OSNMA Anti-Spoofing GNSS Receivers
OSNMA anti-spoofing lets a receiver confirm that Galileo navigation data really comes from Galileo. Eview mosaic-X5 receivers (HB6, HB56, HB62) and mosaic-G5 receivers (HB50, HB52, HBEV11) support it, powered by Septentrio modules, and layer it with AIM+ signal checks to catch spoofing and replay attacks.
Ask a quote See OSNMA receiversHow OSNMA authenticates Galileo signals
OSNMA at a glance
| Item | Detail |
|---|---|
| Service status | Initial Service declared operational on 24 July 2025 |
| Signal | Galileo E1-B, I/NAV navigation message |
| Protocol | TESLA (timed, delayed key release) |
| Keys | Root key signed with ECDSA P-256 or P-521; receiver stores a Merkle-tree root |
| Cost | Free, part of the Galileo Open Service, no subscription |
| What it authenticates | Galileo navigation data |
| Time to first authenticated fix | A few minutes from a warm start; a cold start can take much longer while keys are retrieved |
| What it does not cover | Meaconing (replay of real signals) is not detected by OSNMA alone; AIM+ signal checks cover this layer |
Source: EUSPA / European GNSS Service Centre. Read how this applies to drones in detecting GNSS spoofing on commercial drones.
Eview receivers with Galileo OSNMA
| Product | Best for | Key specs |
|---|---|---|
| HB6 | Lightweight UAV and robot RTK | mosaic-X5, 100 Hz, 45 g, USB-C, microSD, 4.5–12 V |
| HB56 | Flange-mount installations | mosaic-X5, metal housing, SD logging, 100 Hz |
| HB62 base | Authenticated RTK base stations | mosaic-X5, NTRIP, Ethernet, 64 GB logging, IP67, 9–36 V |
| HB50 | Low-power, compact platforms | mosaic-G5 P3, 59 × 44 × 12 mm, 50 g, 0.44 W, 20 Hz |
| HB50H | Compact heading with OSNMA | mosaic-G5 P3H, dual-antenna heading, 0.60 W |
| HB52 / HB52H | Ultralight drones and robots | mosaic-G5, 48 × 35 × 12.6 mm, USB-C, microSD; HB52H heading |
| HBEV11 smart antenna | Base or rover with one cable | mosaic-G5, one M12 cable, Galileo HAS |
All products are quote-based. For a complete datasheet, email sales@gnss-solutions.com. OSNMA is not available on mosaic-H products (HB6 Pro, HB56H). Browse all box receivers and smart antennas.
Where OSNMA anti-spoofing helps
How to use OSNMA
OSNMA anti-spoofing: frequently asked questions
OSNMA (Open Service Navigation Message Authentication) adds cryptographic tags to the Galileo E1-B navigation message. Using the TESLA protocol and an ECDSA-signed root key, the receiver checks that the navigation data came from Galileo. A spoofer cannot create valid tags, so forged Galileo data is rejected.
It does not change positioning accuracy, because it checks the navigation data rather than the measurements. The first authenticated fix takes a few minutes from a warm start, and a cold start can take much longer while keys are retrieved. The receiver can position while authentication completes.
No. OSNMA is free and part of the Galileo Open Service. The Initial Service was declared operational on 24 July 2025. You only need a receiver that supports it, such as Eview mosaic-X5 and mosaic-G5 products.
Not by itself. Meaconing replays real, authentic signals with a delay, so the tags are still valid. That is why Eview receivers layer OSNMA with AIM+ signal-consistency checks on timing, Doppler, geometry, frequencies and constellations.
OSNMA authenticates Galileo navigation data with cryptography. AIM+ is Septentrio’s signal processing that removes jamming and checks signals for spoofing. Used together on mosaic-X5 and mosaic-G5 receivers, they cover more threats than either one alone, including jamming, forged navigation data and replay.
Related reading
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