The term survey ship in the Vorkosigan Saga referred specifically to those ships sent by the Betan Astronomical Survey to unexplored pockets of the wormhole Nexus in order to find new routes and planets. These ships were able to stay out far from contact with Beta Colony for a year at a time.
The only identified survey ship was the Rene Magritte; it was very fast and had a crew of 60.
It would appear that Beta Colony also field-tested some of its newest military developments via these ships - the Rene Magritte had the testing of "projectors" as part of its mission in Shards of Honor.