The M777 howitzer is a towed 155 mm artillery piece, successor to the M198 howitzer in the United States Marine Corps and United States Army. The M777 uses a digital fire-control system similar to that found on self-propelled howitzers such as the M109A6 Paladin to provide navigation, pointing and self-location. The M777 is also often combined with the Excalibur GPS-guided munition, which allows accurate fire at a range of up to 25 miles (40 km). This almost doubles the area covered by a single battery to about 5,000 km2.