The accuracy of the Global Positioning System (GPS) can be improved by differential techniques. For maritime applicationsa 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. Therefore an improvement of spectral efficiency is proposed using a Gaussian-shaped MSK (GMSK). In this case the adjacent channel interference to a radiobeacon direction finder (DF) or a DGPS receiver can be reduced significantly. The GMSK signal can also be received by a coherent MSK receiver the negligible performance degradation. We present the results of numerical calculations for different time-bandwidth products of the GMSK modulation scheme in the transmitter.
Reduction of interference from DGPS transmissions in the MF band using a GMSK modulation scheme
Störreduzierung bei der DGPS-Übertragung
IEEE Transactions on Aerospace and Electronic Systems ; 30 , 4 ; 1104-1108
1994
5 Seiten, 3 Bilder, 5 Tabellen, 12 Quellen
Article (Journal)
English
Satellitennavigation , Messfehler , Funkortung , Frequenzumtastung , Gauß-Verteilung , Navigationsgerät , Navigationssystem , Funkempfänger , Modulation , Schiffsverkehr , Funkbake , Funkstörung , Signal-Rausch-Abstand , Störsignal , Frequenzmodulation , Gauß-Rauschen , Übertragungsgeschwindigkeit , Leistungsspektrum , Impulsantwort , Symbol , Funkentstörung , GPS (Global Positioning System)
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