IEEE International Symposium on Inertial Sensors and Systems (INERTIAL)
Software Ruggedized Atom Interferometry for Strapdown Mobile Quantum Inertial Sensing
P. J. Everitt, P. S. Light, K. Thomas, D. H. White, Henry W. Orton, K. Gill, C. D. Macrae, Alexander Rischka, R. Symon, Kevin C. Stitely, D. Harcombe, Jack Saywell, D. Adams, Stuart S. Szigeti, R. P. Anderson, Nicholas P. Robins, Michael Hush, Michael J. Biercuk
Navigation systems based on quantum sensors are a viable alternative to use of GNSS, however their sensitivity to environmental effects makes deployment in harsh environments challenging. We present results demonstrating that software ruggedization techniques can mitigate these effects and enhance the performance of these systems in real-world environments. Here, we report world-first demonstrations of a dual quantum gravimeter operating in a relevant maritime environment, with an unattended uptime of >144 hours, as well as the first demonstrations of software ruggedized sensing in a real-world motional environment. We demonstrate recovery of signal due to software compensation of motion and a 2X contrast enhancement due to optimized velocity selection. In addition, we present a compact 3-axis quantum inertial sensor capable of high repetition rate operation in extremely harsh environments.
Navigation systems based on quantum sensors are a viable alternative to use of GNSS, however their sensitivity to environmental effects makes deployment in harsh environments challenging. We present results demonstrating that software ruggedization techniques can mitigate these effects and enhance the performance of these systems in real-world environments. Here, we report world-first demonstrations of a dual quantum gravimeter operating in a relevant maritime environment, with an unattended uptime of >144 hours, as well as the first demonstrations of software ruggedized sensing in a real-world motional environment. We demonstrate recovery of signal due to software compensation of motion and a 2X contrast enhancement due to optimized velocity selection. In addition, we present a compact 3-axis quantum inertial sensor capable of high repetition rate operation in extremely harsh environments.
Quantum sensors based on cold atoms have enormous potential to unlock new capabilities in GPS-denied navigation, civil engineering, intelligence, and Earth observation. But operating these devices in realistic environments is currently extremely challenging, and for the most part the advantages of choosing a quantum sensor over a conventional alternative are lost in the transition from laboratory to noisy field-based environments. In this work, we demonstrate for the first time in hardware that tailored light pulses, designed and implemented in software using robust control techniques, can substantially mitigate some of the most nefarious effects in a Bragg atom interferometer. We show experimentally that embedding robust control into sensor operation can improve the signal-to-noise ratio of a state-of-the-art Bragg-pulse cold-atom interferometric sensor by a factor of 4× under ideal conditions. In the presence of laser-intensity noise that varies up to 20% from shot-to-shot, commensurate with common platform vibrations, we show experimentally that using the same robust control solutions preserves fringe visibility with minimal degradation while the utility of the primitive Gaussian pulses collapses, delivering an at least 8× improvement in phase-estimation uncertainty compared with primitive pulse schemes. Across all observations, robust control delivers better performance in a noisy environment than the native hardware performance with primitive pulses under approximately ideal conditions. Finally, building on this demonstration we present a validated theoretical concept to extend this performance improvement to compact devices using concatenated sequences of robust pulses designed to enhance the sensor’s scale factor. Time-domain simulations reveal up to 10× performance enhancement in the presence of realistic atomic-cloud effects at 102ℏk momentum separation. These results show for the first time that software-defined quantum sensor operation can deliver useful performance in environmental regimes where primitive operation is impossible, providing a pathway to augment the performance of current and next generation portable cold-atom inertial sensors in real fielded settings.
Global navigation satellite systems (GNSS) are often disrupted or unavailable at sea, and unaided inertial navigation systems (INS) drift without correction. Quantum-sensing-based gravity map matching offers a passive, infrastructure-free aid, but field demonstrations of GNSS-free quantum gravimetric navigation have not been reported. Here we perform gravity map matching and fine-resolution gravity survey with a mobile quantum gravimeter aboard a 29 m surface vessel. We hybridize an atomic sensor with a classical accelerometer for bias stabilization and independently mechanize a navigation-grade IMU, all installed in an uncontrolled cabin with no environmental stabilization or calibration. Operated in both gimbaled and strapdown configurations over identical traversals, the hybrid sensor corrected the inertial solution over an 83 km maritime trajectory by referencing locally measured gravity to a satellite-derived anomaly map. Gravity-aiding constrains INS drift and delivers bounded positioning at nautical-mile-level accuracy, with GNSS excluded throughout the measurement chain. In a separate GNSS-referenced mode, the same system surveyed coastal routes up to Sea State 4, achieving mGal-level agreement with gravimetric maps and sub-mGal repeatability and stability, with gimbaled and strapdown operation performing comparably. Resolved anomalies reach an along-track scale of ~300 m, 50X finer than the satellite map's half-power wavelength. A 56 h stationary test shows atom referencing lowers long-term drift ~70X versus the classical channel alone. These results provide the first same-instrument comparison of gimbaled and strapdown mobile quantum gravimetry and the first fully GNSS-independent gravity-map-matching navigation demonstration using a quantum gravimeter, pointing toward compact, autonomous-platform-ready quantum sensing for GNSS-denied maritime navigation and survey.
Numerous real-world applications, such as in civil engineering, inertial navigation, and Earth Observation, have demonstrated the utility of quantum sensing with atom interferometers. Today, the biggest challenge to broader market adoption of these sensors is the in-depth knowledge of quantum mechanics required by both the manufacturers and users of these devices. We aim to make the design, construction, and operation of atom interferometers more intuitive using software that incorporates our years of experience in atom interferometry simulation. Here, we provide an overview over our simulation capabilities. Our versatile numerical toolbox enables efficient simulation of atomic test masses interacting with realistic electromagnetic, gravitational and optical forces, as well as prediction of sensor performance in realistic deployment scenarios, e.g., on air, land, and water vehicles.
M Squared is developing quantum sensors for quantum gravimetry and inertial navigation. Using atom interferometry, each promises performance advantages over their classical counterparts. Each system is designed for use in the challenging operational environment of a moving platform, and incorporates active systems that compensate for the effects of environmental noise. Each sensor is presented along with a performance evaluation in laboratory settings and in field trials. An account is also given on how M Squared laser systems are being used to enable some of the world’s most advanced precision metrology experiments.
Atom-interferometric quantum sensors could revolutionize navigation, civil engineering, and Earth observation. However, operation in real-world environments is challenging due to external interference, platform noise, and constraints on size, weight, and power. Here we experimentally demonstrate that tailored light pulses designed using robust control techniques mitigate significant error sources in an atom-interferometric accelerometer. To mimic the effect of unpredictable lateral platform motion, we apply laser-intensity noise that varies up to 20% from pulse-to-pulse. Our robust control solution maintains performant sensing, while the utility of conventional pulses collapses. By measuring local gravity, we show that our robust pulses preserve interferometer scale factor and improve measurement precision by 10× in the presence of this noise. We further validate these enhancements by measuring applied accelerations over a 200 μg range up to 21× more precisely at the highest applied noise level. Our demonstration provides a pathway to improved atom-interferometric inertial sensing in real-world settings.
Abstract Harnessing the potential of quantum sensors to assist in navigation requires enabling their operation in complex, dynamic environments and integrating them within existing navigation systems. While cross-couplings from platform dynamics generally degrade quantum measurements in a complex manner, navigation filters would need to be designed to handle such complex quantum sensor data. In this work, we report on the realization of a high-fidelity model of an atom-interferometry-based gravity gradiometer and demonstrate its integration with a map-matching navigation filter. Relying on the ability of our model to simulate the sensor behaviour across various dynamic platform environments, we show that aiding navigation via map matching using quantum gravity gradiometry results in stable trajectories, and highlight the importance of non-Gaussian errors arising from platform dynamics as a key challenge to map-matching navigation. We derive requirements for mitigating these errors, such as maintaining sensor tilt below 3.3∘, to inform future sensor development priorities. This work demonstrates the value of an end-to-end approach that could support future optimization of the overall navigation system. Beyond navigation, our atom interferometer modelling framework could be relevant to current research and innovation endeavours with quantum gravimeters, gradiometers and inertial sensors.