It is reasonably quick and it produces profiles of the passageway at known distances into the cave system. This approach allows a full and accurate 3D reconstruction for later visualisation. There are a number of computer packages to help cave surveying. These are mainly designed for topological surveys and help with loop closure and error distribution. Laser sources are highly dependent on the precise reflective properties of the target object and are unsuitable when used on rough, bare rock surfaces.
Radar is considerably better, but suitable equipment is neither cheap nor easily portable.
The lack of precision is due to the difficulty in obtaining a narrow ultrasound beam and the problem of shaping a precisely defined sound pulse. The quarry, now abandoned, is located in the side of a natural limestone bluff which overlooks a narrow steep-sided valley formed by the river Yealm. An extensive cave system, the Kitley Show Caves, is open to the public but many more caves and fissures penetrate the limestone on both sides of the river Yealm, including the Kitley Shelter Cave which is the subject of the present study. Kitley Shelter Cave is located at a high level within the limestone outcrop, and prior to archaeological excavation the cave was partially filled with cave breccias, flowstones and unconsolidated cave sediments. Since 1994 an archaeological research project, led by the University of Sheffield and the University of Wales Lampeter, has investigated the archaeological and palaeontological remains in Shelter Cave.