Ask HN: How do spaceships navigate?

I have been very interested in implementing a program to help a spaceship find it's location in relation to earth or what ever NASA and other space agencies align to.

I was curious how do satellites and probes get their bearings in space. Do they align to binary stars (if so how do they know which one is which), do they find the sun and align to that, etc. Any info would be greatly appreciated. Thanks :)