Ask HN: What software will space need?

Intra-system shouldn't be too hard with today's technology. NASA has highly accurate models that could run on a computer that tracks the ship's movement using similar parameters to the calculations they do for space flight today. So instead of GPS satellites you could rely on internal systems. If everyone is calibrated the same, then the results/coordinates should be sufficiently accurate.

Inter-system will be very difficult. If you're talking full universe, then you would need to map the universe. If possible, picking a stationary reference to use as the core of the navigation coordinates would be good, but I wouldn't hold my breath since everything is moving. Otherwise we could use the reference we know the most about - earth. This could work, but would require extensive mapping and testing since at the further distances we would essentially be calculating our trip to where a planet will be based on where it was given that they light we use to observe it took so long to get here.

So really, mapping is the big deal and there's no way of knowing if the greatly distant object we are travelling to is in the place we expect it to be, or if it even still exists today (the light is so "old"). It's a very interesting problem. One I probably will never live to see the answer to.