There are 2 areas where the ships can dock in Barcelona - the inner & the outer docks. Being as large as the Navigator is, I would expect you to be in the outer docks - but will tell you about both.
The Outer Dock : There is a reception marque which houses all sorts of local goods and drinks, so the best part of an hour can easily be spent looking around that.
The outer docks have plenty of parking space, so if your friends were to arrive before you debarked, they would have no trouble waiting. The area is connected to the mainlad by a main road and bridge (which opens for ships going to the inner port)
The Inner Dock : is just to the north of this bridge, and has a proper lounge with seating area. Outside is another fair sized car park - so if your cruise ends in Barcelona, you may find this is where the ship docks.
If you put the entry "moll oriental, barcelona, spain" into maps.google.com
and switch to satellite mode, you will 2 cruise ships docked at the outer dock. If you then move up the picture, you will see another cruise liner in the inner dock.
We hope this all helps,
Alan & Kartina
Last: Cunard Queen Victoria January 2016
Next: Oceania Nautica Aug 2016
Then: P&O Oceana December 2016
Golden, Grand(2), Caribbean, Royal, Sea(4+1 aborted)
Adonia(4+2), Arcadia, Artemis(2), Aurora(5), Azura(2), Britannia, Oceana(3), Oriana(12), Ventura(2), Victoria(5)
QM2(2), QE2(9), QV(7), QE, Caronia(2), Minerva, Minerva II, Fred.Olsen(8), NCL Jade, =X= Eclipse, HAL Ryndam, Aza.Journey