title: Wi-Fi position triangulation
body: <p>Consider this map:</p>
  <p><img src="https://i.stack.imgur.com/d2PeE.png" alt="Enter image description here" /></p>
  <p>I need to understand how Wi-Fi triangulation basically works. The scene is portrayed in the above diagram. In order to implement Wi-Fi triangulation, I need a minimum of three Wi-Fi hotspots and their positions. The setup:</p>
  <ol>
  <li><p>For simplicity, let's assume I have a <strong>1 sq-Km by 1 sq-Km</strong> area, and I have three Wi-Fi hotspots in this area. The coordinate system is as follows: One corner of the square area is (0,0,0), and the diagonally furthest corner will have coordinates (1,1,1). All position determination is to be done relative to this coordinate system alone (for simplicity, I don't want global xyz coordinates). Within this, I have three Wi-Fi hotspots at <strong>(x1,y1,z1) , (x2,y2,z2), (x3,y3,z3).</strong></p>
  </li>
  <li><p>We have a person with a device capable of receiving Wi-Fi signals and calculating the strength of the signal at position <strong>(x,y,z)</strong>. The device could be a phone, a tablet, etc.</p>
  </li>
  </ol>
  <p><strong>The problem:</strong> Calculate position (x,y,z) of the person dynamically, as they move around when you now have the following inputs:</p>
  <ol>
  <li><p>The signal strength of signals received from each of the Wi-Fi hotspots</p>
  </li>
  <li><p>Coordinates of the Wi-Fi hotspots previously-stored in variables or a database.</p>
  </li>
  </ol>
  <p><strong>First Question:</strong> How do I calculate position from the above inputs? I assume signal strength is directly proportional to the distance from the router, but what's the exact relation? How does <a href="http://www.skyhookwireless.com/location-technology/coverage.php" rel="nofollow noreferrer">Skyhook</a> do this so accurately?</p>
  <p><strong>Second Question:</strong> I believe the above inputs are sufficient. Is there anything else required?</p>