The SAT-AIS Data Processing Centre (DPC) Demonstrator is a development co-funded by EMSA (European Maritime Safety Agency) and ESA. The DPC collects SAT-AIS messages, ancillary information for generating and distributing enhanced data services to the maritime community.
The ARTES 20 demonstration project aims to develop the ESA component of the DPC -referred as DPC Block 2- which shall receive SAT-AIS and ancillary data from satellite providers, process and correlate them with Earth Observation data, then store and distribute the enhanced data to EMSA component of the DPC.
The EMSA DPC component -referred as DPC Block 3- on the other hand forms part of the Integrated Maritime Data Environment (IMDatE), a component of the SafeSeaNet (SSN) ecosystem, that ingests AIS data received from terrestrial and satellite sources with other data sources (e.g. LRIT) in order to distribute the enhanced data to its users.
The objectives of the DPC Block 2 project are the specification, design, development, integration, validation and pre-operation of the DPC Block 2.
The project also aims at demonstrating the scalability of the DPC Block 2 to future satellite constellations that might result from on-going or future SAT-AIS initiatives. For this purpose, the DPC Block 2 architecture includes a SAT-AIS simulator which allows for the simulation of SAT-AIS and ancillary data produced by existing or future space segments.
Users and their needs
The user of the services provided by the SAT-AIS DPC Block 2 is the European Maritime Safety Agency (EMSA).
Currently, the SafeSeaNet (SSN) operated by EMSA ensures the effective tracking of vessels and hazardous cargoes based on the data received by coastal stations. From the coastal stations, the AIS messages are transferred via national stations to four regional AIS servers that provide the data to the EMSA SafeSeaNet server.
The SAT-AIS DPC will provide the gateway for an additional data stream of SAT-AIS data and services.
Service/ system concept
The DPC Block 2 provides the following services:
- Service 1. AIS messages provision: it provides well-received AIS messages, without any further enhancement processing;
- Service 2. Missing AIS Messages detection service: it provides indication of the times during which AIS messages were lost as well as times where the contacts were expected;
- Service 3. Enhanced AIS messages service: it provides AIS messages that have been reconstructed and/or enhanced by using ancillary data;
- Service 4. Predicted AIS messages service: it provides AIS messages prediction, based on previous SAT-AIS messages from the same ship;
- Service 5. AIS messages with EO data service: it provides validated positions of ships by correlating VDR data from EO images with AIS messages:
- Service 6. Support SAT-AIS information: it provides satellite orbital data and events information in support of AIS messages processing.
Space Added Value
DPC Block 2 relies on SAT-AIS and EO data.
The general added value of SAT-AIS is to provide extended ship detection and tracking service, at distances from coastlines, that cannot be covered by land-based AIS.
DPC capability to integrate SAT-AIS data with external information (such as Doppler shift measurements and VDRs derived from Earth Observation data) further qualifies and enhances ship position accuracy provided by SAT-AIS.
The provision of SAT-AIS data brings value added to existing maritime information services by providing ship detection
capabilities at distances from coastlines that cannot be covered by land-based AIS. Additional benefits to the user communities lay in the validation of the positional information included in AIS messages which will provide an effective means to identify and counteract illegal (maritime related) activities.
SAT-AIS information will support European entities and institutions in law enforcement, fisheries control campaigns, maritime border control operations, maritime safety and security issues including marine pollution response, search and rescue and anti-piracy.
The DPC Block 2 provides a complex layer for processing SAT-AIS data, enhancing their quality, archiving and distributing SAT-AIS data products to DPC Block 3. To achieve these objectives, DPC Block 2 architecture includes several subsystems, as described below.
The Data Retrieval subsystem performs the acquisition of input data including SAT-AIS and related auxiliary data and vessels detection reports (VDR) derived from Earth Observation data.
DPC Block 2 data are stored in a local Data Management and Archiving subsystem.
The Data Prediction subsystem performs the prediction of ship position based on the last available vessels’ positions, their speed and most likely routes.
The Data Processing and Validation subsystem processes and validates all data acquired by the Data Retrieval subsystem, according to the following workflow:
- each AIS message is validated individually through multiple independent checks, in order to check its data integrity;
- doppler shift measurements associated to AIS messages are processed to provide an independent position of the ship;
- AIS positions are compared with Doppler-estimated positions, predicted ship positions, and/or VDRs; these comparisons provide a level of confidence of each AIS message’s positional information, which is distributed along with the AIS message and other vessel’s position measurements (mentioned above) through the data distribution subsystem.
The Data Distribution subsystem manages the interfaces to the DPC Block 3.
The Monitoring Command and Control subsystem performs technical monitoring and control of the entire infrastructure in order to ensure that systems, applications and services are running properly.
DPC Block 2 performs a variety of functions, including data retrieval, validation, archiving, etc. to provide value-added services. The capability to achieve near real time data feed to the EMSA component of the DPC is a major technical challenge.
In addition, the solution shall be scalable to process the large volume of data that will be generated by the future SAT-AIS space segments.
Following the definition of the system requirements, DPC Block 2 implementation activities and testing were successfully concluded in June 2013.
After successful demo qualification review, the pre-operations of DPC Block2 with real SAT-AIS data started in July 2013 and lasted 8 months, proving DPC Block2 compliance to the requirements and the key performance indicators agreed during the project.
Remarkably, the enhanced positioning service was proved to be fully functional and providing results usable in an operational context.
Following the successful outcome of the project, DPC Block2 is planned to become step-wise part of the EMSA’s Integrated Monitoring Data Environment (IMDatE) services.