An endoscopic surgical navigation system comprises a tracking subsystem to capture data representing positions and orientations of a flexible endoscope during an endoscopic procedure, to allow coregistration of live endoscopic video with intra-operative and/or pre-operative scan images. Positions and orientations of the endoscope are detected using one or more sensors and/or other signal-producing elements disposed on the endoscope. The sensors include optical curvature sensors located along the endoscope, where the length of each optical curvature sensor decreases with increasing proximity to the distal end of the endoscope. Output signals of the sensors can be routed to the tracking subsystem through the light channel in the endoscope. A hybrid approach can be used to separately track the position and orientation of the (rigid) base and the flexible portion of the endoscope.