Overview
The system works by having a series of LF (low frequency 125 kHz) transmitting antennas both inside and outside the vehicle. The external antennas are located in the door handles. When the vehicle is triggered, either by pulling the handle or touching the handle, an LF signal is transmitted from the antennas to the key. The key becomes activated if it is sufficiently close and it transmits its ID back to the vehicle via RF (Radio frequency >300 MHz) to a receiver located in the vehicle. If the key has the correct ID, the PASE module unlocks the vehicle.
The hardware blocks of a Keyless Entry / Go Electronic control unit ECU are based on its functionality:
- transmitting low frequency LF signals via the 125 kHz power amplifier block
- receiving radio frequency RF signals (> 300 MHz) from the built-in ISM receiver block
- crypting and decrypting all relevant data signals (security)
- communicating relevant interface signals with other electronic control units
- microcontroller
Read more about this topic: Keyless Go