iOS -Continuos Location update in background

iOS 11 Continuous Background Location Update by Swift 4:Medium

https://medium.com/@calvinlin_96474/ios-11-continuous-background-location-update-by-swift-4-12ce3ac603e3

Periodic iOS background location updates:StackOverflow

Periodic iOS background location updates

Libraries for Location Handling

https://github.com/malcommac/SwiftLocation

https://github.com/benzamin/BBLocationManager

https://github.com/intuit/LocationManager