You do not need to send NMEA from it, you probably need to send RTCM to it. You probably can not do classical RTK with it.
If you are planning to use a DGPS corrections (not RTK), then it is likely the GNSS chip itself will do the navigation filter for you (in other words it is not externally done with RTKLIB and RTKnavi). If that is your chosen path, seek for a local RTCM2.x data stream (local meaning <50km or so) and figure out how to send that data directly to you GNSS.
I am not familiar with the "Emtac BT GPS receiver" but a quick web search tells me that is uses the older SiRF Star II LP chip set and therefore it seems to use only WAAS/EGNOS corrections. You need to research that point first and foremost to be sure that it can accept DGPS from other sources. As far as I am aware you will not get code and carrier from it, so there is not means to do an RTK style navigation solution. RTKLIB can do a DGPS navigation solution, if you can get raw code from it.
Regards DC Kelley
On 9/18/2016 5:34 PM, Francesco Mancino wrote:
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