RTK (Real-Time Kinematic) GPS systems provide centimeter-level accuracy for grading and site layout without needing line-of-sight. Typical accuracy is 1-5 centimeters horizontally and vertically. These systems use a base station and rover receivers with cellular or radio communication. Typical rental costs range from $200-$500+ per day. RTK systems are revolutionizing earthmoving by allowing operators to grade to precise elevations automatically (integrated into equipment cabs). Modern systems integrate directly with grading equipment for automatic blade control. Common applications include airport runways, highway construction, and large earthmoving. Setup typically requires 30 minutes to 1 hour. Systems work in all weather conditions and don't require line of sight. GPS/RTK has largely replaced traditional surveying for earthwork.