The innate vulnerability of GNSS to signal degradation, spoofing, and interference has increased the importance of robust alternative and augmentation solutions to support resilient positioning, navigation, and timing services.1-3
Among emerging technologies, quantum sensing enables ultra-sensitive, drift-free, and absolute measurements of gravity, magnetic fields, and inertial forces with reduced reliance on external signals and long-term stability by harnessing fundamental quantum phenomena like entanglement and superposition.1-3
Specifically, quantum sensing utilizes the particles’ quantum properties to measure time and electromagnetic fields with more accuracy than classical sensors. This capability improves navigation performance in GNSS-contested or GNSS-denied environments.1-3
Main Components and Performance Metrics
All quantum sensors contain three basic components, including the core quantum system, electronics, and specialized software. The core quantum system consists of highly controlled particles within a specialized container. The particle behavior is highly sensitive to the environment.4
Electronics, which typically include lasers, control and communicate with quantum particles for reading out the information. The key challenge while deploying quantum sensors for positioning and navigation is configuring these components into a hardened, small, and rugged container. Specialized software turns the obtained information into useful data and eliminates unwanted signals.4
Quantum sensor performance is measured using four quality measurement categories, including bandwidth, stability, precision, and Size, Weight, Power, Cost (SWaP-C). While the specific values for each quantum sensor type vary, the primary purposes remain consistent.4
Quantum Gyroscopes and Accelerometers
Quantum rotation sensors, such as spin-exchange relaxation-free (SERF) atomic spin gyroscopes (ASGs) and atom interferometer gyroscopes, which are at the forefront of quantum sensing, leverage quantum-mechanical principles such as atomic interference and spin to achieve exceptional precision in rotational motion measurement. These devices could revolutionize inertial sensing and high-precision navigation, such as autonomous vehicles, aerospace, and geophysical surveys.1
Quantum accelerometers like nitrogen-vacancy (NV) center-based accelerometers and cold atom interferometers are crucial for high-precision navigation applications, where accurate gravity and acceleration measurement is necessary for maintaining positioning without external references like the global positioning system.1
Atom Interferometer Gyroscope
These gyroscopes, a new quantum inertial sensor class, measure angular velocity and acceleration with remarkable precision. These devices leverage the Sagnac effect and the wave nature of atoms to achieve higher sensitivities than conventional optical interferometers. While they operate on principles similar to those of optical interferometers, they use matter waves rather than light.1
Light pulses manipulate cold atoms’ quantum states to create a rotation-sensitive interference pattern by splitting, reflecting, and recombining their wave packets. In 2016, the Paris Observatory achieved a breakthrough by developing a cold-atom gyroscope with 1 × 10−9 rad/s long-term stability. In recent years, large momentum transfer schemes have improved the dynamic range and sensitivity of atom interferometers. 1
In interferometric calibration, a significant development was displayed with a self-calibrating cold atom gyroscope. Here, atomic velocities were modulated by laser frequency detuning to dynamically tune the scale factor. This method successfully eliminated fringe periodicity-induced phase mbiguities and enabled precise Earth rotation measurement with 162 ppm relative uncertainty.1
SERF ASGs
SERF effect is key to SERF ASGs, improving sensitivity by subduing spin-exchange relaxation that expands magnetic resonance lines in alkali metal vapors. In SERF ASGs, alkali metal atoms are polarized by circularly polarized laser light, aligning their electron spins. Frequent collisions in a high-density vapor cell average out spin-exchange interactions, reducing relaxation effects.1
The nuclear spin precession, hyperpolarized through interactions with the polarized electrons, is measured to detect rotations. These nuclear spins provide a stable reference for precise rotational measurements as they are less sensitive to external magnetic fields.1
Polarization changes in the vapor are monitored by a probe laser, enabling accurate rotational velocity detection. Currently, the best sensitivity realized by SERF ASG is 3.58×10−7 rad/(s√Hz) @ 0.1 Hz, with bias stability of 2.76×10−8 rad/s @ 100 s integration.1
NV Center Accelerometer
NV center accelerometers use the distinct quantum properties of diamond’s NV centers for high-precision linear acceleration detection. NV centers feature an electronic spin that is optically initialized, read out, and manipulated. These centers consist of a nitrogen atom adjacent to a vacancy in the diamond lattice.1
The interaction between external magnetic fields and the NV center’s spin state is the key to its sensing capability. Quantum phase shifts induced by mechanical motion, which is coupled to the NV center’s spin state, are detected by NV center accelerometers. The NV center is placed in a magnetic field gradient, where motion induced by acceleration changes the local magnetic field that is experienced by the NV center.1
Sensitivity depends on magnetic field gradient strength, spin coherence time, and optical readout efficiency. Techniques like advanced pulse sequences and dynamic nuclear polarization mitigate decoherence, improving sensitivity.1
Future NV center-based accelerometer advances will focus on improving quantum-state protection, manipulation, preparation, and detection to improve performance. Optical tweezers could refine spin state cooling, fluorescence collection, and position detection in levitated optomechanics.1
Atom Interferometer Accelerometer
Cold atom interferometric accelerometers leverage the ultracold atoms’ wave nature for acceleration measurement with excellent precision. Using a sequence of laser pulses, a cloud of cold atoms is manipulated in a configuration similar to a Mach-Zehnder interferometer. This is achieved by employing laser cooling and trapping techniques. The “π/2-π-π/2” pulse sequence reflects, splits, and recombines atomic wave packets.1
In this process, the atoms accumulate a phase shift proportional to the acceleration of the system. Upon wave-packet recombination, an interference pattern forms, providing an extremely sensitive measure of acceleration. Cold atom interferometric accelerometer sensitivity surpasses the conventional optical accelerometer sensitivity owing to the shorter de Broglie wavelength of atomic matter waves.1
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This allows phase shifts to be directly proportional to acceleration, enabling measurements with exceptional stability and precision. In 2001, a precision of 10−10 g was achieved by cesium fountain interferometers over two days by implementing vibration isolation and optimizing Raman transitions.1
Later, efforts shifted toward robustness and miniaturization for field applications. Initiatives such as the European Space Atom Interferometry project and the Defense Advanced Research Projects Agency (DARPA)’s Precision Inertial Navigation System aimed to integrate cold-atom accelerometers into space missions and navigation systems.1
The Future of Quantum Sensors
Quantum sensors offer unprecedented precision and reliability, enabling navigation systems to function accurately even in GNSS-denied environments and significantly enhancing future positioning technologies. Advancements in miniaturization, robustness, and cost reduction will accelerate real-world adoption of quantum sensors.
Continued research in quantum coherence, error mitigation, and integration with classical systems will expand their use across aerospace, defense, autonomous vehicles, and deep-space exploration, ultimately transforming global navigation infrastructure.
References and Further Reading
- Pei, H. et al. (2025). Navigation in the future: Review of quantum sensing in navigation. Science China Physics, Mechanics & Astronomy, 68(9), 290301. DOI: 10.1007/s11433-025-2699-1, https://link.springer.com/article/10.1007/s11433-025-2699-1
- Li, H. et al. (2026). Quantum sensors for enhanced positioning and navigation: a comprehensive review. GPS Solutions, 30(1), 62. DOI: 10.1007/s10291-026-02030-y, https://link.springer.com/article/10.1007/s10291-026-02030-y
- Sambataro, O., Costanzi, R., Alves, J., Caiti, A., Paglierani, P., Petroccia, R., & Munafò, A. (2025). Current Trends and advances in quantum navigation for maritime applications: A comprehensive review. IEEE Journal of Oceanic Engineering. DOI: 10.1109/JOE.2025.3538941, https://ieeexplore.ieee.org/abstract/document/10965754
- Burkey, M. (2025). How Quantum Sensing Will Help Solve GPS Denial in Warfare [Online] Available at https://www.osti.gov/servlets/purl/2584722 (Accessed on 29 April 2026)
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