GPS Shielding: How to Reduce Spoofing and Jamming at Sea

Tested improved GPS shield design. The goal: reduce spoofing interference even further and stabilize RaceBox GPS data in high-risk areas.

🔧 What’s new in this version:

Pipe lined with copper mesh inside.
Outer layer originally wrapped in aluminium foil (probably no longer needed).
Added two layers of TitanRF Faraday Fabric over the pipe.
RaceBox GPS unit itself placed on additional TitanRF fabric layers.
GPS case shielded from bottom and sides with TitanRF fabric as well.

📸 (see picture)

From above, you can see the RaceBox GPS mounted inside the shielding pipe.

⚡ Why this matters

Copper mesh inside the pipe → filters incoming signals.
TitanRF Faraday fabric layers → absorb and reduce residual spoofing/jamming.
Bottom + side protection → prevents interference creeping in through weak spots.

This design combines reflection + absorption for stronger spoofing resistance.

RaceBox GPS Without Shield (see picture above)

RaceBox GPS With Shield (see picture above)

On screenshots:

Screenshot @10:32 (28 sats, Accuracy 0.099 m, DOP 0.88, TTFF 0.3 s) = WITHOUT shield
Screenshot @10:25 (20 sats, Accuracy 0.763 m, DOP 1.15, TTFF 6.8 s) = WITH shield

What that means

In this test, the shielded setup showed slightly lower raw performance — fewer satellites in use, higher DOP, and accuracy around 0.8 m instead of 0.1 m. However, this trade-off is acceptable in the shipping industry, where sub-meter accuracy is already more than sufficient. The purpose of shielding is not to maximize open-sky precision but to reduce the effect of intentional spoofing and jamming, which can otherwise cause GPS to jump, freeze, or be lost entirely. By filtering interference, the shield sacrifices a little raw accuracy but helps preserve a stable and usable GPS signal in areas where spoofing would otherwise block it completely.

0.8 m accuracy is still extremely good in the shipping industry. For context:

Standard SOLAS ECDIS performance often works fine with ~10 m accuracy.
Pilot Plug (AIS-based position feeds) can drift several meters.
Even professional PPUs (like TRENZ or Wartsila) rarely get sub-meter precision consistently under tough conditions.

So if your shielded setup holds ~0.8 m even under interference/spoofing, that’s actually a big win: you trade a little bit of raw accuracy for much higher robustness in spoofing zones. For pilotage, what matters most is stability (no crazy jumps in COG/SOG), not squeezing centimeters.

Conclusion:

“Even with shielding, GPS accuracy remains around 0.8 m — more than sufficient for pilotage and well within shipping industry standards.”

Developer of Racebox Injector application