The ground segment for the future remote sensing mission Environmental Mapping and Analysis Program (EnMAP; www.enmap.org) is developed by the Earth Observation Center and the German Space Operations Center at the German Aerospace Center. The launch is scheduled for 2017. An operational satellite ground segment is a highly complex heterogeneous system which has to cope with different levels of criticality, novelty, specificity, and to be operated for many years. It consists of equipment, hard-and software as well as operators with their procedures. The strengths of the global coherence of the segment-wide approach bringing these aspects together is examined and not on the local details of segment-specific issues. However, the effects on two software-based elements of the ground segment are considered in more detail, namely the product library and the level 2geo processor. The development methodology and how the critical design of the complete ground segment finished its detailed design phase successfully was achieved is analyzed. As a measure of the maturity of the design, its stability across the project phases is proposed.
Earth observation missions are generally operated by execution of predefined timetagged commands. However, depending on the type of mission, issues relevant to different types of mission may occur. These issues are drivers for the design of the operations system of EnMAP (Environmental Mapping and Analysis Program). The main challenges are limited transfer of telecommands and limited downlink capabilities; also the cloud coverage in the target area -for optical sensors -plays a huge role.There are certain constraints, concerning this satellite bus in particular. For example a limited time tagged list which allows no more than 120 time tagged commands on board. Further the fact that every dumped house keeping packet has to be requested from the space craft which leads to a delay in the reception of telemetry can be a bottle neck. In addition to these S-band related issues it is a real challenge to coordinate the amount of payload data which will be down-linked via X-band. In this paper the strategy of managing all these difficulties and optimally operating the satellite under these conditions, will be described.For handling of cloud coverage a database with weather statistics will be implemented. These statistics are compared with global forecast models as provided by e.g. the German weather service (DWD). With the calculated forecast values, planning priority of datatakes is increased or decreased.
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