Quantum Use Case #75: Quantum sensing for navigation without GPS

Global Navigation Satellite Systems (GNSS), including GPS, form the backbone of modern positioning, navigation, and timing (PNT) services. However, these systems face inherent vulnerabilities to interference, spoofing, and signal degradation. Obstacles such as tall buildings can block satellite signals, while intentional jamming, imitation, or denial can prevent accurate navigation. In many operational contexts, GNSS is unavailable or unreliable. Consequently, there is an urgent need for robust augmentation and alternative solutions to support resilient PNT services. Quantum sensing has emerged as a promising pathway to enhance positioning and navigation performance by harnessing fundamental quantum phenomena, such as superposition and entanglement. These technologies enable absolute, drift-free, and ultra-sensitive measurements of inertial forces, gravity, and magnetic fields with long-term stability and reduced dependency on external signals.

Current backup navigation systems, such as inertial navigation systems (INS), are drift-prone. In the absence of reliable GNSS, INS positioning error accumulates over time. To mitigate this, researchers have explored augmenting INS with additional modalities. One such approach is magnetic-anomaly navigation (MagNav), which provides passive, non-jammable navigation through periodic position fixes. This method involves comparing local measurements of Earth’s crustal magnetic field against known anomaly maps. Despite its potential, existing MagNav efforts have been limited by magnetometer performance and interference issues. Quantum sensors address these limitations by offering superior sensitivity and stability.

Recent research indicates that quantum-assured magnetic navigation can achieve positioning accuracy better than strategic-grade INS in airborne and ground-based field trials. By utilizing quantum-enhanced magnetometers, these systems reduce positioning error in scenarios where GNSS is compromised. The ability to perform drift-free measurements of magnetic fields allows for more reliable periodic position fixes, thereby constraining the drift of the inertial navigation system. This capability offers a significant improvement in navigation resilience without relying on external satellite signals.

In parallel, quantum sensors for inertial measurement are being developed to provide absolute, drift-free measurements of inertial forces. Unlike traditional INS, which accumulates error over time, quantum-based inertial sensors aim to maintain long-term stability. This stability is critical for navigation in environments where GNSS is denied. The integration of quantum sensing into navigation systems represents a shift from relative, drift-prone measurements to absolute, high-precision measurements. By reducing dependency on external signals, these technologies enhance the robustness of PNT services against interference and spoofing.

A prototype quantum sensor built at Imperial College London, with potential application in GPS-free navigation, has been tested in collaboration with the Royal Navy. The testing was a prototype evaluation, not an operational deployment. The sensor aims to provide self-contained, satellite-free navigation capabilities. Such systems are essential for scenarios where GNSS is inaccessible or unreliable. The development of these sensors aligns with the broader goal of creating resilient navigation systems that can operate independently of satellite infrastructure.

The economic and operational implications of GNSS denial are substantial. It has been estimated that a single day of satellite service denial would incur a cost of £1 billion to the UK. This figure underscores the critical importance of developing alternative navigation technologies. Quantum sensing offers a viable solution by providing high-precision measurements that are immune to jamming and spoofing. By leveraging quantum phenomena, these sensors can maintain accurate positioning and navigation even in contested or obstructed environments.

Research in this area is ongoing, with various studies proposing and demonstrating the capabilities of quantum sensors in simulation and field trials. For instance, a 2025 arXiv preprint reports that quantum-assured magnetic navigation achieved positioning accuracy better than a strategic-grade INS in airborne and ground-based field trials. As a preprint, that result has not necessarily been through peer review. These findings suggest that quantum sensing could become a key component of future navigation systems. However, most use cases remain at the research stage, and widespread operational adoption is not yet established. The technology is still being refined to ensure reliability and robustness in diverse operational environments.

The development of quantum sensing for navigation is driven by the need for resilient PNT services. As GNSS vulnerabilities become more apparent, the demand for alternative solutions grows. Quantum sensors offer a unique combination of high sensitivity, long-term stability, and independence from external signals. These attributes make them well-suited for navigation applications where traditional systems fail. By enabling absolute, drift-free measurements, quantum sensing can significantly enhance the performance of positioning and navigation systems.

In conclusion, quantum sensing represents a promising avenue for improving navigation resilience. By harnessing quantum phenomena, these technologies can provide high-precision measurements of inertial forces, gravity, and magnetic fields. Field trials and prototype testing point to the potential of quantum sensors in GNSS-denied environments, though results are still early. While most applications are still in the research stage, the progress made so far suggests that quantum sensing could play a crucial role in future navigation systems. The ability to provide drift-free, high-precision measurements without reliance on external signals addresses the urgent need for robust PNT services. As research continues, the integration of quantum sensing into navigation systems may become increasingly viable, offering a solution to the vulnerabilities of GNSS.

The transition from GNSS-dependent to GNSS-resilient navigation is a critical challenge. Quantum sensing offers a technological solution by providing the necessary precision and stability for alternative navigation modalities. The development of these technologies is supported by the recognition that GNSS is not always accessible or reliable. By reducing dependency on external signals, quantum sensors can enhance the robustness of navigation systems against interference and spoofing. This capability is essential for ensuring the continuity of PNT services in a variety of operational contexts.

In summary, quantum sensing for navigation without GPS is an active area of research with significant potential. Recent studies have shown that quantum-enhanced magnetic and inertial sensors can improve positioning accuracy and resilience. While operational adoption is not yet widespread, prototype testing and field trials are under way. The development of quantum sensing for navigation addresses a critical gap in current PNT services, offering a pathway to more robust and reliable navigation in the absence of GNSS.