|December 5, 2001
Convenience Electronics - Vehicle Access Systems
Vehicle security - a definition
By vehicle security, we mean prevention of the use of a vehicle without permission by unauthorised third parties. It may be subdivided into access security and drive-away security.
Access security is provided by the mechanical locking of the entire vehicle interior, that is to say doors, windows, luggage compartment, and engine compartment. It prevents access to the vehicle by unauthorised persons.
Drive-away security is provided by coding of the ignition/starter lock, by mechanical locking of the steering, and by electronic protection of starting (immobiliser), and prevents unauthorised movement of the vehicle.
History of vehicle security
In the past, vehicle security was provided by the use of a mechanically coded key in combination with a lock cylinder in the driver's door and individual manual locking of the other doors. Drive-away security was provided exclusively by a lock cylinder in the ignition/starter lock, which permitted activation of the ignition and mechanical unlocking of the steering only with the correct key. Increasing demands for convenience led later to the introduction of central locking. This enabled the entire vehicle to be locked or unlocked from a central operating point in the driver's door.
A major success in protection against theft was achieved with the development and universal introduction of the immobiliser. An intelligent, bi-directional coding algorithm with a data security of 264 variants, consisting of a secret, vehicle-specific code with a further variable code element enables a vehicle to be started only with an authorised key.
Remote operation of the central locking system by a button on the key has in the past become established as a further convenience feature. Initially, this was based on infrared data transfer. Today by using radio signals, it offers a generous field of operation all round the vehicle, and has in the meantime become a standard feature right through from premium vehicles to the lower-priced ranges.
Increased convenience through vehicle access systems
With the new "keyless" system, also known as "Keyless Entry/Go", the customer is offered a further significant increase in convenience. In future, all functions associated with activation and de-activation of vehicle security will be available to the vehicle user without explicit operation of a key or corresponding button. The driver only has to have the key on his or her person, it is immaterial whether the key is in a jacket pocket or in a briefcase. However, the well-known functions of remote operation of the central-locking and ignition-key operation remain additionally available to the customer.
The development of future vehicle access systems brings comprehensive changes and further development of the component architecture for vehicle security in its train. Today's mechanical ignition/starter lock will be replaced by an electronic ignition lock in which the key coding is electronic. In this way, it is possible to have a unique, individual key for every vehicle. Mechanical locking of the steering will be carried out by an electric lock.
These functions will be ensured by data exchange on a bus system, in combination with a single electronic control unit. Various antennas in the vehicle will provide for wireless communication with the key. Communication will be bi-directional on the basis of a coding algorithm which contains a vehicle-specific secret code and a variable code element in what is known as a challenge/response procedure. In the key, the electronics for remote operation, Keyless Entry/Go, immobiliser, and the mechanical key will be integrated.
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