Editing Dynamic positioning (section)

== Requirements ==
A ship that is to be used for DP requires:
*to maintain position and heading, first of all the position and heading need to be known.
*a [[control system|control]] computer to calculate the required control actions to maintain position and correct for position errors.
*thrust elements to apply forces to the ship as demanded by the control system.

For most applications, the position reference systems and thrust elements must be carefully considered when designing a DP ship. In particular, for good control of position in adverse weather, the thrust capability of the ship in three axes must be adequate.

Maintaining a fixed position is particularly difficult in [[Polar region|polar]] conditions because [[Sea ice|ice]] forces can change rapidly. Ship-borne ice detection and mitigation is not sufficiently developed to predict these forces, but may be preferable to sensors placed by [[helicopter]].<ref name="Forskning" />