title: Trilateration using 4 fixed points
body: <p>I am trying to figure out a problem where you pretend you're a GPS unit at an unknown target location (latitude and longitude co-ordinates). I was given the data of 4 satellites (latitude and longitude co-ordinate pairs and for each pair a distance in kilometers to the target location and Delta Time). Does anyone know how to calculate the co-ordinates of the target location?  I tried doing research but the math involved is way beyond me. Thanking you in advance for any help.</p>
  
  <p>Here is the data:</p>
  
  <pre><code>Satellite 1
  LAT  24.54653
  LONG  -81.79745
  HEIGHT (m)  20183000
  DELTATIME (s)  0.070808428
  
  Satellite 2
  LAT  63.75088
  LONG  -68.56082
  HEIGHT (m)  20183000
  DELTATIME (s)  0.069105305
  
  Satellite 3
  LAT  53.90460
  LONG  -166.52657
  HEIGHT (m)  20183000
  DELTATIME (s)  0.073341842
  
  Satellite 4
  LAT  43.41038
  LONG  -65.61692
  HEIGHT (m)  20183000
  DELTATIME (s)  0.069680227
  </code></pre>