Airport Drone Mitigation
Part 3: Types of Jammers

In my last post – The Issues with Jamming Drone Frequencies – we started to dig into why jammers may not be the ideal solution to protect airports from rogue drone activity, particularly as jamming the frequencies used by drones could have a detrimental effect on airport operations and nearby businesses and residences.

In this blog, let’s look at the different types of jammers available today and how effective they are.

A Series of Jammers

Radio Frequency (RF) jammers come in many guises and vary from large military-grade multi-sensor jamming systems (costing tens of millions of pounds or dollars) to small, handheld, point-and-shoot jamming guns (costing a few thousand). The characteristics of each vary hugely but, to put into context how they operate, they’re either omnidirectional, directional, or targeted RF energy transmitters:

• Omnidirectional RF jamming transmitters provide 360^o protection around their position, jamming any drones which fly within their effective radial range.
• Directional RF jamming transmitters focus in one direction to provide between 60^o (or sometimes even less) and 120^o of protection, jamming any drones which fly within their effective directional range. These can be fixed to protect known or suspected avenues of approach, or they can be slaved to a radar or optical drone detection system and directed toward the potential drone.
• Targeted RF jamming transmits a much tighter cone of jamming energy, and these are usually found in jamming guns where the operator specifically points the gun to what they believe or know to be a drone, jamming it. It’s important to note that these guns have very limited range (usually an effective range of only a few hundred meters), and a drone can fly at a high enough altitude to avoid such a countermeasure.

As highlighted above, each jammer has its own merits and drawbacks. Now we’ll evaluate just how effective jammers are on drones.

There are four main drawbacks to these jammers:

1. To have any effect at all, a jammer must have direct and unobstructed line of sight with the drone. This is difficult on an airfield with slab sided hangers, terminals, and control towers, – even more so in built-up urban residential and industrial areas, and compounded over longer distances with a greater number of obstacles.
2. If we employ the targeted jammer option, a complex cat-and-mouse chase occurs, taking time and labour. This chase is very visible and noticeable to passengers and the public, potentially causing panic and distraction as a jammer gun looks like err, a gun!
3. Airports may possibly need to turn off any systems that may be affected, grounding and stopping all aircraft from moving before jamming commences, and then keeping aircraft grounded and stationary until the threat subsides. Operating the jammer on a lower power to prevent such interruption to the airfield and aircraft operation could notably limit its range, making it ineffective in many risky scenarios.
4. Once disconnected from the drone operator, the drone could fly out of control, or fly a pre-programmed flight path. It could fly into the take-off or landing path, possibly hitting aircraft or facilities, or crash or force-land, potentially causing damage to property or injury to the public.

In essence, RF jammers can be effective, and may be suitable for a remote location with plenty of land surrounding the facility and nothing to damage. But for a busy airport, it’s not so simple. They could possibly work if they’re positioned well and there’s a well-trained and responsive QRF. However, the impact to airport operations could last for hours or days, and that’s unpalatable to an airport with time-critical airline schedules.

In the next blog post – Drone Jamming Effectiveness at Airports – we will go deeper into jammer drawbacks.