A growing number of concrete foundation contractors are saving time and labor and improving layout accuracy by using robotic surveying instruments to do one-person foundation layouts. One such system--the Geodimeter 600, from Spectra-Precision Surveying Inc., Itasca, Ill.,--consists of an unmanned robotic total station, which is operated from the measuring point, and a remote positioning unit (RPU). The unmanned total station has a built-in tracking module that automatically searches for and locks onto a target on the RPU as the operator moves the RPU rod from survey point to survey point. This automatic tracking greatly reduces surveying time because the operator doesn't have to manually aim and focus. It also can eliminate the risk of compounded errors, which can occur when incorrect points are used as references for the points that follow.