15 
1 The approach 
The analysis of navigational operation presented here forms the basis of the development of a test 
method for integrated navigation systems. The aim of the analysis is to identify the functions funda 
mental to navigational operation. In this context, “fundamental” means considering only those functions 
which have to be available in an integrated navigation system, irrespective of the concrete technical 
implementation, in order to fulfil the tasks of navigational operation. For this reason, identification of 
these functions starts from the global process task. From these are deduced the individual tasks from 
which functionalities and functions are in turn derived. 
The functional analysis of the navigational operation process can be sub-divided into the following 
levels: 
1. Definition of the global process task 
2. Structuring in task areas, i.e. groups of tasks clearly delimitable in relation to one an 
other in terms of content and time 
3. For each task area: identification of the tasks. Tasks are defined within the meaning 
of this study by a purpose which is achieved by carrying out a sequence of functions. 
4. For each task: identification of the functionalities necessary for task fulfilment. De 
pending on the complexity of the task under consideration, this should be carried out in 
several stages. A hierarchical classification of functionalities in levels is thus produced, 
the degree of abstraction decreasing with increasing number of levels, and the degree 
of detailing conversely increasing. 
5. Identification of the elementary individual functions 1 for the lowest-level functionali 
ties defined in the previous stage. The internal structure of the functionality considered 
is described by these functions. Functions are defined by virtue of their “effects”: they 
generate one or more output variables from a defined set of input variables. 
The result of the analysis is a catalogue of functions. The structure of this catalogue follows the break 
down of the navigation process into tasks and functionalities. For each function the necessary input 
data and the supplied output data are listed in detailed form. This catalogue serves as an information 
source for development of the functional model of navigational operation. The catalogue of functions is 
contained in the annex to this report. 
Global process task 
As already mentioned above, definition of the global process task forms the basis for identification of the 
functions. Within the framework of this study, it is not intended that any new comprehensive definition of 
the process of navigational operation will be developed. Ship operation is considered more from the 
aspect of “integrated navigation”, i.e. the focus is on task areas or tasks which are fulfilled with the aid of 
an integrated navigation system. Accordingly, the process of “integrated navigation” is to be defined 
in the following. This process comprises the following aspects: 
1. Voyage planning: fulfilling the planning tasks necessary for subsequent execution of a 
voyage. With a view to integrated navigation systems, planning tasks primarily serve 
the purpose of creating and providing set data which serve as input information for 
1 Called “functions” for short in the following