Sailrocket and Macquarie Innovation have been carrying GPS gear for a while now, mostly to validate the timing post data. It is fairly high end survey gear that I believe uses differential GPS to achieve high accuracy.

My understanding is that L'Hydroptere is benefitting from the validation process Macquarie Innovation went through with the WSSRC to be able to use that gear. Previously you had to use a timing system between two fixed points. Moving those fixed points, then getting your new speed track validated by WSSRC, to the suit the best angle to the wind would be a nightmare without being able to use DGPS. Hence it would've been very difficult for l'hydroptere to hold its current record without DGPS data.

As with most things, there are pros and cons to the different solutions. I happen to think that Macquarie Innovation will probably put together another record breaking run before it is put out to pasture, just a matter of time.