It was a foggy day. We were somewhere in the middle of Nantucket Sound with no bells or horns sounding and no buoys in sight. We did, however, have a nice steady five- to seven-knot breeze blowing from south, southwest. Looking at the charts we could determine the location of two local AM radio-transmitting stations. Holding the portable radio in my hand I tuned it to the first station. Turning the radio left to right, I drew a line on the navigation chart at the corrected compass bearing of the strongest signal from the radio station. Tuning in to the next radio station, I repeated the procedure and drew another line on the chart. Now, according to the latest technology, our sailboat was at sea level where the two lines crossed. My family was safe and we were on course to the next safe harbor. No sextant, timepiece or a view of the horizon was necessary.

Today's GPS technology uses the same general principles. Signals from the many satellites circling our globe have replaced the signals from radio stations. Of course, these signals do much more. The other dimension needed for our construction site surveying operations is the elevation. To provide this, these satellites also transmit Electronic Distance Measurement (EDM). Now we have several electronic signals meeting at an exact 3-D point on our globe. These are the new sources of our construction site line and grade: no transit, no level, no tape, no rod, and no stakes.

How do we use these sources? Take for example, a highway project with cuts and fills for ramps, bridges, culverts, and streams. The plans and specifications have been created on AUTOCAD and loaded on the Internet. The grades and curves that our survey crews used to stake out station by station with their transit, level, tape, and rod are now developed from the transmission of signals from our satellites to a receiver called a rover positioned on our construction site for layout.

Now for the good part! It seems like our operators could go home and we would have a fleet of robots out on the job controlled by the rover who in turn, is controlled by those satellites circling our globe. Once our site plan is loaded on the Internet, the 3-D GPS stakeless line and grade control system can take over. A leader in this technology is Trimble. If you go online to Trimble, you can get all their technical information in seven languages. With the Trimble SiteVision GPS, the line and grade designs of a construction site are transmitted directly to the Rover and this data is transmitted to the equipment operator in his cab. The operator can now sit back and let the automatic blade control of his dozer, grader or scraper take over. The GPS system actually controls the hydraulic system that controls the blade elevation and cross slope position of the blade. He always has the option of taking over manually. This becomes necessary if the cut or fill is too deep for the required final grade. A similar GPS system is used to control the hydraulics of our pavers to create smoother runways and highways. Just think, not only have those satellites in outer space controlled the smooth surface of our runways, but also, the planes can now land on "autopilot." Not only can we control machines on land, but also we can control them in space. I don't want to think about "autopilot" steering my car through city traffic.

I'm in the field office looking at the project plans and checking on the progress schedule. I click onto a screen to check on a cut-and-fill operation a couple of miles away. In a few minutes I can determine the efficiency of the operation:

1. Is there a hold-up at the loading end?
2. Is there too much space between the hauling units?
3. Is there a hold-up at the fill end?
4. Should there be another compaction unit?
5. Are we meeting our progress schedule? Should we add or reduce the number of units.

These are only a few of the questions that can be resolved by the instant graphic display of the location of all units on our project. It's all accomplished by a GPS tracking system that pinpoints the location of any piece of equipment on or off the job.

Now, this new instant graphic display of all units operating at any given time has greatly improved our scheduling efficiency. Two-way radios are still in use but they, too, have seen many improvements. In the past, when the antennas or towers were out of range, we lost communications. Today we have satellites to bounce our radio and television communications as well as GPS. Cell phones, of course, are a must for all employees today from the president of the company on down to the foremen.