Channel modelling for VHF data exchange system via satellite

摘要

The VHF Data Exchange System via Satellite standard is currently being developed and trials are ongoing for testing the downlink waveforms. The satellite NorSat-2 transmits a test signal for verification of the waveform performance. Sea surface reflections and the ionosphere are expected to cause signal fading. A channel model for the downlink has been developed for receiver testing and performance estimation. The dominating fading mechanism in the model is the coherent sea reflection, causing fading exceeding 10 dB for elevation angles below about 50. Fading due to incoherent sea surface reflections and ionospheric scintillation were modelled utilising Nakagami-Rice envelope distributions. These components introduce minor fast variations in received signal power.