GPS Jamming Protection for Drones and Farm Machines: Signs, Checks and Fixes

Updated November 2026

Short answer: GPS jamming protection means three things working together — a receiver that can filter interference instead of losing lock, a multi-band antenna that keeps tracking when one frequency is hit, and logs that prove what happened. You cannot stop interference reaching the antenna. You can stop it reaching the position solution, and you can tell the difference between interference and a hardware fault before you replace parts.

Interference on civil sites is now ordinary rather than exotic. Drones lose fix near roadworks and port gates, tractors drop RTK beside a new cellular mast, and inspection aircraft see signal levels collapse over the same substation every flight. In most of those cases the receiver is not broken and the antenna is not faulty. The receiver is being asked to track signals that are no longer clean, and the outcome depends on how it handles that.

Is it jamming or a fault? The signs

The pattern of the loss tells you more than the loss itself. A hardware fault is usually gradual, permanent or random; interference is usually sudden, repeatable and location-specific.

• All satellites lost at once. A receiver that goes from 24 satellites to 4 in two seconds has not developed a hardware fault. Tracking that collapses across every constellation simultaneously is the signature of broadband interference.
• Signal strength drops in a specific place. If C/N0 falls as you approach a road junction, a site gate or a mast and recovers as you leave, that is a local source, not a receiver problem.
• The same failure at the same place or time. Repeatability is the strongest evidence. Log the position and time of each event; three events in the same 50 m radius is a confirmed pattern.
• Loss of RTK fix before loss of position. Corrections and carrier phase fail before the standalone solution does, so the fix drops from RTK to float to standalone in sequence. That progression is normal behaviour under a degrading signal, not a correction service failure.
• Position jumps while the fix looks healthy. A sudden offset with strong signals and no loss of lock points at spoofing rather than jamming — the receiver is tracking something that is not the constellation.
• Nothing at all, on one vehicle only. If a second machine in the same place works normally, the problem is on the first machine: cabling, connector, antenna or power.

For the underlying mechanisms, see our anti-jamming GNSS technology page.

How to confirm interference

Do not replace hardware on a suspicion. Confirm from the receiver first — every professional receiver records enough to settle the question.

1. Open the spectrum view. Receivers with interference monitoring show the RF spectrum around the GNSS bands and an interference indicator. A raised noise floor in one band, or across several, is direct evidence. This is the single most useful diagnostic and it takes a minute.
2. Log raw data during the event. Record SBF or RINEX with the receiver’s own logging while you repeat the route. An HB56 or HB56H writes to an SD card on board, so the record survives the flight or the shift even if the link to the controller drops.
3. Compare per-band and per-constellation. Interference that kills only L1 tells you the source is narrowband. Everything at once tells you it is wideband or close.
4. Reproduce it with a second receiver. Two receivers, one antenna location, same time: if both fail, the environment is the cause. If one fails, the fault is in that receiver’s chain.
5. Check the machine before the sky. Disconnect non-essential electronics one at a time — video transmitter, cellular modem, DC-DC converter. On-board interference is more common than most operators expect, and it is the cheapest thing to fix.

What actually helps

Multi-band, multi-constellation tracking

Interference rarely covers every GNSS frequency at once. A receiver tracking GPS L1, L2 and L5, Galileo E1, E5a, E5b and E6, GLONASS L1, L2 and L3, BeiDou B1, B2 and B3, plus L-band, has far more signals to fall back on than one that only sees L1. When a source takes out L1, the receiver continues on L2 and L5 and often keeps a usable fix. That redundancy is the first layer of protection and it comes from the antenna and receiver together, not from the receiver alone.

Interference filtering (AIM+)

Septentrio’s AIM+ monitors the RF input, detects narrowband and wideband interference, and filters it before the signal reaches the tracking loops. That order matters: once a tracking loop has lost lock, filtering afterwards cannot recover the measurements. AIM+ is specified to suppress interference by up to 60 dB, which is the difference between a fix that degrades gracefully and one that disappears. Every Eview receiver carries it — it is part of the module, not an option.

Antenna placement and shielding

The antenna is where the physics is decided. Three rules cover most installations:

• Separate the GNSS antenna from every transmitter on the machine. Cellular modems, video links and telemetry radios are the usual offenders. Distance and a metal ground plane between them do more than any cable accessory.
• Give the antenna a proper ground plane. A flat metal surface under the antenna stabilises the radiation pattern and reduces the amount of interference reaching the element from below.
• Mount it where the sky is. Roof, mast or airframe top, clear of the fuselage and of anything that shadows more than a few degrees of elevation. An antenna that can only see half the sky has half the redundancy.

The EV288 for machines and the EV108 for drones are full-band designs with out-of-band suppression, so the antenna rejects some of what the receiver would otherwise have to filter.

Spoofing checks with Galileo OSNMA

Jamming removes signals; spoofing replaces them with false ones, and the second is harder to notice because the receiver looks healthy. Galileo OSNMA (Open Service Navigation Message Authentication) lets the receiver verify that Galileo navigation data is authentic and unaltered. A receiver with OSNMA enabled flags signals that fail authentication, which turns an invisible attack into a logged event. Our guide to OSNMA anti-spoofing covers how the keys and the authentication chain work, and anti-jamming vs anti-spoofing explains why the two problems need different responses.

What doesn’t help

• A bigger antenna on its own. Gain helps with weak signals, not with a strong local source. A high-gain antenna can make overload worse.
• Disabling constellations. Turning off Galileo or BeiDou reduces the signals available and removes the redundancy that keeps you working through a narrowband event.
• Ferrites and filters bought by description. A filter that covers one band does nothing for a source in another. If you cannot state the band it rejects, it is not a solution.
• Assuming a firmware update fixes it. Firmware improves how interference is handled; it does not change the RF environment around the antenna.
• Moving a few metres and calling it solved. If relocation works, that is evidence of a local source — record the position and report it, because the next vehicle will hit the same place.

Which Eview receiver for your machine

All of them are powered by Septentrio and share the same interference handling, so the choice is about mounting, update rate and whether you need heading. For a wider comparison of receiver classes, see our guide to the best anti-jamming GNSS receiver, and for airborne platforms the notes on anti-jamming GNSS on enterprise drones.

Frequently asked questions

How do I know if my drone’s GPS is being jammed?

The usual sign is a sudden loss of most satellites at once, in a place where the drone worked before, with recovery after moving away. If the receiver logs show a raised noise floor and dropping C/N0 across bands, it is interference rather than a fault.

Can an anti-jamming receiver keep RTK working?

Often, yes, at reduced range and with degraded quality. AIM+ filtering removes a large part of the interference before tracking, so the receiver holds lock instead of dropping to standalone. When the source is strong enough or close enough, no receiver keeps RTK — but the position degrades in steps rather than disappearing.

What is the difference between jamming and spoofing?

Jamming overwhelms the signal so the receiver loses it — obvious, because satellites vanish. Spoofing transmits false signals that the receiver accepts, so the fix looks healthy while the position is wrong. Jamming is a loss of availability; spoofing is a loss of integrity.

What is Galileo OSNMA?

Open Service Navigation Message Authentication. Galileo broadcasts cryptographic material that lets a receiver verify the navigation data it receives is genuine and unaltered. A receiver with OSNMA enabled can flag spoofed signals instead of trusting them.

Which antenna is best against GPS interference?

A full-band antenna with good out-of-band rejection and a proper ground plane, mounted as far as possible from every transmitter on the machine. Antenna choice helps, but placement and separation from on-board radios usually matter more than the antenna model.

Talk to us about your site

If you can tell us where the fix drops, which bands disappear and what else transmits on the machine, we can tell you whether the answer is a different receiver, a different antenna position or a logging setup to prove the case. Send the location, the platform and any receiver logs you already have.

Email sales@gnss-solutions.com with your platform and the location where the problem occurs.