Omega Station 10.2 kHz Signal Coverage Prediction Diagrams

Abstract

New Omega station 10.2 kHz signal coverage diagrams for eight month-hour combinations (February, May, August and November at 0600 and 1800 GMT) have recently been developed. The methodology of diagram development, coverage prediction models and a representative subset of the coverage diagrams are presented. Each diagram shows the predicted global accessibility of “usable” signals at a fixed global time for two signal access criteria: Criterion I, requiring signal-to-noise ratio to be greater than –20 dB (in a 100 Hz receiver noise bandwidth), and Criterion II, requiring signal-to-noise ratio to be greater than –30 dB. Both signal access criteria require that the actual deviation of the signal phase from that of the reference (“Mode 1”) signal phase be less than 20 centicycles. These diagrams show the seasonal/diurnal variations in the predicted coverage as compared to previously-published diagrams which display the predicted coverage for the two possible extreme cases of local temporal propagation conditions. These new coverage diagrams are expected to be useful to navigators and to those engaged in Omega navigational receiver design, chart construction, and other disciplines requiring information on signal coverage.