Aukey Dash Cam GPS Antenna

The GPS antenna ($20) has 4-conductor 3.5mm plug that goes into the Aukey Dash Cam for location information to be included in the recorded video. 


We'll try to decipher to the interface signals.  From a picture of the disassembled GPS antenna, we know the pinouts for the plug, VCC, GND, TX, RX.  It is more than just an antenna; it is a GPS module.  We'll take a look what the protocol is.  First we want to know the VCC voltage.  VCC is measured to be 3.3V, so are TX and RX.   The we'll look at the TX and RX to see what kind of signals they are.  There is no activity on RX.  TX shows what appears to be 3.3V UART signals.  The minimum pulse width is about 104us, so the baud rate is 9600.  The messages come in 580ms burst every second.  We connect TX to a UART receiver.  We can see the standard NMEA GPS strings.  The messages include GPRMC (recommended minimum), GPVTG (vector track over ground), GPGGA (fix information), GPGSA (satellite data), GPGSV (detailed satellite data), GPGLL (lat/lon data).

We can tap into the TX signal to extract GPS data for other purpose.