Russian GLONASS, Chinese BeiDou2, Indian regional IRNASS, and Japanese quasi zenith satellite system. Some of these systems use the MEO while some operate in the GEO. The principal behind all these systems is the same: a receiver needs to detect the position of 4 satellites and its distance from them SO it can calculate its own coordinates. While duplication of this infrastructure is inherently inefficient, these countries clearly consider a positioning system as a strategic asset worth the cost of launch and operation. For many of these countries, military applications require accurate positioning to sub-metre levels, presently considered to be available only to the US military through GPS. Some of these sys- tems are already operational such as Russia's GLONASS, and the rest are expected to become operational by the turn of this decade (2020). Details of these systems are listed in Table 11.3. The GEO-based systems (BeiDou, INRSS and Quazi-Zenith) are generally national or regional, whereas the MEO-based systems are global. Broadband Telecommunications Technologies and Management Satellite telecommunications systems are finding a new life in the provision of broadband services and contents. On the one hand they are essential to GPS, which in turn is used in the provision of many location-based services. On the other hand they are the most economic, as well as the quickest, roll-out option for provision of broadband internet in remote, under- served areas of the world. While the latter services are mostly government subsidised, new service provision business models are approaching competitive pricing points. Satellite systems have become an important part of the broadband telecommunications landscape. Review Questions 1. What is a geostationary orbit? 2. What is a sidereal day? 3. Why is link budget calculation necessary? 4. Why did Intelsat's business shrink? 5. How can real-time communication be possible with non-geostationary satellites? Give an example. 6. For a VSAT operator, list cost and revenue items. 7.