System
System Concept
The NELIOTA system consists of four main systems deployed in two remote sites, in Kryoneri and Athens. The Observation and Detection System are deployed in Kryoneri, while the Archive and Publication System are deployed in Athens.
| Component | Type | Description |
| ArchOperHMI | H2M Interface | Archive system operator interface |
| ArchPublIF | M2M Interface | The interface between the archive and the publication |
| ArchSys | Top-level component | Events archiving and expert validation |
| ArcIF | M2M Interface | The interface of the Krioneri-to-Athens events transfer |
| ARCSTO | Sub-System | A database-driven storage array for the NELIOTA archive |
| ArcStoIF | M2M Interface | The archive storage interface |
| CAM | Sub-System | A fast-frame double camera system |
| CamIF | M2M Interface | The camera interface |
| DetOperHMI | H2M Interface | Operator interface for events processing |
| DetSys | Top-level component | Events detection |
| ExpOperHMI | H2M Interface | NELIOTA expert operator interface |
| GPS | Sub-System | A GPS-based time server |
| GpsIF | M2M Interface | The GPS interface |
| MET | Sub-System | A meteorological station |
| MetIF | M2M Interface | The meteorological station interface |
| ObsOperHMI | H2M Interface | Operator interface for observation (camera, frames) control |
| ObsSys | Top-level component | Observations and recording |
| ODSTO | Sub-System | A high-performance storage |
| OdStoIF | M2M Interface | The high-performance storage interface |
| PublOperHMI | H2M Interface | NELIOTA publication services operator interface |
| PublSys | Top-Level component | Events publication and information services |
| TEL | Sub-System | 1.2m Kryoneri telescope |
| TelIF | M2M Interface | The telescope interface |
| WebUserHMI | H2M Interface | Web-based interface for all the external users |
| Operator/User | Component | Description |
| AnonUser | PublSys | Anonymous user of restricted archive services |
| ArchOper | ArchSys | The archiving domain operator |
| DetOper | DetSys | The detection domain operator |
| ExpOper | ArchSys | The NEO impact events expert |
| ObsOper | ObsSys | The observation domain operator |
| PublOper | PublSys | The information domain operator |
| RegUser | PublSys | Registered user of extended archive services |
Hardware
The IT hardware of the NELIOTA system satisfies the requirements of the NELIOTA operation, namely a) high-performance storage resources, in order to support the high data rate, b) high-protection storage virtualization, to ensure integrity for saving the data and c) high-performance processing resources, in order to perform the processing of large volumes of data in a reasonable amount of time.
The Cluster System consists of
- Two (2) nodes HP DL380 Gen9 Servers.
- A storage Subsystem of an HP MSA 2040 SAN DC SFF Storage with an additional HP D2700 Disk Enclosure. The Storage Subsystem is populated with 32xHP 1.2TB 6GB SAS 10K SFF DP ENT HDDs, providing total RAW capacity 38.4TB.
- Network has been implemented in 2-ring concept. Inner (Red) Ring Network: iSCSI network. Very high speed dedicated network for data transfer between servers and MSA Storage Array. Private isolated and secured network. Outer (blue) Ring Network: Typical communication network for device management, routing configurations and remote access to devices for healthy operation monitoring.
The conceptual physical architecture of the system is presented in the following figures:
GPS-based Network Time Server
A local GPS-based NTP server is used as a time reference for all NELIOTA systems. It is characterized as a stratum 1 time server for the local network nodes (the latter could serve as stratum 2), while the remote NTP systems are in the best case stratum 2 time servers. The time server and GPS antenna have been installed at the Kryoneri telescope.
The general architecture of the NTP server is depicted below.
Meinberg Lantime M200 GPS Receiver and NTP Server
High performance GPS antenna