In this research, we propose a pile driver navigation system for accurate and efficient pile driving in construction fields. In the system, a laser range finder is placed in the field and measures the position of a driving pile and pose of a pile driver. The measured pile position and the desired pile position are transformed to the pile driver coordinate system and provided to the operator of the driver to allow easy adjustment of the pile position. This paper focuses on pile position estimation and pile driver pose estimation from laser range finder data. We compare two pile position estimation methods based on circle fitting. One is maximum likelihood estimation under Gaussian noise in Cartesian coordinates whereas in another method Gaussian noise is added in polar coordinates. The pile driver pose estimation method uses markers attached to the machine and the pose is calculated from the measured marker positions in global coordinate system and the corresponding marker positions in the pile driver coordinate system.