SLF,. .. .If you know anyone who is a fellow or member of RIN try and get your hands on the Jan/Feb 2002 issue of "Navigation News", there is a good article "Do we still need DGPS?" which was reprinted from International Ocean Systems.. .. .While I agree with Never Losts comments that the long term aim is to have all these systems interoperable, I am more inclined at this stage to say that older WAAS receivers will not necessarily be EGNOS capable. The newer EGNOS and WAAS receivers generally are both WAAS&EGNOS capable.. .. .These systems are still “works in progress”, 2004-2005 when they are online no doubt aircraft and ships will be able go seamlessly between systems.. .. .Regards. .. .Z