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GNSS signal jamming and spoofing - an underestimated risk?


GNSS signals and time synchronisation

What is GNSS?

In many applications, including time synchronisation, GNSS (Geolocation and Navigation by Satellite System) is now commonplace. The best known constellation is GPS.

However, all these GNSS systems share a common vulnerability: their signals are very weak.

GNSS satellites operate from the Earth’s orbit. The transmitted signal is extremely weak when it reaches the earth’s surface. This low signal strength at the receivers makes GNSS use susceptible to intentional (malicious) or unintentional interference.

Time server - jamming

GNSS jamming

Jamming is the presence of a competing signal that prevents the GNSS receiver from decoding the real satellite signal.

Jamming from other sources of radio transmission can be intentional (malicious) or unintentional.

Unintentional jamming: Radar or communication transmitters, although operating in a different frequency band, may interfere with GNSS reception due to their scattering power.

Intentional jamming: GNSS jammers, although illegal in most countries, are readily available on the Internet. Announced as privacy jammers, they can disable GNSS reception over several kilometres

Time server - spoofing

Signal spoofing

Spoofing is the intentional transmission of fake GNSS signals to divert users from their real position.

Spoofing requires sophisticated equipment to recreate satellite signals. Spoofing is more difficult to detect than jamming.

What solutions to protect against jamming and spoofing?

Jamming is relatively easy to detect, and there are several ways to prevent it. Detecting spoofing is more difficult, especially when using a high quality spoofing equipment.

Bodet offers several solutions to minimise these effects and guarantee optimal synchronisation.

Netsilon Bodet time server - antenna and jamming detection software

Example 1: A robust antenna with software detection

Netsilon Bodet Time Server - Remote multi-site installation

Example 2: Remote multi-site installation

Jamming or spoofing is difficult because of the distance between sites. Synchronisation between servers via private network.

Netsilon Bodet Time Server - Multi-source installation

Example 3: Multi-source installation

The server analyses satellite and radio signals in real time and compares them with its high-performance time base. This way, it can detect any discrepancy.