A Space-Based Polar Augmentation System enabling for

Abstract

Geostationary communication satellites are generally regarded as providers of global communication services ignoring a lack of coverage in polar regions and gaps over the oceans. An increasing regulatory and legislative demand on worldwide positioning and communication capabilities, in particular in the maritime sector, calls, however, for a truly global coverage. Therefore, appropriate space-borne augmentation systems are required and presented in this paper. An innovative augmentation concept is proposed which is especially suited for combined communication and navigation applications based on Global Navigation Satellite Systems (GNSS). The alternatives considered for an augmentation of geostationary communication satellites are the ORBCOMM satellite system, the ARGOS system, as well as a proprietary satellite system. In addition, a concept for a dedicated communication payload on several GNSS-2 Galileo spacecraft has been considered. For the concept evaluation, a Pugh matrix has been established, supplemented by a Gaussian variance analysis to indicate quantitative confidence levels of the achieved ranking. As a result, a proprietary satellite system has been selected to best serve the needs for global communication and navigation services. The concept selection was part of a thorough systems engineering process, which has been established. While traditional systems engineering is primarily driven by functional needs and stakeholder requirements, the presented approach is particularly based on financial and business engineering principles as additional design drivers. Thus, an optimized approach of system development is accomplished which applies classical systems engineering methods to arrive at a system, which in addition represents a sound business concept. As a result of the systems engineering process, the space segment architecture for the polar augmentation will be presented with a focus on the design of the spacecraft communication payload. Here, special attention has been given to an innovative frequency and modulation scheme which allows interoperability and avoids interference with other communication systems, while maintaining the full positioning accuracy based on GNSS signals. The presented approach is considered as an important step towards enforcing regulatory demands and achieving an improved performance for global communication-navigation applications.