12 November 2021
Open Service Navigation Message Authentication (OSNMA) is a data authentication function for the Galileo Open Service worldwide users, freely accessible to all.
Open Service Navigation Message Authentication (OSNMA) is a data authentication function for the Galileo Open Service worldwide users, freely accessible to all.

The new pioneering service of Galileo will pave the way towards robust Position, Velocity and Time information (PVT) for the Galileo Open Service users. An OSNMA Public Observation Test Phase will follow the publication of the Info Note. 

Robustness is part of the design of Galileo services. The evolution is bringing the need to provide the European Union secure and safe satellite navigation services one step further.

Spoofing is a sophisticated form of interfering and falsifying satellite navigation signals (GNSS). During a spoofing attack, a ‘’spoofer’’ uses a radio transmitter to generate fake GNSS signals and fool a receiver into showing its current location, for example, in the middle of the ocean while the smartphone user is climbing a mountain.

GNSS jamming incidents are reported in very large numbers, the vast majority of them caused by so-called “privacy protection devices” (illegal in most countries). GNSS spoofing (including meaconing) incidents are less frequently reported, but they are increasing in number. A possible explanation for the lower numbers is that successful spoofing attacks are not detected or not reported by their victims for security reasons.

GNSS signal falsification can have disastrous impacts on applications and market sectors that rely on precise navigation such as aviation, maritime, or drones. For instance, erroneous data of a vessel’s position, speed, and direction poses real threats to its operations but also surrounding ships, especially those carrying dangerous goods.

To contribute to the detection of GNSS attacks, EUSPA together with the European Commission is currently testing the Galileo Open Service – Navigation Message Authentication (OSNMA). This forthcoming service is an authentication mechanism that allows Open Service users to verify the authenticity of GNSS information, making sure that the data they receive is indeed from Galileo and has not been modified in any way. 

OSNMA is authenticating data for geolocation information from the Open Service through the Navigation Message (I/NAV) broadcast on the E1-B signal component. This is realised by transmitting authentication-specific data in previously reserved fields of the E1 I/NAV message. By using these previously reserved fields, OSNMA does not introduce any overlay to the system, thus the OS navigation performance remains untouched.

Authentication is set to further strengthen service robustness by increasing the capability of detecting spoofing events. However, it should be kept in mind that authentication does not prevent the occurrence of such an event, and does not protect against jamming. Nonetheless, this added layer of protection proposes to be one step ahead of evolving technological trends by amplifying the service’s overall robustness and resilience.

Analytical information can be found in the Info Note that was recently published.

You can download it here or visit the European GNSS Service Centre

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Updated: May 16, 2023