There are three major categories of GPS systems available for earthmoving contractors:
1. Laser-based display systems

• Easy-to-use modular systems are flexible and configurable to machine and site needs
• Used for machine guidance
• Found in a range of construction and earthmoving applications and machines including dozers, backhoes, scrapers, skid steers, and excavators

2. Laser-based grade control systems

• Signals from the laser receiver control a proportional hydraulic valve for blade correction
• Facilitates faster and more accurate grading
• Best suited to contractors involved in large site preparation, such as residential and commercial site development

3. 3D grade control

• Measures the X, Y, and Z coordinates of the machine blade, comparing data to the preloaded digital terrain model and calculating the design elevation and cross-slope for the current position to automatically move the blade to the correct position elevation and slope via the machine's hydraulics
• Grade and slope information along with the blade's position is shown on the cab display 
• Precise to 30 millimeters
• Enables stakeless bulk earthmoving using either automatic or manual blade control
• When combined with an advanced tracking sensor, grading accuracy can narrow to plus or minus 5 millimeters, providing precise finished grade work