How autopilot works in space?

[jtbo]

In space there is no GPS or compass, how autopilot can work there?
How to make two spacecrafts find each other completely by computer control?

Isn't it good thing that object will continue to move without changing speed or direction in space?
Would be difficult to travel longer if you would need to steer all time, few days to moon for example, very hard to maintain direct course in such empty space. How about mars then? Few years you have too keep gripping that wheel

[germ]

Its all automatic as far as i know so you dont have to hold a wheel for hours days years etc

and i believe there is some sort of gps and stuff it goes where its programed to take it but if theres a fault .....

[jtbo]

Well, today they just sling spaceship like a rock, there is nothing exciting, but in future where you can actually travel in space not sitting inside thrown rock and hoping nothing come away, then navigation is going to be problem, how they navigate then?

When you go enough far there is no satellites or anything to help to know where you are, what would be solution to problem?

[A M R]

laser guided?

[jtbo]

To understand problem, get this and start zooming out until you can't separate earth from other dots...

http://www.shatters.net/celestia/