Keyless Go

Keyless Go describes an automatic system, a vehicle without active use of a car key ( ie "keyless ", " keyless " for German ) to unlock and start by simply pressing the start button. This is made possible by a keyless go key with chip, which leads the vehicle operator with it. " KEYLESS GO" is a registered word mark of Daimler AG.

Operation

Once a hand approaches the door handle of a vehicle equipped with Keyless Go vehicle to a few centimeters, the system is woken up by a capacitive or optical proximity sensor of the so-called "Sleep - Mode" and several in-vehicle distributed antennas a coded request signal with an LF frequency of 125 or 130 kHz ( Audi: 20 kHz) emitted. The system goes on in a receiving mode in the UHF range (Europe: 433 MHz or 868 MHz, Japan and USA: 315 MHz) and waits for acknowledgment. Is the key with the RFID transponder within range, he receives 125 kHz signal, decodes it and sends it with a new encoding in the UHF frequency band again. The vehicle is in turn decodes a control device. Since the Keyless -Go controller knows both coding tables, it can compare your original transmission with the signal being received. Is there a defined period no correct answer, nothing happens and the system switches back to standby. Pulling the door handle has no effect, since the state of the door lock has not been changed from the keyless-go - system. Votes, however, the codes tally, which causes authentication, the system releases the lock, and pulling the handle to open the door. Alternatively, the vehicle can also be opened with the remote control. There is also a mechanical emergency key with which at least the driver's door can be opened. Therefore, a key of a vehicle keyless vehicle consists of the mechanical key, the remote control unit and a RFID transponder. In current vehicles, the electronic key is designed both as a remote control as well as a transponder, a mechanical emergency key only serves as an attachment on a key chain.

The engine starting operation substantially corresponds to that of the Türentriegelungsvorgangs, except that the Motorstart-/Stoppknopf is actuated. It is crucial for the function that the keyless go control module located in the vehicle as the transponder has recognized. In the development phase, the inner-outer boundary of one of the most difficult tasks. Thus, the end user should be able to store the key inside the vehicle anywhere, the key must be detected inside always. In addition, it must be taken care that the key is recognized everywhere outside the vehicle than outside and the range is not increased too much.

If its owner desires, the vehicle is automatically locked when the transponder is outside a certain range. According to the given conditions in the vehicle 's size, position, power consumption of antennas and electronics, and permitted transmission power, the ranges obtained are low. This effect is strongly encouraged for safety reasons. This operating scenario is the most controversial with keyless go systems function; it is therefore switched off or is not offered by many manufacturers.

In many vehicles (eg Mercedes -Benz S-Class, Toyota Prius, VW Phaeton ) is to lock the vehicle, a small button or sensor to operate, the outside is located on the door handle. A turn signal lamps confirmed, as in the usual locking, the locking process.

Special cases

Keyless Go is to be able to recognize special cases and to respond accordingly. Standard examples are:

• Transponder is located in the trunk
• Several transponder on the vehicle itself
• Transponder is lost while driving
• Transponder battery empty ( Limp - Home)
• Extremely quick pull of the door handle ( outsmarting the proximity detection )
• Subsequent re-coding the transponder is lost or stolen
• User checks whether the doors are actually locked automatically

Problem cases

It is extremely important that the vehicle can not be started if the Keyless Go Key is outside the vehicle. Here a maximum overlap between detektiertem indoor and outdoor range of 10 cm (measured at the side window / windscreen ) was defined, ie above 10 cm is the key either definitely inside or outside, below 10 cm ( "gray zone" ), the position detection of the transponder key must be wrong. This ensures that in everyday situations, the driver ( assuming he carries the transponder with him ), for example, his vehicle refueling and seated in the interior child can not start the engine. However, this is prevented when the engine of the car only by depressing the foot brake can be switched on (automatic ) and / or clutch (with manual transmission ) (eg VW Golf VI, Audi A4 B8)

The range of the LF antennas used in the keyless go is limited. According to the vehicle interior, it is possible therefore that the transponder of the keyless system is " not available at the vehicle " is detected as though it but is actually there. This phenomenon of " blind spot " is explained indirectly from the previous section: A keyless system is usually optimized to its behavior in the border area to the side windows (or windscreen ) and of course the "everyday items" under normal driving conditions. Due to economic Aufwand-/Nutzenabschätzungen is dispensed with here is a perfect detection in the "border area ". Especially if the loading conditions of the vehicle ( cargo with a high metal volume fraction ) is emitted by the control unit LF frequencies are strongly reflected and / or absorbed, so here can possibly occur false detections.

Security

Functional Safety

Due to the limited allowable transmit power, the range is 125 kHz only at a maximum of 2 meters and at 433 MHz for some 10 meters. An obvious idea for car thieves, it would therefore be to increase the range of the keyless go for their purposes with the help of two relay stations to the required level. This scenario is called " relay station - Attack" RSA.

Large variant of the RSA

An attacker with the first relay station located in the vicinity of the vehicle and a second attacker with a second relay station stays in close proximity to the rightful owner transponder. The attack would therefore be in the form that the large spatial distance between the rightful owner and the vehicle with the help of the relay station technology would be reduced electronically. Both the keyless go control unit in the vehicle, as well as the transponder near his owner would " tricked " a seemingly normal environment.

Small variant of the RSA

, Only with the difference that the 433 MHz UHF return channel of the transponder not being implemented through the relay station, but received by the vehicle directly above. As a result, reduces the maximum range of the attack to a few 10 meters, while in theory it could be almost arbitrarily large at the large version. The advantage (for the car thief ) is the reduced technical effort here.

Measures against relay station -Attack Attacks

Depending on the manufacturer, there are at keyless go systems including the Thatcham criteria, several approaches to prevent or at least impede the. The best known are:

• Measurement of the group delay time and detection is exceeded
• Zweitonverfahren about intermodulation measurement and third order intercept point: detection of illegal intermodulation products in the bearer channel
• Involvement of the received electric field strength in the transponder
• Measurement of the build-up time of the 125 -kHz resonant circuit
• Use of complex modulation types may (e.g., Quadrature Amplitude Modulation ) which is not a simple relay station demodulate / modulate

System Security

Keyless Go communicates with other devices to release their functions or block. Depending on the vehicle type, the following systems:

• ELV: Electronic steering wheel lock (English ESCL Electric Steering Column Lock)
• ESS: Electronic ignition (English EIS Electronic Ignition Switch)
• Central locking, immobilizer and alarm system
• ECM
• Body Control Unit, Door control unit, comfort, control unit

Other product names

Yet there are other product names for Keyless Go. Here is a selection of the best known in the German-speaking countries:

• CID Customer Identification Device ( Lancia )
• Emotion Control Unit ECU (Aston Martin), optional for € 22,000 in a Jaeger LeCoultre clock
• Convenience key (Audi ) until May 2008 " Advanced Key "
• Keyless Access or KESSY (Volkswagen, Skoda, Subaru, Hella)
• Keycard Handsfree Entry and Drive / SES Smart Entry System ( Renault)
• KeyFree Power ( Ford)
• Keyless Drive / Keyless Vehicle ( Volvo)
• Keyless Start ( Suzuki)
• Comfort Access or Comfort Access ( BMW)
• PASE Passive Home Entry system ( Siemens VDO)
• PEPS Passive Entry Passive Start / Open & Start ( Opel, ContiTemic & Hella)
• PEG Passive Entry Go ( DaimlerChrysler, Hella)
• PE / PG Passive Entry Passive Go and CE / CG ComfortEntry Comfort Go ( Bosch)
• Smart Entry & Start (Toyota)
• Smart Key ( KIA )
• Intelligent Key ( Nissan)

Keyless entry and keyless go is not to be confused with remote keyless entry, which is the English name for a wireless remote control.

History

Keyless Go was developed and first introduced in April 1999 in series by Mercedes -Benz and Siemens VDO in the models of the S-Class.

View

The design goals of the various car manufacturers are never uniform. Here is a loose list of some different tendencies in (S) - eries and (V) orentwicklung.

• S: decentralization of some modules for better scaling, ie modules can both Keyless -Go vehicles as well as in those without Keyless Go are used. For example, the same decentralized UHF receiver can without modification in the basic model without keyless go, such as used in the model with keyless-go option.
• S: Reduction of the number of antennas used to outfit also small car with a keyless-go system with little loss of comfort can.
• V: use of biometric techniques for authentication (security and personalization)
• V: communication between transponder and keyless control unit takes over frequencies in the microwave range. Similar to the physics of radar equipment would an accurate distance measurement between the transponder and the vehicle found a comfort control of the system, eg definable areas around the vehicle.
• V: replacement of the magnetic antennas by capacitive panel radiators, which exploit the effect of the electric field (cost minimization).