In its last fiscal year, the New Jersey Department of Transportation (NJDOT) awarded some $300 million in highway paving and resurfacing contracts over the state. This fiscal year, ending June 30, 2011, NJDOT will let contracts for approximately $200 million in highway resurfacing projects. About half of the preliminary survey work for all of those projects is done by a staff of seven, led by John Knapp, supervising engineer for the NJDOT.
Instead of using traditional surveying methods to set control points and provide topographical data for the highway design engineers, the state’s NJ Geodetic Survey Unit uses Leica Geosystems’ SmartNet Real Time Network (RTN) to provide primary survey control in addition to photogrammetric control for all in-house aerial photogrammetry projects, says Frederick Czepiga, PLS, State Transportation Land Surveyor.
In New Jersey, Leica’s SmartNet RTN is seamlessly anchored to the National Spatial Reference System (NSRS) through a network of Continuously Operating Reference Stations, whose coordinates are monitored continuously by the National Geodetic Survey (NGS) for accuracy and integrity. “Since the NJDOT is a host facility to two of these stations, we have free access to the entire statewide network,” Czegpiga says.
“Being connected to SmartNet makes our agency--as well as the consultants employed by the Department that subscribe to this network--much more productive,” Czepiga says. “And in the current economic climate, this may make the difference in completing a project on budget and on time.”
Boston the CenterLeica launched SmartNet North America on March 1, 2010. SmartNet is a subscription-based service offering GNSS network real time kinematic (RTK) corrections throughout North America. SmartNet IT infrastructure is centralized at a facility in Boston with a full disaster-recovery facility in Dallas. “We have over 400 stations online now, and that will be nearly 500 by the end of 2010,” says Wendy Watson, director of reference station operations for SmartNet. “And we currently have approximately 1,600 users registered on the system. By the end of the year, that could easily be 2,000 subscribers.”
In addition to the stations directly in SmartNet, many affiliate networks use Leica technology. Some of these networks are linked to the SmartNet Web site.
Leica also manages more than 200 independent stations under management and support contracts. The services offered by Leica range from full IT management, installation and network adjustments to monitoring and management of these stations. “The Reference Station group at Leica is highly qualified in IT, networks and GNSS technology, so our services are sought out to help others manage their networks,” says Watson.
SmartNet’s first year of operations has been focused on improving the IT infrastructure for long-term growth and on systematically upgrading the network to full GNSS capability. “SmartNet is continually assessing opportunities for expansion of coverage throughout North America,” Watson says.
Geographically, SmartNet covers Ontario, Quebec and the Maritime Provinces in Canada, and some 15 states, including most of those on both coasts (see map). Leica’s goal is not necessarily to cover the 48 states with SmartNet. Rather, it is to grow the network into areas with a large enough subscriber base to support central IT and management functions.
Data from each station in SmartNet is streamed to the central servers in Boston. There, the network solution known as SpiderNET distributes the RTK correction data in multiple formats. When a customer subscribes to SmartNet, they are issued an ID and a password to be entered into their GNSS rover. They dial into the network through their cellular phone service; when their identification is verified, the corrections are ready to begin streaming to the rover.
Watson says the cellular telephone network has definitely improved. “Plus, our data packets are not so big that cellular latency is an issue, but there are still areas that do not have cell coverage. Typically that’s in rural areas where we may not typically have stations, so it’s not a pressing issue.”
SmartNet features interoperability with respect to various manufacturers’ receivers. “If they are capable of signing onto the Internet and capable of receiving data in the industry-standard formats, they can use the network,” says Watson. SmartNet transmits in industry-accepted standard formats such as RTCM3x, RTCM 2.3, and DGPS 2.3(9.2).
When using proper survey techniques for GNSS, SmartNet provides accuracy to within 1 to 2 centimeters horizontally and 2 to 3 centimeters vertically. This level of accuracy makes networks very productive for many applications. Networks have traditionally been used in surveying, but other markets such as machine control, agriculture and GIS are now using networks, as well.
“The majority of machine control applications can be done on networks,” Watson says. “For some of the extremely fine grading or paving applications, it might be better to use another technology such as robotic total stations, because the vertical requirements are beyond those attainable through GNSS technology. In agriculture, networks are used to improve productivity and reduce costs when spraying, harvesting and planting.
Productivity BoosterAt Hillcrest Associates Inc., a Landenberg, Pa., surveying and civil engineering firm, Richard Brittingham, PLS, says he began using a Leica CS15 data collector and a Leica GS15 receiver--with SmartNet--earlier in 2010. “We’re not tied to any base station and we have no 5-mile limit on radio communications,” says Brittingham, who switched to Leica from a different network. “Right now, we are running one crew; two if necessary. I can take the GPS out myself and be a one-man show.”
Brittingham says he used his GPS unit to do some topographical mapping for a quarry in Avondale, Pa. He says the equipment was “perfect” for the application. The quarry comes off a road and consists of a rock face that is 50 or 60 feet high. “The client is supposed to cut it down to a certain elevation, and they wanted to know what volume of rock they had to remove to get to that elevation,” Brittingham says.
“It was a one-day job, and doing it conventionally would have taken four days,” Brittingham says. He also used his GPS equipment to do the as-builts for the utilities and infrastructure involved in a 126-unit housing community. “And again, that would have been a four- to five-day job with conventional surveying equipment,” he says. “We managed to knock the whole thing out in two days.” Once Brittingham downloaded the data from his GS15, he created a map of the infrastructure using TerraModel software.
With SmartNet, there is no hunting for monuments to start surveying, Brittingham says. He simply climbs out of his vehicle and starts surveying. The range he needs to cover is about 100 miles north from the southern point of Fenwick Island, Del. “As long as we can get a cell phone connection, we can run the Leica equipment,” Brittingham says.
Security No Problem“The primary attraction to this SmartNet is that we no longer have to leave a conventional real-time kinematic base station at the side of the road, either unattended or with personnel for security,” says William Derry, PLS and chief of surveys at Merestone Consultants, Wilmington, Del. “And we also now can get very accurate real-time data with a lot less effort and less equipment packing. We know the solutions we get are electronically transferred--we are not inputting coordinates or anything like that. We take some of the human error out of the inputting of receiver data. We have high, high confidence in the stewardship of the data.”
Derry says SmartNet greatly improves his productivity. “We no longer have to put a lot of time and effort into setting up a base station on a site, worrying about the security of it, worrying about radio transmission, technical difficulties due to terrain, or weather conditions or atmospheric conditions. We use it as a cellular data line that rarely gives us a problem. It is as reliable as you can expect something to be.”
Merestone recently used SmartNet to establish state plane coordinates, to set control for aerial surveying, and for boundary surveying involved with construction at a power plant in Millsboro, Del. “Because of SmartNet, we could rove around all over the plant looking for things without any concern for security and the equipment or anything else,” says Derry. “SmartNet made it very easy and confidence-inspiring to be able to move around on site as we needed to set control or map areas, or to do topography.”
Derry estimated that several hundred workers were involved in installing air-quality-control scrubbers on the plant. Merestone and another firm mapped large areas of the site for parking and for areas to store structural steel and other construction materials. After Merestone collected control points, the firm gave the data to an aerial mapping company to create an aerial map.
Prior to getting SmartNet, Merestone had a GPS base station with two RTK rovers. When the firm subscribed to SmartNet, it converted the GPS base to a rover. This solution allowed Merestone to run three GPS crews, each with its own GX1230GG rover. “We have one of these SmartNet rovers in every truck,” Derry says.
Derry says SmartNet has greatly improved his productivity. “It was drastic enough that it really didn’t take a lot of calculations to figure out that it was a huge increase in productivity,” Derry says. “Just having GPS was a huge increase seven years ago when we got it. For SmartNet, we basically bought cellular modems, and that was it. The upgrade cost was a minimal investment.”
On the East Coast and throughout North America, network RTK is giving firms an advantage. “More work in less time translates into more productivity and profit per month--a goal worth shooting for,” says Watson.