NavList:

Robert,

I agree.  But I think think it re-enforces my position.  Navagation is not position finding.   Navagation is knowing where you are as you travel, usually in reference to a fixed site. 

When a lander lands we need to know where it is.  Use stars, moons, satilites, etc to fix your location.  That is not navigation.  Now, get into your rover, drive so many miles in a direction, eat lunch, then drive back to your lander - that is navigation.  I am saying that for moving rovers or even walking people that cel nav would not be used to keep track of where you are.  I think an INS type unit or radio RDF would be better for keeping track of where you are.  After there are several Mars bases that are at known position then to travel between and to different known bases is navigation.  I do not think that cel nav would be used during the trips.