Network corrected real-time is a technological approach to high precision GPS/ GNSS positioning that has been theorized about, studied, experimented with, and implemented in various academic, scientific, and commercial forms for nearly a decade.
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Survey Students Help to Map the Future of Space Travel
Written by Larry Trojak
Thursday, 26 July 2007
A 3.541Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE
In a move designed to bring space travel and space-based scientific experimentation to the masses, citizens of New Mexico recently voted to help fund the nation's first commercial spaceport. Located about 40 miles north of Las Cruces, the $225 million "Spaceport America" will, in addition to becoming the center of the nation's growing private rocket industry, also serve as the headquarters for space tourism company Virgin Galactic, which is already selling $200,000 tickets for a 2˝-hour suborbital flight. Helping make a contribution to the project's early developmental stages, a group of surveying engineering students from the Las Cruces campus of New Mexico State University (NMSU) is using state of the art Topcon GPS technology to locate government boundaries and corners, some of which date back to the late 1800s.
A Group Effort
NMSU's involvement in the project stems from efforts taken by Dr. Steve Frank, coordinator of the university's surveying engineering program, and Dr. Patricia Hynes, Director of the New Mexico Space Grant Consortium. Knowing that one of their colleagues, Bill Gutman, associate director of the university's Emerging Technologies Laboratory, was a huge proponent of the Spaceport project, Frank and fellow surveying professor Dr. Kurt Wurm approached Gutman about getting the surveying students involved.
"He was extremely receptive to the idea," says Frank, "asking us to do some general surveying work and locate some government boundaries. In addition, he is very aware of the importance of maintaining and documenting historic corner markers. So when we asked him if we also could go out and locate all the original government corners, preserve their locations, take photos of them, and so on, he was equally receptive to that."
The general surveying projects took place in 2005 and included construction staking for several roads leading to a proposed launch pad, as well as for the pad itself.
"That pad has since been completed," says Frank, "and recently served as the launch site for a rocket containing the ashes of the late actor James Doohan who played Scotty in the original Star Trek TV series. It was something of a national news event and it's excellent to think our students had something to do with bringing it about."
Hitting the Mark
Locating corners and historic markers has traditionally been a long, time-consuming process that can include finding terrain changes on a map, locating fence posts or other identifiable landmarks, etc. Even that might only get one within 500 feet of the corner being sought; the rest would rely upon leg work and a keen eye. In their effort, Frank and his NMSU students had a distinct advantage.
"We used a trio of Topcon HiPer Lite+ receivers as our base stations in order to allow a solid check and as a fail safe measure. Then, using handheld [Garmin e-Trek] GPS units, we hiked into an area to find a marker and, once located, set another Topcon HiPer Lite+ antenna over it. The Topcon GPS offers us a number of options for gathering the data. We select the mode in this case, static rather than kinematic how often we want the unit to take a reading, and so on."
Frank says he has tested different settings to get the best solutions possible. "If we were doing long lines out there all day, we would probably set it for 30-second intervals; if we were doing fast shots, we set it for one second-interval readings. For this application, we found that with a three second reading for 12 minutes, we can get a good survey fix on the marker and move on to the next one."
Once the data has been gathered, Frank and his students return to the NMSU survey lab and upload those solutions to the NGS site to obtain an OPUS solution. "Once we have the OPUS solution," says Frank, "we feed put those values into the Topcon Tools software to get the coordinates of the points we surveyed. We are still finalizing testing of the data, but our readings thus far look extremely impressive: for north and east I would say we are within one to two centimeters."
Frank says the Topcon units' dual frequency capability and GLONASS feature allowed them to find the corners there are 153 of them much quicker than ever, particularly when compared to older GPS-based equipment.
"In the past we would have to wait as much as 30-45 minutes to get reliable data," he says. "Using the new gear, that part of the work has been reduced by better than one-third, and the accuracy is obviously right on the mark."
Supplying the Future
While Frank is quick to sing the praises of the equipment performance at the spaceport site, he is equally grateful for the circumstances and cooperation that helped make that gear available to him and his survey classes.
"For a number of years now, we have had a good relationship with Tony Trujillo from the Albuquerque branch of Holman's, Inc., one of the area's largest suppliers of surveying equipment. About three years ago he was able to get us a couple Topcon GPS units through his shop on a zero lease deal. When the time came to return the machines, he told us Topcon was getting ready to announce a new program and, if we could wait a few weeks, he felt it would be worth our while."
According to Frank, Trujillo had not exaggerated his claim. When all was said and done, NMSU was able to add two new complete Topcon GPS packages valued at $100,000 for just a small fraction of the cost.
"In all fairness, there are other equipment manufacturers who make similar offers to help out surveying departments like ours. However, Tony really went to bat for us to see that we were able to get two full packages, rather than just one, which has really been a huge plus for us."
Work to be Done
Frank says they have located and coded all but six of the 153 corners in the 27 squaremile site chosen for "Spaceport America." Those six, he says, can be an excellent jumping off point for his next class.
"I think something like this is an excellent opportunity, both for the students to get valuable hands-on experience and to see markers that, in many cases, haven't been seen since 1938. At the same time, they are recording data that will ultimately prove useful to surveying crews as work on the spaceport proceeds. While we're out there in the desert our days generally last abut eight hours situations sometimes arise that make a measurement next to impossible. I try to encourage the students to get creative, to come up with innovative solutions and they really respond to that. This technology is undoubtedly the future of the industry they've chosen and we're grateful that they have the opportunity to learn on some of the best gear available today."
Larry Trojak is a communications writer for his own firm, Trojak Communications of Ham Lake, Minnesota. He is a frequent contributor to construction and survey magazines.
A 3.541Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE
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