U.S. Defense Is Developing Quantum Sensors to Replace GPS

Researchers in government and industrial laboratories around the globe are scrambling to improve technologies and methods to detect changes in motion, electric and magnetic fields at the atomic level.

 

The discovery that small changes in the known properties of atoms can produce extremely precise and accurate measurements is a technique known as quantum sensing.

 

While quantum sensing technology is suitable for a wide variety of applications, quantum sensing technology for navigation is the area of greatest interest to the Pentagon. U.S. warfighters often train in environments where GPS signals are blocked because of the growing realization that technologically advanced "U.S. adversaries" such as China or Russia could disrupt or disable the GPS signals that U.S. forces rely on.

 

 

So much of modern life depends on GPS that some estimate the global economy would lose more than a billion dollars a day in the event of a malfunction - an explanation that is not too far-fetched: Russia is jamming GPS satellite signals in Ukraine during the recent Russia-Ukraine war, and U.S. stealth drones have been hacked and captured in Iran by spoofing their GPS coordinates. spoofing their GPS coordinates to capture them; and by solar flares.

 

At its core, however, GPS is a timekeeping system; and quantum technology is leading a revolution in this technology.

 

Work done by Roger Easton, a research physicist at the Naval Research Laboratory (NRL), laid the groundwork for GPS and led to the launch of NTS-2, the first satellite to transmit GPS signals, in 1977. Today, Adam Black, head of NRL's Quantum Optics Division, is also applying quantum sensors to inertial navigation, another navigation technique that preceded GPS.

 

Scholars believe that using some of the smallest atomic inertial technologies, it may be possible to achieve these goals in just a few years. "Quantum inertial measurement units could be much smaller than the large stationary devices currently used in laboratories for quantum sensing research and development."

 

Inertial navigation uses accelerometers, gyroscopes, and computers-collectively known as inertial measurement units (IMUs)-to continuously calculate the position, direction, and velocity of a moving object without the need for an external reference. The technology has been used in military aircraft and weapons guidance since the 1960s and was replaced by GPS by the early 1990s.

 

Inertial navigation using quantum sensors is less susceptible to jamming than GPS, and is therefore considered a method of navigating with similar or higher accuracy when GPS is compromised, or unavailable.

 

One of the biggest hurdles to using quantum sensing devices in dynamic environments such as warships, submarines, or airplanes is making them small enough and energy-efficient enough for these platforms. Shrinking the quantum sensors developed to date would also reduce their accuracy and precision, Black explained, adding that this is a "trade-off but also a manageable challenge" that researchers at NRL, the Army and Air Force research labs, and private industry are working to address.

 

In National Defense magazine, Black said, "You can imagine a shoebox of quantum IMUs with accelerometers and gyroscopes inside. Although we're not there yet. But I think it falls under the realm of physics."

 

As part of a new inertial navigation system, he added, quantum IMUs would perform the same functions as classical IMUs, "only with more precision and accuracy provided by the sensors over time."

 

Dr. Gerald Borsuk, associate director of research at the NRL Systems Directorate, said that a new generation of small precision atomic clocks, which are also devices for quantum sensors, could be used to keep time when GPS fails.

 

"If the GPS sensor gets accurate time from another source, it can still be used."

 

Atomic clocks that measure time by monitoring the resonant frequency of atoms have been in use since the 1950s. Miniaturized, high-performance microwave atomic clocks and small optical atomic clocks are interference-resistant quantum sensors that measure time based on optical frequencies in the hundreds of terahertz, which can improve GPS immunity.

 

Black notes, "More advanced optical atomic clocks are now being adopted and engineered to have field-ready package sizes."

 

The development of quantum sensors is often protracted because of the need to build physical prototypes for real-world testing, Black said, adding that the Naval Laboratory and other research groups are applying digital engineering (virtual modeling and simulation) to speed up the process.

 

Black also revealed, "Recently we have been involved in a program with the Office of Naval Research aimed at installing quantum gravimeters on ships."

 

Using an accurate model of ship motion, Black's team at the Naval Research Laboratory built an atomic physics-level model to predict how atoms in a gravimeter (a sensor that measures the acceleration of gravity) would behave in the absence of a large, heavy, stabilizing gimbal.

 

The results show that the gravimeter can function properly as long as knowledge of the sources of error in the gravimeter is incorporated and corrected.

 

"We intend to speed things up." Borsuk concludes, "We have established the Institute for Quantum Science to focus on reducing the risk to industry and applying the results we have created."

 

Quantum technology offers a future full of opportunity, using the behavior of light and atoms to improve areas such as computing, communications security, and sensing. Quantum sensors are highly sensitive to their surroundings and can detect data that would otherwise be impossible or require significant resources to collect. Applications of quantum sensors include detecting gravity, electromagnetic fields, single photons, time, temperature and motion.

 

 

In addition to GPS, here are some areas where quantum sensing has been shown to provide significant enhancements:

 

- MRI for medical imaging

- Spectroscopy (for characterizing materials and chemicals)

- Gas leak detection

- Remote target detection

- Radar systems

- Microscopic imaging

- Gravimeters and magnetometers (for industries such as mining)

- Quantum computing and communications components

 

And all of these applications share a common value proposition: quantum sensors can reduce the cost of sensitivity, selectivity, or efficiency of real-world data collection. Given their wide range of applications in high-value industries, the market is expected to be worth more than $1 billion over the next decade.

 

Currently, quantum sensors have a limited range of applications, but this is rapidly expanding as technology advances.

 

Atomic clocks are the oldest quantum sensing technology. They have been in use for decades and are a fundamental part of our Global Positioning System. Recent developments have enabled several companies, such as Microsemi, to provide atomic clocks for precise timing synchronization in communications and navigation systems. One of the most obvious benefits these systems may offer is greater throughput when transferring data between locations.

 

Latimeters and gravimeters are also quite well established in this field and are now being used commercially and in laboratories to achieve previously unattainable accuracy and reliability in subsurface measurements. Portable commercial gravimeters, offered by companies such as Muquans, allow for higher resolution measurements of smaller/deeper features than traditional alternatives on the market. Several studies have found that cold-atom quantum gravimeters are 1.5-2 times more effective than conventional gravimeters in detecting smaller subsurface features and can measure deeper strata.

 

Magnetometers that utilize nitrogen vacancies in diamond are being developed by companies such as SB Quantum, and have a wide range of applications, including exploration and navigation for mining operations. A recent study published in Nature found that when used for gradient measurements, diamond-based quantum magnetometers offer advantages such as higher sensitivity and more localized, clearer images.

 

 

Quantum sensors can also detect velocity, reflectivity and chemical composition over long distances, with many useful applications. For example, companies such as SigmaSpace, Quantum Light Metrology and ID Quantique have introduced quantum lidars that can be used for ground mapping and gas leak detection.

 

What would the world look like with advanced quantum sensing technologies integrated into complete systems?

 

Their commercial prospects now need to be taken more seriously as the technology develops further.

 

An existing challenge is that it is difficult to predict exactly how, and where, emerging technologies will be adopted. The history of physics is full of serendipitous inventions. X-ray generators, for example, were an accidental by-product of "experiments to see if electron beams could pass through glass", but they are now critical to medicine and airport security; Theodore Maiman, the inventor of the laser, describes the technology as "a solution in search of a problem". ".

 

Companies can mitigate such problems in a number of ways, such as building purpose-built hardware to limit noise, averaging measurements, and using entangled sensors.

 

Technologies in their infancy often encounter challenges with miniaturization. The first general-purpose electronic digital computer, ENIAC, covered about 1,800 feet and weighed over 27 tons. Similarly, companies looking to implement quantum sensors struggle with space limitations. This is especially true for companies trying to implement quantum sensors in areas such as space, where minimizing the size and weight of the load is critical. As an example, one quantum sensing founder said that typically it would take a truck-sized system for cooling, laser systems, and noise protection to achieve this kind of sensitivity. However, we are already seeing several quantum startups (e.g., CDL alumni Aquark Technologies) working to reduce the size and complexity of these sensors to accelerate the market adoption of this technology.

 

While academic researchers can develop sensors with the right properties, industry needs to lead this system integration phase. In short, we urgently need a long-term, industry-led approach to quantum sensor innovation.

 

Reference link:

[1] https://thequantuminsider.com/2023/05/03/quantum-sensing-and-its-value-a-brief-overview/

[2]https://thequantuminsider.com/2023/07/27/defense-experts-predict-quantum-sensing-poised-to-replace-vulnerable-gps-systems/

[3]https://thequantuminsider.com/2023/05/03/quantum-sensing-and-its-value-a-brief-overview/

[4]https://www.nature.com/articles/s41467-022-31454-6