Stefan Gewies

ASSESSMENT OF AIS VESSEL POSITION REPORT UNDER THE ASPECT OF DATA RELIABILITY

Abstract Since its introduction the Automatic Identification System (AIS) has played an important part in improving safety at sea, making bridge watchkeeping duties more comfortable and enhancing vessel traffic management ashore. However the analysis of a AIS data set describing the vessel traffic of the Baltic Sea came to conclusion, that specific parameters with relevance to navigation seemed to be defective or implausible. Essentially, it concerned the true heading (THDG) and the rate of turn (ROT) parameters. With the paper we are trying to clarify, which parameters of the AIS position report and to what extent, are affected. The detailed data analysis gives answers on how reliable the AIS data in different traffic areas is.

Deterministic framework for parallel real-time processing in GNSS applications

Starting from the goal developing deterministic realtime applications for high-rate GNSS data this paper shows a number of possible program structures depending on the chosen algorithm complexity using a DLR own software framework. Single-threaded and multi-threaded applications will be compared using a simple example and a real project.

Scintillation of GNSS signals at equatorial latitudes

A particular threat to global navigation satellite systems (GNSS) are small scale ionospheric disturbances. These can lead to fluctuations of the received satellite signal, so called signal scintillations. Strong scintillations can lead to a loss of lock between satellite and receiver. All GNSS signals are affected by this phenomenon. The influence of the short scale disturbances on the different GNSS signals is expected to be different for each signal, since the signals are transmitted by different carrier frequencies and are constructed in different ways.