From GPS to GNSS: Who uses the real-time network – and why?

GPS network diagram

This is part 2 of a 3-part blog.

From a system developed for the U.S. military to a global network with broad commercial applications, today’s GPS is changing the way we live and work.

As the technology advances, so do its applications. Trimble cites five primary applications:

  1. Location: Determining a basic position
  2. Navigation: Getting from one location to another
  3. Tracking: Monitoring the movement of people and things
  4. Mapping: Creating maps of the world
  5. Timing: Bringing precise timing to the world

In this second Q&A, CSDS President Tom Cardenas and Systems Administrator Ed Morrison talk about GPS uses for location and tracking. In today’s article, we also hear about mapping applications.

Q: What are some different uses for the real-time network?

ED: Surveying, mapping or GIS applications, agricultural applications and heavy machinery for machine control and machine guidance.

Whether it’s a tractor for farming applications or a grader for road development, they’d have one or two GPS receivers or antennas on them. They’d sign in to the network and they could get the same accuracies as a surveyor would, essentially going out in the field with the survey equipment, only the application is a little different in that they’re not just taking a single shot, they’re taking a real-time movement.

When they’re tied into the network, they can do actual machine guidance. You can actually program, on a tractor, the route or the piece of land that you’re farming and put that program into the tractor’s on-board computer. It ties to our real-time network and it’ll use the coordination that it’s getting out of the network to guide that tractor through the field.

For tomatoes, farmers will lay what they call tape, and it’s really expensive. It’s like a drip system at home for your plants, but this tape is under the soil along the rows. Farmers will use the GPS network to guide the tractor as they’re laying this tape, and the positioning is stored in the programming of the tractor. They’ll do their production for the season, including the pulling the plants up and harvesting the tomatoes, but next year when they go back, they can plant right over that same tape. They have all these blades going into the ground turning in the soil, but because the accuracy is so exact using the network, they don’t tear up that tape.

TOM: In terms of our agricultural users, I think where the network has really benefited them is not just the overall precision, but increasing their efficient use of space. Farmers can plan how to get the most yield from their acreage, and then do a lot of the production 24 hours a day.

ED: I went down to see a tractor plow and prep an entire field, tilling real-time as they were doing it. The customer needed to average 3 miles an hour to justify the cost of the network. But they were actually traveling at 6 miles per hour, which means they’re cutting their cost.

TOM: In addition to agriculture, there are other uses for machine control, such as those big scrapers on grading systems. They have two GPS receivers on their masts. Traditionally, they were setting up their own base set up on their site, with a radio communicating to the tractor itself. For the construction industry they had to set up a base station on every single job site for their systems to work.

Q: Whether GPS is used for mapping, location or another application, what are the overall customer benefits?

ED: Cost and time are the overall customer benefits.

TOM: You don’t have to set up your own base station. You don’t have to pay for somebody to watch over it. You don’t have to take a lot of extra equipment to every job site. So using our real-time network cuts down on equipment costs, extra personnel and the time it takes to set it all up.

ED: In the past, each job required two receivers and at least two people. By switching to the network, you’ve doubled your workforce. You can have two surveyors out there with two pieces of equipment getting twice the work done. Now, they can subscribe to our network, if their job sites are anywhere between Redding and Bakersfield. And they can use those cellular corrections to provide high-accuracy positioning. This helps engineers and builders with everything from a 3D terrain model to the layout for an entire subdivision or road. Our network sends precise positions of where the blades need to be and the direction that equipment needs to travel in order to start precisely cutting down into the earth.

Q: GPS is also used for mapping. How does that differ from surveying and other location uses?

TOM: Mapping is essential to managing everything that’s out there – all that infrastructure. So if you want to create large-scale geospatial databases, once everything’s been surveyed, designed and constructed, the GIS portion will become vital in precisely locating and managing where everything that must be maintained is actually placed.

In the Mapping department, we work with a lot of government customers, including city, county, state and federal agencies, plus various fields of science and all branches of the military. Most of these professionals go out and collect information with GPS coordinates and then put it into a GIS database. So if you’re mapping fire hydrants, you’re not just mapping a point and calling it a fire hydrant. You’re also filling out what color is it? And what manufacturer is it? What’s the size and condition of that asset? What’s the date and time? I’m going to take photos of that asset and attach those to the database. So now I have 10 or 15 different pieces of attribute information, which describe that fire hydrant or that light pole or that bird nest or whatever it is that you’re mapping.

TOM: Mapping and GIS professionals are primarily focused on the database and what you do with the data after the fact. The surveying professionals are typically more focused on the accuracy and precision of that data to ensure that their property boundaries are correct – that when they’re constructing a multi-million dollar project, they’re constructing it in the correct location. So there’s a very large focus on accuracy and precision when it comes to the surveying division, but it’s also starting to bleed over from the surveying division into the GIS division, where they’re starting to see a growing interest in more centimeter-grade GIS systems. Once databases have been built, they have all the data they need and they’re trying to refine the positional accuracy of that data.

Then on to our construction side of things, they’re a little bit more focused on laying out the designs that come from the engineers and the surveyors in ways that kind of push the boundaries compared to their traditional methods. So before when a construction layout person would rely on grid lines or batter boards on a floor plan, now they can actually incorporate total stations which have layout software that’s built specifically for the construction professional.

Stay tuned for Part 3 of our GPS series:
What are the challenges– now and in the future?

In the meantime, leave your GPS questions, and we’ll answer them in comments below.


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