# Can you find your own location in space by measuring angles between stars?

Imagine you have 3 star points in 3D space A,B and C. From your unknown position P in space you can measure the angles APC, APB, BPC and you know coordinates of A,B and C and therefore the distances between AB,BC,CA. Is there a way to calculate your own position P? Imagine you are floating in space and you're not on a sphere like earth.

Perhaps this is a frequent problem in astronomy and am wondering if there are any techniques to solve it. If you think there is, please point me in the right direction!

Greetings, Matlab M.

• This is straightforward geometry (although it is a little tedious). But in astronomy, you're unlikely to have good 3D coordinates for A, B, & C. Plus, everything's moving. And if the distance to your reference points is large, you're going to need very good angle measurements to narrow down the region of your location. Apr 22, 2019 at 11:30
• Okay, in the situation I'm curious about, the distances to the stars is about 1000 times the distance between stars which are well known, the angles are about ~50 millirad with a accuracy of 1 microrad, I think it might be possible. I'm looking for the straightforward geometry, but am unsuccessful in finding it. Apr 22, 2019 at 11:43
• Hi @MatlabM. go ahead an edit your question and include all of the information that you put in the comment. Stack Exchange runs on question posts and answer posts, not "threads". Many people will answer based only on the question, and not bother to read comments, and comments should be considered temporary and can be unpredictably/unexpectedly cleaned up.
– uhoh
Apr 23, 2019 at 22:30