Quantum Computing's Weakness is Quantum Sensing's Strength
This month, the Royal Australian Navy and Airbus each just demonstrated exceptionally accurate navigation alternatives to GPS, leveraging quantum sensors.
Quantum Computing headlines are dominating the quantum dialogue, with ever increasing qubit counts and improved error rates. One of the main challenges for quantum computers is the difficulty keeping qubits from losing coherence due to various environmental perturbations. Interference from gravity, electromagnetic radiation, temperature fluctuations, loud sounds and even atomic particles from space can destroy the delicate quantum states required to run quantum algorithms. However, this extreme sensitivity is the core strength of quantum sensors which are being designed to detect phenomenally subtle changes in things like gravity or magnetic field.
GPS is Increasingly Vulnerable.
Most of us take for granted that we have nearly ubiquitous access to GPS, which helps us use our phones to navigate to the nearest Starbucks, or route us around traffic in our car. GPS operates by using signals from satellites, but those signals are extremely weak, are not available in some locations (inside buildings, underground, undersea, etc.) and are increasingly being disrupted by spoofing and jamming events. In aviation, spoofing incidents are up by as much as 500% in 2025 over 2024 with a current daily average of 1,500 commercial flights per day experiencing GPS spoofing. Certain geographies are particularly vulnerable including areas around and above Israel, Lebanon, Ukraine, Russia, Iraq, and others. This problem also has a major and increasing maritime impact. For example, in the Arabian Gulf and Strait of Hormuz, about 1,000 ships per day suffer from GPS jamming. These events are prominent in hot spots around the world but are by no means isolated to those areas.
GPS jamming can be done with a $50 device which, while illegal to operate in many jurisdictions, is easily obtained. GPS spoofing is even more nefarious where hostile actors can overwhelm the weak GPS signal and instead broadcast its own signal to take control of missiles, drones, autonomous vehicles and other GPS guided objects and divert their trajectories.
“Quantum” to the Rescue
Trapped Ion and Neutral Atom quantum computers isolate and trap individual atoms which are then used as qubits to perform computing operations. The trapped atoms are extremely sensitive to environmental changes, making quantum computing difficult. But that same extreme sensitivity is being used to sense ever smaller changes in things like gravity and magnetic fields for gravimeter navigation (GavNav) and magnetometer navigation (MagNav).
Earlier this month, Airbus’s Acubed innovation center used SandboxAQ’s shoebox sized MagNav quantum sensing device on a Beechcraft Baron aircraft and was able to pinpoint the plane’s location within 2 nautical miles (slightly more than 2 standard miles) 100% of the time during 150 hours of flight time, exceeding the Federal Aviation Administration’s requirements.
Also earlier this month, the Australian Royal Navy’s MV Sycamore vessel successfully completed a maritime trial using Q-CTRL’s software ruggedized quantum dual gravimeter, demonstrating over 144 hours of successful and continuous operation. For various reasons including ship vibrations, MagNav has troubles with maritime operation, so Q-CTRL’s gravimetric navigation enables quantum sensing to now guide navigation at sea.
Both of these accomplishments exhibited strong navigation capabilities that are not dependent on GPS and cannot be impacted by hostile actors. They also involve modest footprints and power requirements so inclusion on planes or ships would not be challenging. While not quite ready to fully replace GPS, such systems would provide important redundancies for navigation.
How Does Quantum Sensing Help with Navigation?
Both MagNav and GravNav trap atoms with lasers, and then read out how they are impacted by the earth’s magnetic fields or gravity, although the specifics are different as described below:
Magnetic Navigation - Step-by-Step Overview
Atoms are used as tiny sensors: a small cloud of atoms, often rubidium or cesium, is placed in a glass cell under strong vacuum.
These atoms have a quantum property called “spin”, which make them act like tiny bar magnets.
A laser shines through the glass cell, causing the atoms to align their spins, akin to pointing all the compasses in the same direction.
When exposed to the earth’s magnetic field, the atom’s spins start to wobble (this is called “precession” and is similar to what happens to a spinning top when you nudge it). The speed of this wobble depends on the strength of the magnetic field.
Another laser measures the wobble and can determine the strength of the magnetic field that caused it.
The earth’s crust contains a unique pattern of magnetic fields. By matching the readings against a detailed map of this magnetism, vehicles can determine where they are.
Gravimeter Navigation - Step-by-Step Overview
Similar to Magnetometers, Gravimeters use a small cloud of atoms placed in a strong vacuum and manipulated by lasers, but in this case the lasers trap the atoms and hold them in place, thereby chilling them, causing them to move incredibly slowly which makes them act almost like waves.
The atoms are then allowed to “fall” for a short moment and as they fall, gravity pulls on them just like it would a dropped ball.
While the atoms are dropping, they are zapped with more laser pulses which temporarily splits their wave-like paths. As they come back together, an interference pattern is created, and that pattern is strongly influenced by gravity. The lasers act as rulers and stopwatches, showing the tiniest gravity scale changes.
By matching the gravity signature against a detailed map of the earth’s gravity, vehicles can determine where they are.
It’s quantum mechanics that enable the mind-blowing precision of measurement of changes in gravity or magnetic field. Using software, AI and cataloguing the globes diverse fields, this precision is translated into Geo positioning.
While the acute sensitivity of trapped atoms is beguiling quantum computing makers, it’s being used to help provide back-up navigation in this ever-increasing climate of GPS interference and manipulation. Given the strong success of the two programs highlighted, I expect we are not far from commercial implementation of these systems. Companies to watch in this rapidly evolving field include SandboxAQ and Q-CTRL which were featured in this post, but also includes Vector Atomic, AOSense, Infleqtion, Muquans and SBQuantum.
References
Bennington, Jeremy, “GPS Spoofing and eGPWS: The risks for the commercial aviation industry,” Spirent.com, March 20, 2025
“Q-CTRL’s New Maritime Quantum Navigation Solution Successfully Undergoes First Defense Trials at Sea,” Q-CTRL.com, July 16, 2025
“SandboxAQ and Acubed Achieve Remarkable Progress in Magnetic Navigation,” SandboxAQ.com, July 15, 2025
Graphic and additional details from Perplexity (2025). Perplexity.ai (AI Chatbot) https://www.perplexity.ai/
Did you check out FEIM ? It has some interesting quantum sensing technolgy with goverment funding...