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Inland shipping is an important pillar of the European transport system; however the challenges of inland navigation due to dense traffic, increasing ship dimension, reduced maneuver space and visibility are multifaceted and increasing. About 20 to 30 collisions per year, partially caused by carelessness, demonstrate the necessity of driving assistance systems for inland waterway applications. The project LAESSI (Guiding and assistance systems to improve safety of navigation on inland waterways) is developing efficient navigation assistance functions for inland waterway transport which aim the reduction of risk of collisions by supporting the skipper in its task. Therefore, nautical information like position, height, velocity and heading has to be determined. One focus in this contribution is a bridge collision warning system, which provides a timely alert to the skipper, whenever the vessel, particularly the wheelhouse or radar mast, will not safely pass the bridge. A feasibility study has identified Global Navigation Satellite System (GNSS) technologies as basis for the reliable height determination for such a bridge collision warning system. This approach requires information about the vertical clearance of the bridge superstructure as well as precise height information in the same height reference system at least 300 m before the vessel will pass the bridge. The high accuracy level of less than 10 cm in the vertical position necessitates the Real Time Kinematic (RTK) as suitable GNSS processing method. RTK is a phase-based differential GNSS technique and uses additional observations from permanent reference stations to mitigate or eliminate effects like tropospheric and ionospheric delays or satellite clocks and orbit errors. As bridge collision warning system is a safely critical application, this means that beside the provision of accurate height information also an integrity monitoring for the complete RTK procedure has to be introduced. The shore-based architecture is designed in such a way that correction data, based on a permanent GNSS reference station network, will be checked for their integrity before they are broadcasted (Pre-Broadcast Monitoring) to the processing computer on the vessel. Furthermore, several station dependent effects like signal interferences, signal losses or multipath effects, caused due to obstacles near the inland waterways, impact the GNSS signals, which hamper or falsify the ambiguity fixing and finally the position results. To prevent the provision of faulty results a further integrity monitoring for the shipborne architecture has to be applied. This shipborne integrity monitoring utilizes on the one hand a number of internal statistical parameters from the RTK algorithm like the conventional used fixed ratio value and on the other hand additional information from other sensors or observations. The contribution will present the derived requirements for accuracy, integrity and time to alert for different inland waterway assistance functions. Furthermore an overview about the system architecture and a communication concept based on VHF Data Exchange System (VDES) communication channels will be given. The main focus, however, is an RTK-algorithm which not only estimates position, velocity and heading, but also provides integrity information. This concept considers in a first realization internal statistical parameters from the RTK adjustment, other observations (e.g. Doppler shift) and physical information (e.g. baseline length of two GNSS antennas). A first measurement campaign was done in July 2016 in Koblenz/Germany on the river Moselle. This test area is characterized by three bridges in a relatively short distance of only 300 m which make the provision of reliable and precise RTK position data rather challenging. The preliminary analyses based on three hours GPS and GLONASS observations showed a high rate (> 85%) of evaluated position and height results, which fulfilled the required cm-level accuracies. The first implementation of the internal integrity check could detect and eliminate faulty results. The results have shown that beside a good height performance also fast provision of the heights after the vessel sailed through the bridges is recognizable. This position data between the bridges allows a provision of information to the skipper to check or adjust the wheelhouse or radar mast height before the next bridge will be passed. In the next implementation the rate of turn and acceleration data from an Inertial Measurement Unit (IMU) will be tightly coupled with the raw GNSS observations. Thereby additional information will be available to evaluate the position, height, velocity and heading results and increase the integrity validation. Furthermore it can be expected that the ambiguities after a complete signal interruption can be fixed faster.

In einem Kurzvortrag wurden kurz die Themen der Arbeitsgruppe Nautische Systeme im Zusammenhang mit Weltraumanwendungen und der Partnerschaft zur Maritimen Universität Stettin vorgestellt.

Die Positionsbestimmung an Bord von Schiffen ist eines der Kernelemente der von der Internationalen Maritimen Organisation (IMO) 2006 initiierten e-Navigations Strategie. Die gesammelten Nutzeranforderungen belegen den Handlungsbedarf insbesondere bezüglich der Integrität von Positions-, Navigationsund Timing (PNT) Informationen. Basierend auf einer Analyse der aktuellen maritimen Standards sollen in diesem Vortrag ein Konzept für die zukünftige schiffseitige Bereitstellung von PNT Daten sowie erste experimentelle Ergebnisse zur schiffseitigen sensorfusionsbasierten PNT-Bestimmung vorgestellt und diskutiert werden.

Improvement and Indication of Reliability have been identified as important user needs within the e-Navigation strategy of the International Maritime Organization (IMO). This paper address the question, how these user needs can be satisfied in future with respect to resilient provision of position navigation and timing (PNT) data onboard the vessel. The idea of an onboard PNT Module is proposed as front-end between an integrated PNT system and ship-side applications like INS, AIS and ECDIS. The paper focuses on the integrity monitoring within the PNT Module. The concept is introduced and first experimental results are presented.

A high-level user need recognized by the IMO is the resilient provision of position, navigation, and time data (PNT) to ship-side applications such as Automatic Identification System (AIS), Electronic Chart Display Information System (ECDIS) and Integrated Navigation System (INS). In order to avoid collisions and groundings, a reliable knowledge of ship’s position and movement in relation to other traffic participants is necessary and enables an improved situation awareness taking into account the own maneuver possibilities in relation to external geo-referenced conditions. The PNT data provision should be ensured for all phases of ships’ navigation such as ocean, coast, port and docking. Therefore different and increasing requirements on accuracy, integrity, continuity and availability of PNT data should be taken into account. Resilience describes the aimed ability of the PNT system to provide the PNT data with the required performance in case of internal and external disturbances. Typical examples of such disturbances are the vulnerability of GNSS or the occurrence of malfunctions and failures in applied sensors and services. Overarching objective of the PNT enhancement can be derived from the user needs “improvement of reliability” and “indication of reliability”. The current and desired reliability of the PNT system should be measurable to quantify the aimed improvement of reliability. For instance, in IMO A.915(22) the minimum requirements on future GNSS are specified for the horizontal position and given in terms of accuracy, integrity, continuity and availability. A comparable norm for all desired PNT data is still missing. A consolidated specification of desired PNT data and assigned technical requirements are prerequisites for the identification of technical gaps of the current PNT system as well as for the provision and assessment of suitable approaches to overcome the existing gaps. However, the greatest challenge on the maritime PNT system comes from the user need “indication of reliability”. Indication of reliability describes the desire that in future the accuracy and integrity of all navigation relevant data should be automatically assessed. Initial point for an automatic assessment is the complete and unambiguous performance specification of all required output data and assigned tasks. For this purpose the generally admitted processing chains for PNT data provision composed by GNSS, PNT relevant terrestrial services as well as additional ship-side sensors should be taken into account. In minimum the current status of contributing PNT subsystems should be comprised to estimate their residual influence on resilient PNT data provision. Nevertheless, an automatic assessment of accuracy and integrity requires the implementation of integrity monitoring functionalities on the one hand as well as the deployment of redundancy within the PNT system to enable integrity monitoring on the other hand. Due to the multi-system, multi-service and multi-sensor based architecture of the maritime PNT system the development of an overarching integrity concept should be aimed. Such an integrity concept regulates responsibilities of single subsystems for integrity monitoring, identifies the minimum on redundancy and specifies additional interfaces to ensure the integrity messaging in an unambiguous manner. Regarding safety the integrity concept supports that the achieved and desired level of reliability will be measurable and specificable. Furthermore the tolerable residual risk of resilient PNT data provision (incidents) can be distributed on contributing components and can be optimised among them. Otherwise, approaches to improve critical components or to overcome gaps will be rateable regarding their benefits. The paper presents an initial guideline for the development and establishment of an Integrated PNT System to meet identified user needs in the future.

With respect to "GNSS in marine appications" the presentation was used to discuss some fundamental aspects concerning the new proposed resilient PNT unit as well as the role of integrity within the maritime community.

This paper focuses on a maritime integrated PNT Module as the on-board part of maritime PNT system. The aim of the PNT Module is the robust provision of position, navigation and timing information in accordance with the performance requirements of the actual operational region. The core of the PNT Module is a PNT Unit. This PNT Unit is a processing system, which combines by means of sensor and data fusion methods all available PNT sensors. The PNT Module is on the one hand part of the integrated PNT System and on the other hand part of the on- board INS. After a short discussion of the sensors of a PNT Module we have introduced a preliminary integrity monitoring concept for a PNT Module. In a first step towards the development of a PNT Module demonstrator system we have performed first measurement campaigns and derived PNT output data from different sensors. The analysis of these data shows, that for their usage within compatibility tests, the different locations of the sensors onboard the vessel needs to be considered.

A robust electronic position, navigation and timing system (PNT) is considered as one of the core elements for the realization of IMO-s (International Maritime Organization) e-Navigation strategy. Robustness can be interpreted as the capability of an integrated PNT system to provide PNT relevant data with the desired accuracy, integrity, continuity and availability under consideration of changing application conditions and requirements. Generally an integrated PNT system is a composite of service components – like GNSS, Augmentation Systems and terrestrial Navigation Systems – and an on-board integrated PNT Unit, which uses the available navigation and augmentation signals in combination with additional data of sensors aboard to provide accurate and robust PNT information of the ship. In this paper a concept of such an on-board integrated PNT Unit will be presented, which is designed to fulfill the specific user requirements for civil waterway applications. At first, the user requirements for an integrated PNT Unit will be overviewed. After that, existing integrity monitoring approaches will be analyzed. Finally, a first integration scheme for an inte-grated PNT Unit will be presented with a special focus on the internal integrity monitoring concept.