IOS uses positioning based on cell towers and Wi-Fi access points, so if your phone has its location services active Apple can tell that a device with a specific ID is near a certain location. This ID is rotated periodically and not linked to your device or to you but you can’t turn this off.

AGPS means the phone downloads the GPS almanac, the dynamic dataset you need for using GPS, from the internet as opposed to watching the satellites for about 30 minutes to download it. That would be stupid and would not have any positive impact on your privacy.