I've used a phone that didn't have a built in compass and one that does. The one that has an actual compass knows which direction I'm facing even without moving

I've used a phone that didn't have a built in compass and one that does. The one that has an actual compass knows which direction I'm facing even without moving. The one that didn't would usually have no idea until I started moving. They make external GPS units that plug into your car and connect to your phone wirelessly for example Garmin GLO that are supposed to improve accuracy although I haven't used one myself and thus can't vouch for it.