Google researchers demonstrated the ability to use GPS signal measurements from millions of anonymous Android mobile devices to map the ionosphere with high accuracy, potentially improving GPS navigation worldwide.
An open-source device, kv4p HT, connects to an Android smartphone and turns it into a radio transceiver for about $35. It uses an ESP32 and transmits one watt, featuring APRS and scanning capabilities. The PCB is simple and affordable with a 3D-printed case.
noaa-apt 1.3.0
Image decoder for APT signals from NOAA satellites
Image decoder for APT signals from NOAA satellites
