MBLTDev: Phillip Connaughton, RunKepper
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The document discusses the history of GPS on mobile devices from iOS 3 to iOS 9. It covers how early versions of iOS had limitations that impacted battery life and background GPS tracking. It also discusses how later versions of iOS and features like background refreshing helped address these issues. The document then talks about techniques for filtering and smoothing GPS data as well as presenting location information to users.
![History of Mobile GPS
Phillip Connaughton
iOS 9 & watchOS2
[self.locationManager setAllowsBackgroundLocationUpdates:NO];
Nothing too exciting,
changed some permissions
watchOS 2 adds CoreLocation](https://image.slidesharecdn.com/evolutionofmobilegps-151124145532-lva1-app6892/85/MBLTDev-Phillip-Connaughton-RunKepper-10-320.jpg)
![History of Mobile GPS
Phillip Connaughton
Setting up
Location Services
• Setting up location services is really easy
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{
}
• Location Services is very noisy
self.locationManager.delegate = self //Register your class to receive updates
self.locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters // How close do we need to be?
self.locationManager.distanceFilter = kCLDistanceFilterNone //We will be informed of any movement
self.locationManager.requestWhenInUseAuthorization() // add NSLocationWhenInUseUsageDescription to
plist to explain location usage
self.locationManager.startUpdatingLocation()](https://image.slidesharecdn.com/evolutionofmobilegps-151124145532-lva1-app6892/85/MBLTDev-Phillip-Connaughton-RunKepper-11-320.jpg)
![History of Mobile GPS
Phillip Connaughton
Reverse Geocoding
let geocoder = CLGeocoder()
geocoder.reverseGeocodeLocation(locations[0]) { (placemarks, error) -> Void in
if (placemarks?.count > 0){
let placemark: CLPlacemark! = placemarks![0]
if(placemark.locality != nil && placemark.administrativeArea != nil){
NSLog(String(format: "Locality: %@, Area: %@", placemark.locality!, placemark.administrativeArea!))
}
}
}
Geocoder geocoder = new Geocoder(context, Locale.getDefault());
try {
List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1);
if(addresses.size() > 0)
{
Address address = addresses.get(0);
if (address.getAdminArea() != null && address.getLocality() != null)
{
Log.d("Location Example", "Locality:" + address.getLocality() + " Area:" + address.getAdminArea());
}
}
}
catch (IOException e)
{
e.printStackTrace();
}
iOS
Android](https://image.slidesharecdn.com/evolutionofmobilegps-151124145532-lva1-app6892/85/MBLTDev-Phillip-Connaughton-RunKepper-16-320.jpg)
MBLTDev: Phillip Connaughton, RunKepper
- 1. History of Mobile GPS Phillip Connaughton The Evolution of Mobile GPS {MBLT} Dev ‘15 Phillip Connaughton Principle Engineer @Runkeeper @pconno3
- 2. History of Mobile GPS Phillip Connaughton Overview • History of GPS on iOS • Runkeeper filtering algorithms • GPS bugs and gotcha’s • Conserving battery life
- 3. History of Mobile GPS Phillip Connaughton Runkeeper and GPS 1. Collect finite points during the activity 2. Broader location data post activity Used for realtime feedback (distance, pace, calories, etc.) Used for show the general area a user ran in, location based messaging and music
- 4. History of Mobile GPS Phillip Connaughton iOS 3 • Couldn’t operate in the background • Keeping in foreground demolished battery life • Introduction of ‘Silent Audio Trick’ http://service.o2.co.uk/IQ/srvs/cgi-bin/webcgi.exe? New,KB=Companion,question=ref(user):str(Mobile),CASE=19044
- 5. History of Mobile GPS Phillip Connaughton iOS 4 & 5 authorizationStatus() significantLocationChangeMonitoringAvailable() headingAvailable startMonitoringForRegion(_:) Introduced Region and Heading API’s
- 6. History of Mobile GPS Phillip Connaughton • Deferred updates • Conserve battery life with Hi-fidelity points iOS 6 https://developer.apple.com/library/ios/documentation/CoreLocation/Reference/CoreLocationConstantsRef/index.html#//apple_ref/c/data/kCLLocationAccuracyBest https://www.siliconbeachtraining.co.uk/blog/ios-7-new-features - (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray<CLLocation *> *)locations; - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation; • To enable • Set accuracy to kCLLocationAccuracyBest or kCLLocationAccuracyBestForNavigation • Distance Filter kCLDistanceFilterNone
- 7. History of Mobile GPS Phillip Connaughton iOS 7 • Background Refresh (no longer impact on location services in iOS 8 and up)
- 8. History of Mobile GPS Phillip Connaughton Background Refresh
- 9. History of Mobile GPS Phillip Connaughton iOS 8 Introduction of Location services Authorization CLAuthorizationStatusAuthorizedAlways CLAuthorizationStatusAuthorizedWhenInUse Necessary for region monitoring and for launching apps from the background Great for in the moment location features or tracking
- 10. History of Mobile GPS Phillip Connaughton iOS 9 & watchOS2 [self.locationManager setAllowsBackgroundLocationUpdates:NO]; Nothing too exciting, changed some permissions watchOS 2 adds CoreLocation
- 11. History of Mobile GPS Phillip Connaughton Setting up Location Services • Setting up location services is really easy func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) { } • Location Services is very noisy self.locationManager.delegate = self //Register your class to receive updates self.locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters // How close do we need to be? self.locationManager.distanceFilter = kCLDistanceFilterNone //We will be informed of any movement self.locationManager.requestWhenInUseAuthorization() // add NSLocationWhenInUseUsageDescription to plist to explain location usage self.locationManager.startUpdatingLocation()
- 12. History of Mobile GPS Phillip Connaughton Filtering Algorithm • You will not receive points that are as accurate as you asked. While Location Services start up you will receive inaccurate points • Need a large dataset for making real improvements to filters • Important to see every point given by the OS so that you are improving filtering with complete dataset
- 13. History of Mobile GPS Phillip Connaughton GPS Point • Horizontal accuracy within radius of certainty • Points we throw out • No cell tower points! • Age - are they older than the last point we got?
- 14. History of Mobile GPS Phillip Connaughton • Horizontal accuracy within radius of certainty • Points we throw out • Acceleration, did the person just jump across the city in a few seconds? • Horizontal accuracy < 0 GPS Point • No cell tower points! • Age - are they older than the last point we got?
- 15. History of Mobile GPS Phillip Connaughton GPS Accuracy Level Fine grained GPS Data • City Level Accuracy
- 16. History of Mobile GPS Phillip Connaughton Reverse Geocoding let geocoder = CLGeocoder() geocoder.reverseGeocodeLocation(locations[0]) { (placemarks, error) -> Void in if (placemarks?.count > 0){ let placemark: CLPlacemark! = placemarks![0] if(placemark.locality != nil && placemark.administrativeArea != nil){ NSLog(String(format: "Locality: %@, Area: %@", placemark.locality!, placemark.administrativeArea!)) } } } Geocoder geocoder = new Geocoder(context, Locale.getDefault()); try { List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1); if(addresses.size() > 0) { Address address = addresses.get(0); if (address.getAdminArea() != null && address.getLocality() != null) { Log.d("Location Example", "Locality:" + address.getLocality() + " Area:" + address.getAdminArea()); } } } catch (IOException e) { e.printStackTrace(); } iOS Android
- 17. History of Mobile GPS Phillip Connaughton AutoPause Don’t want runners to have to mess with phone in armband while running
- 18. History of Mobile GPS Phillip Connaughton Smoothing with Kalman Filter Normal GPS points Filters GPS points
- 19. History of Mobile GPS Phillip Connaughton Android Shuffle
- 20. History of Mobile GPS Phillip Connaughton Android Shuffle
- 21. History of Mobile GPS Phillip Connaughton Android Shuffle
- 22. History of Mobile GPS Phillip Connaughton Android Shuffle Something wrong with sort? Collections.sort(points, new Comparator<TripPoint>() { @Override public int compare(TripPoint lhs, TripPoint rhs) { return Double.compare(lhs.getTimeAtPoint(), rhs.getTimeAtPoint()); } }); We were setting the timestamps as point.setTimeAtPoint(System.currentTimeMillis()); Returns the current time in milliseconds since January 1, 1970 00:00:00.0 UTC. This method shouldn't be used for measuring timeouts or other elapsed time measurements, as changing the system time can affect the results. Use nanoTime() for that. http://developer.android.com/reference/java/lang/System.html#currentTimeMillis()
- 23. History of Mobile GPS Phillip Connaughton Elevation We haven’t had much luck with the OS but give it a shot! http://topocoding.com https://www.pinterest.com/pin/320459329711121377/ http://www.cliparthut.com
- 24. History of Mobile GPS Phillip Connaughton User Presentation Thin Line Thicker Line
- 25. History of Mobile GPS Phillip Connaughton Battery Life Don’t be here! GPS is a killer Limit network calls
- 26. History of Mobile GPS Phillip Connaughton Conclusion • iOS and Android continue to make location data easier and easier to use • Consider the users perception when displaying location data to them • Always be thinking about battery life