To support the development of advanced algorithms for hand-held detectors, it is desirable to collect data with a specific sweep rate, height and spacing. In addition, it is also important that the position of each data point produced by the detector is known. Since it is impossible for a human operator to precisely control these sweep parameters, we have developed a semi-autonomous robotic data collection system. It is designed as a portable robot with a 2-axis manipulator that can be used to sweep any hand-held detector at a precise sweep rate, height, and spacing. It is also equipped with an interface to the hand-held detector, so it can log the output data during the sweeping motion. It also tags the output data with the position data from the on-board positioning system. As a result, we can construct an accurate 2-D or 3-D grid of the detector's output as a function of horizontal and vertical position of the detector. The manipulator is also equipped with force sensing capability that can be used to sense terrain height or collision. To increase deployment flexibility, all functions of the robot are controlled through a wireless communication link by a hand-held computer with a maximum operating distance of at least 100m. Through the hand-held computer, the operator can move the robot, and program its behavior using a script based motion sequencer. The robot has been deployed successfully on several data acquisition activities, and successfully produced high-resolution 2-D map of the buried targets.