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Nowadays there are more than 30 GNSS satellites equipped with laser retro-reflectors. Orbits of these satellites can be independently validated with a high precision using range observations by satellite laser ranging (SLR). China has completed the Asia-Pacific area COMPASS Satellite Network, and is committed to the establishment of the international GNSS Monitoring and Assessment System (IGMAS). Orbit validation is one of the key factors in the development of IGMAS, so this paper validated almost all GNSS satellites carrying reflectors to see whether the IGMAS orbits is qualified, including all 24 of GLONASS, 4 of COMPASS, 4 of GALILEO based on the rapid orbits from BACC IGMAS Analysis center. According to IERS2010 convention, correction models such as station coordinates, laser propagation delay models were introduced to establish the measurement model. The validation of the BACC orbits shows a mean deviation around 5–10 cm for the GLONASS satellites, 10–15 cm for the COMPASS MEO/IGSO satellites, 2.65 m for the COMPASS GEO satellites, and 20–25 cm for the GALILEO satellites.

Satellite constellation design plays an important role in satellite network robust QoS routing technology. Although robust QoS routing technology should not depend on constellation design, constellation design can affect the system cost, the effective communications of the entire network, and the effective and convenient management of the satellite network. At the same time, it is the basis of the implementation of routing strategies and routing algorithms.

Traffic engineering is a method to optimize the performance of a satellite network through dynamically analyzing, forecasting, and balancing the network traffic [1].

LEO/MEO Multi-Layered Satellite Network (MLSN), consisting of low and medium earth orbit satellites, is capable of providing higher coverage and better service than most Single-Layered Satellite Network. Its performance, however, has been longly encumbered by obsolete routing protocols and algorithms. This paper takes the predictability of satellite movements into consideration, based on which a novel routing protocol—Predictable Satellite Network Routing Protocol (PSNRP), is proposed. In this protocol, all topology changes due to satellite movement are classified into predictable and unpredictable changes. This predictability assists to reduce the protocol overhead. The simulations show that except for obtaining better routing performance, PSNRP also successfully allocates calculation resources evenly among all nodes, separates user data from protocol control data, and achieves stronger robustness on undergoing satellite failures and link congestions.

Low Earth Orbit (LEO) satellite networks are playing an important role in current global mobile communications. An optimized handover scheme can greatly improve performance in respect of end-to-end communication delay and link bandwidth utilization of LEO satellite networks. Various handover schemes in LEO satellite networks are researched in this paper. Ground-satellite link handover and recomputing routes problem is analyzed in detail. Then, a link handover algorithm for LEO satellite mobile communication network is proposed. Simulation results show that the satellite link handover algorithm proposed has less end-to-end delay, and is more stable and customizable.

Using directional crosslinks could help significantly improving the performance of satellite network because of the high safety, low power consumption, long communication range and little self-interference of the directional crosslink. The more in-depth study on satellite network with the directional crosslink, the more urgent to study the route of the network becomes. It is necessary to formulate scheduling of links with various constraints and facts before constellation operation and deployment for narrow-beam directional crosslink in the network. This article is based on a typical Walker model to analyze the routing of the network with directional crosslink, and proposes two route schemes. Finally, these two routing schemes are compared and summarized.

Satellite networks are evolving and changing its elements to converge with the NGN concept. The use of IP in satellite networks facilitates convergence, but also opens the door to integrate from the beginning the satellite IP services which would be part of the Future Internet. It is therefore necessary to analyze the applications and services that are typically susceptible of being used in a satellite network, so that its evolution goes online with the Future Internet. Actors and triggers of the evolution are analyzed as well as the critical points in the provision of services are identified.

There are many types of Performance Enhancing Proxies (PEPs). Different types of PEPs are used in different environments to overcome different link characteristics which affect protocol performance [1]. The main examples concerns satellite and wireless networks, which represent the most challenging environments.

The ability of an IP backbone network to deliver robust and dependable communications relies on quickly restoring service after failures. Service-level agreements (SLAs) between a network service provider and customers typically include overall availability and performance objectives. To achieve the desired SLA, we have developed a methodology for the combined analysis of performance and reliability (performability) of networks across multiple layers by modeling the probabilistic failure state space in detail and analyzing different restoration alternatives. This methodology has been used to analyze large commercial IP-over-Optical layer networks. In this paper we extend our methodology to evaluate restoration approaches for an IP-based satellite backbone network. Because of the environment in which they operate (long delay links, frequent impairments), satellite networks pose an interesting challenge to typical restoration strategies. We describe the potential multi-layer restoration alternatives and compare their performability. Interestingly, while it is commonly thought that SONET ring restoration at the lower layer improves overall reliability, we find that it may not always improve performability in this environment.

Audiovisual broadcasting has taken advantage of progress in telecommunications and, in accordance with needs and regulations, generated its own innovations, among them many new services.

The Broadcasting world has evolved very quickly towards the Digital technology supported by the DVB consensus for the harmonization of technical specifications for Satellite Digital TV distribution as well as for Satellite Master Antenna Television (SMATV), Cable, Terrestrial and Microwaves based systems. Nowadays interactivity is the key upgrading to enhance Direct Broadcasting Satellite systems for getting user acceptance in a very competitive world. Internet access through the satellite is one of the target services which makes very attractive the convergence between the broadcasting and the computers world. Interactive broadcasting systems are under definition in the frame of the DVB for the several transmission media. This paper describes the DVB Interaction Channel solution for Satellite Master Antenna Television (SMATV) systems based on the concatenation of the coaxial and the satellite sections. The satellite section is based on inexpensive low power Ku band satellite terminals known as Satellite Interactive Terminals. The coaxial section can be implemented following the Interactive Cable system compatible with DVB and DA VIC but selecting the adequate subset of options with the aim to get nearly consumer type SMATV headend equipment. Alternative Coaxial section solutions are under development in order to cope with the cost requirements of small SMATV systems with less than 40 users. The DVB Interaction Channel solutions for the SMATV users have been developed in the frame of the European ACTS Project DIGISAT. DIGISAT has developed prototy es in order to demonstrate the technical and commercial feasibility of the Interaction channel for SMATV based on Satellite Interactive Terminals and the corresponding coaxial section.

This paper describes briefly the packet satellite technology developed by the Defense Advanced Research Projects Agency and several other participating organizations in the U.K. and Norway and provides a biblography of relevant papers for researchers interested in experimental and operational experience with this dynamic satellite-sharing technique.

The French Administration decided in february 1979 to establish a domestic satellite network “TELECOM 1”