Transition to the back-up communication system
A major concern related to operating in a satellite-denied/degraded environment is the manner in which users transition from a heavy reliance on satellite communications to the back-up communications system if one is made available. Such issues include:
- being aware that the satellite communication system is underperforming;
- determining that the underperformance is the result of malevolence rather than some ‘normal’ cause such as the malfunction of one or more internal element(s) of the system;
- disseminating the loss of performance to users in order to apply mechanisms to reduce the effect of the malevolence (such as minimizing traffic loading, dropping low-priority users, puncturing channel codes, and utilizing redundant channels); and
- on degradation of satellite communications, transitioning users to alternate systems within an appropriate timeframe, and preferably before the satellite system is finally denied.
In order to address the final issue, it should be noted that users transition to a back-up system unless that back-up system is already deployed and is operational (at least at a minimal level). That minimal level will require systems to be in place, antennas to be erected (although short-range HF sky-wave antennas can be erected in minutes to hours, for ranges greater than 500km, such antennas can cover a football field and take two days to erect by a rigger), frequencies to be available and promulgated, cryptographic keys to be distributed, and links engineered at least daily. To be useful when required, the back-up system must be exercised as part of business as usual.