We have presented a new approach for Optical HMT (Head Motion Tracker) last year (Proc. SPIE 6955, 69550A1-11,
2008) . In existing Magnetic HMT, it is inevitable to conduct
pre-mapping in order to obtain sufficient accuracy
because of magnetic field's distortion caused by metallic material around HMT, such as cockpit and helmet. Optical
HMT is commonly known as mapping-free tracker; however, it has some disadvantages on accuracy, stability against
sunlight conditions, in terms of comparison with Magnetic HMT. We have succeeded to develop new Optical HMT,
which can overcome particular disadvantages by integration with two area cameras, LED markers, image processing
techniques and inertial sensors with simple algorithm in laboratory level environment. We have also reported some
experimental results conducted in laboratory, which proves good accuracy even in the sunlight condition. This time, we
show actual performance of the Optical HMT in flight condition, including evaluation of stability against sunlight.
Shimadzu Corp. and JAXA (Japan Aerospace Exploration Agency) is conducting joint research named SAVERH
(Situation Awareness and Visual Enhancer for Rescue Helicopter)  that aims at inventing method of presenting suitable
information to the pilot to support search and rescue missions by helicopters. The Optical HMT has been evaluated
through a series of flight evaluation in SAVERH and demonstrated the operation concept.