A satellite system for broadband communications to polar areas

Over the last few years the ship traffic in polar areas have been steadily increasing, especially north of Norway. This is largely due to the growing activity in that area and in northern Russia, mainly from oil and gas exploration and production. All indications suggest that this will continue into the foreseeable future. In this report a satellite based system for broadband communications to the area north of 65 northern latitude is discussed. Possible carrier frequency configurations and their propagation properties is analysed, and it is found that Ka-band, 20/30GHz, will give best performance. Various satellite orbits are then discussed, and a constellation that give continueous coverage and allow for easy handover is designed. It consists of four satellites in Molniya orbits with an eccentricity of approximately 0.72. Each satellite is then operational and quasi-stationary for six hours of every orbit, with two satellites above the coverage area at any time. Solutions for the satellite antennas are considered, and link budgets are presented. Active phased arrays are found to provide the best performance. A total uplink capacity of 1.6 Gbps is teoretically possible with a user terminal output power of 100W, but it is not deemed realizable. Instead a configuration with a total capacity on both uplink and downlink of about 1 Gbps is suggested. At the end of the report a range of issues, related to the realization of the satellite system, requiring future attention is summarized and briefly discussed