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4.2.3 Voyage execution 
The process represented in DFD 2 models the execution of the voyage. On the abstract level repre 
sented here, voyage execution can be modelled by two processes: 
- “Determining set/actual deviations" (Process 2.1): determining the deviations between current state 
variables (position, courses, speeds) and set values. Set values originate from the following 
sources: 
1. from the current voyage plan 
2. from other processes within integrated navigation - particularly Process 4 “Dealing with un 
planned incidents” 
3. from other sources, e.g. instructions from vessel traffic services 
- “Determining set values” (Process 2.2): this process models the actual control process (on this point, 
see also part A). The output information from this process goes in two directions: 
1. The result of the control process amongst other things constitutes set values for courses and 
heading (“Course/heading controller”). The information determined in this way goes back to Pro 
cess 2.1. 
2. Process 2.2 supplies the central output data flows of the system “integrated navigation”, i.e. set 
values for the rudder angle or set engine data. 
DFD 2: Task area “Monitoring and executing the voyage’