This is an example sketch that shows how to retrieve GPS information with the ESP32 from a smartphone.
For this to work, you need to install Share GPS in your Android device first.
Then, you need to enable your Android device Wi-Fi Hotspot and replace your credentials accordingly in share-gps.ino:
const char* ssid = "***";
const char* password = "***";
Remember to update the IP address of your phone as well. const IPAddress server = IPAddress(192, 168, 52, 141); // Server IP address
In the app, add a GPSD connection (leave the default port as 2947) and click on it to enable it. It should turn from Idle to Listening.
For more info about setting up the app, this repo can be helpful even though it is intended for LoPy.
After flashing the ESP32, the serial monitor should start displaying the GPS coordinates of the phone and some debug information.