CONCEPTUAL DESIGN OF DATA ARCHIVE AND DISTRIBUTION SYSTEM FOR GEO-KOMPSAT-2A

Transcription

1 CONCEPTUAL DESIGN OF DATA ARCHIVE AND DISTRIBUTION SYSTEM FOR GEO-KOMPSAT-2A In Jun Kim, Won Chan Jung, Byoung-Sun Lee, Do-Seob Ahn, Taeyoung Kim, Jaedong Jang, Hyunjong Oh ETRI, 218 Gajeong-ro, Yuseong-gu, Daejeon, Korea InSpace Co.,Ltd., Gwahak-ro, Yuseong-gu, Daejeon, Korea NMSC., Gwahak-ro, Yuseong-gu, Daejeon, Korea Abstract The meteorological satellite, GEO-KOMPSAT-2A, is being prepared to take over the role of COMS (Communications, Ocean, Meteorological Satellite) in Korea. GEO-KOMPSAT-2A is going to equip with advanced meteorological imager exhibiting high-performance and collect a variety of meteorological data. It also will be a satellite including space weather sensors like Medium-energy Particle Detector. Therefore, GEO-KOMPSAT-2A will acquire large amounts of data and transmit them to the ground station. Accordingly it is self-evident that the amount of data handled by the ground system must be managed to increase significantly compared to the existing COMS satellite. Korea Meteorological Agency (KMA) is promoting the development of ground systems for GEO- KOMPSAT-2A which can process, manage, and serve the high-level meteorological data. Until now, the development plan, the basic system configuration and deployment have been studied and from 2014 the development phase will be started in earnest. Data Archive and Distribution System discussed in this paper is one of the systems which consists the ground segment of GEO-KOMPSAT-2A and in particular, the system will manage all of satellite raw data and processed data and distribute them to the users who need it in a variety of ways. Data Archive and Distribution System will be located in both primary and backup sites and constructed with the same configuration. A remote backup centre is also placed separately. Finally, we re looking forward to be consolidated into Korea s Data Collection or Production Centre (DCPC) of WMO Information System (WIS). To design data archive and distribution system, first the amount of data to be stored for whole mission life was assumed and secondly system configuration for reliable data service was considered. Data archive system has been designed to have 3-tier structure considering the archive period and the frequency of use. Data distribution system will provide data retrieval service and data analysis service differentiated according to user group such as internal user, external specialist, general user and industry. Especially, Open API for industry application will be served. In this paper, the concept of Data Archive and Distribution System designed by ETRI will be presented and discussed. INTRODUCTION Ministry of Science, ICT & Future Planning (MSIP), Ministry of Environment (MOE), and Ministry of Land, Infrastructure and Transport (MOLIT) are promoting the development of GEO-KOMPSAT-2A and 2B with the goal of launching them in 2017 to maintain the continuity of the weather monitoring mission utilizing Korea s own meteorological satellite started as Chollian satellite (COMS). Accordingly, to prepare the weather observation mission of the follow-up meteorological satellite, the ground segment will be also developed and constructed to carry out the reception, processing, analysis, storage, and services of subsequent satellite observation data.

2 Chollian satellite provides three missions of communications service, ocean observation service, and meteorological observation service at degrees latitude. On the other hand, the missions of GEO-KOMPSAT series will be meteorological observation, ocean observation, and environmental observation except communications service. In particular, GEO-KOMPSAT-2A is a dedicated weather satellite which will be equipped with ABI-class meteorological sensor. As a result, it is expected to provide more spectral bands, higher spatial resolution and u frame rate, and increased the amount of data than weather sensor of Chollian satellite. GEO-KOMPSAT-2A will load some space weather sensors like Medium-energy Particle Detector(MEPD), Magnetometer(MAG), and Spacecraft Charging Monitor(SCM) as well as meteorological sensor[1]. The ground segment for GEO-KOMPSAT-2A consists of the system for receiving, pre-processing, processing, analysing the sensor data, the system for controlling and monitoring spacecraft bus and missions, and the data archive and distribution system which will be presented in this paper. In this paper, the conceptual design results of data archive and distribution system, one of the ground systems, are described, which stores the meteorological data and serves it to user. OVERVIEW OF GEO-KOMPSAT-2A GROUND SEGMENT ARCHITECTURE As mentioned before, ground segment for GEO-KOMPSAT-2A consists of three main systems. Meteorological data processing system performs the receiving, re-processing, processing, and analysing of the data gathered from the sensor. Satellite ground control system is responsible for controlling and monitoring the spacecraft and its missions. And data archive and distribution system archives, manages, distributes and serves the sensor data and products. Figure 1 shows the configuration and interfaces of ground segment for GEO-KOMPSAT-2A. Figure 1:Ground segment architecture of GEO-KOMPSAT-2A. Meteorological data processing system has 6 subsystems and each subsystem is interfaced with other subsystems based on products. The 6 subsystems are categorized as follows: Meteorological & Space weather data acquisition & transmission subsystem, Meteorological & Space weather data preprocessing subsystem, Meteorological & Space weather data processing subsystem, Meteorological & Space weather data analysis subsystem, MDUS(Mass Data Utilization System)/SDUS(Small Data Utilization System) subsystem, and Simulator subsystem for algorithm verification. Meteorological data processing system deals with sensor data acquired from meteorological sensor and space weather

3 sensor, and generates the products needed for weather forecast. The generated products are served to users via MDUS and SDUS systems[2]. Especially, meteorological & space weather pre-processing system and satellite ground control system are located separately in backup ground segment. And systems in primary ground segment are configured in dual structure. Therefore, the pre-processing system has the triple configuration and other systems are dualized. Data archive and distribution system is composed of data archive system which stores and manages raw data received from the satellite and products generated from data processing algorithm, and data service system which distributes archived products to users. Also the management system controls and monitors the configuration and data flow of both systems. Data archived and distribution system is constructed with the same configuration in primary and backup ground segment, and remote backup centre is located in the head office of KMA. So, data archive and distribution system conserves data under the triple protection. CONCEPT OF DATA ARCHIVE AND DISTRIBUTION SYSTEM Data archive and data distribution system consists of three systems: data archive system, data service system and management system. The satellite data service system has the missions that provide the data collected from the satellite and serves various products generated by satellite data processing system. The satellite data archive system stores satellite raw data and products obtained through the interface with data acquisition system and data processing system. The management system controls and monitors satellite data archive system and satellite data service system, and provides the tools for cooperative work. Each system will be designed and implemented to satisfy the following requirements shown in table 1. Subsystem Items Requirements Satellite Data Service Subsystem Satellite Data Archive Subsystem Management Subsystem Capacity Service Coverage Users 1000 concurrent users 200 subscript requests 100 Ad-hoc queries 500Mbs continuous data transfer Meteorological Data: Level 1B, Leve2 Space weather data Open API General users, Public users, Developers Service Device Service by Smart devices (smartphone, tablet, TV) 15k hard disk for 1 week data Storage Performance 7.2k hard disk for 1 year data Tape backup for all data Storage Availability 99.95% Storage Capacity 20TB for 1 week data 1PB for 1 year data Data Backup Plan primary centre, backup centre, and remote backup centre Network Converged Storage network based on 10/20GbE or infiniband Monitoring Tools Dashboard-type monitoring system Process management Collaboration Tools Users and privilege management Community service management Meta DB Performance 7PB/10years, over 100 milion data Table 1: Essential Requirements of Data Archive and Distribution System. In satellite data service system, the general users can make use of web service for meteorological product data. The products also can be accessed through application of smart devices which the satellite data service system supports. Tool kit service like Open API will be provided for supporting that individuals, industries, and public organizations develops new services using meteorological and space weather data. The management system is responsible for the following functions: the management of various contents provided by satellite data service system, the provision of dashboard environment for

4 macroscopically and microscopically monitoring the data collected from internal/external systems, and the operation of process for managing data input, approval, and update. The satellite data archive system has a plan to manage other satellite data as well as GEO- KOMPSAT-2A data. The total amount of data to be managed is shown in table 2. The amount of COMS data is 96.3TB per year and it is estimated that data for GEO-KOMPSAT-2A will be produced more than 883.9TB. Additionally, data of overseas satellites including GEO, polar orbit and earth resource satellite will be archived as about 28.3TB. Satellite Category Daily increment Monthly increment Yearly increment Domestic Satellites COMS GB GB 96.3 TB GEO-KOMPSAT-2A GB GB TB Overseas Satellites GEO satellites 29.3 GB GB 10.7 TB Polar orbit satellites 9.36 GB GB 3.4 TB Earth resource satellites 39.0 GB GB 14.2 TB Total GB GB TB Table 2:Total amount of Satellite Data Archiving. The storage hardware for archiving the data will be constructed to have 3-layer. Tier-1 is used for realtime data processing and is based on the SAS 15K rpm disks. It provides the total storage of 20TB. Tier-1 stores raw data and products and it is possible to process data in rapidly because it has SAS 15K rpm disk. Raw data is saved during 5 days in Tier-1 and products are stored during 7 days in this tier. N-way data protection function protects data from a failure of system. Tier-2 is the layer for long-term archive. It is composed of 7.2K rpm SAS disks. All of tier-1 data is also archived in tier-2 after data of tier-1 is archived. This system is able to extend its capacity according as the data is increased. In tier-3, data is archived for tape backup firstly. Secondly, it is transferred to the remote backup centre. In remote backup centre, data is firstly stored in virtual tape library (VTL). And then data is archived in physical tape library (PTL). The tapes of PTL are kept permanently. Figure 2 shows the storage configuration as mentioned above. Figure 2: Layered storage configuration.

5 Figure 4 presents the configuration of data archive and distribution system. The dedicated network and the internet network are operated separately for internal and external services respectively. Satellite data services system is located in both positions, the one is within the dedicated network and the other provides a service for the external users. Servers for each service are virtualized using virtual machine. Virtual servers have primary and backup machines for redundancy. Internal network and external network are divided by network separation system and communicate through it. There are storages for data management and for data service in storage system. The internal satellite data service system uses the storage for data management and the satellite data service system for the external users accesses the service storage. The data between primary ground segment and backup ground segment is synchronized by a storage solution. There are some legacy systems in primary ground segment. For new system to interact with legacy system, data archive and distribution system is designed to apply ibrix solution which is able to interface between systems in heterogeneous environment. Figure 3: Conceptual configuration of data archive and distribution system. Figure 4 shows the way of approach that the services separated by the user group are provided. General users can receive a service of satellite data through NMSC Web service. Internal and external experts can retrieve a satellite data through data retrieval web service for them and the service for

6 request of data analysis and confirmation of its result is provided to especially external experts through the web service for data analysis. Also, to activate the industry for the satellite data service, Open API will be supported for industries and it will be able to access services for retrieval and analysis of satellite data using this interface. Figure 4: Services classified by users group. CONCLUSIONS In this paper, we presented the ground segment configuration for GEO-KOMPSAT02A and one of systems included in ground segments, data archive and distribution system, was described in the aspect of conceptual design. The data archive and distribution system was designed to basically ensure the redundancy. Data Archive and Distribution System discussed in this paper will archive and manage the satellite data and products derived from the raw data and serve them to several well-classified users. Eventually, data archive and distribution system will be merged into Korea s Data Collection or Production Centre (DCPC). Various services to satisfy users with different concerns and purposes will be provided by the data archive and distribution system, for example, data retrieval service, data analysis service, and Open API service etc. To implement ground segment for GEO-KOMPSAT-2A as well as data archive and distribution system, officially the development project is plan to start in REFERENCES [1] [2]