We noticed since iOS 11 that in some specific car models, the GPS speed that didUpdateLocations of the CLLocationManager returns is significantly different when connected to CarPlay compared to without.
In most cases the speed is ~10km/h (~6mph) higher than without connection to CarPlay. It doesn't seem to be related to CarPlay Navigation support in iOS, as this demo project doesn't have that and the issue still occurs.
It only seems to occur on specific car models.
Models that we have confirmed this issue occurs in:
- Volvo XC90
- Ford transit with Sync 3
- Renault Megane IV model 2018 with Rlink2 and latest firmware
- Opel Astra station (2018)
- Ford Focus 2017
- Opel Astra (model K, 2017) — Gets half of GPS speed
- Ford Mondeo of 2019