Sub main()
Dim acadapp As AcadApplication
Dim thisdrawing As AcadDocument
Set acadapp = GetObject(, "autocad.application.15")
Set thisdrawing = acadapp.ActiveDocument
Dim sel As AcadSelectionSet
Set sel = thisdrawing.ActiveSelectionSet
sel.Select acSelectionSetAll
thisdrawing.Export "c:\xx.sat", "sat", sel
End Sub