Andrzej Felski

Comprehensive Assessment of Automatic Identification System (AIS) Data Application to Anti-collision Manoeuvring

The use of radar information for collision avoidance is common, however it is effective only for constant values of ship motion parameters. As information delays or information errors occur, it is reasonable to supplement the information derived fromradar with another information system. An ideal systemshould operate automatically and continuously.Asystem that appears to be suitable to provide this kind of information is theAutomatic Identification System (AIS),whichmay be classified as a radio communication systemthat uses radiowaves to transmit datawith regard to ship motion parameters. In this paper the topic of integrity and completeness of AIS information is discussed and the research results for the completeness and integrity of dynamic information are presented. In addition, the outcomes ofAIS information correctness fromthe Gulf of Gdansk were compared with studies carried out in the Baltic Sea, east of Bornholm, between Trelleborg and Arkona. The results of research for AIS dynamic information with the highest completeness (Position, Course over Ground and Speed over Ground) are presented. The research outcomes presented in the paper lead to the conclusion that AIS could deliver useful supplementary information in the process of collision avoidance.

Information unfitness as a factor constraining Automatic Identification System (AIS) application to anti-collision manoeuvring

ABSTRACT Common use of shipboard AIS creates conditions for the use of a new kind of dynamic data in the situation of the risk of collision. AIS position report is a source of supplementary information derived from error leveraged radar measurement. However, in view of the results of the studies there are opinions with regard to inconsistent AIS dynamic data in the process of decision-making by the officer of the watch. By taking into consideration the recordings of the studies and technical specification of AIS it can be concluded that the results of inconsistent data have significant role in collision avoidance manoeuvring.

Application of the Least Squares Method for Determining Magnetic Compass Deviation

This paper describes an algorithm for evaluation of magnetic compass deviation based on the least squares method. An automatic system was built, coupled with a magnetic compass recording device, for fine estimation of the deviation curve on the basis of an incomplete compass swing circulation.

INFORMATION UNFITNESS OF AIS

Abstract Commonly used AIS devices on the ships covered by SOLAS Convention creates ideas of the use of AIS data in the situation of the risk of collision. AIS position report is a source of supplementary information derived from error leveraged radar measurement. However, many of users has opinions with regard to inconsistent AIS dynamic data in the process of decision-making by the officer of the watch. Taking into consideration the recordings of the studies and technical specification of AIS, the results of inconsistent data has been analysed in the context of collision avoidance

ON EGNOS MONITORING IN LOCAL CONDITIONS

ABSTRACT Any SBAS system should deliver to the user corrections to pseudoranges as well as information about the system integrity. In theory, as soon as the system is permanently monitored by RIMS stations, it is impossible to deliver the fault information to the user. However many observations shows that accuracy of EGNOS service in the same time are different in different places, which shows the influence of local conditions on them. In addition evidences on possibilities in jamming or spoofing of GPS signals should be seriously taken into account. According to many sources of information, among them observations of authors, present accuracy of EGNOS service has better than declared. In fact EGNOS accuracy is about 1,5m (95%), but availability of the service happens still controversial and it has random character. According to reports essential differences as well as lack of correlation of this parameter in the different point of observations has been observed. So in author’s opinion Local Monitoring of EGNOS service can contribute to better confidence of local users, especially in critical operations, like for example berthing of big ships or in landing operations with EGNOS procedures. An example of such system which works in real time has been elaborated in Polish Naval Academy and will be presented.

Local monitoring of EGNOS services

Abstract Any SBAS system, as soon as it is permanently monitored by Earth stations, should deliver to the users correct information about quality of the augmented system. According to many sources of information, among them observations of authors, present accuracy of EGNOS service has accuracy about 1,5m (95%), but availability of the service is still controversial. First of all the quality of the system is guaranteed only inside the border of the system coverage which still do not affect all territory of European Union, however observed accuracy at times is better outside this area than next door to the RIMS station. In addition there are evidences that availability has random character and essential differences as well as lack of correlation of this parameter in the different point of observations has been observed. So in author’s opinion Local Monitoring of EGNOS service can contribute to better confidence of local users, especially in critical operations, like for example berthing of big ships or landing operations with EGNOS procedures. The example of EGNOS monitor which is working in real time and performed by the authors will be presented

Current State of Deep Ocean Bathymetric Exploration

Abstract The paper presents current state of bathymetric survey concerning deep ocean rather than shallow areas, which are better surveyed due to safety of navigation concerns. Rules and requirements of the new challenge, called the Shell Ocean Discovery XPRIZE, became a starting point for a discussion about the possibilities of mapping large areas of the ocean using up-to-date and new technology. The amount of bathymetric data available nowadays and the current state of ocean map compilations are also discussed in the paper as a motivation to inspire the new initiatives in the deep ocean.

The problem of the instrument stabilization during hydrographic measurements

Abstract Performing any measurement on watercraft is connected with many additional difficulties caused by the sea-environment. The most important is the problem of spatial stabilization of measurement systems, which are usually fastened to craft body. As soon as usually these measurement are executed during the move of the craft additional question is the accuracy of execution the planed trajectory. This is a problem for all investigators, especially when system use spatially configured beams of any antennas or other sensors, regardless is it receiving or transmitting one. Different aspects of these question are the subject of research activity of Institute of Navigation and Maritime Hydrography of Polish Naval Academy. In this paper the review of works executed in last years are presented.

Methods of Improving the Jamming Resistance of GNSS Receiver

Abstract Jamming of GNSS signals can be both a consequence of accidental activities and an intentional act. This issue is lately discussed as an essential threat for the use of satellite navigation systems. This is especially dangerous in the face of common usage of GPS - like systems in everyday life and the great belief of everyday users in the truth of devices indications. In spite of the legal prohibition of using them, jammers are commonly accessible, especially in the Internet. Until recently even specialists have shared the conviction that the broadband GPS signal is not a subject of disturbances in contrast to older wireless communication techniques because its power level is below natural level of noises and in addition it is randomly coded. But nowadays jammers are very often successfully applied, which is confirmed in many reports. The average user has not the suitable knowledge about the specificity of the jamming and has no technical possibilities of the detection of jammer signals. Receivers, which can indicate the presence of perturbative signals, became accessible a few months ago only. Presently accessible jamming monitors can also determine the direction of interferer signal transmission. There are also specially designed receivers with anti-jamming mechanism, which are, however, not commonly accessible. The possible way of countermeasure the jamming in the GNSS receiver are discussed in this paper.

Some aspects of development in radar technology in the context of accurate positioning

Abstract In the end of XX century we were witnesses of the revolution in a radio-navigation, which led to the present domination of GPS. Dozens of radio-navigation systems disappeared. However now in many papers more and more often we can read an opinion, that GNSS monopoly becomes dangerous. This results from the similar sensibility of all GNSS systems on the same disturbances consequential from the similar radiofrequency band and similarly low powers of the signal. There is a growing approval in the maritime world that GNSS will not provide a required resilience because of common vulnerabilities. An anticipated radio navigation system should be a combination of systems, providing redundancy and effective work when GNSS does not work properly. Lately a lot of authors commonly pointed-out a potential advantages of modified Loran (e-Loran), however surely still it will be only a potential option, particularly for the southern hemisphere, where this system has never existed. An issue of alternative systems becomes urgent, because of the growing concern about GNSS system operation. The solution should not demand high financial effort, well fit to the existing law and utilize a present technology. The paper presents a general outlook of potential development in a present radar devices considering their use as an element of a positioning system. In this context radar seems to be an attractive option, however its utilization as an alternative for GNSS should reach considerably higher technical performances. The accessible information prove that it is possible to reach a higher accuracy of the position obtained from the modified radar in the future, especially with the suitable navigational infrastructure on shore.