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1. Origin: 
Special requirements on the origin of information or specification as to which data must be given in 
formation on their origin as an attribute. 
2. Validity: 
The concept of validity involves an attribute of an item of information which is set by the particular 
information source. Since no other independent information sources are used for determining this 
attribute, it constitutes an “internal variable” of the source. It should be borne In mind that this attrib 
ute does not make a statement concerning the “quality” (see below) or “usability” of a piece of infor 
mation. 
3. Quality 
The quality of an item of information is the deciding criterion in assessment of the usability as an in 
put for the execution of a certain function. The term “quality” comprises three aspects within the 
meaning of this report: 
• Accuracy in the sense of a tolerance range within which the “true value” is located, based on the 
“determined value”. 
• Topicality, i.e. age of an item of information or frequency with which certain information is updated. 
• Plausibility: compatibility of an item of information with information from other independent sources. 
It must for example be ensured that items of information of the same type from independent sources 
do not contradict one another. 
4. Harmonisation 
This term covers requirements which deal with the joint processing of information from different 
sources. It should therefore be required practice, for example, that items of information which are 
compared with one another have a uniform reference system. 
5. Criticality 
Requirements which result from a special “protection need” for a certain item of information; eg pro 
hibition on modifying the track section of the current voyage plan presently being followed. 
6. Alarm facilities and limit values 
List of all necessary limit values and alarm facilities necessary for the information concerned. 
7. Representation/display 
This criterion initially appears as a break with the underlying functional approach. However, since 
the human being still represents an essential link in the navigation process, it is absolutely necessary 
to demand an appropriate visual display method for certain data. It is thus inadequate, for example, 
to merely request the presence of sea chart information. Its application is always governed by suit 
able chart representation in the minimal case. Although evaluation and monitoring are theoretically 
conceivable even without graphic display, it is simply not acceptable from the viewpoint of current 
navigational practice. 
For the purpose of defining the requirements, a “top-down approach” is used. In this instance - apart 
from the level of task areas - the data flow diagrams of the model of integrated navigation (see part B) 
are analysed and requirements are identified with an increasing degree of concrete description. 
This report therefore follows the procedure developed in part A and B of this study for breaking down 
the process of integrated navigation into task areas. The particular test requirements are represented 
on forms which are orientated to the structuring according to processes, as outlined above (i.e. task