Felix Baumgartner
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GPS data will track skydive bid

GPS will play an important role as Austrian Felix Baumgartner attempts to make the highest ever skydive.

Four separate sat-nav units on his body will help determine if he is successful in establishing new altitude and descent speed records.

Brian Utley will ensure the rules laid down by the official records body, the Federation Aeronautique Internationale, are followed properly. He explained his job to our correspondent Jonathan Amos.