Quantum sensing is improving situational awareness for defense and military operations

In today's era of evolving security threats and the relentless pursuit of technological superiority through the adoption of novel deep technology ventures, the convergence of quantum science and military applications has become a pivotal moment in the defense sector.

Traditionally, the defense sector has been considered an early adopter of new technology trends, in this case the so-called quantum 2.0 technologies (defined as technologies that exploit and explore the nuances of quantum mechanics). However, due to the high rate of adoption and financial investment by the commercial sector, government and defense end-users are at risk of being left behind, which is a huge risk for the field, but also for other countries that are accelerating the development of the field.

The groundbreaking field of quantum sensing, a transformative technology, promises to revolutionize situational awareness in defense and military operations. In the course of our exploration, we will reveal the promise of quantum sensing: a field where accuracy, sensitivity, and detection capabilities will reach unprecedented heights, ushering in a new era of sensing paradigms and sensor overmatch.

Evolution of military situational awareness

Before delving into quantum sensing, it is critical to understand the importance of situational awareness in defense and military operations. Historically, effective situational awareness has been a cornerstone of military success, providing the ability to understand the environment, anticipate threats, and respond decisively. Traditionally, this situational awareness has been decentralized through radar systems, satellite imagery, and other means such as infrared. More recently, with increased computing power and the emergence of multiple sensors, the battlefield has become increasingly interconnected, fusing sensor data through a variety of platforms and relying on critical communications infrastructure. This is vulnerable to interference or loss of coverage.

However, the advent of quantum sensing promises to elevate situational awareness to unprecedented levels. When we consider the evolution of situational awareness, it becomes clear that the contemporary threat environment is characterized by complexity and requires advanced solutions. Traditional sensors, while valuable, are often limited in terms of accuracy, sensitivity, and range. However, quantum sensing promises to provide new and, more importantly, resilient capabilities, such as navigation using cold atom-based systems in the powerful PNT domain, thereby reducing reliance on GPS.

How to realize quantum sensing

To grasp the transformative potential of quantum sensing, it is important to understand its underlying principles. At its core, quantum sensing utilizes the unique properties of quantum mechanics, particularly superposition and entanglement. While these concepts are discussed in detail in many other sources, when summarized, it is possible to gain an advantage by utilizing aspects of quantum mechanics. This is not without risk, however, as the adoption of new technologies requires specialized systems engineering to create a robust system that can be deployed in land, sea, and air environments.

There are various technological paradigms for realizing quantum sensing, which can be summarized as follows:

- Superconducting circuits

Superconducting circuits for sensing applications are often considered superconducting quantum interference devices (SQUIDs). Although these devices rely on cryogenic cooling, they have become the basis for some of the most sensitive magnetometers available today. 

SQUIDs are often overlooked as quantum sensors because they predate their development, but they are still interesting. They are also a pioneering example of how quantum sensors can create entirely new and advanced applications, such as magnetoencephalography (MEG).

- Atoms and Ions

Atoms and ions offer a wide range of possibilities for forming quantum systems for sensing applications. Atoms can be contained in atomic vapor cells or magneto-optical traps (MOTs); ions can be contained in RF traps. Quantum sensors based on atomic vapor cells are already in commercial use in compact atomic clocks and optical pump magnetometers (OPMs).

In these applications, MOTs and RF traps will compete with atomic evaporation cells and form a new generation of broadband RF sensors based on so-called Rydberg states.

A key technology for sensing and communication is based on timing and clocks. Without sensitive clocks, the Global Positioning System (GPS) cannot function properly. The quest for better clocks illustrates the opportunities unleashed when components are miniaturized and rugged enough to be deployed outside the lab. Clocks also illustrate the interplay between quantum sensing and modern metrological reference standards, as well as the subtle advantages in avoiding external calibration. Advanced clocks, especially optical clocks, hold the promise of improving GPS sensitivity and, when combined with other areas of quantum technology, can provide new navigation modes that reduce reliance on external GPS and enable platforms to navigate in environments free of GPS interference.

In addition, MOT enables a completely new form of sensing based on atomic interferometry, which is particularly promising for sensing gravity and acceleration.

- NV Diamond

NV diamonds highlight a new trade-off between performance and environment for quantum sensors. Their development is a good example of how advances in materials science and manufacturing technology can lay the foundation for a new generation of sensors. This could have implications for the RF field through the fabrication of ultra-stable RF oscillators for radar applications.

- Photonics

Photonics is already a large and diverse field of technology. Existing sensing categories range from basic process control to high-performance ring laser gyroscopes and lidar systems. Quantum photonics technologies are expanding on traditional photonics. These technologies allow us to use single photons to provide higher sensitivity and enhanced resolution for time-of-flight applications.

In more advanced applications, we can expect to use entangled photons and unique "squeezed" light states in the future; these provide a way to further radically improve signal resolution and sensitivity.

Photonics is of central importance not only as a sensing platform, but also for its ubiquitous role in the control and readout of other quantum systems, and for the prospects it offers for coherent quantum networks.

Specific defense applications and technical challenges

The applications of quantum sensing in defense and military operations are vast, but not without challenges. From identifying stealthy submarines to early warning of ballistic missile launches, quantum sensors promise to enhance detection and tracking capabilities in a variety of fields. In addition, they offer significant advantages in the areas of navigation, communications and cybersecurity.

In the area of navigation, quantum gyroscopes and accelerometers can provide ultra-precise measurements that can improve guidance systems in environments where the Global Positioning System (GPS) has failed.

In the field of field-deployable medical technology, optically pumped magnetometers (OPM) are an interesting alternative to cryogenic MEG systems such as magnetic resonance imaging. The idea of field-deployable, wearable MRI systems has some interesting implications for frontline head injury assessment.

Another area of particular interest to the US (ARL) is RF sensing, with work currently underway in the so-called Rydberg Atom field to generate ultra-wideband RF sensors. In particular, BAE and Infineon aim to develop a 1 cm3 sensor capable of sensing signals from 10 MHz to 40 Ghz; Infineon's Maxwell RF sensor platform has been successfully demonstrated in 2022 with a sensitivity of 10 nV/cm/√Hz in the SHF band.

Gravity sensing (both absolute gravity sensing and gravity gradient sensing) is also an area of technology that promises to have a disruptive impact in sensing. Changes in the gravity gradient can be detected using cold atom systems, thus enabling sensors to detect voids. In the defense sector, this technology is being used to detect air pockets underwater, which could have implications for submarine detection, improvised explosive devices, and underground tunnel detection. This technology is being developed globally through a variety of projects and requires further engagement from defense customers to ensure engineering and optimization of sensor deployment platforms.

While the potential of quantum sensing is promising, it is important to recognize the challenges that must be overcome for its widespread application. These challenges include temperature sensitivity, noise, and the need for a secure, easy-to-understand supply chain for quantum components. Researchers and defense agencies are actively working to address these obstacles to ensure the practical viability of quantum sensing technology. These technology providers and defense customers must be engaged to discover a wide range of use cases; the defense field is complex and sensors can be deployed on many types of platforms.

In the case of an atomic clock used for timekeeping, for example, the engineering requirements for SWAP-C may vary if the sensor is deployed on a fast jet platform, a space platform, a land-based radar unit, or a submarine.

In each of these cases, careful consideration will be required to ensure that the associated system engineering is maximized while maintaining the versatility of the sensor for each use case.

Quantum Sensing Technology a Watershed for Military Situational Awareness

The emergence of quantum sensing technology is a watershed moment in the field of military situational awareness. It has the potential to revolutionize the way we detect and respond to threats, enhancing the security of nations and militaries around the world. However, this transformative journey is not without challenges and ethical considerations.

As we explore this uncharted territory, it is imperative that governments, researchers and policymakers work together to realize the full potential of quantum sensing, and in particular to ensure that defence customers and end-users are actively engaged in the field in order to understand the capabilities and limitations of quantum sensing, and that vendors are aware of the operational environments and requirements for deploying their systems in this area.