title: convert from GPS week number,time of week to datetime
body: <p>I have a GPS device that sends some objects including a GPS time to my server.<br>
  It's coming in format of week number,seconds into week.</p>
  
  <p>I want to convert that to a datetime format. I found some codes for that but all I found is how to convert week number to date, not including the second into week.</p>
  
  <p>I found <a href="http://dominoc925.blogspot.com/2011/05/convert-gps-weekseconds-to-local-date.html" rel="noreferrer">this web page</a>, which is doing that but I can't find out how to do that in c# windows app code.</p>
  
  <p>Sample data:</p>
  
  <pre><code>GPS Week number 1643
  GPS second into week 377505
  </code></pre>
  
  <p>That should be <code>2011/07/07 10:51:44</code>.</p>