What latency?

They're talking about measuring millisecond pulsars, there's no latency

Indeed.

But if you're travelling significant distances, you're not going to be able to assume the space between you and all your beacons is flat.

For good accuracy you'd need a predictive spacetime curvature map for the entire galaxy, and that might not be an easy thing to generate.

it would probably be an advantage to measure the shift effect from multiple sources as you travel whatever fraction of the speed of light, giving both your position and derivatives such as velocity

Not at all, if you take it into account.

Would you be happy to wait for tens of minutes to get a position lock?

Tens of minutes to get a position lock for your location in the entire Galaxy? Yes, that sounds completely reasonable.

Of course, if that was the best I could do.

People will happily spend an entire day becoming unlost if they're lost.

As long as they have the means to survive, they'll be willing to spend much longer than that.

Likely, after the first calibration you could keep moving around and updating your location, so as long as the system doesn't go down you always know your (relative) position as you travel through the galaxy.

Regular GPS does this, too. It takes about 12 minutes to download the list of currently active satellites and their attributes. The data is part of the signal from the satellites.

Most GPS units do this in the background. But if you leave it unpowered for too long, it will need to update itself before it begins to work properly. The GPS in my dad's car used to have a flaky ROM, and it would show the car flying across the wilderness at over 400mph while it was updating.

I thought of this as well. After the first lock, you can use inertial navigation.

One wouldn't be transmitting to pulsars and awaiting a response, but treating them as what they are: always-on beacons. The signals would always be present.

Not even GPS transmits to the satellites, it only relies on observations of what the satellites sent.

And pulsars are quite a bit further away than tens of light minutes :) Mars is currently 14 light minutes from Earth. PSR J2144-3933 is one of the nearest known pulsars, and it's some 587 light years away.

Yes but if we're using it as a beacon the distance is irrelevant, isn't it? It's been "transmitting" for much longer than 587 years, we're already receiving a signal, and that's what we're using?

Exactly. The post I replied to said "One wouldn't be transmitting to pulsars and awaiting a response", and I expanded on that. The whole subthread of https://news.ycombinator.com/item?id=16288955 doesn't make much sense because nobody defined what they mean by "latency" and people are talking about different things.

Yes, especially if it’s just to occasionally recalibrate an inertial guidance system.

If I can then keep the lock indefinitely, I don't see much of a downside.