A system for instrument positioning, comprising: a robotic system with a robotic arm having four or more degrees of freedom, DOF, of control; and a system controller with an interface unit; wherein the robotic arm comprises an instrument interface connectable to an instrument; wherein the instrument has an elongated shape; wherein the interface unit of the system controller is configured to provide sensor data comprising pose information of the instrument and target position with respect to an object of interest, wherein the pose information of the instrument comprises location and orientation of the instrument; wherein the interface unit of the system controller is further configured to provide image data at the target position, wherein a target trajectory is planned in the image data for positioning the instrument to the target position and wherein the target trajectory is defined by a skin entry point and the target point; and wherein the system controller is configured to: transfer the pose information of the instrument and the planned target trajectory into an object coordinate system; calculate a positional error between the tracked pose information of the instrument and the planned target trajectory; control the robotic arm during a first motion of the robotic arm for each new targeting session to move the instrument in a predefined movement to generate a rough six degrees of freedom registration between the object coordinate system and a robot coordinate system based on pose information before the movement and pose information after the movement for each of the instrument and the robotic arm, wherein the predefined movement comprises a predefined rotational movement; and transfer the positional error into the robot coordinate system of the robotic system for controlling the robotic arm to align the instrument with the planned target trajectory, wherein the positional error comprises at least one of a translational error and a rotational error. a robotic system with a robotic arm having four or more degrees of freedom, DOF, of control; and a system controller with an interface unit; wherein the robotic arm comprises an instrument interface connectable to an instrument; wherein the instrument has an elongated shape; wherein the interface unit of the system controller is configured to provide sensor data comprising pose information of the instrument and target position with respect to an object of interest, wherein the pose information of the instrument comprises location and orientation of the instrument; wherein the interface unit of the system controller is further configured to provide image data at the target position, wherein a target trajectory is planned in the image data for positioning the instrument to the target position and wherein the target trajectory is defined by a skin entry point and the target point; and wherein the system controller is configured to: transfer the pose information of the instrument and the planned target trajectory into an object coordinate system; calculate a positional error between the tracked pose information of the instrument and the planned target trajectory; control the robotic arm during a first motion of the robotic arm for each new targeting session to move the instrument in a predefined movement to generate a rough six degrees of freedom registration between the object coordinate system and a robot coordinate system based on pose information before the movement and pose information after the movement for each of the instrument and the robotic arm, wherein the predefined movement comprises a predefined rotational movement; and transfer the positional error into the robot coordinate system of the robotic system for controlling the robotic arm to align the instrument with the planned target trajectory, wherein the positional error comprises at least one of a translational error and a rotational error. transfer the pose information of the instrument and the planned target trajectory into an object coordinate system; calculate a positional error between the tracked pose information of the instrument and the planned target trajectory; control the robotic arm during a first motion of the robotic arm for each new targeting session to move the instrument in a predefined movement to generate a rough six degrees of freedom registration between the object coordinate system and a robot coordinate system based on pose information before the movement and pose information after the movement for each of the instrument and the robotic arm, wherein the predefined movement comprises a predefined rotational movement; and transfer the positional error into the robot coordinate system of the robotic system for controlling the robotic arm to align the instrument with the planned target trajectory, wherein the positional error comprises at least one of a translational error and a rotational error.