I don't have any inside knowledge of the Deere system, but I'd be very surprised if it was. My guess is that most of the Deere stuff comes NavCom. That is certainly the case for their GPS system.
> "NavCom's involvement with Deere & Company began with Deere's GreenStar precision farming system in 1994 and has expanded into many areas of Deere's product activities. The commitment by the most senior Deere management to information systems leadership motivated the NavCom shareholder-employees to join with Deere & Company,"
You sure? Satloc was doing GPS guidance for aerial guidance for decades (crop dusting planes). They adapted it for ag guidance in the 1990s I believe. This technology has been evolving for years and saying that John Deere or some single company invented it sounds like a gross oversimplification.
http://www.asirobots.com/news/
http://www.asirobots.com/farming/
http://www.asirobots.com/products/mobius/