Reporter Magazine Vol. 65

65

The Global Magazine of Leica Geosystems

Dear Readers, The world's seven billionth living inhabitant will be born this year. The UN has estimated that in 2025 there will be eight billion and in 2050 over nine billion people living on and therefore off our small planet.

Using space and resources efficiently is becoming an ever greater challenge and one in which precise geodata can play an immensely important role. With this in the background, the burning issues are the rising demand for energy, the provision of food to all these people and the efficient exploitation of new and renewable energy sources.

Up-to-the-minute geodata – absolutely reliable and in real time – are necessary to make optimum use of space, resources and energy. With new approaches to solutions and innovative products that offer high quality, interoperability and compatibility – as with, for example, the new Leica Viva Series, Leica Geosystems is making its contribution to the future.

Some exciting examples can also be found in this issue of the Reporter, such as those our customers have adopted to make the best use of resources – surveying the Cumberland Trail with the Leica Viva GNSS, reliably determining the areas of photovoltaic panel systems with the Leica Builder, or the way Leica SmartNet allows access to GNSS corrective data in real time.

We shall be presenting further new, innovative products and solutions such as the Leica GS25 GNSS receiver, the Leica GR25 reference server and the Leica Viva TS15 Robotic Imaging Totalstation at Intergeo in Nuremberg from 27 – 29 September. I look forward to your visit to the Leica Geosystems exhibition stand in Hall 7A!

CONTENTS

Editorial

03 A New Network for a Town Torn in Two 06 Passing a Tough Test 10 Environmental Research with GNSS 12 Accurate GNSS Everywhere with SmartNet 16 A Smooth Runway in Record Time 18 Teaming up with the Sun 20 Scanning Beyond Retrofit Design 22 Flying 60 Knots Above the Colorado River 25 Monitoring Toronto’s Union Station 28 Swiss Bridge, Visible World-wide 30 Mobile Robots with Leica GPS1200 32 GNSS for Ethiopia’s Sustainable Development 34 Leica Geosystems @ facebook

Imprint Reporter: Leica Geosystems customer magazine Published by: Leica Geosystems AG, CH-9435 Heerbrugg Editorial office: Leica Geosystems AG, 9435 Heerbrugg, Switzerland, Phone +41 71 727 34 08, reporter@leica-geosystems.com Contents responsible: Alessandra Doëll (Director Communications) Editor: Agnes Zeiner, Konrad Saal Publication details: The Reporter is published in English, German, French, Spanish and Russian, twice a year.

Reprints and translations, including excerpts, are subject to the editor’s prior permission in writing.

Juergen Dold CEO Leica Geosystems

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© Leica Geosystems AG, Heerbrugg (Switzerland), September 2011. Printed in Switzerland

A New Network for a Town Torn in Two

by Karl-Friedrich Weber

The town of Staufen in the Black Forest has literally been torn apart: following failed geothermal borehole drilling, the ground on which the town and its 7,800 inhabitants stand has risen by up to 40 cm (15.7 in) in the last three years.

This has had serious consequences for some of the houses in this historically listed town, some of which have cracks running through them that are up to 10 cm (3.9 in) wide. The town council commissioned surveying engineers Weber to set up a geodetic deformation network to monitor the continuing rise of ground levels.

Situated at the edge of the Black Forest about 18 km (11 mi) south of Freiburg, Staufen is dominated by the ruined castle that has stood watch over the fate of the town since the Middle Ages. However, the small-town tranquility is deceptive: as part of a major refurbishment of the historical town hall,

the council unanimously decided to heat the building and its rear extension using geothermal energy.

The application to install the boreholes to a depth of up to 140 m (460 ft) was submitted to the Freiburg Regional Council, Office for Geology, Raw Materials and Mining (LGRB) and then approved by the local water authority. A specialist firm commenced drilling at seven locations near the town hall buildings in autumn 2007.

267 Buildings Affected By the end of the year, hairline cracks were appearing in the town hall and in 179 further properties in the historic city center. The cracks continued to grow. In spring 2008, engineers from the Surveying Department of the Breisgau-Hochschwarzwald District Council started to record the precise movements of 26 leveling points using a Leica DNA03 level. They found the ground at the centre of the affected area was rising by up to 12.5 mm (0.5 in) per month. Three years later leveling was extended to cover the entire

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Location of Staufen Staufen stands on both banks of the River Neumagen at its exit from the M체nstertal valley. Here the Black Forest valley with rolling foothills becomes the Rhine plain.

The castle rises above the valley on the north, while the gentle hills of the Markgr채flerland begin to the south. The town's administrative area lies between 260 m to 810 m (853 ft to 2,657 ft) above sea level.

town with a total of 89 points. Within just three years, 260 private and seven council buildings were showing signs of damage. The number of affected buildings continued to rise each year until 2011, when it remained the same.

In 2008 Freiburg District Court presented an initial report from its appointed specialist consulting engineer. In the report he concluded that water had evidently penetrated a gypsum-sandstone layer and the subsequent reaction with the anhydrite had caused an increase in volume of about 60 %. Putting it simply: the gypsum layer under the town was rising like a loaf of bread. An exploratory borehole in March 2009 confirmed the report's findings.

The penetrating water makes the gypsum layer under Staufen rise.

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Geodetic Deformation Network In 2010 the geologists decided to determine the horizontal movements of the ground. With the help of the LGRB's Surveying Department and the Geodetic Institute at the Karlsruhe Institute of Technology (KIT) the Staufen Town Council put out a tender to establish and monitor a geodetic deformation network. Weber engineering consultancy was awarded the job of setting up the measurement points and surveying the geodetic network employing a combination of GNSS observations with RTK and a bearing and distance survey carried out with a precision total station. We have been using Leica Geosystems products successfully for years, including on many precise geodetic networks for major construction projects.

Therefore we opted for the precision of the Leica TPS1201+ and the Leica GPS1200+ GNSS receiver for this project as well.

The deformation network consists of six stable points (datum points) and 72 points on various items of infrastructure (non-datum points). The network was

receiver the phase ambiguities were resolved first, the epoch saved, and then the new survey saved in a second epoch. After quitting all satellite connections, this procedure was repeated to obtain four saved epochs per survey point. A time window of at least 30 minutes was maintained between two observations.

After processing the data, the survey results were sent to KIT for evaluation. The terrestrial data were combined with the GNSS observations and adjusted with an evaluation program at the Geodetic Institute, Karlsruhe. The achieved average point error of 7 mm (0.28 in) and the resulting accuracy of approximately 1 mm (0.04 in) on lengths in the direction of the predicted principal axis of deformation fulfilled the requirements of a reliable deformation analysis and were completely within the required positional accuracy of ± 5 mm (0.2 in). This was also confirmed

by KIT. The next survey is planned for the winter months of 2011/2012.

Has Staufen Stabilized yet?

augmented by existing cadastral reference points, change points used for the level surveys, and new fix points on curb stones and buildings, with mounts for precision prisms. The required positional accuracy in the unconstrained network was specified as ± 5 mm (0.2 in).

Top Precision with TPS and GNSS In accordance with the specification, the Leica TPS1201+ was checked on the instrument calibration baseline at KIT before surveying commenced.

The corrective values obtained from the calibration, which are taken into account in the network adjustment, are essential to achieve the precision required on this project. To attain the most precise and reliable results, measurements had to be taken using two different methods – terrestrial and satellite (GNSS) – at different times.

The full extent of the damage cannot be predicted – not only for the town hall, which was renovated in 2007 and was particularly affected, but for the historic city center. Current estimates put the cost of the damage to buildings alone at 42 to 50 million Euro. The offices of the building authority were evacuated because of the danger of collapse and many buildings have had to be shored up. The cracks are up to 10 cm (3.9 in) wide and the occupants of some of the buildings can look through them onto the street, while ground levels have risen up to 40 cm (15.7 in).

Since March 2011, Staufen has stabilized at least to some extent: after completion of a second relief borehole to pump out the water, the highest expansion rates of up to 12 mm (0.47 in) per month have been reduced to about 5.5 mm (0.22 in) per month.

About the author: Karl-Friedrich Weber is the owner of the surveying consultancy of the same name in Müllheim/Germany. (info@weber-vermessung.de)

Temperature and barometric pressure were recorded during the surveys to achieve still higher precision from the total station. In the survey with the GNSS

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Passing a Tough Test

by Brad Longstreet

“I spent about three weeks up there – I wouldn’t have missed it.” says RLS founder Shane Loyd, PLS (Professional Land Surveyor) about his work on the soon-to-be-completed Cumberland Trail in Tennessee, “but I have to admit, I was glad to get home too!” RLS, based in Chattanooga, Tennessee, has been around since 1999. Starting in 2007, they began to offer scanning and have established a good reputation for applying cutting edge techniques and equipment to surveying projects. On the Cumberland Trail project, the survey equipment used was a Leica Viva GNSS system and it was about as cutting edge as possible: “We picked up two systems and I think we were the first firm in the South to have one,” says Loyd, laughing, “Even the Allen Precision (Leica Geosystems’ dealer in the US) guys hadn’t been fully trained yet, so in some respects we were on our own. We got them out

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of the box and drove straight to the job, so it was a tough test for new equipment. Fortunately, the system worked great.”

The Cumberland Trail in Tennessee, inspired by the popular but crowded Appalachian Trail, begins at Cumberland Gap National Historic Park and ends just outside Chattanooga. Currently, 190 km (118 mi) of trail — out of more than 480 proposed kilometers (300 mi) — are completed, and remaining sections are being added about as fast as they can be surveyed and developed. The 30 km (19 mi) section surveyed

by RLS stretches from the park to LaFollette, and includes the historically significant McClean Rock, where Justin Wilson and others are said to have been standing when they conceived of the trail.

In this case, the Molpus Timber Company, along with several private owners, owned most of the land being acquired for the trail. Legal descriptions and maps were needed to complete the transfer, and RLS

crews also set rebar, boundary marker posts, and painted as needed to identify the trail alignment.

As part of the transfer process, a private group, The Trust For Public Land (TPL), temporarily owns new acquisitions before they are transferred to state agencies. Everyone involved wanted to minimize the period of private ownership, which explains the short time frame of the survey. “The negotiations involved kept pushing back our start date,” Loyd says, laughing, “but somehow that didn’t push back the due date. We’d originally planned on six months to do this work, but ended up having to do it in three!”

Why in Winter?

During the eleven weeks that RLS crews worked and camped in the Tennessee bluffs, a total of 1.5 m (60 in) of precipitation fell. Snow was bad enough, but “rain was worse,” according to Loyd, “because we’d get soaked, the equipment would get soaked, and rainy days were still extremely cold.” Many days were so cold and uncomfortable that work would stop midday just to build fires and warm up. And because winter light is scarce, workdays were rela-

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tively short and crews would cook, melt water, and tend to survey chores in the dark. All of which begs the question, ”Why do this project in the winter?”

“Even with the cold and the snow, winter was better,” explains Loyd, “because of the deciduous foliage, it was easier to see and to get around without clearing a lot of brush. This was a major factor for us when using the Leica Viva GNSS system in order to meet our deadline.” The area is also “snaky”, with large populations of rattlesnakes, copperheads, and even bears that hibernate in winter.

So, all things considered, winter really was the best time. But that meant that surveying, camping, cooking, battery charging, calculations, and all the other business of life and work had to take place in extreme conditions, several hours from the nearest city. It was a severe test for both humans and survey equipment.

ing parcels in the area, create a 60 m (200 ft) wide trail corridor, mark the corridor with rebar, boundary markers, and paint, and provide maps and legal descriptions of the corridor. Simple enough as boundary surveying goes, but in addition to the everpresent weather and terrain difficulties, there were other significant challenges.

“Parcel descriptions around here go back to the North Carolina Land Grant of 1785, before Tennessee was even a state,” Loyd explains, “and the scribed trees that were called to just don’t exist anymore.

Other descriptions made very vague calls like ‘bluff lines’ or ‘top of ridge’ and it can be very hard to know exactly where these lines are now.”

Even though this wasn’t a topographic survey, interpreting available descriptions meant that bluffs and other features had to be located. “With all the oneto-one slopes out here, and the snow cover and the brush, traversing with total stations would have been ridiculous,” says Loyd, “Fortunately, the Leica Viva GNSS system really came through for us. We put it to the test and we were never disappointed by the reliability, accuracy, and durability of the equipment."

On a good day, crews could locate about two miles of ridgeline a day, sometimes crawling through mountain laurel patches to find clear spots. In some areas, a real-time kinematic network, operated by the Tennessee Department of Transportation, was available and in other areas RLS relied on static surveying. “We always had the coverage we needed,” Loyd says, “We did have some issues on the northwest side of steep ridges, but even there we learned what times of day we could work and it wasn’t a problem.”

Loyd, and Project Manager Scott Carter, PLS, also gathered a lot of parol evidence to help with boundary work. Owners would come out on weekends, on four-wheelers, to meet with the surveyors and relate what they knew about boundaries. In many cases they had knowledge of longstanding agreements about the precise location of vague topographic calls, or could point out the minimal existing monumentation. “In the entire 30 km (19 mi) we surveyed,” says Loyd, “there were only about 20 points I could really ‘hang my hat on.’ But with the evidence we gathered we were able to put together a solid boundary.”

Surveying the Trail The actual project requirements were straightforward. RLS was asked to locate and mark underly-

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A brand new survey system and data interface could have been a problem, but the Leica Viva system

worked very well, according to Loyd. “We’ve been using Leica Geosystems products for a long time, and we were sure the new system would work out.” Even so, Loyd and Carter were very happy with how quickly employees picked up the new system. “It took just a few hours and everyone was able to do everything with this system,” says Loyd, “the menus and the buttons are very clear, we were getting satellite lock with exceptional speed and reliability, and everything held up well in the cold and damp. Basically there was no learning curve. We couldn’t be happier with how well Leica Viva GNSS worked for us.”

Since part of the job was to create and mark the corridor on the fly, crews used the Viva Field to Office feature with the cellular link to upload data at the end of workdays. An RLS office technician would stay late to download the data, calculate an alignment, and upload the alignment to the site. In the morning, crews would log in, download the alignment, and get to work. “We could have done the calcs in the field,” says Loyd, “but that would really have cut into the

time available for survey work and camping chores.

The cellular links worked very well for us and made life a lot easier.”

Living Rough In some ways, the Cumberland Trail project resembled surveying from the sectional survey days. Crews spent weeks in the field, living rough; and dealt with tough conditions every day. In other ways it seemed like the future thanks to the use of progressive GNSS systems, cellular uplinks, and personal GPS beacons.

By bringing together the skills of the past and equipment of ‘right now’, The RLS Group was able to complete a project that will benefit future hikers for generations to come.

About the author: Brad Longstreet is a freelance writer specializing in land surveying, GIS, and laser scanning technology.

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Environmental Research with GNSS

by Agnes Zeiner

On three closely linked interdisciplinary projects, two of which are within the remit of the Competence Center Environment and Sustainability of the ETH Domain (CCES), the Institute of Geodesy and Photogrammetry (IGP) at the Swiss Federal Institute of Technology Zurich (ETH) opted for the Leica GRX1200 reference station receiver. The scope of the projects extends from research into tectonics, the movements of block glaciers right up to the determination of atmospheric water vapour content. The common denominators are sustainable studies in the fields of energy and environmental catastrophes as well as the Leica ATHENA Program for Higher-Education and Non-profit Organizations.

“The three projects demonstrate how GNSS can be used in a wide range of research. We see GNSS as a valuable multifunctional tool in geodetic seismology and tectonics, in hazard monitoring and last but not least in atmospheric research,” explains Professor Alain Geiger from the Geodesy and Geodynamics Lab (GGL) at the Institute of Geodesy and Photogrammetry. The aim is to make new discoveries and gain better knowledge of particular processes so that natural

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catastrophes can be predicted and even more importantly, averted.

Earthquake Research In COGEAR (COupled seismogenic GEohazard in Alpine Regions), an ETH Domain project in the canton of Wallis, high-precision Leica GRX1200 reference stations are used to study tectonics, in particular the longterm movements of the earth’s crust and to detect the displacements arising from earthquakes. “This task requires a whole network of stations,” explains Geiger. The project studies earth crust movements and the team around Geiger hopes to highlight zones under high and increasing strains. “We also wish to research earthquake risks in the Alpine area and the associated displacements that could lead to soil slips and rock falls,” says Geiger.

Water Vapour APUNCH (Advanced Process UNderstanding and prediction of hydrological extremes and Complex Hazards), another ETH Domain project, uses Leica GRX1200 reference stations to determine the distribution of water vapour in the atmosphere. “If a network has enough receivers, the high-precision measurements can be processed to reveal a threedimensional image of the distribution of atmospheric

water vapour,” explains Geiger: “Water vapour and rain are at the start of the chain that can lead to flooding, soil slips and build-ups of water. We wish to work out when and how much rain will fall by studying the whole chain.”

Block Glaciers In the third project X-Sense, part of the Swiss federal programme Nano-Tera, research is taking place on block glaciers, among them the Dirru in the Mattertal valley. “In this study we are looking into the detailed movements of block glaciers and trying to assess the potential risk of slips, because thawing block glaciers pose a danger for whole valley communities,” says Geiger, who along with Dr. Philippe Limpach and doctorate students is supporting this project from the GNSS side. Low-cost receivers from a third-party supplier are used as local references on the glacier, with the Leica GRX1200 GNSS receiver acting as the regional reference instruments. The Computer Engineering and Networks Laboratory from ETH Zurich, the Department of Geography from the University of Zurich, the Swiss Federal Office for the Environment and the company GAMMA Remote Sensing are working alongside Geiger’s team on the X-Sense project.

The three projects are spread over a period of time and overlap one another and will take up to six years to complete. “The GNSS stations, which are used for all three projects and form our ‘backbone network’, will be maintained afterwards. To augment the information from the reference stations, we are working very closely with the Federal Office of Topography (swisstopo), we can use its AGNES network as a higher-order reference network and therefore also include its data, for example, in our atmospheric research,” explains Alain Geiger.

The Leica ATHENA Program The use of the high-precision GRX1200 reference stations falls within the framework of the Leica Geosystems ATHENA Program. ATHENA stands for “Advanced Technology for Higher-Education and Nonprofit Associations”. The objective is to support academic and research bodies with the latest GNSS and monitoring technology.

About the author: Agnes Zeiner is Director Corporate Messaging at Leica Geosystems in Heerbrugg/Switzerland. (agnes.zeiner@leica-geosystems.com)

Reference station on a swisstopo trig point above the Randa avalanche zone (Wallis Canton, CH). The Dirru block glacier can be seen on the opposite side of the valley.

ETH Domain and the CCES In addition to the two universities of applied sciences, ETH Zurich and EPF Lausanne, ETH Domain also includes four federal research establishments: Paul Scherrer Institute (PSI), Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) Swiss Federal Laboratories for Materials Testing and Research (Empa) Swiss Federal Institute of Aquatic Science and Technology (Eawag) The ETH Board has supported four theme-oriented competence centres for interdisciplinary research in which the relevant areas of each institute work closely together. They form a platform that interlinks basic research and applied research to produce innovations with economic or social benefits and provides a point of contact for external enquiries. One of these is the Competence Center Environment and Sustainability of the ETH Domain (CCES).

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Accurate GNSS Everywhere with SmartNet

by Mark Burbidge

Ten years ago, RTK surveys typically involved two GPS receivers (a base and a rover), a lot of batteries and cables, two radios, a tripod, a pole, and a backpack to carry it all. Today users can choose between a GPS or a GNSS receiver, and a radio or a mobile phone, and it all fits on the pole. With the establishment of RTK networks, they can also choose to work with an RTK rover within these networks instead of setting up their own base-station. Leica Geosystems SmartNet gives users easy access to precise Network RTK data, where they experience the best availability, reliability, and traceability using internationally recognized standards, combined with flexible and affordable subscription options that meet the needs of the local market.

Traditionally users of precise GPS equipment would use a reference station (base station) set up over a known point to transmit relative corrections to their rover equipment (often by a UHF radio). The limitation of this solution is that as the distance between base and rover increases, it becomes more difficult to rapidly resolve the carrier phase ambiguities. This

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is caused by the distance-dependent errors associated with the GPS measurement, such as ionospheric and tropospheric refraction and satellite orbit errors.

However, by using the reference station network technique with inter-station distances of up to 70 km (44 mi), these errors can be mitigated and the GPS rover, when connected to the network control center, can operate within the entire network, free of distance-dependent constraints. This also means that with the latest technology developments from Leica Geosystems, the rover receivers have all the advantages of working with the raw data or modeled corrections, within the entire network.

More than ten years ago Leica Geosystems had the vision to span the world with their own GPS networks. Today, many SmartNet services are installed across most of Europe, North America (including Canada), and Australia, with a broad range of real time and web products. SmartNet has become the de facto standard for GNSS network services. Many professionals benefit from using SmartNet to efficiently complete their daily tasks, including Surveying, Engineering, Construction, Agriculture, Machine Control, Utility Surveys, Archaeology, Monitoring, Police Accident Investigation, and many more.

Stepping back in Time In 1991 Leica Geosystems launched the era of Kinematic GPS, which became a successful addition to the surveyor’s toolbox of measurement devices. Then, in 1996 the world saw the first Leica Geosystems network RTK system for an engineering project: the nearly 8 km (5 mi) long Øresund Bridge connecting Denmark and Sweden.

With the launch of System 500 in 1999, rapid development of remote applications for managing GPS reference stations began. Initially based on direct serial connections, control applications were developed to take advantage of dial-up communications, using the public switched telephone network (PSTN).

Then came the use of TCP/IP protocol suite in local or wide area networks. But it wasn’t until the evolution of the Internet with Networked Transport for RTCM over Internet Protocol (NTRIP), that a whole new world of possibilities in the development of end-user solutions opened up. Wireless digital cellular services also began to compete with UHF radios to help route GPS corrections transmitted from a reference station directly to the rover in the field.

In June 2000, Leica Geosystems was already well aware of the large potential offered by the Inter-

net to transmit data in real-time: Web-based applications to transmit GPS data with low latency were now being developed for the first time at Leica Geosystems on a demonstration network in Atlanta. The goal was to showcase the usefulness of the Internet for low-bandwidth applications and to develop the functionality to facilitate the dissemination of realtime data in areas beyond the reach of line-of-sight radios, and with more reliability.

In 2001 Leica Geosystems installed the first large reference network in Michigan (USA). Also in 2001, Leica Geosystems and Geo++ presented a paper to the RTCM SC104 that contained a proposal to standardize network RTK correction messages. This new RTCM proposal would overcome the problems of the existing approaches and would benefit the whole surveying industry. The proposal, which is called the “Master-Auxiliary Concept” or MAC, put forward by Leica Geosystems and Geo++, has since undergone small refinements based on input from other manufacturers.

Following extensive research and development, Leica Geosystems produced the Leica GRX1200 in 2004, the first GPS reference receiver with an internal network interface card, which could connect directly to

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Great Britain – Pioneers of the New Revolution The first country to pioneer the Leica Geosystems SmartNet concept was Great Britain. On 20 th December 2005 Leica Geosystems UK announced that they were the first organization to market and offer a commercial delivery of a GPS network solution across Great Britain, in partnership with the UK’s national mapping agency, Ordnance Survey.

The reference station infrastructure was built on 130 stations, mainly from the Ordnance Survey reference station feed (OSNet), but supplemented with additional stations via The Survey Association members, Universities, and Leica Geosystems UK. Nottingham University IESSG also undertook independent monitoring and integrity checking to validate the “user experience”. Today over 1,000 users take advantage of the service.

In 2008 Leica Geosystems also won the Ordnance Survey tender to upgrade the entire network to

the Internet. This now simplified the approach for having the reference receiver continuously attached to an Internet line to stream raw data.

In December 2005 Leica Geosystems SmartNet was first launched in Great Britain (see box). The brand name brought together all the hardware and software innovations that Leica Geosystems had been

“The Leica Viva NetRover automatically connects to the SmartNet GNSS RTK network service.

Locating and surveying services is very easy but, more importantly, it is efficient and accurate.”

Peter Eimansberger, Stadtwerke Bad Tölz

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the latest GNSS reference enabling the tracking for all signals. This immediately capability to allow full GPS to end users.

stations and antennas, current and future GNSS enhanced the network & GLONASS corrections

Today, SmartNets are operating in many countries around the world, such as the UK & Ireland, Germany, Spain, Denmark, Italy, Norway, Sweden, Finland, Greece, Bulgaria, Lithuania, Slovakia, Holland, and parts of America, Canada, and Australia, just to name a few. RTK Networks can vary in size, from small local networks consisting of only a few reference stations, to dozens of reference stations covering a whole country.

Europe: http://smartnet.leica-geosystems.eu North America and Canada: http://smartnet.leica-geosystems.us Australia: http://smartnetaus.com

working on for the previous five years. In partnership with the national mapping agency, Ordnance Survey (OSNet), Leica Geosystems was the first manufacturer to launch a fully enabled commercial Network RTK solution to users in Great Britain.

Quality of Service (QoS) Within a Network RTK solution there are many factors that need to be synchronized, such as the satellite signals at the rovers position, raw data streams from all reference stations across the Internet, network software processing, and mobile communications between the user and control center. And it all has to happen within a few seconds! To provide users with the best quality of service, every part of the system must have the highest reliability for a continuous service, running 24/7, every day of the year.

The network reference station infrastructure is the backbone of any GNSS Network service and availability of sites is critical to its operation. For this task Leica Geosystems supplies the highest performance GNSS reference receivers and antennas, such as the GRX1200+, GR10, GR25, and AR10 / AR25 reference station antennas. Together with the latest Leica GNSS rover systems (Leica GPS1200, Leica Viva, Zeno GIS), the net result for the end user is the best quality of service available.

All RTK network services “powered by Leica Geosystems” provide a variety of real-time products, including Leica MAX (based on the RTCM Master Auxiliary Concept), the first and only International Network RTK standard, lead by Leica Geosystems and other RTCM council members; i-MAX, Virtual Reference Stations; and FKP. SmartNet also offers a number of value added services including RINEX and Virtual RINEX downloads, an online coordinate computation service, and more.

track all future signals from modernized GPS and GLONASS, the European Galileo, and Chinese Compass systems.

About the author: Mark Burbidge is SmartNet Manager at Leica Geosystems based in Milton Keynes, United Kingdom.

(Mark.Burbidge@leica-geosystems.com)

Future Views As on-demand GNSS applications and services increase, especially in agricultural and machine control markets, SmartNet will be further enlarged throughout the world, with the latest technology from Leica Geosystems. To enable these new, expanded services, we will continue to rely on the latest technology and mobile communication developments to bring everything together, as a single GNSS business platform for end users.

Today SmartNet is already the largest Network RTK data centre in the world, operating in over 15 countries in Europe, North America, Canada, and Australia. The services are already comprised of GNSS capable receivers, with the full capability to

Powered by Leica Geosystems As described in the logo strap line, SmartNet is “powered by Leica Geosystems”. This means that the system is fully enabled to support all Leica Geosystems hardware and software innovations, such as Leica System 1200 and the new Leica Viva products, Leica SpiderNet, Leica SpiderQC, and Leica CrossCheck.

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A Smooth Runway in Record Time It's the runway reconstruction project whose impact was felt worldwide. New York's John F. Kennedy (JFK) International Airport’s main Bay Runway, was in need of repair. JFK's governing organizations intensively researched the best possible methods and procedures to either repair or replace the aging runway. Flight delays resulting from a completely shutdown Bay Runway could potentially impact worldwide flight timetables. JFK International Airport serves 48 million passengers and 440,000 flights annually, with the total number of air passenger traffic expected to increase by 20 percent over the next decade. Bay Runway handles about one third of the annual operations, including more than half of all departures. The newly rebuilt runway was expected to reduce delays overall by an estimated 10,500 hours per year.

Rebuilding the runway efficiently and quickly was a major consideration in the preplanning phases of the project. The runway was planned to be widened from 46 to 61 m (150 to 200 ft) and to include a new drainage system, new electrical infrastructure, the addition of delay reduction taxiways and accommodations for future navigational aids. Tutor Perini Corporation, based out of Sylmar, California, was awarded the Bay Runway contract and given just 120 days to complete the bulk of the project. Company offi-

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cials immediately began looking for the most reliable and productive equipment to use in all phases of the reconstruction. For the concrete slipforming work, including the new runway, Tutor Perini Corporation executives looked to Gomaco and Leica Geosystems.

“We spent a lot of time planning out each aspect of this project,” Damon Petrillo, Project Manager for Tutor Perini, said. “We even had back-up plans for our back-up plans. We knew we’d be paving 168,000 m³ (220,000 yd³) of concrete on the project.” Their main paving train included both a Gomaco placer and a placer/spreader in front of the four-track concrete slipform paver with Auto-Float® and Leica Geosystems’ PaveSmart 3D machine control system.

A Gomaco texture/cure machine completed the paving train.

Before any work began on the Bay Runway, a test section had to be completed. The test section was new Taxiway KC, 305 m (1,000 ft) long, 30.5 m (100 ft) wide, and 50 cm (20 in) thick. The taxiway mimicked all of the same conditions as the runway, including excavation, milling, paving, and more. It also gave the authorities and Tutor Perini a chance to test their concrete mix design and paving methods. “This was our first time running exclusively "stringless" (with 3D machine control) and that was a bit of a learning curve for us. We got a lot of support from Gomaco

and Leica Geosystems and it all went pretty seamlessly. The test strip afforded us the opportunity to learn and figure it all out,” Petrillo said.

The construction schedule was designed to include three and one-half months between the completion of the test section and the beginning of the 120 day runway closure. During that time, a series of meetings were held to discuss the lessons learned while constructing the test section and perfecting their paving plan. Tutor Perini was also busy stockpiling their supplies, trucking in aggregates, cement, and other raw materials.

Then, on March 1, 2010, the Bay Runway was officially closed for 120 days. By mid March, Tutor Perini was paving concrete. “Our concrete paving went very well,” Petrillo said. “Keeping the concrete placement on schedule was the key factor for the project’s overall success. The utilization of Leica Geosystems’ PaveSmart 3D system was one of many contributing components.”

The Gomaco pavers were slipforming passes 7.6 m (25 ft) wide, so it required eight passes to slipform the 61 m (200 ft) wide runway. A GP-4000 would work

during the daylight hours on the longer paving runs.

At night, while the GP-4000 went through cleaning and routine maintenance, a GHP-2800 worked on the shorter runs and fill-in sections of the project.

Smoothness specifications on the runway required a profile index with a two-tenths blanking band of 35 cm/km (22 in/mi) or less. Between 24 and 35 cm/km (15 and 22 in/mi) was subject to a penalty reduction and over 347 mm (22 in) required grinding.

Straight-edge specifications allowed a 6 mm (0.25 in) plus or minus grade differentiation in 152 m (500 ft).

Tutor Perini easily achieved and exceeded both specifications.

The runway reopened on June 28 with all navigational features, beating their required July 1 deadline. Total length was 3,330 m (10,925 ft), requiring 122,330 m³ (160,000 yd³) of concrete. The early completion earned Tutor Perini a $5 million bonus. The remaining 1,112 m (3,647 ft) of runway was completed in the next few months with the total volume of work completed by mid-November 2010, one year ahead of their contractual schedule.

Article courtesy of GOMACO Corp

Leica Geosystems and Gomaco Corporation Over the last 12 years, the successful relationship between Leica Geosystems and Gomaco Corporation has brought the industry an unrivaled 3D stringless paving technology solution, getting it to the point of acceptance it is at today. In January 2011, Leica Geosystems entered into an OEM value added agree-

ment with Gomaco Corporation. This new business relationship will enable further collaboration between these industry powerhouses – concrete paving contractors will benefit from technological innovations that will take stringless paving technology to the next level.

The Global Magazine of Leica Geosystems | 17

Teaming up with the Sun

by Frank Schmidt

Against the background of fresh doubts about the safety of nuclear energy and our awareness of climate change caused by global CO2 emissions, the search for alternative methods of energy is assuming new urgency. Alongside wind and geothermal sources, free solar power supplies our cleanest form of energy. Solar technology is “hot” as never before and photovoltaic systems are enjoying a lasting boom in Germany, where for many years the Renewable Energy Act (EEG) has guaranteed two decades of enhanced feed-in tariffs for the owners of new systems with an output of up to 30 kW. The state subsidy offers an additional incentive to refinance a system. Optimizing the size of photovoltaic systems, and therefore their output, requires the latest technology: in solar energy and in surveying. Elektro Staudt offers its customers an outstanding service with the Leica Builder Total Station.

Elektro Staudt Installations-GmbH has operated from its Upper Bavarian base in Bruckmühl (near Rosenheim) for more than 30 years. In addition to traditional electrical work, Staudt has also made a name for itself in the region as a photovoltaic contractor, installing 2 megawatts of capacity a year. In the past,

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quotations were often found to contain errors that could be traced back to incorrect roof shape information.

Roofs were measured using traditional methods: usually the client made drawings available that were often only of limited use, either because of undocumented design changes or because the owners had made alterations or extensions over the course of time. The survey was done as well as possible, a photo taken, the roof tiles counted, and, last but not least, the area estimated instead of precisely determined! All this had serious consequences both for the quotation phase with the customer and later during the installation, after the order had been won.

Frequently the quotation was based on too many or too few photovoltaic panels. “Often an error of a few centimeters is enough for a panel not to fit. Chimneys encroach, satellite dishes get in the way, and so on. All to the detriment of the capacity of the quoted system,” explains Staudt. He was looking for a measuring system with which he could simply, quickly, and above all reliably, determine the available roof area. After trying out various methods, he turned to the Munich-based Leica Geosystems agent Vermex.

A demonstration on site at the premises of one of his customers was enough for Josef Staudt to appreciate

the possibilities offered by the Leica Builder. By the time he left the site, he had made himself familiar with the instrument's simple and logical operation.

With reflectorless distance measurement and userfriendly programs at his disposal, all Staudt has to do is capture the corner points of the roof from the eaves to the ridge to immediately obtain the area and even the inclination of the roof.

Staudt also uses the Leica Builder to pick up other objects in the vicinity of the measured roof. For example, there may be tall trees, houses, or chimneys that could cast shadows on the photovoltaic panels and therefore reduce the system's theoretical output. Staudt can take this information into account and advise his customers. Even the height of trees can be quickly and precisely determined using the instrument's integrated measuring program, without the need to clamber over the roof. Staudt: “Safety is paramount for us. With the Leica Builder, we can measure safely from the ground.”

Staudt stores the captured data in the instrument and transfers it to his Smartphone. From there he

sends the data directly to the office, where the quotation can be completed in the shortest possible time.

“The Leica Builder has been excellent from day one – quick, simple, and safe. I no longer have errors in my dimensions,” says Staudt, who is happy enough to share the Leica Builder with his two sons for the moment – but it won't be long before a second Leica Builder appears on the company's books. Quotations are now more reliable and correspond to the actual roof area, which also simplifies the work on site.

Delivering too few or too many modules for the available roof area to a site is now a thing of the past.

About the author: Frank Schmidt is the Managing Director of Vermex, an authorized Leica Geosystems dealer with headquarters in Munich. (info@vermex.de)

© Photo courtesy of Linc Energy Ltd.

Scanning Beyond Retrofit Design

by Geoff Jacobs

MegChem Engineering & Drafting Services (Pty) Ltd, South Africa, is a multi-discipline engineering company serving a diverse client base in the oil, gas, power generation, and energy related industries. The company, founded in 1995, is ISO 9001-certified and has more than 300 employees. They also have a Leica HDS6100 scanner, Cyclone, and CloudWorx software as part of their engineering services toolkit.

Performing plant design for “retrofit” or “revamp” projects at existing plants is a common task for MegChem and for many other plant engineering companies. MegChem originally acquired Leica Geosystems laser scanning technology for the purpose of performing accurate as-built surveys of existing sections of plants intended for modification or expansion. Accurate as-built information of existing plants enables accurate retrofit design, which, in turn, makes retrofit installation and construction go smoothly. This type of application of laser scanning is the very type of application for which high-accuracy laser scanning was first developed; today, it is used this way for hundreds of plant retrofit projects every day, worldwide.

What is especially interesting about MegChem’s use of their Leica High-Definition Surveying™/HDS™ tools is that, over time, MegChem and an Owner/

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Operator client have also made valuable use of these tools for a variety of applications that are not retrofit design projects, but rather support “Operations & Maintenance” needs of the plant.

Accurate plant documentation using intelligent 3D models One of MegChem’s clients has begun an initiative to document portions of their existing plant, parts of which are very old, via intelligent 3D computer models using Integraph’s SmartPlant 3D software.

(This initiative was the subject of presentations at the Hexagon 2011 International Conference, June 2011 in Orlando, FL.) These models not only contain accurate geometry of key objects in the plant, but also include detailed information about the types of materials, spec ratings, etc. of each object (hence, the term “intelligent” model). From these comprehensive intelligent 3D models, the Owner/Operator can extract accurate, up-to-date information needed for regulatory compliance, as well as 2D and isometric drawings needed by Maintenance and Operations personnel for various tasks.

Exact fit replacements In many cases, plant maintenance staff simply replaces old equipment or piping with precisely matching new equipment and piping. Although there is no re-design or new design involved, “as-is” geometry information derived from laser scanning has also proven valuable in this application. Accurate

Fragment of a destroyed shipping container – as picture, laser scan and mesh. This way, MegChem's customer can find out the cause of the explosion.

Left: Construction of Linc Energy’s Gas to Liquids demonstration plant in Chinchilla during 2008.

laser scan data can uncover slight but very important changes in object geometry, for example in flange orientation and pipe bends, that have occurred over time due to thermal and structural stresses.

Location of a vessel’s internal welds for external ultrasonic weld testing Periodic testing of welds is regular practice in the highly safety-conscious plant industry. External ultrasonic testing of internal vessel welds used to be subject to the availability of the vessel interior to first locate the welds; however, access to a vessel’s interior does not always line up well with weld testing schedules. By scanning the vessel’s interior when it’s accessible, MegChem was able to precisely locate interior welds for external tests that could be conducted when convenient.

Kiln coating thickness assessments & monitoring High-Definition Surveying has proven valuable for assessing and monitoring critical coating thicknesses on the interior surface of kilns. Scanning is performed on the kiln interior and exterior. Geo-referenced concentric scans are overlaid to determine coating thickness. Such evaluations can be done periodically to establish wear trends.

Structural analysis of bulging vessels using Finite Element Analysis (FEA) software Although bulging and warping of vessel exteriors may be visible to the naked eye, it is not easy to precisely characterize the extent of such bulging for analysis purposes. Operating staff needs to know if the bulging represents an imminent safety hazard, if remediation is possible and if so, what extent of

remediation is needed, or whether or not the vessel walls need to be replaced. Leica Geosystems scanning tools have proven valuable for producing mesh files that can be fed into FEA software for suitable structural analyses. With accurate as-is information, better informed decisions can be made.

Forensic analysis to establish root causes of incidents or material failures When accidents happen at industrial plants, consequences can be severe. So, it’s important for Owner/ Operators to understand why and how such incidents occur in order to prevent future accidents. MegChem has used their Leica Geosystems scanning tools to precisely analyze fragments of an exploded shipping container. All fragments were scanned, surface areas established, and then analyzed to identify possible causes.

Although MegChem Engineering initially added laser scanning capabilities to aid in the design of plant retrofit (brown-field) projects, MegChem has found over time that they can also provide additional, valuable as-built surveying services to a key Owner/ Operator client for a wide variety of Operations & Maintenance applications. These services provide significant added vale for the client and represent a significant additional revenue stream for MegChem – a win-win situation for all.

About the author: Geoff Jacobs is Senior Vice President, Strategic Marketing, Leica Geosystems, Inc. (geoff.jacobs@hds.leica-geosystems.com)

The Global Magazine of Leica Geosystems | 21

Mapping the 64 km (40 mi) powerline along the canyon (orange line).

Flying 60 Knots Above the Colorado River

by Mary Jo Wagner

When veteran pilot, professional engineer, and land surveyor Gary Grigsby took off from Rifle/ Colorado in his helicopter last June to survey a canyon with newly fitted Leica Geosystems LiDAR sensor and digital camera, he harbored some doubt about how well the technology would perform over the challenging terrain ahead.

“Though I was confident in the abilities of the LiDAR and camera system, I was still unsure how the technology would acquire the very high accuracy and density required while the helicopter was constantly maneuvering,” explains Gary Grigsby, president of Western Research & Development (WR&D), a small engineering and survey company based in Cheyenne, Wyoming. “But it was flawless. And that both surprised and impressed me.”

The high quality results of that survey were also a welcome relief for Grigsby, who one year prior, had gambled that acquiring Leica Geosystems’ ALS60 LiDAR sensor and Leica RCD105 digital camera would boost his small company’s growth. “At the time, no other companies in the area were flying LiDAR or digital imaging surveys with a helicopter,” says Grigs-

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by. “That presented a business opportunity, but the investment was also a big risk for our small company.

That’s why I chose the Leica Geosystems airborne system. I knew it would bring us notable growth and new business.”

Indeed, within only a few short months of fitting the Leica ALS60 sensor and RCD105 camera into WR&D’s Bell 206L LongRanger helicopter, Grigsby and his colleague Alan Moore, a project engineer, were testing that risk in the Colorado canyon, meandering along the narrow corridor and hugging its walls – at times to within 61 m (200 ft) – at varying speeds, directions, and changes in elevation, to survey an existing power line. A veritable success in all aspects, the canyon project not only proved that acquiring the Leica Geosystems technology was a solid bet, it was the triumph WR&D needed to confidently pursue and pioneer new business developments and reap the rewards of an expanded service area, project portfolio, and revenue stream.

Rolling the Dice WR&D was predominantly an aircraft instrumentation research and development company when it began in 1983. The R&D focus of WR&D has remained strong through its shift into civil engineering, surveying, and photogrammetry. While standard survey work has

been a steady part of its diverse portfolio, historically, WR&D has left photogrammetry and LiDAR survey work to other companies. And that was a wasted opportunity, says Grigsby. “As avid end users of photogrammetric and LiDAR data, we understand well how to acquire these data sources and how they can benefit our clients,” describes Grigsby. “Acquiring our own technology would afford us the business development tool to enhance our core business offerings, challenge the status quo of traditional survey applications, and pioneer new uses of the techniques.”

After a two year analysis of LiDAR and digital imaging technologies, WR&D chose to purchase both the Leica ALS60 Airborne Laser Scanner and the Leica RCD105 Digital Frame Camera, providing a versatile, high performance “plug and play” platform to collect very dense and very high resolution data. “With the helicopter’s low air speeds and altitudes, we can capture up to 150 LiDAR points per square meter and come to within three-tenths of a foot (9 cm) vertically,” qualifies Grigsby. “That’s extremely high accuracy and density. And with the pod-mounted RCD105, we can collect georeferenced photography at a two-inch (5 cm) pixel resolution.”

The Colorado canyon survey, commissioned by engineering, architecture and surveying firm Merrick &

Company, would be one of the first tests of this combined technology. Merrick tasked WR&D to capture 64 km (40 mi) of an existing power line with both the ALS60 and the RCD105 to ultimately create very high-resolution orthophotos, 30 cm (1 ft) contours and a classified LiDAR digital elevation model.

Into the Canyon In preparation for the aerial survey, Merrick sent ground crews into the field to map the position of the transmission line on the ground and provided the base map to WR&D. For a better visual of the area, personnel pinpointed the path of the power line in Google Earth, cross-checked it with the base map and noted any “blind” areas – spots where the line couldn’t be identified in Google Earth or accurately mapped on the ground – that would require extra attention in flight. They then created the most efficient flight plan using the Leica Flight Planning and Evaluation Software (FPES) and overlaid it onto a Google Earth map. In mid-June Grigsby and Moore flew to Rifle for the survey.

Every morning for four days, a WR&D surveyor would set up two Leica GPS1200 base stations while Grigsby and Moore prepared the imaging payload for the scheduled flight. Once in flight, Moore controlled the mission; monitoring the scanner returns and qual-

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The Global Magazine of Leica Geosystems | 23

ity of the pictures in real-time, keeping a visual on the power line below the helicopter, and instructing Grigsby of any necessary lane changes. Grigsby says the stability of the Leica Geosystems airborne system was the one constant that they could confidently rely on throughout the ever-changing conditions.

“We would come across a plateau at 61 m (200 ft) and suddenly the ground underneath would drop down to 300 m (1,000 ft),” he says. “Those drastic changes in elevation cause constant up drafts and down drafts and wind shifts, causing our flight speed to

vary and requiring frequent on-the-fly adjustments.

Throughout it all, the Leica Geosystems system performed perfectly. It automatically compensated for our variations in speed and elevation and alerted us if we exceeded speed.”

Flying at an average speed of 111 km/h (60 kts) and 460 m (1,500 ft) above the Colorado River, the team collected about 250 GB of raw LiDAR data –at 20 points per square meter – and photographs of the winding power line from Rifle to Grand Junction. As the Leica RCD105 camera collects imagery in synch with the Leica ALS60, the two data sets were automatically tied together geographically by the onboard airborne GPS and inertial measurement unit, as well as with GPS base stations, eliminating the need for ground targets and streamlining the post processing.

After each flight, Moore downloaded the data and performed quality control to ensure they had the coverage, accuracy, and data density needed. They then sent the data to Merrick for post processing.

Knowledgeable themselves with LiDAR and photography, the Merrick team was impressed with the accuracy and quality of the data sets.

“With the RCD105 imagery, we developed natural color orthophotos at a quarter-foot (8 cm) resolution,” says Roger Hanson, director of operations at Merrick, based in Aurora, Colorado. “That’s very, very high-resolution imagery.”

“Quite simply, the capabilities, features, and quality of the instruments allowed us to successfully complete this project,” concludes Grigsby. “Leica Geosystems provided us with a complete LiDAR/digital imaging package and have backed that with quality service.”

Indeed, though WR&D is reaping the rewards of its successful gamble, it is unlikely Grigsby will try to transfer that winning luck to a blackjack table.

About the author: Mary Jo Wagner is a Vancouver-based freelance writer with nearly 20 years experience in covering spatial technology. (mj_wagner@shaw.ca)

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© Taxiarchos228, de.wikipedia.org

Monitoring Toronto’s Union Station

by Brad Longstreet

Downtown Toronto’s Union Station is Canada’s busiest rail terminal, handling about 65 million passengers annually. Built from 1915 to 1920, it’s considered to be a masterpiece of Beaux Arts architecture, expressed in the ornately colonnaded front and the 76 x 27 m (250 x 90 ft) Grand Hall, which is famous for its marble floor, soaring arched roof, and four-story windows at each end.

To cope with modern demands, Union Station is now undergoing a $650 million refurbishment, begun in early 2010. The aboveground portions of the historic building are being restored, the upper three levels of the west wing will be renovated into the head office of Metrolinx (the regional transportation agency), and the concourse is to be tripled in size to a total of 11,300 m² (2.8 acs).

All this expansion requires new foundation work.

Each column in the lowest basement level will, one by one, be supported by jacks, cut away to permit foundation work, slightly lengthened, and reloaded. Two

factors make this difficult job even more demanding: Damage to the historic structure is simply not permissible, and train service cannot be interrupted.

Both of these factors require monitoring to ensure public safety and to prevent any settling or shifting that might damage the 100-year-old architecture.

With these two factors combined, and considering the extremely high-profile nature of the project, foundation contractors knew that they needed very precise, real-time monitoring of the column replacements. There aren’t many firms that can confidently take on monitoring work at this level. Fortunately, one of them is in Toronto.

Monir Precision Monitoring, Inc., is a subsidiary of Isherwood Associates, a geostructural engineering firm based in Ontario. Monir has been a separate business for nine years, employs 17 people, and has been growing about 20 % annually.

For the Union Station project, Monir had to combine precision and speed; onsite contractors had to know immediately if column movement was exceeding modeled predictions during the foundation work.

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The Global Magazine of Leica Geosystems | 25

The thresholds were tiny: movement of just 2.5 mm (0.1 in) would trigger an alarm, and movement of more that 3.0 mm (0.12 in) would immediately suspend work. And there was a significant complicating factor: because heavy trains would be arriving and departing directly overhead, train-caused movement had to be accounted for in the monitoring system.

precise. The hang up was distance measurement. “In practice,” says Gondo, “the EDM actually is accurate enough. But we would be exceeding manufacturer’s specs, and no one wanted to assume the liability for that.”

Monir partnered with Leica Geosystems to determine a method for obtaining sufficient accuracies. Leica Geosystems’ Don Edgar suggested fixing the distance measurement on a few critical measurements during foundation work. For some of the prism readings during the work a previously measured distance would be held as constant, and movement would be derived from angular readings alone. This would work because manufacturer’s specifications for angular measurement (at the distances being considered) were well within the tolerances required.

The Monir crew set 23 prisms on and around each column being worked on. The three most-critical prisms (one actually on the column and the two nearest to the column) were measured as described above with a fixed distance, and the rest were measured normally. A Leica TS30 robotic total station was used for measurement, set well away from the work in a stable area.

Instead of strain gauges, total stations were used to measure tiny movement thresholds due to construction and train movement .

Total Station Advantages Monir began by determining the right equipment.

The project’s lead contractors had assumed that strain gauges would be the only sensors that would be accurate enough, but Monir surveyor specialist Thomas Gondo, RLS, wasn’t so sure. “Strain gauges are very accurate,” he explains, “but they work by precisely measuring movement in a small area and then extrapolating. And that requires that properties be uniform throughout the monitoring area – we didn’t feel we could make that assumption.”

Instead, Gondo wanted to use a total station, which could rapidly measure the entire area of concern and surrounding areas. But Monir had to convince their clients that the total station could be sufficiently

26 | Reporter

To process and obtain real-time results, Monir used GeoMoS, Leica Geosystems’ automatic deformation monitoring system, to control the Leica TS30, guiding it through a series of automatic shots. In this case, all 23 prisms were sighted and measured automatically every seven and a half minutes, and the three mostcritical prisms were measured once every minute.

GeoMoS was also used to incorporate data from pressure transducers, which are sensors that measured pressure at the jacks that unweighted the column.

This data was displayed along with TS30 data on one GeoMoS screen. “Basically, what you see on screen is the change at each target and the pressure,” Marcelo Chuaqui, CEO of Monir, explains. “What’s neat is that we were able to read and display everything at once.”

To rule out sighting errors due to dust and exhaust, some critical monitoring work was scheduled for 3:00 a.m., when air was clear and the station was quiet. To account for movement caused by trains, Monir used train schedules and pre-gathered measurement data to establish baselines. GeoMoS then correlated train

schedules and baseline data so that train-caused movement, as opposed to movement due to foundation work, would not trigger alarms.

As it turned out, project engineers were surprised by how little movement was caused by trains. “The biggest movement we saw was 0.6 mm (0.02 in),” says Monir survey manager Colin Hope, RLS, “which the structural engineers had a hard time believing. But we confirmed that we were providing good numbers.

Sometimes, we’re the first ones to really measure performance, and the results can be a surprise. In this case, the station’s slabs are much stiffer than anyone knew.”

Redundant Readings with Independent Methods “We stress redundant readings with independent methods,” says Chuaqui. On the Union Station project, the independent methods included the pressure transducers and two additional techniques: levelling and before-and-after as-built surveys.

station readings before, during, and after foundation work. The results corroborated the total-station readings and reassured project engineers who were expecting to see more movement during the lifting and reinstating of column loads.

When asked if the Union Station monitoring is a typical project, Chuaqui laughs and says, “It’s a typical ‘special’ project. We don’t really have typical projects — we’re usually assembling different techniques and equipment to suit particular tasks.”

Chuaqui says that the clients on this monitoring project have been “impressed with our ability to convey results immediately; they could just look at one screen and know exactly what was going on. That’s helpful to them and lets them do their work with greater confidence.”

Reprint with permission of Professional Surveyor magazine.

For levelling, Monir used a digital level with invar staffs, which helped them independently verify total-

The Global Magazine of Leica Geosystems | 27

Swiss Bridge, Visible World-wide

by Agnes Zeiner

A bridge over the Rhine near the village of Diepoldsau, not far from the headquarters of Leica Geosystems AG, is one of the most thoroughly monitored bridges in the whole of Switzerland. However, it is not about to collapse at any moment. The reason for this is the cantonal highways department gave Leica Geosystems permission to install any number of sensors and convert the cable-stayed bridge into a “test structure”. The canton benefits from this arrangement, as do (potential) customers, university students and last but not least, the Leica Geosystems product specialists.

“There is nothing more boring than monitoring a completely stable structure, even for testing purposes,” says Michael Rutschmann, Product Manager Structural Monitoring at Leica Geosystems, who is delighted that he and his team are allowed to treat the bridge at Diepoldsau as a “research structure”.

“This 250-meter bridge (820 ft) is not far from our

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main office and crossed by around 20,000 vehicles every day, which makes it ideal for us.”

Over the last few months, the monitoring team supporting Michael Rutschmann has come up with a detailed concept involving not only a wide range of sensors but also energy supplies, communications and data processing systems. Geotechnical sensors (Leica Nivel220 inclinometers), Leica GMX902 GNSS receivers and AR10 GNSS antennas were installed in the first phase to measure the movements of the bridge and their influence on the bridge piers. Meteorological sensors inform us of the weather conditions, thermal sensors measure the cable temperatures, ultrasonics are used to record water levels.

“The highways department engineers were sure that we would not detect any movement of the lower part of the piers, but the high-precision measurement capabilities of the Leica Nivel220 have surprised them,” smiles a delighted Rutschmann.

Further GNSS antennas and receivers will be attached to both piers in a second phase. The monitoring spe-

cialists are expecting to be able to measure substantial movements there, above all due to the effects of wind and temperature fluctuations. A Leica TM30 total station and prisms will be installed at a later date.

The data obtained from the various sensors and the full range of Leica monitoring software from GeoMoS to GNSS Spider, allow the engineers to see the movements of the bridge in context. “Our idea was to install the entire Leica Geosystems Monitoring product portfolio on this bridge, encompassing everything from hardware and software to communications and energy-generating equipment,” explains Rutschmann. We can also test alternative energy supplies.

The customers benefit firstly from the opportunity to take a look for themselves at the monitoring solution on the bridge at Diepoldsau in action and secondly from all the possibilities offered by immediate access to the data through the Leica Geosystems support engineers all over the world, who can view the data over Leica GeoMoS Web, live and in real time. Rutschmann comments: “We can show the potential of our solutions and how simply they can be tailored to a customer's particular requirements.”

Monitoring Concept for Rhine Bridge, Diepoldsau Sensors: TPS: Leica TM30 total station and prisms GNSS: Leica AR10 GNSS antennas and Leica GMX902 GNSS receivers Geotechnical: Leica Nivel220 inclinometers, extensometers Other: Meteorological, wind and temperature sensors, ultrasonics, webcams, data loggers Software: Leica GeoMoS (monitoring software) Leica GeoMoS Adjustment (data analysis) Leica GeoMoS Web (visualisation) Leica GeoMoS HiSpeed (high frequency deformation analysis) Leica GNSS Spider (reference stations) Leica CrossCheck (deformation monitoring) Customer Care Packages (CCP) Communication: Leica ComBox20

Leica GeoMoS Web can be found at http://geomos. leica-geosystems.com. If you are interested, please ask your Leica Geosystems sales advisor for a free user login ID and password.

The Global Magazine of Leica Geosystems | 29

Mobile Robots with Leica GPS1200 Open Street Map format of measured park Botanická záhrada in Bratislava, captured with Leica GPS1200.

by František Duchon, Marián Kl’úcik, Ladislav Jurišica, Anton Vitko, Dušan Kaštan

Robots, robots, robots – you find them everywhere. Often unbeknownst to us, they have considerable impact on our lives: we buy products made by robots, we use them in science, and they explore unknown environments. Robots aren’t “stupid” machines, but solve many complicated tasks without human help. They “live” in our world and can observe it with their sensors. To be able to move, robots need to know where they are, where they want to get to, and how to get there. These basic robotics tasks are called localization and navigation. They cover a large spectrum of different technologies and applications, drawing on some very ancient techniques, but also some of the most advanced space science and engineering. Amongst them Leica Geosystems’ technology, as tests with a Leica GPS1200 at the Institute of Control and Information Technology at Slovak University of Technology in Bratislava recently showed.

The majority of outdoor robots today use standalone GPS for their localization, which provides a horizontal

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position estimate to within about 20 m (66 ft). Such precision is sufficient for vehicle navigation, but it’s insufficient in robotics, where centimeters can determinate success or failure. Software and hardware solutions can improve location calculations and many robots use complicated mathematical procedures to improve the accuracy of GPS location estimation.

Advanced receivers can solve this problem: They can utilize other GNSS systems (e.g. GLONASS and Galileo in the future), are capable of DGPS phase measurements, use complicated Earth surface models, and many of them are capable of RTK measurements.

With these capabilities, these systems can improve horizontal position estimates to within centimeters.

Our team from the Institute of Control and Industrial Informatics, Faculty of Electrical Engineering and Information Technology at Slovak Technical University in Bratislava, was searching for a solution for the localization problem and tested some non-surveying GPS receivers, but wasn’t satisfied. At first, we decided to improve the estimation quality with mathematical procedures (Kalman filtering and moving average). Although this improved position estimate, it still wasn’t good enough for the precise localization of the robot. At this point we decided

to obtain a superior GPS receiver and finally chose a Leica GPS1200 instrument. Although usually used for geodetic applications, we wanted to try it in robotics – and we were surprised! Its centimeter accuracy in position estimate totally solved our problem of outdoor localization, so we could use it in many ways.

Our first test with the Leica GPS1200 was a position estimate of our outdoor mobile robot. This robot is richly equipped with hardware components such as a rotating visual system, gyroscope, optical encoders, ultrasonic rangefinders, laser scanner, and GPS. It is a great challenge to get data from all these sensors.

Moreover, there are other procedures for data processing that use complicated calculations. Our nonsurveying GPS receiver wasn’t capable of providing an adequate position estimate, not even with the application of Kalman filtering. Leica GPS1200 solved the position estimate problems and also improved the calculating time of the data processing.

The second test of the Leica GPS1200 was for the international “Robotour 2010” (www.robotika.sk).

“Robotour” is a contest of autonomous robots navigating on paved park roads. In previous years, there was abundant mapping of the environment shortly before the contest itself. These maps ranged from simple records of the traveled distance (dead reckoning) and direction (compass) to a non-trivial image analysis saving notable points along the way. For the contest, the robots only get the map and coordinates of the final destination – they do not know their exact starting position and operator interaction is limited to entering the final destination. The goal is for the robots to successfully solve this task to demonstrate their navigation skills by navigating using the map provided.

In the run up to the contest, our Leica GPS1200 receiver was used to create a map of the park Botanická záhrada in Bratislava. Measured data were then transformed to the Open Street Map format and made public via the Internet. Each of the contesting teams at “Robotour 2010” used this map.

Even though the results of the teams varied, we are proud to say that the Leica GPS1200 provided a precise map of the park.

Leica GPS1200 is a very powerful device that provides a complete solution for localization, as well a partial solution for navigation in robotics. From a number of tasks suitable for this system, we used it for the outdoor mobile robot localization and as a mapping system for the “Robotour 2010” contest. With some improvements in our control algorithms, we are planning to use the Leica GPS1200 in fully autonomous outdoor mobile robots we are developing.

We would like to thank Ing. Erik Frohmann from Leica Geosystems’ partner Geotech for his dedicated and helpful work on our project and utilization of the Leica GPS1200.

About the authors: František Duchon, Marián Kl’úcik, Ladislav Jurišica, Anton Vitko and Dušan Kaštan are members of the Institute of Control and Industrial Informatics at the Slovak Technical University in Bratislava. (frantisek.duchon@stuba.sk)

Outdoor mobile robot with Leica GPS1200.

The Global Magazine of Leica Geosystems | 31

GNSS for Ethiopia’s Sustainable Develop

by Hugh Anderson and Jacques Malaprade

The River Nile has sustained life in North Africa for millennia, during which time Egypt has successfully tapped into this resource. But in the area of the headwaters of the Blue Nile, Ethiopia has lacked the infrastructure to harness the river’s potential. In order to redress this imbalance the Ministry of Water and Energy for the Republic of Ethiopia commissioned a feasibility study for 800 km² (198,000 acs) of net irrigation development in three schemes, which required a total study or search area of 1,700 km² (420,000 acs)in Ethiopia’s Nile basin.

The project was funded by the World Bank and is being undertaken by UK based consultancy company Halcrow, who mapped the river catchment areas of Megech, Upper Beles and Negeso using Leica Geosystems GNSS equipment and stereo photogrammetry from satellite imagery.

The work areas were mostly in beautiful mountain landscapes, with the largest of the three schemes in the Upper Beles, west of Lake Tana, where the team could feel the temperature rising as they descended down the winding road into the valley. Disease was also present in the form of malaria and parasites such as tapeworms and giardia, with the added possibility of snakebites and scorpion stings, which could

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be fatal. Access to the Upper Beles landscape of rolling hills and mountains provided another challenge as teams would walk some 25 km (16 mi) a day in temperatures up to 40 °C, with changes in altitude of some 600 m (2.000 ft). Accommodation in the bush was basic and primitive and the team soon realized they lacked many things we take for granted, such as electricity, clean running water, clean washing and toilet facilities.

In these conditions the last thing that the team wanted to think about was the reliability of their survey equipment and the Leica GPS1200 and Leica GPS900 instruments did not let them down. Traditionally, one would consider airborne LiDAR or aerial photogrammetry for a survey of such large size in the terrain and location of Ethiopia. However, this would have been costly and there was also the problem of getting permission to fly in Ethiopian airspace, complicated by administrative barriers and security risks.

Research on methods to survey vast inaccessible areas of the globe brought up the possible use of 0.5 m (19.7 in) resolution satellite imagery using stereo-photogrammetric processing, which could be used to survey ground levels to under 0.32 m (12.6 in) accuracy in height. This would mean changing the survey methodology to make use of Ground Control Points in selected areas of the imagery to accurately

Halcrow and the Nile basin project With over 6,000 employees operating worldwide through a network of 98 offices, Halcrow is a global multi-disciplinary consultancy which delivers services for developing infrastructure and buildings, topographical mapping, in shore hydrography, Geographical Information Systems (GIS) analysis, and software support.

Halcrow’s involvement in the Nile basin project is the latest in a series of significant commissions recently undertaken in Ethiopia, including the Awash basin flood control and catchment management project as well as the Rift Valley lakes basin development plan.

ment resect the satellite positions. After a trial area was processed and the results compared with previously surveyed ground heights, a decision was made to purchase imagery for all the areas.

As far as the team were aware, this is the first time that an area of this size had been surveyed using satellite imagery to such a high accuracy. Previous surveys at similar accuracies were for only one image pair, whereas the Beles survey contained 30 image pairs.

The decision was made to complete the survey with terrestrial methods using long range GPS-RTK. Leica

More information: http://www.halcrow.com

GPS1200 and Leica GPS900 instruments were used for geodetic control surveys, tying in to the IGS network and local country datums and map projections to provide photogrammetric ground control points for the stereo satellite imagery. The Leica Geosystems GNSS instruments were chosen, as they were rugged enough to withstand the tough physical environment. At the same time they provided the team with peace of mind about reliability and accuracy of data, critical aspects when working in such demanding conditions. The Leica Geosystems instruments were also easy and quick to learn which helped when training the local Ethiopian team.

As a result of this project the Halcrow team have learned new skills with respect to photogrammetric mapping from satellite imagery, the Ethiopian surveyors have learnt new surveying skills with Leica GNSS and the local people in Ethiopia will benefit from the design of irrigation projects that could feed future generations.

Satellite image used as reference for GPS surveying.

About the authors: Jacques Malaprade, Land Surveyor, is Land Surveying Project Manager at Halcrow.

Hugh Anderson, Land Surveyor, is Technical Specialist at Leica Geosystems Ltd. based in Milton Keynes, United Kingdom. (hugh.anderson@leica-geosystems.com)

The Global Magazine of Leica Geosystems | 33

Leica Geosystems @ facebook Almost 100 photographs of markers, taken by our customers from all over the (surveying) world, can be found on our Facebook page www.facebook.com/LeicaGeosystems in the album “Markers�. Here you can find a random

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selection of photographs that have been sent to us. We are pleased to announce that within only a few months since the Leica Geosystems facebook page was launched, we have more than 4,500 fans!

The Global Magazine of Leica Geosystems | 35

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