| The daily variability of the ionosphere can greatly affect HF or SATCOM
communications. HF skywave operators plan frequency schedules months in
advance, however, they also require daily knowledge of the ionospheric
conditions in order to modify assignments. SATCOM operators also require
daily information about the levels of scintillation, which are variations in
phase, amplitude, polarisation and angle of arrival that can cause severe
degradation of the received signal.
Using a number of ionosonde measurements and geomagnetic and solar values, a
Daily Ionospheric Forecasting Service (DIFS) has been developed, which
provides HF and SATCOM operators with daily forecasts of predicted
ionospheric conditions. The system uses in-house algorithms and an
externally developed Global Ionospheric Scintillation Model (GISM) to
generate HF and SATCOM forecasts. HF forecasts consist of a past summary and
a forecast section, primarily displaying observed values and predicted
categories for the Maximum Usable Frequency (MUF), as well as an Ionospheric
Correction factor (ICF) that can be fed into the ionospheric propagation
prediction tool, WinHF. SATCOM forecasts give predictions of global
scintillation levels, for the polar, mid and equatorial latitude regions.
Thorough analysis was carried out on DIFS and the results conclude that the
service gives good accuracy, with user feedback also confirming this, as
well. |