Quantum inertial sensors on a moving platform

Lead Research Organisation: Imperial College London
Department Name: Dept of Physics

Abstract

Global Navigation Satellite Systems (GNSS), such as Galileo, GLONASS, BeiDou, or the Global Positioning System (GPS), are established navigation technologies used extensively the world over. However, GNSS does not work underground or underwater and it is vulnerable to disruption by the weather, or through malicious jamming, spoofing and even total denial of service. Obviously, when used as a primary method of navigation, having the system fail could lead to disastrous consequences.
Inertial Navigation Systems (INS) offer an attractive alternative to GNSS. They do not need to send or receive satellite signals or any external references, and as a result, can be deployed in any environment. INS's work by measuring the acceleration and rotation of a vehicle and then calculating its relative change in position using a complex set of equations, which rely on integrating multiple inertial signals twice with respect to time. State-of-the-art inertial sensors suffer from unstable drifts in their measurement bias, which randomly vary, giving a growing error in the accuracy of the system. These growing position errors limit the range and amount of time that these devices can be used for. The best, military-grade INS's (e.g. iXblue-Marins M8) have position accuracy of up to 1 nautical mile per 96 hours. This means that after around 2 hours, the position accuracy will no longer be comparable to that of standard GNSS systems (~1ft), which inhibits navigation on timescales much longer than this.
Quantum Inertial Sensors (QIS) offer an exciting route to overcome the performance limitations that arise from bias drift. QIS's exploit matter wave interferometry using ultra-cold clouds of free atoms to measure the acceleration and rotation of a vehicle. These free atoms constitute an almost perfect inertial observer, which does not require calibration, does not suffer from aging, and has potentially no drift. QIS's have already shown great promise in a laboratory setting, demonstrating sensitivities and stabilities exceeding those of conventional methods. Navigation systems based on a hybridisation of classical inertial sensors (favoured for their high dynamic range and bandwidth) with low-bias-drift QISs have already been proposed.
The CCM navigation team at Imperial has already realised high performance laboratory scale quantum accelerometers, which has stimulated significant interest from a range of industrial sectors, who are keen to develop quantum navigation technologies. The focus of my PhD will be to translate quantum accelerometers from laboratory scale research into a technology that can be deployed, and tested, on a moving platform.
I am going build a new transportable quantum accelerometer and test it on a moving platform. I will begin by building a new apparatus that combines an M Squared laser system, UHV science chamber and control system in a single 19" rack. The system will be capable of running on battery power, and will be designed for ease of transportation. I will first demonstrate the performance of this new system in a laboratory environment and compare it with existing lab scale systems. Comparing two similar systems will enable me to assess the bias drift of our devices for the first time, which will enable me to assess the long-term performance that this technology can achieve. I will then trial my new system on a moving platform and compare its performance in the field with a laboratory system.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509590/1 01/10/2016 30/09/2021
2439629 Studentship EP/N509590/1 01/12/2019 15/03/2024 Henry George Sewell