Reduction of interference from DGPS transmissions in the MF band using a GMSK modulation scheme

The accuracy of the Global Positioning System (GPS) can be improved by differential techniques. For maritime applications a DGPS service with transmissions by maritime radiobeacons in the MF band is provided. It offers a position accuracy of approximately 5 m. For the data link a minimum shift keying (MSK) modulation scheme has been recommended. The adjacent channel interference at the maximum transmission rate might not be consistent with existing frequency plans.<
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