https://www.yahoo.com/tech/report-police-increasingly-asking-google-012725405.html
As the outlet notes, most modern phones, tablets and laptops have built-in location tracking that pings some combination of GPS, Wi-Fi and mobile networks to determine each device's position. Users can switch off location tracking, but if they're using a cellular network or relying on WiFi to connect, their devices are still transmitting their coordinates to third parties.