MAPPING THE UNDERWORLD: MULTI-SENSOR DEVICE CREATION, ASSESSMENT, PROTOCOLS

Lead Research Organisation: University of Bath
Department Name: Electronic and Electrical Engineering

Abstract

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Description GPR is used to 'see through' the ground, either to establish the structure of the ground or to find buried objects. Here we seek to detect pipelines that might be made of a variety of materials (e.g. metal, plastics, ceramics, concrete) with a variety of contents (e.g. water, gas, optical fibre cables). The radar signal, an electromagnetic wave, is transmitted into the ground. Reflections, whether from sub-soil interfaces or the buried objects, are captured by a nearby surface-mounted receiver and the data interpreted.GPR operates on very short ranges, often over 1 or 2 metres range, unlike radars used for navigation of ships and planes. This research looked into more novel technological approaches to accurately discern the targets, in particular looking at Orthogonal Frequency Division Multiplexing (OFDM), Frequency Modulated Continuous Wave (FMCW) and Step Frequency Continuous Wave (SFCW) techniques. OFDM is used in Digital TV, Digital Radio and Wireless Local Area Networks and provides very good, and adaptable, control of the radiated pulse shapes and frequency content. FMCW and SFCW also possess this advantage, but to a lesser degree. A technique for improving FMCW GPR was developed where linearising the frequency sweep more accurately, allowed clearer resolution of targets.In addition the notion of placing the transmitter or receiver in a buried pipeline was investigated. This gives a one-way signal propagation path that can potentially greatly increase the range of measurement through the ground. To realise these schemes research was also undertaken into long, thin ultra-wideband antennas that can fit into pipes. This in-pipe scheme was seen to quite easily identify the permittivity of the ground surrounding the pipes and targets. This information is very useful in improving our ability to focus GPR data into images of the sub-surface. The MTU research has also improved our understanding of propagation effects that can cause the well known problem of poor GPR detection of cast-iron pipe targets. This came about due to the wide range of expertise within the group on electromagnetic propagation and device modelling combined with expertise on decay processes of pipes within soils. Extensions of this research indicate that the propagation effect is also likely to be applicable to bitumen-coated or leaking gas pipes, which can also be problematic to detect with GPR. Part of the research is concentrated on signal processing and focussing techniques to remove the clutter of unwanted reflections, hence making the pipes more clearly visible. Moreover, it produces images that are more easily understood than traditional data presentation methods. The signal processing techniques developed also allow data from different sensor systems, such as acoustic and magnetic field data, to be combined in a manner that reinforces the identification of the targets. A significant focus of the MTU research was investigating ways to make a step change in utility surveying practices with a truly integrated approach to analysis and interpretation taking advantage of all possible information. In combining sensor packages their mutual interaction was minimised by appropriate physical layout. As expected, combining data from the four sensors has been shown to produce a more reliable assessment of buried targets and therefore increased the confidence in utility location. This is most apparent when the sensors produce target signatures that agree in plan and depth, and therefore reinforce each other. The diversity of approaches means that where one or more of the sensors are performing poorly due to ground conditions, the remaining sensors can still providing target information. Thus combining data from several sensors produces a more resilient system that can operate in a wide variety of situations and detect a wide variety of targets.
Exploitation Route Basic ideas on Ground Penetrating Radar were developed and evaluated, which could now move on to developing new Ground Penetrating Radar systems, and in more generic radar systems. Likewise the signal processing strategies investigated showed improvements over the traditional, and very widely used Fast Fourier Transform techniques.
Sectors Aerospace

Defence and Marine

Construction

Digital/Communication/Information Technologies (including Software)

Electronics

Culture

Heritage

Museums and Collections

Transport
URL http://www.mappingtheunderworld.ac.uk
 
Description General techniques for surveying roads by mapping introduced into surveying practice.
First Year Of Impact 2011
Sector Construction,Digital/Communication/Information Technologies (including Software),Transport
Impact Types Economic
 
Description Potential influence of improved detection and mapping on work practice in street works.
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
Impact Mapping the Underworld multi-university research team has promoted strong interactions with industry in the surveying, construction and asset management areas through its Steering Committee, annual dissemination events and other interactions. This has helped maintain the relevance of the research to industrial and societal needs while informing industry of the developments made in our and other academic research. The developments made at the University of Bath in GPR techniques, signal processing and system integration have contributed to the team's aim to investigate ways to produce a step change in the area of detecting and mapping buried assets in the UK and overseas. The work within the programme has led to the development of a new British Standard, influenced government policy on streetworks, guided industry practice in the UK and overseas, given rise to a national Centre of Excellence and accredited vocational training centre, and raised public awareness of the problems associated with maintaining and expanding the buried infrastructure.
 
Description ASSESSING THE UNDERWORLD - AN INTEGRATED PERFORMANCE MODEL OF CITY INFRASTRUCTURES
Amount £5,782,838 (GBP)
Funding ID EP/K021699/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 05/2013 
End 05/2017