On Common Ground
October 1, 2007
A real-time GNSS network has gone online in Albuquerque, N.M., just in time to support the surveying requirements of the huge Mesa del Sol development project on the city’s south side. The Albuquerque Real Time GNSS Network (ARTGN) will give surveyors, engineers and many others unprecedented freedom and accuracy, along with substantial cost savings.
“This is GPS on steroids,” says Anthony Trujillo, vice president of Holman’s Inc., the local distributor of Topcon Positioning Systems (Livermore, Calif.) components for the ARTGN system and an early supporter of the project. “A surveyor working anywhere within the 400 square miles covered by ARTGN only needs a rover on a pole and a subscription to be part of the network and perform centimeter-accurate observations that are directly related to the city’s network of control.”
With the system, every user utilizes the same data based on the same network of control. “[There’s] no more finger pointing when things don’t work out quite right; no more streets, sewers and pipelines that don’t quite meet; no more lawyers and lawsuits to fix the blame for mistakes,” Trujillo says. “The indirect savings are huge.”
A Model for Mesa del SolThe Mesa del Sol development south of Albuquerque will include new industrial, retail and residential development in a three-by-five-mile area that’s essentially undeveloped.
“Mesa del Sol is a blank sheet of paper,” Trujillo says, “and it will be totally developed start to finish using one common data set provided by ARTGN. Everything will conform to the same network of control, and that’s the one maintained by the city of Albuquerque.”
The ARTGN consists of five continuously operating base stations connected to a pair of HP ML350 servers located in the city’s data center. The redundant servers ensure data availability on the network all day, every day, all year round. Topcon TopNET network software is used to process the incoming data to provide centimeter-accurate positioning in real time. Field crews can access real-time corrections from the network via cell phone or radio.
“Anywhere inside the polygon formed by the five stations, the software creates our own virtual reference station,” explains Cliff Wilkie, the city’s geodetic surveyor who originated the ARTGN concept in 2004. “In practical terms, that means a surveyor can walk around anywhere in that area with a rover on a pole and get centimeter-accurate observations, just as if a mobile GPS base station were operating a few meters away. And you get the benefit of short baselines to give you better error cancellation with the GNSS mathematics as a bonus.
“Outside the ‘box,’ you just switch to RTK using one of the five permanent base stations and continue surveying the way we’re all used to. Between the area inside the ‘box,’ and the roughly ten kilometer range of the base stations outside the ‘box,’ more than 400 square miles of the city and surrounding area is covered by the ARTGN system.”
Trujillo explains that the Mesa del Sol developers have installed their own base station on a high point right in the center of the area and everything will be related to it. “As part of the ARTGN coverage area, it’s tied into the existing network of control with high precision,” he says. “This is how all of our cities and infrastructure will be built in the future--and it’s a reality today in Albuquerque.”
Surveyors, engineers and land developers aren’t the only groups who will benefit from the precision location capabilities of the ARTGN. Emergency services, homeland security, and myriad other city services and private businesses will also see tangible results.
“Anybody who needs to answer the question ‘Where is this thing?’ and can handle instruments like the Topcon GMS-2 handheld receiver is going to benefit from ARTGN,” Trujillo says. That list includes everyone you would automatically think of, but also includes landscape architects, park and recreation designers, even archeologists and botanists.
But surveyors and engineers will be among the first major beneficiaries of ARTGN, both in terms of reduced field workloads and substantial cost savings. The savings in time and cost made possible by the system are estimated to be as high as $69,000 per year. These savings come from reduced setup time because no mobile base station is required within the ARTGN service area; reduced downtime from radio interference/communication issues due to the cell phone primary network interface; reduced travel because fewer trips are needed with no mobile base setup requirement; reduced waiting time due to “instant-on” rover availability; and reduced losses to theft and vandalism of costly mobile base station equipment.
A Three-year Plan of ActionARTGN is the product of more than three years of cooperative effort by the Albuquerque Department of Municipal Development and interested local users.
“Mayor Martin Chavez is a staunch advocate of new technologies that can help Albuquerque maintain and enhance its reputation as a great place to live and do business,” says John Castillo, director of the city’s Department of Municipal Development. “This project has had a high level of support throughout the city’s government. There is no doubt that by making the surveyor’s job easier and more precise, the benefits will be seen by everyone who lives or does business in Albuquerque.”
ARTGN began with a meeting between Wilkie and a group of local surveyors and engineers in 2004. Wilkie had followed GNSS developments as a matter of both personal and professional interest for several years, and recognized that Albuquerque was a nearly ideal location for a networked real-time system like ARTGN.
“Albuquerque has a very high density of control monuments that were put in place in the late ‘60s and early ‘70s,” Wilkie explains. “More importantly, they have been regularly maintained and upgraded over the years, and surveyors are required to make ties and show them on plat maps under the subdivision rules. That gave us an exceptionally good foundation to build on.”
But, Wilkie points out, “ARTGN is not unique--there are 35 or more similar systems in the United States, and Japan and Europe are very well covered. China has at least ten systems, and there is even one in Dubai. What makes ARTGN different is its tri-constellation capability and the fact that it’s owned by the city government. Both of those are ‘firsts’ in New Mexico for sure, and I believe in the United States as well.”
The tri-constellation capability refers to the fact that the Topcon TopNET G3 receivers at ARTGN’s five permanent base stations are able to use signals from the 24 active American GPS satellites, the 18 active Russian GLONASS satellites, and eventually the European Galileo constellation when it becomes available in the 2011- 2013 timeframe.
Encouraged by the favorable response he received in the initial meeting, Wilkie began to discuss the idea of the system with others both inside and outside the city government. Eventually, this led to a meeting with Castillo, director of Wilkie’s department, representatives of six prominent Albuquerque surveying firms and two large land developers. Included in the latter group were representatives of Forest City Enterprises Inc., a firm involved in planning the massive Mesa del Sol project.
“After listening to the presentations, it was obvious that this was an idea worth pursuing,” Castillo says. “We did some additional research in the survey/engineering and land development communities, and determined that a user fee for the system would be well accepted.” With that information, Wilkie got the go-ahead to take the next step, Castillo said.
“Actually,” Wilkie says, “with the mayor’s interest in technology and the obvious financial advantages for system users, it was an easy sell. Within a few days, John Castillo was able to locate funding for the project.
“The plan also fit in with some changes to the subdivision regulations we had already been working on. It required an ordinance change to require surveyors to show reference to NAD 83 and NAD 88 values, which the new system supports. But we were already moving in that direction, so the additional changes were relatively minor.”
He adds: “It was an interesting process because the higher up we went in the city government, the more support we found. I would strongly recommend that anyone trying to implement a system like this not be discouraged by initial negative responses. There were a lot of meetings and explanations required to get the approvals we needed to mount equipment on public buildings like fire stations and to install infrastructure on public property elsewhere. The support we got from Mayor Chavez’s office helped a lot.”
Practical ConsiderationsOnce Wilkie received permission for the system, the next step was determining what kind of hardware and software was needed to make ARTGN a working reality. The choice of a vendor is relatively easy for a privately owned network, but the city had to accommodate virtually everyone who was interested in using ARTGN, regardless of what kind of equipment they had.
Wilkie had worked with Holman’s Inc. while developing the ARTGN concept, so when the time came to bid the project, Holman President Trujillo enlisted the support of the national Topcon organization to put the winning package together.
“We worked with Cliff and the city for more than two years helping develop this project,” Trujillo says. “Topcon recognized how important ARTGN was and pulled out all the stops to help us with the bid. They even accessed a Topcon software expert to tweak the software to make it work with some equipment they don’t even sell.”
“Topcon also has given a grant to Central New Mexico Community College to support training programs for the technicians we are going to need to handle the equipment that makes this system work,” Wilkie notes. “Based on our success to date, we are going to need a lot of them.”
Eventually, of course, the benefits of ARTGN will be reflected in lower overall costs of living and doing business in Albuquerque and the surrounding region. With surveying and engineering as the ultimate foundation of all economic activity, any change that makes these disciplines more efficient is eventually reflected in the cost structure of everything that follows.