The Challenge

Wherever construction takes place in the world, rollers are the most common machines on any site.

Earthmoving stands at the beginning of the construction. Here, Single Drum Soil compactors are used to compact the material filled by dozers, graders, excavators, and dump trucks to the highest density to ensure stable foundation roads, buildings and airfields. Later on, Tandem Rollers are used to compact the final layers, built with asphalt.

Roller equipped with MCA2000 and SBAS receiver

In all cases, rollers are seen as expensive and unproductive machines on site, which reduces the margins and profits in construction. On the contrary due to the use of rollers, well-prepared soil and asphalt will comply with the specifications. Well-compacted material ensures increased lifetime and less repair and rework on sites all over the world.

So what is the issue?

After the first passes, the operator gets lost on his compaction area. There is no indication on which places he has been, how often, and which compaction results he has achieved. In order to optimize and support the process, MOBA has introduced a GNSS based MCA 2000 compaction mapping system.

The GNSS receiver delivers, with the help of SBAS signals, relative position accuracies of about 80 cm and a pass-to-pass accuracy of 15cm that is adequately precise to guide a roller on site.

How does SBAS work?

Satellite-based Augmentation Systems is the generic term that includes WAAS, EGNOS and MSAS systems as signal providers that are actual available today. Others will follow.

Photo Credit: navipedia

SBAS systems are satellite systems that provide services for improving the accuracy, integrity, and availability of basic GNSS signals. Accuracy is improved through the transmission of wide-area corrections for GNSS range errors. SBAS systems include reference stations, master stations, uplink stations and geosynchronous satellites. Reference stations, which are geographically distributed throughout the SBAS service area, receive GNSS signals and forward them to the master station. Since the locations of the reference stations are exactly known, the master station can accurately calculate wide-area corrections.

Photo Credit: hsto.org

As shown, corrections are uplinked to the SBAS satellite, then broadcasted to GNSS receivers throughout the SBAS coverage area.

The Result

Optimized compaction efforts. Less passes, higher efficiency, less fuel consumption, and reduced operating cost. However, more importantly, homogeneous compaction that meets the specifications is easily achievable.

What do you think about compaction mapping systems using SBAS? Are they the easy answer to optimized compaction?