMA, as well as a spoofing scenario from Jammertest 2023. A detailed discussion of the benefits and limitations of OSNMA is presented.
OSNMA benefits and limitations.
| Benefits | Limitations |
|---|---|
| Navigation message protection | Limited availability in dense and degraded environments |
| Relatively high security and low operational complexity | Reliability concerns under low latency meaconing and non-navigation message-based spoofing attacks |
| Tenable for civil applications | Implementation challenges and manufacturing costs |
| Compatible with existing GNSS signals | Latency in time-to-alert |
| Cross-authentication as an additional benefit | Cross-authentication as a vulnerability concern |
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