By measuring subtle changes (<10-8) in the acceleration of gravity we can infer the local density of nearby objects. When the density is lower (e.g. a tunnel) the local gravity becomes slightly less. While this technique is readily adopted in the oil & gas industry to (i) search for new resources (ii) perform long term monitoring at active wells, broader uptake of gravimetry in other fields is limited due to the high upfront cost of gravimeters ($80k for a Scintrex CG6), the fragility of devices and the time it takes to undertake field surveys with a single instrument. There are disruptive opportunities for gravimetry to breakthrough into other fields including environmental monitoring and security & defence. For environmental monitoring, a smaller-lighter-cheaper gravimeter will open-up opportunities for (i) deployment of sensors arrays of volcanos as a technique to image the magma plumbing system and provide resilience against eruptions, (ii) performing rapid field surveys to identify collapsed culverts, sinkholes or underground tunnels. Within the field of Security & Defence there are further opportunities of monitoring ports of entry with underwater sensors, detecting underground tunnels and monitoring compounds. Beyond this, we see opportunities in monitoring dam infrastructure, carbon capture, geothermal engineering detection/monitoring of underground aquifers. Wee-g is a precision MicroElectroMechanicalSensor (MEMS) that has been developed within the Institute for Gravitational Research (University of Glasgow). It is a spin-off from the Gravitational-Wave research activities led by Prof . Hammond. Wee-g is the world's first gravimeter, capable of monitoring the Earth tides; elastic deformations of the Earth caused by the tidal potential of the Moon and Sun. As typical gravity signals are 10-50% of the Earth ides, this is an essential measurement to show devices have sufficient stability and sensitivity. The Wee-g sensor has the potential to be made much cheaper than existing gravimeters, and thus can open-up these new opportunities in Environmental monitoring and Security & Defence. Field trials are underway with partners in both the Environmental and Security & Defence fields. Wee-g Mk I systems are being deployed on Mt Etna as part of a H2020 project (Newton-g) to monitor magma intrusion in volcanoes, and we estimate the TRL is 5. We also have a system being trialled by DSTL for underwater monitoring at a port of entry. We will use this proposal to further develop the Wee-g gravimeter (Mk II system) to put us in a prime position to spinout. We will address some of the challenges found in the Mk I system including temperature sensitivity of the MEMS chip, miniaturisation and temperature stability of the front-end electronics, and removing reliance on evaluation FPGA boards which are liable to be discontinued.

The Quantum Technology Hub in Sensors and Timing, a collaboration between 7 universities, NPL, BGS and industry, will bring disruptive new capability to real world applications with high economic and societal impact to the UK. The unique properties of QT sensors will enable radical innovations in Geophysics, Health Care, Timing Applications and Navigation. Our established industry partnerships bring a focus to our research work that enable sensors to be customised to the needs of each application. The total long term economic impact could amount to ~10% of GDP. Gravity sensors can see beneath the surface of the ground to identify buried structures that result in enormous cost to construction projects ranging from rail infrastructure, or sink holes, to brownfield site developments. Similarly they can identify oil resources and magma flows. To be of practical value, gravity sensors must be able to make rapid measurements in challenging environments. Operation from airborne platforms, such as drones, will greatly reduce the cost of deployment and bring inaccessible locations within reach. Mapping brain activity in patients with dementia or schizophrenia, particularly when they are able to move around and perform tasks which stimulate brain function, will help early diagnosis and speed the development of new treatments. Existing brain imaging systems are large and unwieldy; it is particularly difficult to use them with children where a better understanding of epilepsy or brain injury would be of enormous benefit. The systems we will develop will be used initially for patients moving freely in shielded rooms but will eventually be capable of operation in less specialised environments. A new generation of QT based magnetometers, manufactured in the UK, will enable these advances. Precision timing is essential to many systems that we take for granted, including communications and radar. Ultra-precise oscillators, in a field deployable package, will enable radar systems to identify small slow-moving targets such as drones which are currently difficult to detect, bringing greater safety to airports and other sensitive locations. Our world is highly dependent on precise navigation. Although originally developed for defence, our civil infrastructure is critically reliant on GNSS. The ability to fix one's location underground, underwater, inside buildings or when satellite signals are deliberately disrupted can be greatly enhanced using QT sensing. Making Inertial Navigation Systems more robust and using novel techniques such as gravity map matching will alleviate many of these problems. In order to achieve all this, we will drive advanced physics research aimed at small, low power operation and translate it into engineered packages to bring systems of unparalleled capability within the reach of practical applications. Applied research will bring out their ability to deliver huge societal and economic benefit. By continuing to work with a cohort of industry partners, we will help establish a complete ecosystem for QT exploitation, with global reach but firmly rooted in the UK. These goals can only be met by combining the expertise of scientists and engineers across a broad spectrum of capability. The ability to engineer devices that can be deployed in challenging environments requires contributions from physics electronic engineering and materials science. The design of systems that possess the necessary characteristics for specific applications requires understanding from civil and electronic engineering, neuroscience and a wide range of stakeholders in the supply chain. The outputs from a sensor is of little value without the ability to translate raw data into actionable information: data analysis and AI skills are needed here. The research activities of the hub are designed to connect and develop these skills in a coordinated fashion such that the impact on our economy is accelerated.

The surface urban transport infrastructures - our roads, cycle ways, pedestrian areas, tramways and railways - are supported by the ground, and hence the properties of the ground must control to a significant degree their structural performance. The utility services infrastructure - the pipes and cables that deliver utility services to our homes and which supports urban living - is usually buried beneath our urban streets, that is it lies below the surface transport infrastructure (usually roads and paved pedestrian areas). It follows that streetworks to install, replace, repair or maintain these utility service pipes or cables using traditional trench excavations will disrupt traffic and people movement, and will often significantly damage the surface transport infrastructure and the ground on which it bears. It is clear, therefore, that the ground and physical (i.e. utility service and surface transport) infrastructures exist according to a symbiotic relationship: intervene physically in one, and the others are almost inevitably affected in some way, either immediately or in the future. Moreover the physical condition of the pipes and cables, of the ground and of the overlying road structure, is consequently of crucial importance in determining the nature and severity of the impacts that streetworks cause. Assessing the Underworld (ATU) aims to use geophysical sensors deployed both on the surface and inside water pipes to determine remotely (that is, without excavation) the condition of these urban assets. ATU builds on the highly successful Mapping the Underworld (MTU) project funded by EPSRC's first IDEAS Factory (or sandpit) and supported by many industry partners. The MTU sandpit brought together a team that has grown to be acknowledged as international leaders in this field. ATU introduces leaders in climate change, infrastructure policy, engineering sustainability and pipeline systems to the MTU team to take the research into a new sphere of influence as part of a 25-year vision to make streetworks more sustainable. ATU proposes to develop the geophysical sensors created in MTU to look for different targets: indications that the buried pipes and cables are showing signs of degradation or failure, indications that the road structure is showing signs of degradation (e.g. cracking, delamination or wetting) and indications that the ground has properties different to unaltered ground (e.g. wetted or eroded by leaking pipes, loosened by local trench excavations, wetted by water ingress through cracked road structures). For example, a deteriorated (fractured, laterally displaced, corroded or holed) pipe will give a different response to the geophysical sensors than a pristine pipe, while wetting of the adjacent soil or voids created by local erosion due to leakage from a water-bearing pipe will result in a different ground response to unaltered natural soil or fill. Similarly a deteriorated road (with vertical cracks, or with a wetted foundation) will give a different response to intact, coherent bound layers sitting on a properly drained foundation. Taking the information provided by the geophysical sensors and combining it with records for the pipes, cables and roads, and introducing deterioration models for these physical infrastructures knowing their age and recorded condition (where this information is available), will allow a means of predicting how they will react if a trench is dug in a particular road. In some cases alternative construction techniques could avert serious damage (e.g. water pipe bursts, road structural failure requiring complete reconstruction) or injury (gas pipe busts). Making this information available will be achieved by creating a Decision Support System for streetworks engineers. Finally, the full impacts to the economy, society and environment of streetworks will be modelled in a sustainability assessment framework so that the wider impacts of the works are made clear.

The Hub will create a seamless link between science and applications by building on our established knowledge exchange activities in quantum technologies. We will transform science into technology by developing new products, demonstrating their applications and advantages, and establishing a strong user base in diverse sectors. Our overarching ambition is to deliver a wide range of quantum sensors to underpin many new commercial applications. Our key objective is to ensure that the Hub's outputs will have been picked up by companies, or industry-led TSB projects, by the end of the funding period. The Hub will comprise: a strong fabrication component; quantum scientists with a demonstrated ability to combine scientific excellence with technological delivery; leading engineers with the broad collective expertise and connections required to develop and use new quantum sensors. We have identified, and actively involved, industry enablers to build a supply chain for quantum sensor technology. As well as direct physics connections to industry, the engineers provide strong links to relevant industrial users, thus providing information on industrial needs and enabling rapid prototype deployment in the field. To establish a coherent national collaborative effort, the Hub will include a UK network on quantum sensors and metrology, which will also exploit the connections that Prof Bongs and all Hub members have forged in Europe, the US and Asia. This inter-linkage ensures capture of the most advanced developments in quantum technology around the world for exploitation by the UK. Quantum sensors and metrology, plus some devices in quantum communication, are the only areas where laboratory prototypes have already proven superior to their best classical counterparts. This sets the stage, credibly, for rapid and disruptive applications emerging from the Hub. The selection of prototypes will be driven by commercial pull, i.e. each prototype project within the Hub must demonstrate, from the outset, industry or practitioner engagement from our engineering and/or industrial collaborators. We have strong industry support across several disciplines with the structures in place actively to manage technology and knowledge transfer to the industry sector. Particular roles are played by NPL and e2V. We will closely collaborate with NPL as metrology end-user on clock, magnetometer and potentially Watt balance developments with a lecturer-level Birmingham-NPL fellow contributed by Birmingham University and our PRDAs spending ~17 man-years in addition to 3-5 PhD students on these joint projects in the Advanced Metrology Laboratory/incubator space. E2v have a unique industrial manufacturing/R&D facility co-located within the School of Physics and Astronomy at Nottingham that has already catalysed the expansion of their activities into the Quantum Technology domain. Public Engagement conveying the Hub's breakthroughs will be a high priority - for example annually at the Royal Society Summer Exhibitions. In addition to cohort-training of 80 PhD students working within the Hub, the Hub will contribute to the training of ~500 PhD students via electronically-shared lectures (many already running within the e-learning graduate schools MPAGS, MEGS, SEPNET and SUPA) across the institutions within the Hub. The Hub will create an internationally-leading centre of excellence with major impact in the area of quantum sensors and metrology. To widen the impact of the Hub and ensure long-term sustainability, we will actively pursue European and other international collaborative funding for both underlying fundamental research and the technology development.