title: iPhone CLLocationManager updates every 0.5 seconds
body: <p>For an app that does lots of calculation from the GPS, I need to get the latitude/longitude and speed every 0.5 second to be very accurate and avoid delay.</p>
  
  <p>I am using:</p>
  
  <ul>
  <li><code>[locationManager setDesiredAccuracy:kCLLocationAccuracyBestForNavigation];</code></li>
  <li><code>- locationManager:didUpdateToLocation:fromLocation:</code> function to store the value in 3 variables: <code>newLatitude</code>, <code>newLongitude</code> and <code>newSpeed</code></li>
  <li>An <code>NSTimer</code> object that call a function every 0.5 second.</li>
  </ul>
  
  <p>See below a graph generated by Excel representing the latitude values during 18 seconds:</p>
  
  <p><img src="https://i.stack.imgur.com/Qp9EZ.png" alt="Latitude values during 18 seconds"></p>
  
  <p>We can clearly see that we have location updates every second, and not every 0.5 second as wished. I do samples driving around my office, so my speeds vary between 0 and 65 MPH. So when I am driving 50MPH, I should get different values for lat/lon/speed from the iPhone every 0.5s right?</p>
  
  <p>Please tell me how I can get those location updates every 0.5s if you know anything about the accuracy with the <code>CLLocationManager</code> object.</p>
  
  <p>Thanks!</p>