Modelling of ground penetrating radar backscatter for water pipeline leakage detection

Subsurface water leaks not only waste precious natural resources, but also create substantial damages to the transportation system and structures within urban and suburban environments. While many geophysical techniques have been suggested for detecting water leakage including ground-penetrating radar (GPR), acoustic devices, gas sampling devices and pressure wave detectors, there is no ideal solution for it. Nonetheless, GPR, a non-destructive geophysical technique which uses high frequency electromagnetic waves to acquire subsurface information has been regularly utilized as GPR responds to the changes in electrical properties, which is a function of soil and rock material, and moisture content. To evaluate the feasibility of GPR in detecting water pipe leakage, a finite-difference time-domain (FDTD) numerical modelling is conducted together with water pipe leakage detection fieldwork and experimental test. To properly design the features of the imaging approach, and test its capabilities in controlled conditions, the synthetic data was generated in a two dimensional FDTD forward modelling solver capable of accurately simulating real world GPR scenarios. Different types of simulate conditions involving sizes of leakage area, frequencies (250 MHz and 700 MHz), pipe materials (AC, DI, PVC, MS and HDPE) and pipe sizes (100mm, 200mm and 300mm) were conducted. For the fieldwork, case studies were carried out using GPR scanning equipment (Detector Duo) to validate FDTD numerical model. For the experimental test, Detector Duo was used to collect data on top of District Metering Areas testbed. More understanding regarding the signature of leakage was gained in radargram. Compared to a distinct hyperbola or line as shown in radargram of intact pipes, the leakage zone is disturbed by the wave reflection caused by saturated soil. Numerically simulated results seem to be in agreement with the case studies and experimental results. The signature of pipe and leakage are clearly visible in the simulated radargram compared with those in the case studies and experimental radargram. Therefore, GPR survey seems promising as an efficient non-destructive geophysical technique for leakage detection approach. This finding is useful to provide protocols for GPR profile interpretation, particularly in underground water pipe leakage detection

Development of a Wall Climbing Robotic Ground Penetrating Radar System for Inspection of Vertical Concrete Structures

This paper describes the design process of a 200 MHz Ground Penetrating Radar (GPR) and a battery powered concrete vertical concrete surface climbing mobile robot. The key design feature is a miniaturized 200 MHz dipole antenna using additional radiating arms and procedure records a reduction of 40% in length compared to a conventional antenna. The antenna set is mounted in front of the robot using a servo mechanism for folding and unfolding purposes. The robot’s adhesion mechanism to climb the reinforced concrete wall is based on neodymium permanent magnets arranged in a unique combination to concentrate and maximize the magnetic flux to provide sufficient adhesion force for GPR installation. The experiments demonstrated the robot’s capability of climbing reinforced concrete wall carrying the attached prototype GPR system and perform floor-to-wall transition and vice versa. The developed GPR’s performance is validated by its capability of detecting and localizing an aluminium sheet and a reinforcement bar (rebar) of 12 mm diameter buried under a test rig built of wood to mimic the concrete structure environment. The present robotic GPR system proves the concept of feasibility of undertaking inspection procedure on large concrete structures in hazardous environments that may not be accessible to human inspectors

Planetary Exploration Reinvented

During the past 50 years, we have learned to explore and work in space. Much of what we know about the Solar System we owe to observations and sampling made by robotic spacecraft, landers, planetary rovers, and astronauts. As we look to the future, however, there is ample opportunity to reinvent planetary exploration: to develop new techniques and systems that will enhance and enable discovery.In this talk, I will describe how the NASA Ames Intelligent Robotics Group (IRG) is working to reinvent planetary exploration. First, I will present IRG's development of robots for human exploration. These robots are designed to perform work before, in parallel, and after human activity. Next, I will show how IRG is building automated planetary mapping systems to process the enormous amount of data that NASA collects from orbit. Finally, I will discuss how IRG is changing the way ground control software is created, particularly for supporting science operations

Planetary Exploration Rebooted! New Ways of Exploring the Moon, Mars and Beyond

In this talk, I will summarize how the NASA Ames Intelligent Robotics Group has been developing and field testing planetary robots for human exploration, creating automated planetary mapping systems, and engaging the public as citizen scientists

Surface and Sub-Surface Analyses for Bridge Inspection

The development of bridge inspection solutions has been discussed in the recent past. In this dissertation, significant development and improvement on the state-of-the-art in the field of bridge inspection using multiple sensors (e.g. ground penetrating radar (GPR) and visual sensor) has been proposed. In the first part of this research (discussed in chapter 3), the focus is towards developing effective and novel methods for rebar detection and localization for sub-surface bridge inspection of steel rebars. The data has been collected using Ground Penetrating Radar (GPR) sensor on real bridge decks. In this regard, a number of different approaches have been successively developed that continue to improve the state-of-the-art in this particular research area. The second part (discussed in chapter 4) of this research deals with the development of an automated system for steel bridge defect detection system using a Multi-Directional Bicycle Robot. The training data has been acquired from actual bridges in Vietnam and validation is performed on data collected using Bicycle Robot from actual bridge located in Highway-80, Lovelock, Nevada, USA. A number of different proposed methods have been discussed in chapter 4. The final chapter of the dissertation will conclude the findings from the different parts and discuss ways of improving on the existing works in the near future

Human and Robotic Mission to Small Bodies: Mapping, Planning and Exploration

This study investigates the requirements, performs a gap analysis and makes a set of recommendations for mapping products and exploration tools required to support operations and scientific discovery for near- term and future NASA missions to small bodies. The mapping products and their requirements are based on the analysis of current mission scenarios (rendezvous, docking, and sample return) and recommendations made by the NEA Users Team (NUT) in the framework of human exploration. The mapping products that sat- isfy operational, scienti c, and public outreach goals include topography, images, albedo, gravity, mass, density, subsurface radar, mineralogical and thermal maps. The gap analysis points to a need for incremental generation of mapping products from low (flyby) to high-resolution data needed for anchoring and docking, real-time spatial data processing for hazard avoidance and astronaut or robot localization in low gravity, high dynamic environments, and motivates a standard for coordinate reference systems capable of describing irregular body shapes. Another aspect investigated in this study is the set of requirements and the gap analysis for exploration tools that support visualization and simulation of operational conditions including soil interactions, environment dynamics, and communications coverage. Building robust, usable data sets and visualisation/simulation tools is the best way for mission designers and simulators to make correct decisions for future missions. In the near term, it is the most useful way to begin building capabilities for small body exploration without needing to commit to specific mission architectures

Science Mapping for Recent Research Regarding Urban Underground Infrastructure

The presented research conducted a bibliometric analysis regarding academic publications, especially journal publications, in the area of urban underground infrastructure (UI) systems (which include sewer pipes, drinking water pipes, cables, tunnels, etc.). In total, 547 journal papers published from 2002 to July 2022 (around 20 years period) were retrieved from Scopus using the proposed data collection method. Bibliometric analysis was conducted to extract and map the hidden information from retrieved papers. As a result, networks regarding co-citation, co-authorship, and keywords co-occurrence were generated to visualise and analyse the knowledge domain, patterns, and relationships. The eight most investigated topics in the UI research are identified and discussed, which provides an overview of the research history and focuses. Further, five potential research directions are suggested for researchers in the UI research area. The main contribution of this research is on revealing the knowledge domain of UI research in a quantitative manner as well as identifying the possible research directions