Won Chan Jung

Preliminary design for satellite mission operation from mission request to command planning

Communication, ocean, and meteorological satellite (COMS) is a geostationary satellite system which performs multi-mission such as communications services, ocean data acquisition, and meteorological data acquisition. Each mission is operated by different users, but it is the COMS satellite ground control system (SGCS) that practically controls all missions at an end. Therefore, all requests for performing the COMS mission have to be collected into COMS SGCS, and then the gathered mission requests shall be converted into the command to be transmitted to satellite after scheduling the requested mission in an optimal schedule. This paper introduces mission planning system and process which gathers mission requests, performs interactive mission scheduling, and generates command plan in order to carry out the various satellite missions of the COMS. First of all, we will see the system configuration and developing environment for mission planning. This paper will describe the main functions such as mission request gathering, mission scheduling, mission timeline reporting, and command planning. It deals with the role and design of each function in detail, and finally represents the operation concept to have the operator perform the mission planning efficiently when the COMS will be on orbit later on

Design and prototyping of high availability architecture for satellite ground control system

A satellite ground control system (SGCS) that monitors and controls a geostationary satellite 24 hours a day has to achieve the distributed architecture assuring high-level availability. The SGCS for communication, ocean, and meteorological satellite (COMS) is currently being developed in Korea, which is implemented to satisfy high availability, expansibility, and compatibility in design. In order to implement the system architecture to meet these characteristics, this paper introduces the concept of the real-time distributed system structure based on fault detection and recovery, data replication and sharing using CORBA middleware and redundancy scheme. This paper also describes down-sized hardware and software configuration to perform the mission operation of geostationary satellite, and the prototyped services for 24-hour operation SGCS assuring high availability is presented in detail

CFTUE: "Construct First-finished Task avoiding Unconditional Exclusion" Algorithm for Single-Resource Satellite Mission Scheduling

In this paper, we propose an Construct First-finished Task avoiding Unconditional Exclusion (CFTUE) Algorithm for Single-Resource Satellite Mission Scheduling. At each step of the algorithm, the task which is able to be finished first is considered earlier to be scheduled based on a greedy approach. By selecting the task, however, another task might be discarded even though both of them may coexist. In this case, we schedule the discarded one instead of the former one. This principle does not follow the conventional wisdom that the current partial schedule should be compressed as much as possible so that more tasks are to be inserted later. However, performance evaluation shows that CFTUE algorithm contains more tasks than Construct First-finished Task (CFT) algorithm.

Design of Multi-channel Telemetry Processing and Data Management of ROS in COMS SGCS

Real-time Operations Subsystem (ROS) is one of subsystems of Satellite Ground Control System (SGCS) for Communication, Ocean and Meteorological Satellite (COMS). ROS receives telemetry data from COMS for 24 hours, processes telemetry data in real-time and stores telemetry data for off-line telemetry processing. Using ROS, operators can monitor the State of Health (SOH) of COMS and control COMS. We designed ROS to process general multi-channel telemetry data those frame compatible with CCSDS (Consultative Committee for Space Data Systems) international standards. We also designed the mechanism of storing and managing multi-channel telemetry data. In this paper we will describe the design of multi-channel telemetry processing of ROS in detail.

Development of the Satellite Ground Control System for Multi-mission Geostationary Satellite COMS

A multi-mission GEO satellite, COMS has three payloads including Ka-band communications, GOCI, and MI. COMS SGCS is the only system for monitor and control of the satellite in orbit. In order to fulfill the mission operations of the three payloads and spacecraft bus, COMS SGCS performs the following functions such as reception and processing of telemetry data via S-band link, planning and transmission of telecommand, tracking and ranging of the satellite, control and monitoring of SGCS equipment, analysis and simulation of the satellite, processing and analysis of flight dynamics data, and mission scheduling and reporting. By the proper functional allocations, COMS SGCS is divided into five subsystems such as TTC, ROS, MPS, FDS, and CSS. COMS SGCS is linked with MSC, KOSC, and IDACS for satellite related data exchange. The software in the COMS SGCS is designed using the object-oriented methodology and implemented using Microsoft C# .NET environment on Intel microprocessor based computers. The hardware in the COMS SGCS includes 13-m S-band mono-pulse Cassegrain antenna and RF/BB equipment. In this paper, development of the COMS SGCS is described with respect to system functional allocations, software and hardware design, system implementation, and system test.

Design of Real-Time Operations Subsystem in COMS SGCS

ROS (Real-time Operations Subsystem) is main subsystem of SGCS (Satellite Ground Control System) for COMS (Communication, Ocean and Meteorological Satellite). The ROS performs reception and processing of telemetry data from COMS, planning and transmission of telecommand to COMS via S-band link. ROS supports satellite simulation using DSSS (Dynamic Satellite Simulator System) and CSS (COMS Simulator Subsystem), dwell telemetry management in case of satellite anomaly state, dump telemetry management for analyzing satellite status, ancillary telemetry transmission to MSC (Meteorological Satellite Center), KOSC (Korea Ocean Satellite Center) and IDACS (Image Data Acquisition and Control System) in SOC (Satellite Operation Center) periodically for image processing, operation procedure support by converting FOP (Flight Operation Procedure) delivered from Astrium into operation procedure for ROS and executing using command executor, telecommand authentication for satellite authentication. We designed ROS as UML (Unified Modeling Language) which includes use case modeling, domain modeling and also includes package design, component design, process design and deployment design. In this paper we will show the modeling and design of these ROS in detail.