Propagation management systems for HF communications

OTHR systems are driven by a frequency management system (FMS) whose principal task is to evaluate the remote ionosphere with a view to assigning a frequency, or frequencies, to the radar which will optimise target detection. Modern HF skywave communications systems, in order to compete with other forms of communications, and in order to act as an adequate backup, must guarantee high availability, a respectable grade of service (GOS) and survivability. Data rates are increasing all the time. It is suggested that large modern HF communications installations, particularly when networked, would benefit from use of a Propagation Management System (PMS) which uses many of the modelling and diagnostic techniques used in a radar FMS. Such a PMS is envisaged as an adaptive system whose principal objectives would be to optimise the above attributes of availability, GOS and survivability. Various levels of PMS are possible and this paper presents the results of an analysis of these levels in terms of effectiveness and likely cost