For low-level airspace managers seeking to develop uncrewed air system traffic management (UTM) or U-space eco-systems in which drones and electric vertical take-off and landing aircraft (eVTOLs) can fly beyond-visual-line-of-sight (BVLOS) safely there has been a rather large elephant in the room for many years. To wit, how can they ensure that drones and electric aircraft in their airspace are fully authorised and not under the control of the clueless, the careless, the criminal or, worst of all, the terrorist? This technical and institutional challenge requires integrating into airspace management a counter uncrewed air system (C-UAS) that can detect rogue, unco-operative UAS operations at an early stage and mitigate the problem.
There are more than 300 C-UAS companies worldwide such systems, but as each UTM/U-space geo-zone is unique, most of them will not be compatible in terms of effectiveness or affordability. For example, a UTM/U-space area which overlaps a security critical geo-zone such as an airport, seaport or prison may require a different level of detection and mitigation technologies than a more rural-based geo-zone.
The ideal C-UAS solution is ‘layered’, which means it employs a number of sensors – radar, RF detection, acoustic, optical – and integrates information from these sensors into a command-andcontrol system that gives the operator the earliest possible warning of the threat, identifying intent and selecting an optimum mitigation system: RF jamming and/or message spoofing, cyber takeover, a laser weapon, kinetic response drone, a net capture system, a small missile or a gun. And it will need to be scalable, as drone threats evolve and new sensors and mitigation measures are needed.
The cost of installing such a layered C-UAS solution that offers at least 95% effectiveness against all drone threats has traditionally run into the millions. According to a recent report from Statistica: “The civilian C-UAS hardware costs $5 million for municipal airspace customers, with an annual subscription cost of $1.7 million in 2020.”
UTM/U-space geo-zone managers also face other hurdles. At present, their job ends with detecting the presence of rogue drones and it is up to national security agencies to deploy appropriate mitigation measures. So there is a disconnect between the agencies responsible for securing low level airspace operations and often a lack of clarity over their roles and responsibilities.
However, the problem may not be quite as large as many once feared. New rules, new technologies and a new understanding of the risks involved are starting to make this challenge far more manageable. Over the last few months, the first integrated UTM/counter drone systems have entered the market, providing a new resource for UTM/Uspace service providers to cope with the issue in more affordable, efficient and scalable ways. And new ownership models have also started to appear, providing geo-zone managers with the option to subscribe to cloud-based services rather than pay directly for expensive hardware.
The nature of the threat
At the heart of the challenge is an understanding of the nature of the threat. Although the number of rogue drone incursions is on the rise - Norway’s airport owner, Avinor reported 50 drone incursions per month at Oslo airport alone during 2022 – the overwhelming majority of these are from commercially-available drones flown by amateurs or petty criminals. In other words, most UTM eco-system managers will not have to invest in deep-layered defence networks to provide protection against military-grade and autonomous drone attacks designed to avoid detection. At least, not yet.
Commercial drones still offer a considerable threat to UTM/U-space geozone managers. According to 2020 RAND Corporation report Small Unmanned Aerial System Adversary Capabilities: “Overall, the commercial small UAS market has been moving toward smaller, lighter and more-difficult-to-detect systems. There have also been notable increases in speed, range and endurance and decreases in acoustic signatures. Certain sUAS models have adequate payload capacity to carry a significant amount of explosive material or illicit goods.” However, because they transmit command-and-control and telemetry data over radio frequency (RF) ranges, they can be relatively easily detected.
Initial measures
The first line of defence is the mandated equipping of all commercial drones with remote identification systems, which give security agencies an indication of the drone’s serial/registration number, geographical position and location of the ground control station. In Japan, remote IDs have been mandated since June 2022, while in the US the deadline from the Federal Aviation Administration (FAA) to fit IDs to drones is September 16, 2023, and in the European Union from January 1, 2024, although there are some regional differences in the information sets that each regulator requires.
“The existing air traffic system and surveillance infrastructure that's been in place for decades to monitor manned aircraft was not designed for this lowaltitude mission over cities, where we'll have to monitor potentially hundreds of drones and urban air mobility vehicles,” said Jeff Cole, CEO of US-based urban C-UAS company Hidden Level. “The FAA's remote ID requirement helps, but there are gaps. Remote ID is meant to be like an identifiable license plate and a transmission of where a drone is located. However, remote ID signals can be spoofed or simply not transmitted, introducing a need for verification.”
In early 2023, a number of new integrated UTM/counter-UAS and cloud-based technologies have appeared on the market to meet the challenge of the second line of rogue drone defence: detection systems which, alongside the UTM system, can track both co-operative and non-co-operative drones.
“Just as air navigation service providers needed to invest not only in an ATM system – including flight planning – but also in a flight tracking system through mainly co-operative detection technologies (Mode-S radar and ADS-B, for example), we’ll be obliged to do the same as a U-space service provider,” said Hendrik- Jan Van Der Gucht, managing director of Belgian UTM company SkeyDrone. “A risk assessment will determine where additional building blocks will be needed to manage safety and security risks induced by unauthorised and nonco- operative drones. Our integrated co-operative/non-cooperative drone detection system integrates with operational UTM systems, so safety and security managers can focus on the high risk, unauthorised drone flights.”
SkeyDrone solutions
In February 2023, SkeyDrone launched its Radar Pro with a C-UAS hardware partner to build an RF-signal based detection system which is fully integrated within the UTM/U-space eco-system. As head of sales Didier Decaestecker explained: “You need a detection network that can identify and track drones and our system, which is a pre-U-space services offering to both the geo-zone and the drone operator, not only detects co-operative and non-cooperative drones, but integrates the flight authorisations from the UTM system, so that the security guard or geo-zone manager can immediately see which drone has received prior authorisation and which has not.”
In April 2023, Dedrone launched its City-Wide Drone Detection solution, available in 40 major cities across the globe. It is entirely cloud-based and available on the web and via the App Store and Google Play for both fixed-site and on-the-move monitoring. “Dedrone's City-Wide drone detection solution is an example of how easy it is to get started with counter-drone technology,” said chief marketing officer, Mary-Lou Smulders. “The system uses existing infrastructure and monitors multiple drones and geographical areas at once with a streamlined alerting system that provides a notification with a pilot’s location and drone-specific data as soon as an alert zone is breached. It's easy to further augment City-Wide with additional tools, such as cameras or radars for enhanced airspace security.”
The advantages of this new generation of remote, cloud-based C-UAS system-as-a-service offerings are that they are more affordable, scalable and far more flexible than before. Using artificial intelligence (AI) technology they can quickly identify the drone type (based on a known library of commercially available drones) and operator position, and by modelling its behaviour, classify the type of threat it offers. New sensors can be added to the network quickly to ensure it evolves to stay ahead of future threats.
Hidden Level
“At Hidden Level, we build multipurpose sensing technology to address markets such as drone and manned aircraft detection,” said CEO Jeff Cole. “Most commercial applications utilise our data as a service model, where we deploy our sensor technology onto existing infrastructure to create coverage that can be expanded by layering on additional sensors. We own and operate the hardware, removing cost and maintenance burden from customers. Multiple users can subscribe to the same network, which creates a common operating picture and is cost effective.”
As for having to spend $5 million for a municipal airspace C-UAS system, that may have been the case for 2020 but, since then, costs have reduced considerably. In February 2023, the UK’s Operational Solutions Ltd, which implemented its C-UAS system at London Heathrow, released its Drone Alert Service (DAS), a hardware-free intuitive detection system available through a range of subscription-based offerings, so users can be alerted to drone activity in their perimeter and view three years’ worth of historic data, with subscriptions starting at just £24 per day. Nevertheless, technical challenges remain. Integrating C-UAS and UTM systems can be a major challenge, as is the requirement to add new sensors to stay ahead of the threat. Potentially, an even larger challenge is how to deal with a rogue drone once it has been detected. This requires a range of technical and institutional solutions where the technological challenges are proving less formidable than the institutional ones.
Broadly speaking, AI-based library classification systems are understood to work well for civil installations whereas, on the battlefield, other technologies will be required to detect non-commercial drones. Each mitigation technology type has its own strengths and weaknesses, and in a layered network these weaknesses can be reduced by introducing complementary technologies. But relatively new concepts such as ‘cyber takedown’ have emerged as effective and precise methods of disabling rogue drones by seizing control and landing the drone or returning it to its take-off position. This is particularly useful in environments around airports, where jamming or spoofing communications systems are not permitted.
Taking responsibility
Governments are finally addressing the issue of who should be responsible for dealing with a rogue drone once it has been detected. In Europe, the EC’s C-UAS package is taking shape, supported by its Joint Research Centres in Belgium and Italy. This envisages the creation of a digital drone incident platform, including classified data that can be shared by authorised EU users, establishing a methodology for testing and assessing C-UAS systems, compiling an annual report on C-UAS technical developments and supplying risk assessments of mitigation strategies. Separately, the European Aviation Safety Agency (EASA) is due to publish its own proposals for C-UAS detection and mitigation measures.
In the US, in March 2023 the FAA published its Counter-Unmanned Aircraft Systems Interagency Coordination Process report, which explains how the Departments of Defense (DOD), Energy (DOE), Justice (DOJ) and Homeland Security (DHS) would develop a co-ordinated response to C-UAS challenges. According to the conclusion of the report: “These five agencies spent eight months developing the building blocks, roadmaps and objective standards for the use of UAS detection and mitigation systems. During this time, they overcame several challenges, including determining the extent to which UAS detection and mitigation systems could interfere with the NAS and what processes were needed to standardise the co-ordination process.” The FAA’s National Security Programs and Incident Response department is also testing drone detection technology at Atlantic City Airport.
Potential UTM/U-space service providers are not waiting for the regulators to develop granular rules for UTM/C-UAS integrated service deployment, but are becoming proactive. “If you look at U-space service provision from a business standpoint, there is not much of a business case for the services we are legally obliged to provide,” said Hendrik-Jan Van Der Gucht. “So we are looking at value added services and this is may be one of the highest value ranking services we can provide.”
Article originally published in Air Traffic Management magazine, issue 2, 2023. Want to receive all of the latest stories as soon as they are published? Register now for your free digital subscription.
