Passive Keyless Entry (PKE) combined with Passive Keyless Go(PKG) is a passive concept for electronic locking systems, such as car keys. This combination is often also referred to as Passive Entry Passive Start( PEPS), which, however, works with Phone-as-a-Key. PKE/PKG functions can be integrated into remote keyless entry( RKE) chips or electronic immobilizers.
PKE/PKG car keys are radio keys. They form the passive component that is activated by a periodically transmitted radio signal. For this purpose, a transmitter sends a low- frequency signal of approx. 130 kHz. The correct car key recognizes the LF signal transmitted as a modulation signal and then transmits a UHF signal in amplitude shift keying( ASK) or frequency shift ke ying( FSK) with its identification. The locking system is released only after the authentication procedure between the car key and the car.
The low-frequency link is used for data communication from the car to the electronic car key, whereas the UHF link provides communication from the car key to the car. The UHF frequency used in Europe is 433 MHz and 868 MHz in the ISM bands. A PKE system consists of several low frequency and UHF transmitters located in the car. In the car key there is a receiver for the low frequency signals, a UHF transmitter, a microprocessor and the push button. The car door of the car can be opened by pressing the button of the car key. The procedure behind it includes the authentication of the car key.
In the PKG system, Passive Keyless Go (PKG), the car key does not have to be inserted, it is sufficient if it is in a pocket of the driver. The vehicle is started via a start button. The PKG processchecks the authentication of the car key and whether it is inside and not outside the vehicle.