SPACER 1531853 - Caterpillar

Introduction
The AccuGrade TM system is designed for earth moving equipment in the construction application. The system can be used with a wide variety of sensors in order to provide information. The information that is provided can assist the operator in order to maintain machine bucket control according to the site plan.Conventional Systems
Conventional systems provide elevation or slope control. Conventional systems continually measure the offset between a reference surface and the cutting edge of the machine. This measured offset is compared against a design offset that has been entered into the system. If the measured offsets and the design offsets differ, the AccuGrade system will inform the operator that the cutting edge is not at the desired location.Conventional systems do not provide a horizontal position. Therefore, the following items are not used in a conventional system: design files, background maps and avoidance zones.Global Navigation Satellite System (GLONASS)
Newer GPS receivers will be able to receive data from the Global Navigation Satellite System (GLONASS). GLONASS consists of twenty-one (21) satellites in three orbital planes. There are three spare "on-orbit" satellites. The three orbital planes are separated by 120 degrees. The satellites that are within the same orbit plane are separated by 45 degrees. Each satellite completes one orbit in approximately 11 hours and 15 minutes. The position of the satellites and the time for one orbit allows more GPS satellites to be used for the machine position solution.Low Accuracy Corrected GPS Satellite Based Augmentation System (SBAS)
If low accuracy GPS positions are adequate for the required job site work, then you can use "Satellite-Based Augmentation Systems" (SBAS) error corrections. SBAS corrected systems do not require additional site infrastructure. SBAS are free-to-air GPS correction services. SBAS networks consist of ground stations that are set at known positions around the world and geostationary satellites that maintain a fixed position above the Earth. The ground stations receive GPS signals from all GPS satellites that are in view. The GPS data is then sent to a master control site, which then transmits GPS corrections to the geostationary satellites. The satellites broadcast the information to all SBAS enabled GPS receivers. The following SBAS networks are currently available:
WAAS – Wide Area Augmentation System (United States)
EGNOS – European Geostationary Navigation Overlay Service (Europe) 10 (For more information, refer to the Operation and Maintenance Manual, SEBU8292. The information is located in the "Product Information" section under the sub-title "General Information".
MSAS – Multi-Functional Satellite Augmentation System (Japan)Global Positioning System (GPS)
The GPS uses sensors that can measure horizontal position and vertical position. The resulting X,Y, and Z coordinates are compared against a design that was loaded into the AccuGrade system. The system uses two "Global Positioning System" (GPS) receivers as the position sensors. There are other sensors that are used by the AccuGrade system in order to provide feed back information to the AccuGrade system display about the machine position and bucket position.The GPS system uses two GPS receivers that are attached to the machine. The GPS receivers are mounted on masts