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On the night side, you could get a decent idea of your absolute position by observing the stars, just like how you can do this on Earth if you have a good clock. On a tidally locked planet, your clock doesn’t need to be very good.

I imagine that a similar if somewhat more complex trick works on the day side if there’s a visible moon.

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The stars would still rotate around the planet, but the rotation would be that of the planet rotating around its star.

So one would need timekeeping to track where you are in that cycle.

Indeed, but process is quite a bit slower, so you could likely get away with a worse clock.

Since the cycle of stellar observation repeats each solar year, the observation would itself be a method of time keeping. One would need only to track the azimuth of a series of regularly positioned star constellations to determine time, and from there one could then ascertain location.

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