Winning the defence technology arms race with acoustic sensors

Information about adversaries is essential in modern military operations, and in this context, acoustic sensors represent a valuable tool.

Defence forces and companies within the defence industry worldwide have intensified their pursuit of technological advancements. Adding to this, the Russo-Ukrainian war has accelerated this pursuit, as national and international defence organisations now rush to enhance their battlefield intelligence capabilities.

A central component to winning this arms race comprises various sensors that support information gathering. Among the most important components are acoustic sensors, which are configured to detect and record sound waves.

Monitoring the market closely

One of the key applications for acoustic sensors is in the detection of hostile drones. As the drone industry evolves rapidly, it is important to monitor developments in the acoustic sensor market closely. Ole Hestbæk Sønderup, Technical Case Officer at the Fires and Sensors Capability Centre within the Danish Ministry of Defence Acquisition and Logistics Organisation, therefore, actively tracks advancements in this field.

We have increased our monitoring of the market and review our options more frequently. We have certainly become aware of more suppliers than we had just six months ago, he says. 

As the organisation responsible for equipment and procurement, FMI conducts ongoing market assessments. Staying informed about technological advancements enables a comprehensive understanding of current possibilities and provides insight into the latest available equipment. This knowledge can be effectively utilised when addressing operational requirements.

A versatile technology

Acoustic sensors are microphones that detect sound waves, thereby, identify hostile activity, including vessels and projectile launch points. Ole Hestbæk Sønderup highlights two factors that make acoustic sensors particularly interesting.

There are two clear advantages to acoustic sensors. The first is that they are passive, meaning they do not emit any electrical signals and, therefore, cannot be detected by the enemy. The second is that they are inexpensive, enabling them to be deployed on a large scale, he explains.

Their low cost and invisibility to the enemy make them a powerful source of data collection, especially when used in combination with other, more expensive sensor systems.

Four applications of acoustic sensors

1) Gunfire detection systems are designed to register, identify and report discharge, acoustic sensors, can therefore: Confirm, that you are under fire, determine the direction of the incoming fire, and establish the distance to the shooter.

2) As with gunfire detection, acoustic sensors can utilise sound waves to pinpoint artillery and mortar launch points and thereby their positions.

3) In addition to locating hostile artillery and mortar fire, acoustic sensors can record and locate projectile impacts from, for instance, artillery systems during exercises. This is useful in terms of mitigating friendly fire.

4) Following the same principles as with gunfire and artillery detection, acoustic sensors can be installed with their microphones oriented vertically which enables detection of aerial drones.

Sensors gaining ground

In the competition for the high ground, passive acoustic sensors provide an obvious advantage. However, the demand for new technology is driving an accelerated development of all sensor types, both active and passive. This is the view of Thomas Galasz Nielsen, Head of the Institute for Military Technology at the Defence Academy.

 Sensors play a central role in a modern defence force. They help us gather data on all fronts, and the more we know, the better we can assess the resources needed for a given task, he explains.

Acting vs reacting

The significance of comprehensive and efficient data collection cannot be overstated. The key consideration, however, concerns the speed at which data can be transformed into actionable insights, notes Thomas Galasz Nielsen.

Data is everything, especially when we can process it faster than the enemy. Being the quickest to turn data into knowledge grants you the lead. You can be the acting party, while the enemy is forced to react.

It is particularly in the context of data processing that quantum computers and other quantum technologies are expected to play a decisive role. You can read more about the significance of quantum technology for the defence of the future here.

 Detecting drones and artillery is the future

Gunfire detection, localisation of enemy artillery, registering impacts during exercises, and drone detection are the four main areas where acoustic sensors are used. Looking ahead, Ole Hestbæk Sønderup predicts that acoustic sensors will become particularly important for detecting artillery and drones.

I expect that acoustics will play a greater role in locating artillery and detecting drones. We have seen how the war in Ukraine has accelerated the development and use of drones, and with that comes a natural need to detect them more effectively, he says.

The technological frontier

In wars and conflicts, technology has always had to provide new solutions to gather more and better information about the enemy, giving an advantage on the battlefield. From scouts, messengers, and smoke signals in the earliest times to radio, radar, aerial reconnaissance, and satellites, this is nothing new, emphasises Thomas Galasz Nielsen. What has changed is the speed at which new and existing technologies are developed and implemented.

We find ourselves in a time where the focus is increasingly placed on the technological race rather than gunpowder and bullets. It has always been crucial to have more and better intelligence than the enemy, but today this is achieved by staying at the forefront of technological development, and sensors play a decisive role in that, he concludes.