This question is a little different. I don't know enough about the John Deere system to comment on what kind of correction signal format it will use. But the current Trimble receivers that I am familiar with will accept more than one type of RTK format. I am currently running a Trimble RTK system, but we use a "non-Trimble" base station. It is just a matter of setting the receiver to receive the correct format. You have to manually set the receiver and some tricks are involved. None of the required settings are "documented" in the operators manual.

On a Trimble system that uses the NAV II controller, the controller is set to "auto configure" to receiver every time is powered on. Every time you turn on the system, it configure the GPS receiver to output the correct formats at the correct speeds, etc. One of the things it configures is that it tells the receiver to look for a Trimble RTK correction source in a Trimble format. We had to turn the auto configure function off and do the configuration manually. Again, that is undocumented.

As to the OEM RTK tower networks. Obviously they are using proprietary formats. These proprietary formats are protected. There would not be much financial incentive to broadcast an open signal that anyone could pickup and use. Yes, it would be very nice to use the JD RTK correction signal on this farm where the Trimble signal is too weak and the Trimble signal on the next farm that the JD signal does not reach, but I don't think we are going to see that ability come from the OEM arena. There is no economic incentive for it.

If that happens, it will have to come from the civil sector. There are some areas where there are now free open broadcast government sponsored RTK correction signals. These signals would be similar to WAAS or Coast Guard beacon signals. But you are going to encounter heavy resistance from the OEMs on this. There is big profit in RTK base equipment and correction signals. I have heard rumors that the next generation of Trimble RTK receiver will be limited to Trimble RTK correction sources.