GBAS-Technologies for High Precise Safety-Critical Maritime Navigation

Abstract

As a result of the high quality of positioning and timing service, satellite navigation becomes the primary means of navigation for most of civil applications, worldwide. The trend of integrating satellite navigation with other technologies to obtain very precise and reliable position and time information is highly promoted by the development of the future European satellite navigation system Galileo and the modernization of GPS. In the future a large variety of safety-critical maritime applications will depend on this infrastructure. This paper presents the DLR activities for the development of a maritime ground based augmentation system (GBAS). GBAS in general are focused on users who need assurance of high precise positioning service performance (decimetre) in real-time. In the maritime sector, due to IMO requirements, these are applications as: automated docking, dredging, hydrographical surveying, cargo handling, etc… The paper starts with a brief overview of the ALEGRO project, the frame of this research and development activity. The project has been initiated in 2006 by DLR under the support of the Government of the German Federal State Mecklenburg Western Pomerania and aims for the further development of state-of-the-art real-time kinematic (RTK) technologies towards a maritime GBAS, taking into account the services of the future Galileo. Subsequently, the paper describes the hard- and software architecture of the ALEGRO environment in Rostock, currently consisting of a single Monitoring and Control Station embedded in a data and processing network named EVnet. The description includes details about the service that can be provided to the user of the Test Environment within the vicinity of the port of Rostock. The final section of this paper shows the recent results of the validation activities carried out at the port of Rostock and the results of the algorithm development. The validation activities performed within the project were followed by extensive analysis of the data to identify and evaluate signal disturbances in the port surrounding. These activities have been the base for the design and validation of algorithms for the detection of environmental and atmospheric propagation effects. As discussed in the paper, such effects - decreasing the signal quality and availability - with a strong impact on position and integrity can be a critical issue for the operation and the use of a continuous reliable GBAS service.