Differential Global Navigation Satellite Systems (DGNSS) are based on the principle that the main sources of errors in satellite navigation are consistent over substantial geographical areas. These errors can be measured by employing reference receivers at fixed, known, locations. The correction messages they generate are broadcast, and used by mobile receivers in the region to adjust their own position measurements.
Currently one of the oldest aids-to-navigation technologies, that of marine
radiobeacons, is being used to transmit correction signals. Such radiobeacon DGNSS installations are being planned and commissioned in many countries. However, the frequency band for the radiobeacon DGNSS service in Europe is crowded with marine and aeronautical beacons and, as a result, the coverage and performance of these transmitters are seriously degraded by interference.
This aim of this research is to minimise the effects of interference on the coverage of rad iobeacons by frequency planning. In order to achieve our goal, methods of evaluating the interference are analysed and, where existing methods are not sufficient, better methods are developed. A suite of computer programs has been developed to analyse the performance of radiobeacons when interference is present,to help the system planner select the best frequency for a new radiobeacon and to replan the frequency allocations of all the radiobeacons in the European Maritime Area.