How Acoustic Detection of Drones Enhances Drone Defense Systems

The most effective drone detection systems are networked and multi-layered, with integrated specialised sensors providing the end-user with a clear and early picture of the threat. Acoustic sensors are a vital part of this.

But designing an effective multi-layered defence network around the unique characteristics of a site requires a niche understanding of the strengths and weaknesses of each sensor type. The integrator must also have a clear understanding of the optimal ways that sensors can best work together to provide the most capable, affordable and scalable protective system possible.

“Integrating different sensor types may sound like a simple concept but ensuring the resulting threat picture is clear and unambiguous will require a certain collection of rare skills-sets,” said Philip Butterworth-Hayes, Editor of Unmanned Airspace.

At Operational Solutions, we believe that every sensor type has a role to play in an effective, layered counter UAS network.

Working alongside other intelligent sensors such as radar or radio frequency (RF) solutions,  systems for acoustic detection of drones can help classify incursion threat levels and inform responses. They can be vital cogs in the machinery which help C-UAS teams understand the intent of the rogue drone operators and take early mitigating actions.

Read on to learn more.

What are acoustic sensors?

Acoustic sensors equip security teams with the additional intelligence needed to begin coordinating effective proactive responses. They can accurately determine the direction of drone threats, identify drones that might be operating without RF signal communications, or locate drones in complex environments, such as in urban areas.

Acoustic sensors use precision audio capture technology to detect the unique sound signature of a UAS – even in complex or noisy acoustic environments., Acoustic sensors operate ‘passively’, which is critical for avoiding acoustic detection when deployed in hostile situations.

There are a wide range of acoustic sensor types, including:

Omnidirectional sensors – capable of detecting signatures on a 360-degree basis;

Long-range sensors – can reach a coverage of more than 10x the traditional detection capabilities area.

As these sensors don’t have to rely on identifying encrypted RF signals, they are effective at identifying potential threats in almost any environment.

However acoustic sensors also have their limitations. Relying on sound detection they have a limited range capability and are prone to being obscured by other signals. In complex sites such as airports, many other acoustic sources can mask and disrupt important audio signatures. These include, but aren’t limited to:

• Wind noise
• Road vehicles
• Aircraft engine noise
• Sirens or alarms
• Birds
• Environmental sounds
• Airport personnel comms

Why Use An Acoustic Sensor Against Drones?

Acoustic sensors can detect both manually controlled and autonomous drones. When combined with radar, cameras, and radio frequency detectors, they can close a critical gap in your drone system defences.

These sensors are also useful in anti-drone technology. This is due to their capacity to identify the acoustic fingerprints left by various types of drones. Unlike radar systems or RF detectors, which depend on optical or electrical signals, acoustic detection of drones is based on the sound made by drone propellers and motors. This makes it especially useful under conditions where drones operate in stealth mode or beyond the standard radar range.

Pros and Cons of Acoustic Sensors Against Drones

Pros

• Passive Detection: Acoustic sensors don’t emit signals. This means drones cannot easily detect or avoid them, allowing you discreet monitoring of drone activity;
• Works in RF-Silent Zones: Acoustic detection is effective even when acoustic drones aren’t transmitting radio frequency signals. Such a feature is perfect for detecting drones operating in stealth mode;
• Real-Time Alerts: These sensors provide instant detection thanks to a microphone array, enabling rapid responses to potential drone threats;
• Cost-Effective: Acoustic sensors are more affordable which makes them a cost-effective option.

Cons

• Acoustic detection has a limited range. This can be very obvious in loud surroundings where drone sounds are difficult to pick up.‍
• Weather-related elements can affect your acoustic sensors. Things such as wind, rain, and harsh weather can all have an impact on the sensors functioning.

The need for a multi-layered security system

Acoustic sensors can be extremely effective in certain environments, but their full potential is truly unlocked when integrated into a multi-layered security ecosystem.

Combined with a cluster of smart sensors and an integrated C2 platform, these sensors play an important role in producing a unified picture of site activity. An optimised ecosystem will effectively align all data and leverage the unique strengths of each tool to enhance overall site security.

Enabling another level of insight

The most immediate advantage of integrating acoustic sensors into a multi-layered security ecosystem is the ability to access another unique level of insight. If drones have been modified to mask their RF signal, RF sensors will be unable to identify the threat. But acoustic signals are extremely difficult to mask. Traditional radars can be very effective at detecting the presence of a flying object, but they can’t classify or identify the object to any great degree. But as each drone type has a unique acoustic signature, acoustic sensors have a clear role to play here.

Generating a unique picture of threat intent

A multi-layered security system also aids in building a distinct picture of intent. Increasing situational awareness helps teams understand if incursions are most likely accidental intrusions or deliberate trespass. Some characteristics used to identify intent include:

• Speed and direction of drone movement
• The inclusion of a payload on the drone vehicle platform
• The deliberate masking of RF signals, or the use of autonomous capabilities

Find out more: Why is understanding site-specific threats important, and how can an integrated C2 platform can help?

Creating multi-layered security solutions for sites of any size

We specialise in creating effective detection solutions for sites in almost any industry. Our deployments incorporate acoustic sensors, AI-enabled optical sensors, RF sensors, radars and more – and we have a niche expertise in ensuring that any bespoke layered ecosystem will deliver a clear picture of threat, no matter how many sensors are added to the network.

This is all integrated into a single C2 platform so teams can reliably respond to incursions with a clear awareness of current threats, regardless of sensor latency.

We help create safer spaces, enabling teams to confidently close the window of vulnerability armed with streamlined intelligence.

To learn more, why not arrange a free discovery call with a member of the OSL team today?