Ground Based Augmentation System (GBAS) also named Local Area Augmentation System (LAAS) describes a system that relies on so called differential techniques and use reference stations that continuously monitor the GPS signals. Since the positions of the reference stations have been precisely surveyed, the errors in the satellite signals can be calculated and corrections broadcast to users in the service area. The user's differential GPS receiver applies the corrections to improve the accuracy and integrity of its own position.
The development of GBAS\LAAS has been started in the late nineties. It was mainly driven by the intention of the aviation industry, to replace the Instrument Landing Systems (ILS and MLS) by a more flexible and cost-saving system. In parallel, and at approximately the same time, the IALA Beacon differential GNSS has been introduced in the maritime sector, replacing the LORAN-C terrestrial radio navigation system. DGNSS is now the primary navigation mean that meets the 8-10m harbour/harbour approach accuracy requirement of the International Maritime Organisation (IMO). Nowadays follow-up activities aim for the further development of DGNSS towards a maritime GBAS, able to fulfil the stringent IMO navigation performance requirements for port operations and automatic docking.
The GBAS in the port of Rostock currently consist of one reference and one integrity monitoring station. Current research objectives in the maritime field are:
Both experimental systems are used for the development and testing of new methods and algorithms for the estimation of position, integrity and error models. The platform for the development, validation and demonstration of the systems is the so called EVnet. It enables easy acquisition, processing, combination, management and distribution of the data within the different systems.