Crisdel Group strives to stay current with state-of-the-art technology used in the construction industry. The appearance of bulldozers, graders, and milling and paving machines have changed very little over the years, however; their functionality has evolved greatly.
For the past six years, Crisdel has been utilizing Topcon’s Global Positioning Systems Machine Control (GPS-MC) on our machines to assist with exact measurements of location while grading, excavating, and milling and paving. This method is sometimes referred to as “stakeless” construction, as GPS-MC eliminates stakes set by a land surveyor. Thus, productivity increases significantly. GPS-MC is useful when constructing roadways, ponds, curbs, and even building foundations.
Currently, we have Topcon GPS-MC mounted to dozers, pavers, excavators, motor graders, and milling and paving machines. Dozers equipped with this technology can grade a site quickly and accurately using GPS. Excavators have both horizontal and vertical GPS control, which helps while excavating footings or basins. The paver and milling machine has Millimeter GPS (MMGPS) which incorporates the use of lasers to improve accuracy up to 300% compared to traditional GPS machine systems.
GPS-MC works by establishing three known points of contact, which include: satellites that are in orbit around the Earth, signal transmitters and receivers on equipment, and a base station located on the job site, which also transmits and receives signals. These three points triangulate the equipment’s position.
Several steps must be taken to initiate the use of GPS-MC. Using project drawings and design CAD files, a survey/GPS consultant will first prepare a computer model file consisting of lines and points that represent the various features on the site. Our equipment will then be outfitted with an integrated system from Topcon, comprising of a control box, or “brain”, in which the model file is uploaded. There are sensors and antennas on the equipment that send and receive control signals providing location information, as well as automation control of the machine hydraulics.
On the job site, a base station/antenna is installed at a predetermined location that will send and receive signals without interruption. The base station must have a clear line of sight to the equipment and often has an elevation level above site elevation. One base station can manage several acres and multiple pieces of equipment. To verify and correlate the accuracy of the base station and equipment, an engineer will establish known fixed points, or physical features, with an exact horizontal and vertical position.
Machines equipped with GPS-MC can run in two different modes. Full Machine Control enables grading with a dozer or grader and excavating with an excavator. In this mode, the machine receives signals that determine both horizontal and vertical location. The software controls the hydraulics of the machine; manipulating the angle, pitch, and down pressure to follow proposed grades and contours shown in the model file.
Indication Mode allows the operator to control the machine while using the software to identify location and proposed grades and contours based in the model file. This mode assists in constructing roadway sections including subbase courses, drainage layers, final base, and top courses.
GPS-MC is currently in use at our Tampa Airport / SkyCenter Project and Newark Airport Terminal A Project. In the past, we have utilized this equipment on such projects as the Goethals Bridge Replacement, Bristol-Myers Squibb Site Development, UPS Newark Air Gateway, and LG Headquarters Development. Project managers and engineers find that we are using the equipment on more than 50% of our job sites, including all site work, regardless of project size.
Ensuring quality and accuracy on a job site is one of our greatest priorities. Staying well-versed in the latest technology allows us to deliver spectacular results and separates us from our competitors. To learn more about the technology we utilize visit the Blogs section of our website.