A camera tracking bar of a camera tracking system for computer assisted navigation during surgery, the camera tracking bar comprising: - a first set of stereo tracking cameras having a first resolution, a first field of view, and spaced apart on the camera tracking bar by a first baseline distance ; - a second set of stereo tracking cameras having, a second field of view, and spaced apart on the camera tracking bar by a second baseline distance that is less than the first baseline distance , - wherein the second set of stereo tracking cameras is positioned between the first set of stereo tracking cameras, and the field of view of the second set of stereo tracking cameras is different from the field of view of the first set of stereo tracking cameras ; and - a communication interface configured to provide video streams from the first set of stereo tracking cameras and the second set of stereo tracking cameras to the camera tracking subsystem; characterized in that - the second set of stereo tracking cameras has a second resolution that is different from the resolution of the first set of stereo tracking cameras ; and in that the bar further comprises - a high rate inertial measurement unit comprising a 3-axis gyroscope and a 3-axis accelerometer, wherein the inertial measurement unit is configured to output motion data indicating measured motion of the camera tracking bar and the communication interface is further configured to provide the motion data to the camera tracking subsystem, wherein the inertial measurement unit is preferably configured to include in the motion data measurements of an angular velocity of the 3-axis gyroscope and measurements of a linear acceleration of the 3-axis accelerometer; - a processor configured to align orientation of the video streams and the motion data measurements to a gravity reference. - a first set of stereo tracking cameras having a first resolution, a first field of view, and spaced apart on the camera tracking bar by a first baseline distance ; - a second set of stereo tracking cameras having, a second field of view, and spaced apart on the camera tracking bar by a second baseline distance that is less than the first baseline distance , - wherein the second set of stereo tracking cameras is positioned between the first set of stereo tracking cameras, and the field of view of the second set of stereo tracking cameras is different from the field of view of the first set of stereo tracking cameras ; and - a communication interface configured to provide video streams from the first set of stereo tracking cameras and the second set of stereo tracking cameras to the camera tracking subsystem; characterized in that - the second set of stereo tracking cameras has a second resolution that is different from the resolution of the first set of stereo tracking cameras ; and in that the bar further comprises - a high rate inertial measurement unit comprising a 3-axis gyroscope and a 3-axis accelerometer, wherein the inertial measurement unit is configured to output motion data indicating measured motion of the camera tracking bar and the communication interface is further configured to provide the motion data to the camera tracking subsystem, wherein the inertial measurement unit is preferably configured to include in the motion data measurements of an angular velocity of the 3-axis gyroscope and measurements of a linear acceleration of the 3-axis accelerometer; - a processor configured to align orientation of the video streams and the motion data measurements to a gravity reference. <EOS>