Surgical navigation is a crucial concept in computer assisted surgery. The use of robots in the surgery room largely benefits from this concept recent developments, namely with the use of non-invasive and radiation free imaging systems, like ultrasound (US). This paper presents the algorithms and software tools developed for US based orthopedic surgery navigation. In the second part of the paper are presented the algorithms and software tools developed for controlling a robotic manipulator, that can be used both in simulation and in a real scenario. The paper also presents the developed simulation scenario, for a surgical procedure in Hip Resurfacing, e.g., the first drill of the femur head. For navigation, the system, during surgery, acquires a 3D US bone surface from a sequence of US images. This bone surface will then be registered to the pre-operative bone model, for a precise knowledge of the bone position and orientation. The measured bone movement is used by the simulation tool to control the robot manipulator drilling trajectory.