Yes they used stars and sun conventional system to stablish an aproximate position. It was used inplanes time later of the war, in the ceiling of the cockpit of B-747 you can see a hole to put the star scope.
They use RDF too (Radio Diraction Dinder) similar to ADF of the planes. You can see the RDF circular antena hiden into the conning tower of a Type IX D2 at the front right part of the tower.
Sadly star or radio navigation was not modelled.... may be we need to wait for SHV
