Author(s)

M. Marcovina, G. Perona, V. Albanese & M. Zambotto

Abstract

Satellite is a good communication system for disaster recovery and civil protection operations. However, the reliability of the communication must be ensured with respect to the operative scenario to be faced. The major parameter concerning the reliability of a satellite link is the outage probability, Po, i.e. the time per year over which the link is down. Po mainly depends on the occurrence of rain attenuation along the radio path. For commercial systems it is customary to accept a Po about 10-3, which means 9 hours per year. But, if we consider a communication system facing a flood, those hours can be exactly when the system is required to operate. For this reason, system requirements must be rethought. Moreover, lower frequency bands are virtually immune to radio attenuation, but are crowed, expensive and require larger antennas. It makes sense then to explore the possibility of reliable all-weather communication using higher bands (namely Ku and Ka), which are more sensitive to attenuation but less expensive. Research was performed, in cooperation with Eutelsat, Italian Civil Protection Department and Italian Fire Department, to address these issues. The first step was to analyze rain measurements taken by a meteorological radar during relevant rain events, in order to estimate the actual rain attenuation that can be experienced during a real operative scenario. The second step was to set up a mobile satellite radio link, in the Ku band, to stress the suitability of this band for all-weather emergency communication. The research has shown the values of attenuation that can be experienced and that the Ku band can guarantee a less expensive alternative for emergency purposes, while the Ka band remains too unreliable, at least without the use of next generation regenerative satellites. The paper also shows the system dimensioning for reliable use of the Ku band. Keywords: satellite, Ku band, Ka band, attenuation, civil protection, flood, disaster recovery, reliability, rain, fading.

Keywords

satellite, Ku band, Ka band, attenuation, civil protection, flood, disaster recovery, reliability, rain, fading.