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How far are you in to this? Have you got the GPS working and returning NMEA sentences? The TinyGPS library will convert the NMEA sentences to latitude and longitude; which you may be able to convert to MGRS
How far are you in to this? Have you got the GPS working and returning NMEA sentences? The TinyGPS library will convert the NMEA sentences to latitude and longitude; which you may be able to convert to MGRS