Overviews of systems that are available for voice and/or data communications in high latitudes are presented. Geostationary satellite systems can be used up to about 74° latitude. Polar orbiting satellites extend the coverage to the poles, but at a degraded throughput. Terrestrial systems can extend communications connectivity where infrastructure might exist at inhabited sites.
Communications System ComparisonsA quick comparison of Iridium and Inmarsat BGAN terminals was conducted to measure the total energy needed for 100-kB and 1-MB FTP file transfers. The Iridium transceiver operates at lower power (~4 Watts), but only at 2400 bps nominal. The Inmarsat BGAN terminal (a Nera WorldPro 1000) consumes much more power (~22 Watts) but it operates with up to 200 kbps datarate. In these tests, the Nera WorldPro 1000 took at least half of the total energy (power * time) than did the Iridium 9505.
Iridium RUDICSRUDICS is an acronym for "Router-based Unstructured Digital Inter-working Connectivity Solution" and it provides a direct connection between an instrument in the field and a server on the Internet. It offers rapid network connection, because modem training and PPP negotiation stages are eliminated. It scales well for handling small or large deployments. Because it receives data from the Iridium Gateway via the Internet, it eliminates the need for an Iridium modem to receive the connection. Doing so also eliminates one Gateway to satellite to modem link, improving link reliability.
Iridium OpenPortThe Iridium OpenPort hardware and network allow Internet connectivity at link speeds to 128 kbps. While targeted for deployment on ships at sea as a competitor to Inmarsat, it is well suited for fixed and mobile deployments in the polar regions because of the orientation of the Iridium satellite constellation. The greater bandwidth is achieved through advanced modem technology that utilizes up to 16 adjacent Iridium satellite channels. Some preliminary information is available at: http://polarpower.org/technologies/communications/iridium/OpenPort/