The Common Ground System for both satellite ground test and on-orbit operations

摘要

Although the EGSE (Electrical Ground Support Equipment) for satellite ground test prior to launch and MCS (Mission Control System) for on- orbit operations after launch have many similar or even identical functions, the EGSE used for assembly, integration and validation phase and the MCS for the mission operations phase are normally developed separately and used by different groups of engineers. However, the demand for the single common ground system for EGSE and MCS has increased rapidly in order to minimize risk, reduce cost and improve overall product quality. To keep up with the increasing demand, the CGS (Common Ground System) has been developed over recent years for Korean satellite program. It tries to provide all essential functions to monitor and control a satellite both in orbit and during testing. In practice, many space missions for Korean satellite programs have used or will use it. In this paper, we introduce CGS (Common Ground System) and give a brief overview on the CGS. The current version of CGS runs on Microsoft Windows operating systems (Windows Server 2010 / Windows 7) and the DBMS (database management system) used in CGS is MS SQL Server which is a relational model database server produced by Microsoft. All the software components of CGS are based on the Microsoft .NET Framework installed on computers running Microsoft Windows operating systems. The .NET Framework is a software framework including a large library of pre-coded solutions to common programming problems. The client side application of CGS can access spacecraft database running on server side via ADO.NET which is a part of the base class library that is included with the Microsoft .NET Framework. The client application of CGS is also RIA (Rich Internet Application) being capable of delivering a rich experience to the user over the web. To be more concrete, it is based on Microsoft Silverlight which is an application framework for writing and running RIA in order to be able to be accessible via a browser anywhere at any time. Additionally CGS relies upon SOA (service-oriented architecture) to design and implement more robust, maintainable, and reusable software components which is easily assembled and combined efficiently and rapidly for different purpose. The CGS has multi-mission capability. It can be used to control and monitor multiple satellites at the same time with single hardware platform. That is, CGS is able to share servers and clients across missions for minimizing the amount of hardware platform. In order to perform automated operations and describe scripted procedures, it also supports the procedure automation language for both satellite ground test and mission operation such as PLUTO (Procedure Language for Use in Test and Operations) which is published as an ECSS standard and Spacecraft Test and Operations Language (STOL) which is developed by NASA (National Aeronautics and Space Administration) and is used in numerous ground systems today. The procedure automation language in CGS is easy to use and used to monitor spacecraft telemetry and send commands to ground equipment or a spacecraft. Moreover, the telemetry data received from satellite in real-time are used to monitor satellite both in orbit and during testing. However, it is impossible to check all the incoming telemetry data from satellite in real time in order to detect abnormality of satellite quickly. MIMIC within the CGS is used in order to display summarized information about spacecraft in a visualized way that is quickly and easily understood. That is, it provides essential function to monitor a satellite both in orbit and during testing. In future work, we plan to enhance the CGS in order to improve the reusability, maintainability and portability. For example, the CGS will minimize the dependencies on COTS (commercial off-the-shelf) products for future Korean space missions. Some COTS products such as NetAdvantage (Infragistics), RadControls(Telerik), and SyntaxEditor (Actipro) are currently used in CGS. In order to make CGS be more open and flexible system, the dependencies on COTS products should be minimized to a negligible level in the near future. This paper also will include the lessons learned from the design and implementation of the CGS.