Just thinking out loud here--what about just using RFID for most of the pallets, and then putting powered electronics w/GPS only in some fraction of them? Say, 1 out of 20 or 50 (or whatever) pallets would have a battery, GPS, and an RFID reader; then those could read the RFIDS on any nearby RFID-equipped pallets. And transmit their location and the nearby RFIDs back to home base.
That's an interesting idea,and while RFID can be read up to nice distances(16 meter) but the RFID is quite power hungry and is dependent on antenna quality to achieve that , so it becomes a very challenging task and maybe an impossible one to build a decent concentrator.
