Localization and mapping are essential elements in the design of mobile robots used for search and rescue mission. Localization is a key-function of remote control and mapping in an unstructured environment. However, in general, odometry in tracked vehicles is ambiguous because of the track slippage. To solve this problem, we developed a three-dimensional gyro-based odometry that considers the compensation of slippage on the basis of an empirical model. The method was successfully implemented in a tracked vehicle, and its validity was confirmed by initial tests in real environments. Mapping is also very important in a searching task. A small three-dimensional laser range scanner provides operators and rescue crews with a wealth of information for understanding environments. However, to obtain this information, the operators must wait a few seconds and halt the robot's operation. To solve this problem, we propose the continuous acquisition of three-dimensional environment information for tracked vehicles using the three-dimensional gyro-based odometry reported above. In this paper, odometry and continuous acquisition methods are introduced for use by tracked vehicles operating in hostile environments.