In July 2010, I saw a demonstration of the Carlson Software All-in-One Surveyor+ GPS System. I’ve been using GPS in my practice for the past three years, mostly for small topographic surveys and occasionally to set up networks for other surveyors. Since I already use Carlson software in the office, I was curious about the new Carlson hardware.
In early November 2010, Carlson sent me a Surveyor+ GPS System to use for a couple of weeks and evaluate how it performed in a standard surveying practice. The nice black plastic case (about the size of a large briefcase or small suitcase) contained the GPS receiver, four batteries, multiple cables and the Carlson Surveyor+ data collector. Also included in the case were chargers for the batteries, including 12-volt car chargers, as well as an aluminum 2-meter staff.
The weather wasn’t very cooperative for the first few weeks, and the Thanksgiving holiday caused a further delay. Finally, in early December, I was able to take the system on a test run.
I typically use a base rover setup in my surveying practice because network RTK can be tricky on Cape Cod and the additional monthly expense isn’t justified for my work. However, the Carlson system does run on a network and is easily customized for use on a specific network, as a base and rover, or even simply for use as a static data collector. I opted for the network version, and the unit was initialized to a locally available network. (We have at least two networks up and running, one courtesy of Maine Technical Services, using Leica, and the other from Keystone Precision Instruments using Trimble receivers.)
I already use Carlson Survey stand-alone 2008 (the fourth upgrade for our office) and SurvCE for my GPS data collector, so the Carlson GPS unit was instantly familiar to me. It had the same program and the same “think like a surveyor” commands. After checking it out near my office, I was ready to take it on the job.
My first project for the GPS system was a small topographic survey, inland on Sheep’s Pond in Brewster, Mass. The client is an engineer that I do a lot of work with locally. The homeowner had a dock in place but had neglected to license it with the state. The goal was to get topographic data from the “front” of the house (the part that faces the water on the shorefront land) to the water and then some lake-bottom topography to determine depths.
We first had to recover property monuments and the FEMA benchmark and then identify the area for survey. As soon as I opened a file on the Surveyor+ GPS data collector for the project, it had a lock and was ready to go. The tree coverage was moderate to heavy, but I didn’t have any problem maintaining a lock or retrieving a lock if I lost it.
I did the upland topographic work first, locating the bounds and site features as well as my traverse points. Then I borrowed a small aluminum boat from the client’s property and obtained about 30 sounding shots. I was tempted to get my hip boots, but I couldn’t get quite deep enough.
It is my practice to use my total station for “tight” work such as house corners, property corner bounds and traverse points. This gives me a check between my GPS work and the more conventional method of total station data collection. I also broke out my own GPS units to verify the data collected by the Carlson units.
The Carlson GPS was as quick as my units at obtaining a lock, if not a little quicker. One huge advantage to the Carlson system is that the unit weighs close to nothing (~2 pounds). The rod and data collector are where the weight is, but since the radio receiver and radio transmitter are on top of the staff, the balance feels great. The staff has a slot to run the communication wire from the receiver to the data collector. And since the receiver uses the batteries in the data collector, there isn’t any extra battery weight to carry around on the top of the rod.
After downloading the data, I couldn’t differentiate between the Carlson data or “my” data (except by point number since I was sure to make that obvious for my use). The elevations were within half a tenth, and the locations of traverses and bounds were within hundredths.
The next available project was a shorefront topographic survey on the bay in Wellfleet. The flats were clear, and it was easy to gather data to the west and south of the property.
Once again, I unloaded the instrument, opened a file and--bingo--the RTK locked. Each time I used the Carlson GPS, it obtained a lock before I was completely ready to start. (It reminded me of my first party chief, way back when, who was always ready to roll before I had a grasp on what we were doing!)
I again took a number of topographic shots, tied down a few FEMA benchmarks and property bounds, and then got out the total station to verify the tight work. One benefit of using the RTK network instead of the base/rover setup is that I was not severely limited by distance from the project. The FEMA benchmarks for this project were across Wellfleet Harbor, and my GPS UHF radio units are only good for up to 1 mile of separation--and that’s if I have line of sight. There was no such issue with the Carlson.
My general impression of the unit is the same that I have for Carlson Software: It works great! I did find myself wishing the package included a bipod or light tripod so I wouldn’t have to lay the whole setup down, and it would also be nice to have a rubber gasket around the holes in the staff where the cable enters and exits. However, I really liked having the cable inside the rod, and I did not have any problems with the cable getting caught on branches or bushes. The onboard hardware for the receiver comes from Novatel, a proven circuit board manufacturer based in Canada, and the software is all Carlson. The system is made by surveyors for surveyors.
If you are in the market for GPS, definitely put this on your demonstration list and check with your dealer. Carlson has been proven in the office. It’s clearly time for them to move into the hardware world.
For more details about the Carlson Surveyor+ GPS System, visit www.carlsonsw.com.