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Recording the meteorological situation in particular is problematical since only a proportion of the mete
orological data are based on automatically recorded sensor values. Integration of these functionalities in
an INS therefore has little point - apart from exceptional cases.
Fundamental areas of this task therefore tend to be of subordinate importance with regard to usage
within an integrated system, and generally the display of wind and current (true/relative, based on the
own ship), measured water depth or under keel clearance is undertaken, as well as the fundamental
weather parameters of air temperature and pressure, relative air humidity and water temperature - along
with the display of sea chart information.
4.2.1 Purpose of task
The purpose of this task is observation of the external influences of relevance to navigational operation,
with the exception of foreign vessels.
The parameters to be monitored can be classified in the following areas:
1. Hydrographic parameters:
• Tides
• Current direction/speed
• Swell: wave height, length and period of wind-affected sea and swell
• Ice conditions
• Water temperature
2. Meteorological parameters:
• Wind direction and speed
• Air temperature and pressure, relative air humidity
• Cloud cover and rainfall
• Visibility conditions
The environmental parameters to be monitored moreover include the drift which is produced from the
combination of wind and current influence. The drift thus comprises the external forces which influence
the adjustment and control of the set course as disturbance variables. This parameter is generally de
termined indirectly by evaluating the difference between the movements through the water and move
ments over ground.
4.2.2 Functionalities
From the parameters to be monitored are directly obtained the functionalities which have to be available
for the purpose of fulfilling the task “Observing the current environmental situation”. The following func
tionalities are of relevance with regard to integration with an INS:
1. Observing hydrographic data:
1.1 Observing the water depth
1.2 Observing the current direction and speed