Multiple long range VLF emitters disseminate time over Europe: DCF77 (Germany), TDF (France), MSF (UK), eLORAN (UK). While time dissemination using such techniques do not match the accuracy of GNSS based solutions, the high emitted power and poor efficiency of any reasonably-sized antenna make attacks necessarily local and short range. We thus consider VLF receivers — and most significantly with the advent of fully software defined receivers — relevant complements to GNSS based receivers. Previous activities [1] have focused on DCF77 time receiver using a sound-card based software defined radio decoder exploiting the phase modulation, and current investigations aim at comparing timing signals from multiple sources.

[1] J.-M Friedt, C. Eustache, É. Carry, E. Rubiola, Software defined radio decoding of DCF77: time and frequency dissemination with a sound card, Radio Science 53 (1) 48–61 (Jan 2018) (manuscript)

Auteur : | Date : 20/02/2019