如何使用swift 4 iOS在特定时间间隔内更新用户的后台位置？

import CoreLocation

class LocationManager: NSObject, CLLocationManagerDelegate {
    let locationManager = CLLocationManager()
    
    override init() {
        super.init()
        locationManager.delegate = self
        locationManager.allowsBackgroundLocationUpdates = true
        locationManager.requestAlwaysAuthorization()
    }
    
    func startUpdatingLocation() {
        if CLLocationManager.locationServicesEnabled() {
            locationManager.startUpdatingLocation()
        }
    }
    
    func stopUpdatingLocation() {
        locationManager.stopUpdatingLocation()
    }
    
    // CLLocationManagerDelegate方法，获取到位置信息时调用
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        // 处理位置信息
    }
    
    // CLLocationManagerDelegate方法，定位权限发生变化时调用
    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        if status == .authorizedAlways {
            startUpdatingLocation()
        }
    }
}