Major new initiatives to enable mapping underground utilities

I remember being immensely and very happily surprised at the Geo Business 2016 conference in London when on the street outside the conference I spotted a towable combined above ground/below ground scanner which combined a mobile laser scanner with a ground penetrating radar (GPR) array. This configuration was designed to make it possible to survey once, covering above and below ground simultaneously. To me it signaled that underground utility mapping was beginning to attract the interest of major survey equipment vendors. This and the Open Geospatial Consortium's recent initiative to develop interoperability standards for underground infrstructure represent a significant new advance in mapping underground utilities. This article is intended as a follow-on to the article "Accelerating world wide initiatives to map underground utilities " I published several years ago.

About 4 million excavations are carried out on the UK road network each year to install or repair buried utility pipes and cables. Not knowing the location of buried assets causes practical problems that increase costs and delay projects, but more importantly, it increases the risk of injury for utility owners, contractors and road users. The problems associated with inaccurate location of buried pipes and cables are serious and are rapidly worsening due to the increasing density of underground infrastructure in major urban areas. In the U.S. it is estimated that an underground utility is hit about every minute. Underground utility conflicts and relocations are the number one cause for project delays during road construction. Assuming the average direct cost of underground strikes is roughly $1000 per strike, the estimated total cost to the U.S. economy is $1.5 trillion annually. If indirect costs such as traffic disruption, project schedule delays, and others are included the economic cost is significantly higher.

Nicole Metje of the University of Birmingham has researched the direct costs of utility strikes in the U.K.

Electricity ￡ 970 Gas ￡ 485 Telecom ￡ 400 Fibre-optic ￡ 2,800 Water ￡ 300-980

Direct costs include the costs of sending a crew to assess and repair the damaged pipe or cable. Indirect costs include the impact of traffic disruption as a result of the strike, any injuries and other impacts on the health of the workers directly involved or people in the immediate neighbourhood, and the lost custom that businesses would have experienced as a result of the traffic disruption. Dr. Metje has found that the true costs associated with utility strikes is much higher than the direct costs. Her estimate is that the true cost is about 30 times the direct cost. 

A number of return on investment (ROI) studies have identified the significant benefits of knowing where underground utilities are located. A USDOT-sponsored survey conducted by Purdue University in 1999 quantified a total of US$4.62 in avoided costs for every US$1.00 spent on accurately location underground utilities. Although qualitative savings (for example, avoided impacts on nearby homes and businesses) were not directly measurable, the researchers believed those savings were significant, and arguably many times more valuable than the quantifiable savings. A Pennsylvania State University study commissioned by the Pennsylvania DoT found a return on investment of US$21.00 saved for every US$1.00 spent on elevating the quality level of subsurface utility information. An economic analysis of the costs and benefits of applying GPR to detect the location of underground infrastructure in in Lombardy, Italy estimated that the return on investment is about €16 for every euro invested in improving the reliability information of underground infrastructure.

A new standards initiative for underground utilities

Standards for reporting the reliability of the locational information about underground utilities have been in place for decades but there have been recent developments that reflect improvements in underground remote sensing technology.  In the U.S. the ASCE 38-02 - Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data is widely used for classifying location information about underground infrastructure according to its estimated reliability. Quality classes A,B, C, and D classify location information about underground infrastructure according to how the location is detected. A,B, C, and D refer to different ways of collecting information about underground infrastructure, with A representing potholing, B using remote sensing, C estimating from visible above ground facilities and D the paper record. In France the standard defines three levels of cartographic accuracy for underground structures defining explicit precision levels (< 40 cm, 40 cm - 1.5 m, >1.5 m). In the UK the Publicly Available Specification (PAS) 128 developed under the auspices of the British Standards Institution (BSI) and sponsored by the Institution of Civil Engineers (ICE) not only includes A,B, C, D quality levels similar to the U.S. standard, but also includes explicit precision levels (denoted as Bx). The new PAS 256 standard "Buried services – Collection, recording and sharing of location information data" which is intended to complement the existing PAS 128 standard was released in April of this year.

Currently, the exchange of underground utility information between infrastructure organizations within the same jurisdiction or in adjacent jurisdictions has been greatly hampered by incompatible and incomplete data. The Open Geospatial Consortium (OGC) intends to make a significant contribution towards facilitating improved information management, sharing and collaboration which should make infrastructure planning, operations and maintenance, and emergency response less costly and time consuming, and more effective. The OGC has initiated a three-phase project to develop interoperability standards for underground infrastructure. The Underground Infrastructure CDS project is supported by the Fund for the City of New York and its sister organization, the National Center for Civic Innovation, the Ordnance Survey and other organizations. The underground infrastructure data interoperability project will take two and a half years to complete and it is intended to involve the collaboration of many cities, utilities, and engineering and technology companies.

Current underground utility detection technology

Remote-sensing tools for underground utility detection have been available for over a decade. For example, in 2005 Leica Geosystems acquired UK-based Cable Detection. Leica Gsosystems has also had a partnership IDS (Ingegneria dei Sistemi) for a number of years. As a result Leica Geosystems offers both electromagnetic (EML) and ground penetrating radar (GPR) hardware and software for detecting underground utilities. 

Electromagnetic detection wands (for example, the Leica DIGiSYSTEM and Leica ULTRA) that can be combined with a signal generator to detect conductive pipes and cables are the industry standard tools. They use several frequencies to detect shallow and deep infrastructure, but basically these are 2D locators. EML wands are simple to use and effective for detecting underground infrastructure as long as it is conductive and accessible (so as to be able to induce a signal in the pipe or cable).

GPR devices (for example, the Leica DS2000) not only can detect nonmetallic objects but also provide 3D location - reporting depth as well as X,Y location - which makes GPR a superior mapping technology to EML wands. When combined with GNSS locators GPR can determine accurately the geolocation of underground infrastructure in 3D.  The use of GPR has become almost mandatory in the water industry that is increasing its use of plastic piping (GPR is not particularly good at detecting the plastic pipe itself, it detects the contents of the pipe such as water). 

But GPR does have drawbacks. The most important is that it requires an expert, typically a trained geophysicist, to interpret the scans. Secondly, current devices are intended to operate at a walking pace making GPR inefficient compared to mobile laser scanning, for example. In addition identifying the type of utility (water, electric, fiber optic) generally requires supplementary information from other sources. In some soil types such as aggregate and clay GPR does not perform well. 

Leica Geosystems and IDS (Ingegneria dei Sistemi) have worked together on GPR for years. The DS2000 is a joint Leica/IDS development. Two years ago Hexagon acquired IDS' GeoRadar division. The first significant technology annonced by the Hexagon GeoRadar groups was the towable Pegasus: Stream array. Designed to be towed by a vehicle at speeds up to 15 km/hr (though 5-10 km/hr are more typical), it was designed to provide simultaneous above and below-ground 3D scanning. It includes a mobile laser scanner with laser scanners, optical cameras and GNSS receivers ( Leica Pegasus: Two) for above ground features and a Stream EM GPR array for below ground objects. This was a major technology announcement at the 2016 HxGNLive event where I had the opportunity to briefly chat with Stuart Woods, Leica Geosystems Vice-President of Mobile Mapping, who made it clear that Leica Geosystems was seeing a major opportunity in underground utility detection and that the GeoRadar investment would be followed by more significant investments in underground mapping technology.

A vision of the future for underground utility mapping

Last week in Heerbrugg, Switzerland I had the opportunity to chat with Katherine Broder, President Construction Tools Division at Leica Geosystems, about Leica Geosystem's vision for the future advancement of underground mapping hardware and software. 

Katherine said that Leica Geosystem's current focus is on the expert market and the immediate goal is to bring positioning and underground detection together so that the same set of tools for detection, positioning and GNSS work together to provide accurate location for underground infrastructure. The customers for this technology tend to be high-end: utilities, DoTs and MoTs, and government mapping agencies. But Leica intends to democratize this technology to the broader professional market by making the technology more accessible. In addition to bringing detection, positioning, and data sharing together with "one button" simplicity Leica's longer term goal is to tie them together with vertical applications such as machine control for automated construction. Hexagon's focus on cross-discipline integration is an important driver for this integration for vertical industries.

According to Katherine currently the largest market for underground detection is the U.S. The European market, outside of the Netherlands and the U.K., tends to be conservative. Each utility does its own maintenance and there is little coordination among utilities and communications companies to minimize traffic disruption. The result is that the same stretch of road can be dug up multiple times inconveniencing the public each time. To date infrastructure maintenance in Europe hasn't invested in technology. Underground detection is basically limited to potholing which is a hugely expensive way of locating underground infrastructure. Katherine estimates the cost of a pothole, including indirect costs such as traffic disruption, is roughly $30,000 per pothole. Katherine believes the potential for technology in Europe is huge - once the cost to the economy of current practices is realized allowing GPR and other technologies to begin to penetrate the utility and telecommunications infrastructure maintenance market.

As with laser scanning where Leica Geosystems is democratizing the market and has just introduced the BLK360 with one button operation and a low price intended to broaden laser scanning to the non-expert professional market, Leica's goal is to make underground utility detection accessible to the broad market of non-expert professionals including surveyors and geospatial professionals. The biggest constraint limiting GPR penetration is the difficulty of interpreting GPR scans. A trained geophysicist is essential. To get around this hurdle and make it possible for non-expert professionals to use GPR, Leica Geosystems has just announced DX Office Vision Utility Post Processing software. This enables users with minimal training to extract pipes and other infrastructure from GPR data into a CAD drawing with minimal training. In addition it supports overlaying EML scans beginning to enable multi-sensor analysis. 

Hexagon's IDS GeoRadar division has just introduced the Stream C, a compact GPR array solution for real-time 3D mapping of underground utilities which is equipped with software for automatically mapping underground infrastructure. A massive antenna array with two polarizations provides an increased level of accuracy and together with software for tracing signals across multiple scans the system automatically detects and locates the position of pipes in real time and displays them on screen. The system can be towed manually or with a small vehicle, increasing the acquisition speed up to 6 km/h.

Another major software initiative is to enable real-time collaboration between field staff and the office so that above and below surveying can occur simultaneously. Leica DX Manager provides a single dashboard for users of underground detection systems like the DS2000, GIS collectors, and GNSS positioning systems to manage spatial data, tasks and field teams. The platform allows users to locate, map and share subsurface utility information simultaneously. For example, DS2000 users can integrate location data including depth measurements with GNSS measurements.  This makes it possible to have field operators with limited training and experience to collect data that is viewed and interpreted in real-time by geophysical experts in the office.

A related opportunity is to enable condition assessment simultaneously with below and above ground survey. This involves integrating other technologies and is analogous to multi-sensor scanners such as the Pegasus: Two and the Pegasus Backpack which include laser scanners, photo cameras and IR cameras. Location and condition data would be very helpful to utilities in prioritizing their maintenance work.

Katherine said that Leica Gosystems sees a major opportunity is managing and sharing documentation about underground infrastructure. Right now there is vast duplication of detection because each utility and communications company does its own scanning and potholing and the data collected is rarely shared. Leica Geosystems in investigating the market opportunity for software tools that provide a way of sharing this information about underground information. The technology enabling this to happen are already there, the challenge is organizational. Should a government agency have this responsibility as is already the case in several cities around the world or could a commercial company collect the data and charge for sharing it.

An innovative pilot in Chicago led by City Digital, Cityzenith, Accenture, HBK Engineering, and the City of Chicago uses a mapping platform that collects digital images of open excavations, extracts 3D information from them and shares the information. When local engineering firms and utilities excavate in streets or sidewalks, workers take a digital photo of the visible pipes and wires exposed by the excavation. The images are then scanned into the mapping platform, which extracts key data points from it: location, depth, and diameter of the pipes and other attributes of the infrastructure in the photo. The collected 3-D infrastructure data can then be searched geographically and displayed over a digital map of Chicago’s streets.

Summary

In the last few years, there has been a growing recognition of the benefits of accurately geolocating underground infrastructure and the business opportunities this creates. The business benefits of accurate geolocation of underground infrastructure have been documented by a number of ROI studies. Some countries, municipalities, utilities and communications companies around the world have created 3D models of underground utility infrastructure. Remote sensing technologies such as electomagnetic (EML) and ground penetrating radar (GPR) have been available for decades, but partly because of the difficulty of using these technologies for non-experts, potholing remains the default method of geolocating underground facilities in many parts of the world.  There are signs that this is changing. A significant investment in underground detection, positioning, and documentation management is being made by a major survey equipment vendor. Already this has resulted in advances in processing software that have begun to make GPR accessible to the non-expert market. In addition, a major new standards initiative is underway by the OGC to enable improved information management, sharing and collaboration for underground municipal infrastructure. An innovative pilot in Chicago tested technology for the low cost acquisition and sharing of information about underground infrastructure including location. I have seen signs that the service sector is beginning to realize significant business opportunities in underground utility mapping - at the last GeoBusiness conference in London, there were at least five or six companies offering underground utility detection and mapping services.