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1. System configulation
1.1
Scope of SMART KEY SYSTEM
The System offers the following features:
•
passive access for two doors, driver side and passenger side as well as trunk/tailgate
•
passive start after interior detection of the SMART KEY FOB (without interior trunk and
hat shelf detection)
•
LF-RF communication (based on Siemens' SMART KEY system)
•
passive access trunk/tailgate via the trunk lid switch at the trunk
•
max. 2 SMART KEY FOBs can be handled by the system
•
communication to the engine management system via a single line interface
•
communication to the ESCL via a single line interface
1.2
Short description of the SYSTEM
1.2.1
General Definition of SMART KEY
The SMART KEY system is a system that allows the user to access and operate a
vehicle in a very convenient way. To access the vehicle no traditional key or remote
control unit is needed.
The user carries a SMART KEY FOB which itself does not require any conscious
actions by the user (e.g. operate a button).
After being triggered the vehicle sends out a request in a limited range. If the
SMART KEY FOB receives this request, it automatically sends a response to the
vehicle. Then the system decides whether to perform a particular action (unlocking,
locking...) or remain inactive.
1.2.2
Wireless Communication
Electromagnetic waves are used to exchange information between the vehicle and the
SMART KEY FOB. Both, vehicle and SMART KEY FOB are equipped with a transmitter,
a receiver and several antennas.
1.2.3
Concept Description
With this concept it is possible to have a set of interior antennas that covers the vehicle's
interior and a set of exterior antennas that covers the vehicle's exterior.
For an unambiguous separation between the vehicle's interior and exterior it is sufficient
that at least one area is covered exactly by the corresponding operating ranges of the
antennas.
The functions of the SMART KEY system have to be provided in a clearly defined and
limited range. For the up-link from the vehicle to the SMART KEY FOB, a magnetic field
with a frequency of 125 kHz and ASK modulation is used. Inductive antennas in and at
the vehicle radiate the electromagnetic energy.
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