iOS Location Services: updates not received when device has been locked for a while.

Question

alpennec OP

Created Oct ’22

Replies 2

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Views 2.3k

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Hello

I’ve a question regarding CLLocationManager as I’m observing a strange behaviour when receiving location updates. And I don’t really know what could be the culprit here.

Some information regarding the device:

Device: iPhone Xs Max
OS: iOS 16.1 beta 4
App Background Modes: locations updates checked.

CLLocationManager setup:

CLAuthorizationStatus: authorizedWhenInUse
CLAccuracyAuthorization: fullAccuracy
allowsBackgroundLocationUpdates is ON
pausesLocationUpdatesAutomatically is OFF (but toggle to turn in on in the POC)
activityType (CLActivityType): .otherNavigation (but tried other options).
desiredAccuracy (CLLocationAccuracy) : kCLLocationAccuracyNearestTenMeters (to receive GPS updates, and not cell towers)
distanceFilter CLLocationDistance): kCLDistanceFilterNone (-1) or 0.

When I record with the device unlocked, everything is working fine with the app either in foreground or in background. It receives location updates as I walk around with quite good accuracy (between 5 and 15 meters, see attachment).

But I notice that when the device is locked in my pocket, the location service stops receiving updates after a while (like few minutes). I tried with Wi-Fi off and it behaves the same. You can see that in my screenshots attached: many values are incorrect (speed, course). When I open the app again (not crashed), the locations are received again but the horizontalAccuracy is not very good: it’s as if it was not using the GPS anymore.

I tried with low power mode enabled and disabled, and I think it behaves the same but maybe not? Is the low power mode responsible for this discrepancies? As far as I know, it does not modify location services accuracy (only network, background tasks, etc.).

Thanks

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Answer 1

alpennec OP

Oct ’22

I include some basic code to better illustrate how the CLLocationManager is configured and used.

class LocationDataManager: NSObject, CLLocationManagerDelegate {
    private let locationManager: CLLocationManager
    var activityType: CLActivityType = .automotiveNavigation {
        didSet {
            locationManager.activityType = activityType
        }
    }

    var desiredAccuracy: CLLocationAccuracy = kCLLocationAccuracyBestForNavigation {
        didSet {
           locationManager.desiredAccuracy = desiredAccuracy
        }
    }

    var pausesLocationUpdatesAutomatically: Bool = false {
        didSet {
           locationManager.pausesLocationUpdatesAutomatically = pausesLocationUpdatesAutomatically
        }
    }

    var distanceFilter: CLLocationDistance = kCLDistanceFilterNone {
        didSet {
            locationManager.distanceFilter = distanceFilter
        }
    }
 
    init() {
        locationManager = CLLocationManager()
        locationManager.activityType = .automotiveNavigation // controlled by the Picker
        locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation // controlled by the Picker
        locationManager.pausesLocationUpdatesAutomatically = false // controlled by the Toggle
        locationManager.distanceFilter = kCLDistanceFilterNone // controlled by the Picker
        locationManager.allowsBackgroundLocationUpdates = true
    }
    
    func start() {
        locationManager.requestWhenInUseAuthorization()
        locationManager.startUpdatingLocation()
    }
    
    func stop() {
        locationManager.stopUpdatingLocation()
    }
    
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print(error)
    }
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        print(locations.last)
    }

   func locationManagerDidPauseLocationUpdates(_ manager: CLLocationManager) {
        print(#function)
   }
    
   func locationManagerDidResumeLocationUpdates(_ manager: CLLocationManager) {
        print(#function)
   }
}

0

Answer 2

alpennec OP

Oct ’22

My previous code was not functional (edited in this forum without compiling), but the problem is the same (the correct configuration provided below was used during my tests).


class LocationDataManager: NSObject, CLLocationManagerDelegate {
    private let locationManager: CLLocationManager = CLLocationManager()
    var activityType: CLActivityType = .automotiveNavigation {
        didSet {
            locationManager.activityType = activityType
        }
    }

    var desiredAccuracy: CLLocationAccuracy = kCLLocationAccuracyBestForNavigation {
        didSet {
           locationManager.desiredAccuracy = desiredAccuracy
        }
    }

    var pausesLocationUpdatesAutomatically: Bool = false {
        didSet {
           locationManager.pausesLocationUpdatesAutomatically = pausesLocationUpdatesAutomatically
        }
    }

    var distanceFilter: CLLocationDistance = kCLDistanceFilterNone {
        didSet {
            locationManager.distanceFilter = distanceFilter
        }
    }
 
    override init() {
        super.init()

        locationManager.delegate = self
        locationManager.activityType = .automotiveNavigation // controlled by the Picker
        locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation // controlled by the Picker
        locationManager.pausesLocationUpdatesAutomatically = false // controlled by the Toggle
        locationManager.distanceFilter = kCLDistanceFilterNone // controlled by the Picker
        locationManager.allowsBackgroundLocationUpdates = true
    }
    
    func start() {
        locationManager.requestWhenInUseAuthorization()
        locationManager.startUpdatingLocation()
    }
    
    func stop() {
        locationManager.stopUpdatingLocation()
    }
    
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print(error)
    }
    
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        print(locations.last)
    }

   func locationManagerDidPauseLocationUpdates(_ manager: CLLocationManager) {
        print(#function)
   }
    
   func locationManagerDidResumeLocationUpdates(_ manager: CLLocationManager) {
        print(#function)
   }
}

0