A few years ago, when I played with the Air Force on the GPS III study, there were two major manufactures of GPS equipment; Garmin (civilian) and Trimble (military). Today there are Magellan and Leica. I don't know if the military is into either of the new efforts. Leica is foreign, so I doubt the military in interested but NATO and the Europeans are.
If there is anything new in GPS user equipment, these manufactures would have what you're looking for. <--- preposition; tisk, tisk, tisk.