WO2000006858A1 - A security system - Google Patents

A security system Download PDF

Info

Publication number
WO2000006858A1
WO2000006858A1 PCT/GB1999/001943 GB9901943W WO0006858A1 WO 2000006858 A1 WO2000006858 A1 WO 2000006858A1 GB 9901943 W GB9901943 W GB 9901943W WO 0006858 A1 WO0006858 A1 WO 0006858A1
Authority
WO
WIPO (PCT)
Prior art keywords
frequency
signal
security
signal component
security system
Prior art date
Application number
PCT/GB1999/001943
Other languages
French (fr)
Inventor
Kevin Trevor Talbot
Original Assignee
Bayerische Motoren Werke Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bayerische Motoren Werke Aktiengesellschaft filed Critical Bayerische Motoren Werke Aktiengesellschaft
Priority to AU45190/99A priority Critical patent/AU4519099A/en
Priority to EP99928063A priority patent/EP1101005B1/en
Priority to DE69920233T priority patent/DE69920233T2/en
Publication of WO2000006858A1 publication Critical patent/WO2000006858A1/en

Links

Classifications

    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00—Individual registration on entry or exit
    • G07C9/00174—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C9/00309—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00—Individual registration on entry or exit
    • G07C9/00174—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C9/00309—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks
    • G07C2009/00555—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated with bidirectional data transmission between data carrier and locks comprising means to detect or avoid relay attacks
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00—Individual registration on entry or exit
    • G07C9/00174—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys
    • G07C2009/00753—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys
    • G07C2009/00769—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys with data transmission performed by wireless means
    • G07C2009/00793—Electronically operated locks; Circuits therefor; Nonmechanical keys therefor, e.g. passive or active electrical keys or other data carriers without mechanical keys operated by active electrical keys with data transmission performed by wireless means by Hertzian waves
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C2209/00—Indexing scheme relating to groups G07C9/00 - G07C9/38
    • G07C2209/60—Indexing scheme relating to groups G07C9/00174 - G07C9/00944
    • G07C2209/61—Signal comprising different frequencies, e.g. frequency hopping

Definitions

  • This invention relates to security systems and in particular to a
  • the remote transponder sends a coded response
  • unit can be used by a thief to capture the interrogation signal and relay it to
  • the security signal comprises first and second signal components
  • transmission of the second signal component is encoded in the first signal
  • the unit which is arranged in use to receive the security signal may be
  • the frequency of the second signal component may be generated in a
  • second signal component may be achieved by a substantially random
  • the unit arranged to receive the security signal may be arranged to
  • transmission of the second signal component may be selected is such that
  • the unit arranged to receive the security signal may be arranged to
  • the frequency of the first signal component may be in the order of 120
  • the frequency of the second signal component may be in the order of
  • the difference frequency may be in the order of 40 kHz
  • the security system may comprise a security system of a vehicle.
  • the invention also provides a method of controlling a security system
  • the security system comprising a security control unit and a remote
  • transponder unit arranged in use to communicate with each other using a
  • the method including: a) transmitting the security signal in first and second signal
  • components said components being transmitted at different frequencies
  • the method may include decoding, in the unit which is arranged in use
  • the method may include generating the frequency of the second signal
  • the method may include tuning the unit arranged to receive the
  • the method may include selecting the frequency of transmission of the
  • frequency of the second signal component and the frequency of the first signal component is substantially the same as the frequency of the second
  • the method may include determining the difference frequency as well
  • the method may include transmitting the first signal component at a
  • Figure 1 is a schematic diagram of a vehicle including a security system
  • FIG. 2 is a schematic diagram of the vehicle of Figure 1 while an
  • the security system of the present invention is a passive entry system
  • remote transponder which is carried by the user and which identifies itself
  • the security control unit opens the vehicle on receipt of a
  • a security system comprising a security control unit 12 fitted to the
  • the security control unit 12 transmits a coded security
  • This coded security signal is transmitted in the form of two signal
  • the frequency F2 of transmission of the second signal component S2 is
  • the remote transponder unit 14 is capable of tuning itself to receive the
  • transponder unit 14 is arranged to de-code the frequency F2 of the second
  • the frequency F2 of the second signal component S2 is generated
  • control unit 12 such that its difference frequency with respect to the
  • component S2 may instead be selected substantially randomly from a
  • control unit 12 and all of which would conform to the requirements laid out
  • the remote transponder unit 14 is arranged to determine the difference
  • the frequency of the first signal component SI is set to
  • the frequency F2 of the second signal component S2 is
  • the relay units 16, 18 are of the code grabber type known to car
  • One of the relay units 16 is positioned close to the vehicle 10 and
  • the second relay unit 18 is positioned close to the remote transponder unit
  • Such relay units 16, 18 commonly operate with a large bandwidth and
  • the relay unit 18 as a captured signal S4.
  • the relay unit 18 then re-transmits the signal it
  • the relay unit 16 can re-transmit the response signal S3 at its
  • the remote transponder 14 can, during normal communication
  • transponder unit 14 cannot determine the frequency F2 of the second signal

Abstract

A security system is disclosed in which a security control unit (12) transmits a coded signal component (S1) at a first frequency (F1) to a remote transponder unit (14). The security signal has two components (S1, S2) which are transmitted at different frequencies (F1, F2) and the frequency of transmission of the second signal component (F2) is encoded in the first signal component (S1). The remote unit (14) is arranged to decode the frequency (F2) of the second signal component (S2) from the first signal component (S1) and therefrom to tune itself to receive the second signal component (S2).

Description

A Security System
This invention relates to security systems and in particular to a
security system for a vehicle.
It is known to provide a vehicle with a passive entry security system in
which a security control unit in the vehicle sends a coded interrogation
signal to a remote/portable transponder carried by the vehicle owner and
one such prior art system is disclosed in EP 0218251. On receipt of the
coded interrogation signal, the remote transponder sends a coded response
signal back to the security control unit, for comparison with an expected
response code.
It is a problem with some passive entry security systems that a relay
unit can be used by a thief to capture the interrogation signal and relay it to
the remote transponder and thereafter to relay the response signal back to
the vehicle.
One solution to this problem is disclosed in DE 40 20 445, in which a
specific time slot is provided for reception of the response signal and any
signal received outside this time slot is ignored.
It is an object of this invention to provide an improved security system. According to the invention there is provided a security system
comprising a security control unit and a remote transponder unit arranged
in use to communicate with each other using a coded security signal,
wherein the security signal comprises first and second signal components
which are transmitted at different frequencies and the frequency of
transmission of the second signal component is encoded in the first signal
component.
The unit which is arranged in use to receive the security signal may be
arranged to decode the frequency of the second signal component from the
first signal component.
The frequency of the second signal component may be generated in a
variable manner by the unit arranged to transmit the security signal.
The variability of the generation of the frequency of transmission of the
second signal component may be achieved by a substantially random
selection, from within a predetermined range of frequencies, by the unit
arranged to transmit the security signal.
The unit arranged to receive the security signal may be arranged to
tune itself to receive the second signal component after it has decoded the
frequency thereof from the first signal component. The range of frequencies of transmission from which the frequency of
transmission of the second signal component may be selected is such that
the difference frequency between the frequency of the second signal
component and the frequency of the first signal component is substantially
the same as the frequency of the second signal component.
The unit arranged to receive the security signal may be arranged to
determine the difference frequency as well as the frequency of transmission
of the first and second signal components and thereby to determine whether
or not a relay unit has been used to relay the security signal between the
units.
The frequency of the first signal component may be in the order of 120
kHz. The frequency of the second signal component may be in the order of
40 kHz to 80 kHz. The difference frequency may be in the order of 40 kHz
to 80 kHz.
The security system may comprise a security system of a vehicle.
The invention also provides a method of controlling a security system,
the security system comprising a security control unit and a remote
transponder unit arranged in use to communicate with each other using a
coded security signal, the method including: a) transmitting the security signal in first and second signal
components, said components being transmitted at different frequencies;
and
b) encoding the frequency of transmission of the second signal
component in the first signal component.
The method may include decoding, in the unit which is arranged in use
to receive the security signal, the frequency of the second signal component
from the first signal component.
The method may include generating the frequency of the second signal
component in a variable manner and may include achieving that variability
by a substantially random selection from within a predetermined range of
frequencies.
The method may include tuning the unit arranged to receive the
security signal such that it receives the second signal component after it has
decoded the frequency thereof from the first signal component.
The method may include selecting the frequency of transmission of the
second signal component such that the difference frequency between the
frequency of the second signal component and the frequency of the first signal component is substantially the same as the frequency of the second
signal component.
The method may include determining the difference frequency as well
as the frequency of transmission of the first and second signal components
and thereby determining whether or not a relay unit has been used to relay
the security signal between the units.
The method may include transmitting the first signal component at a
frequency in the order of 120 kHz and/or may include transmitting the
second signal at a frequency in the order of 40 kHz to 80 kHz. The method
may include transmitting the signal components at a difference frequency in
the order of 40 kHz to 80 kHz.
The invention will now be described by way of example only and with
reference to the accompanying drawings, in which:
Figure 1 is a schematic diagram of a vehicle including a security system
according to the invention; and
Figure 2 is a schematic diagram of the vehicle of Figure 1 while an
attempt is being made to defeat the security system. The security system of the present invention is a passive entry system
and a general example of a known arrangement of this type is disclosed in
EP 0218251. In this known system, a security control unit detects the
approach of a user to the vehicle and transmits a coded command signal to a
remote transponder which is carried by the user and which identifies itself
by returning a response signal to the security control unit on receipt of the
command signal. The security control unit opens the vehicle on receipt of a
valid response signal.
Referring now to the Figures and in particular to Figure 1, a vehicle 10
includes a security system comprising a security control unit 12 fitted to the
vehicle 10 and a portable/remote transponder unit 14 carried by a user. The
units 12, 14 are arranged in use to communicate with each other by passing
coded security signals.
On detecting the approach towards the vehicle 10 of a remote
transponder unit 14, the security control unit 12 transmits a coded security
signal. This coded security signal is transmitted in the form of two signal
components, comprising a first coded signal component SI at a first
frequency FI and a second coded signal component S2 at a second frequency
F2. The frequency F2 of transmission of the second signal component S2 is
encoded in the information conveyed by the first signal component SI. The remote transponder unit 14 is capable of tuning itself to receive the
range of frequencies sent by the security control unit 12. The remote
transponder unit 14 is arranged to de-code the frequency F2 of the second
signal component S2 from the first signal component Si and is then
arranged to tune itself to also receive the second signal component S2 at its
respective frequency F2.
The frequency F2 of the second signal component S2 is generated
internally by the security control unit 12 and is selected by the security
control unit 12 such that its difference frequency with respect to the
frequency FI of the first signal component SI is substantially the same as
its generated frequency F2. The frequency F2 of the second signal
component S2 may instead be selected substantially randomly from a
number of second frequencies F2 which could be stored in the security
control unit 12 and all of which would conform to the requirements laid out
above for the difference frequency.
The remote transponder unit 14 is arranged to determine the difference
frequency as well as the first frequency FI and the second frequency F2.
When the remote transponder unit 14 has de-coded the first signal
component SI and from that the second signal component S2, it transmits a
response signal S3 back to the security control unit 12 at a fixed frequency F3 and upon receipt of the response of signal S3 the security control unit 12
disarms the alarm and opens the vehicle 10.
In this example, the frequency of the first signal component SI is set to
a nominal 120 kHz. The frequency F2 of the second signal component S2 is
selected variably or randomly in the range of 40 kHz to 80 kHz such that it
results in a difference frequency also in the order of 40 kHz to 80 kHz. The
frequency of the response signal S3 is conveniently preset in the region of
433 MHz.
Referring now in particular to Figure 2, the vehicle 10 of Figure 1 is
shown in a position in which the remote transponder unit 14 is out of range
of the vehicle 10 and a pair of relay units 16, 18 are interposed between
them 10, 14.
The relay units 16, 18 are of the code grabber type known to car
thieves. One of the relay units 16 is positioned close to the vehicle 10 and
the second relay unit 18 is positioned close to the remote transponder unit
14. Such relay units 16, 18 commonly operate with a large bandwidth and
are used to try to trigger and capture the coded security signal from the
security unit 12 and then to modulate it onto a higher frequency carrier
wave F4, of for example 27 MHz, after which it is transmitted to the distant
relay unit 18 as a captured signal S4. The relay unit 18, which is in the vicinity of the remote transponder
unit 14, demodulates this higher frequency signal S4 and generates sum
and difference frequencies. The relay unit 18 then re-transmits the signal it
has received from the first relay unit 16 to the remote transponder unit 14
at its original frequency FI of 120 kHz as a relayed signal S5. This is done
in an attempt to cause the remote transponder unit 14 to transmit its
response signal S3, which would then be captured by the relay unit 18 and
transmitted back to the relay unit 16 at, for example, 418 MHz. If this can
be achieyed, the relay unit 16 can re-transmit the response signal S3 at its
frequency of 433 MHz to the security control unit 12 and thereby defeat the
security system.
Because the frequency F2 of the second signal component S2 is in the
range of 40 kHz to 80 kHz and the difference frequency is also in the range
of 40 kHz to 80 kHz, however, it is significantly more difficult to reject the
difference signal without also rejecting what may be the genuine second
frequency F2. This means that the relay units 16, 18 have great difficulty
in relaying the second signal component S2 to the remote transponder 14.
Thus the remote transponder 14 can, during normal communication
with the security controller 12, receive the first signal component SI and
from that decode the frequency F2 of the second signal component S2 and
determine the difference frequency. If an attempt is made to relay the security signal, however, the remote
transponder unit 14 cannot determine the frequency F2 of the second signal
component S2 from the relayed signal S5. The remote transponder 14
cannot then receive the second signal component S2 and therefore does not
transmit its response signal S3.
It can therefore be seen that it is possible for the security system of this
invention to determine whether or not a relay transmitter arrangement 16,
18 has been used and for it then to take defensive action, i.e. by not
transmitting its response signal S3. In this manner, it is made more
difficult to make an effective code grabber 16, 18 without incurring high cost
and therefore the security of the vehicle 10 is improved.

Claims

1. A security system comprising a security control unit and a remote
transponder unit arranged in use to communicate with each other using
a coded security signal, wherein the security signal comprises first and
second signal components which are transmitted at different
frequencies and the frequency of transmission of the second signal
component is encoded in the first signal component.
2. A security system according to Claim 1, wherein the unit which is
arranged in use to receive the security signal is arranged to decode the
frequency of the second signal component from the first signal
component.
3. A security system according to Claim 1 or Claim 2, wherein the
frequency of the second signal component is generated in a variable
manner by the unit arranged to transmit the security signal.
4. A security system according to Claim 3, wherein the variability of
the generation of the frequency of transmission of the second signal
component is achieved by a substantially random selection, from within
a predetermined range of frequencies, by the unit arranged to transmit
the security signal.
5. A security system according to any preceding claim, wherein the
unit arranged to receive the security signal is arranged to tune itself to
receive the second signal component after it has decoded the frequency
thereof from the first signal component.
6. A security system according to any preceding claim, wherein the
range of frequencies of transmission from which the frequency of
transmission of the second signal component is selected is such that the
difference frequency between the frequency of the second signal
component and the frequency of the first signal component is
substantially the same as the frequency of the second signal component.
7. A security system according to Claim 6, wherein the unit arranged
to receive the security signal is arranged to determine the difference
frequency as well as the frequency of transmission of the first and
second signal components and thereby to determine whether or not a
relay unit has been used to relay the security signal between the units.
8. A security system according to any preceding claim, wherein the
frequency of the first signal component is in the order of 120 kHz.
9. A security system according to any preceding claim, wherein the
frequency of the second signal component is in the order of 40 kHz to 80
kHz.
10. A security system according to any one of Claims 7 to 9, wherein the
difference frequency is in the order of 40 kHz to 80 kHz.
11. A security system according to any preceding claim comprising a
security system of a vehicle.
12. A security system substantially as described herein with reference to
the accompanying drawings.
13. A method of controlling a security system, the security system
comprising a security control unit and a remote transponder unit
arranged in use to communicate with each other using a coded security
signal, the method including:
a) transmitting the security signal in first and second signal
components, said components being transmitted at different
frequencies; and
b) encoding the frequency of transmission of the second signal
component in the first signal component.
PCT/GB1999/001943 1998-07-29 1999-06-17 A security system WO2000006858A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU45190/99A AU4519099A (en) 1998-07-29 1999-06-17 A security system
EP99928063A EP1101005B1 (en) 1998-07-29 1999-06-17 A security system
DE69920233T DE69920233T2 (en) 1998-07-29 1999-06-17 SECURITY SYSTEM

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9816409.8 1998-07-29
GBGB9816409.8A GB9816409D0 (en) 1998-07-29 1998-07-29 A security system

Publications (1)

Publication Number Publication Date
WO2000006858A1 true WO2000006858A1 (en) 2000-02-10

Family

ID=10836300

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/001943 WO2000006858A1 (en) 1998-07-29 1999-06-17 A security system

Country Status (5)

Country Link
EP (1) EP1101005B1 (en)
AU (1) AU4519099A (en)
DE (1) DE69920233T2 (en)
GB (1) GB9816409D0 (en)
WO (1) WO2000006858A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003060835A2 (en) * 2002-01-17 2003-07-24 Philips Intellectual Property & Standards Gmbh Method of operating an access control system
WO2017067892A1 (en) * 2015-10-19 2017-04-27 Valeo Comfort And Driving Assistance Method for estimating a distance and electronic unit for a vehicle

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0218251A1 (en) 1985-10-11 1987-04-15 Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 Safety device for motor vehicles
DE4020445A1 (en) 1990-02-03 1992-01-02 Bayerische Motoren Werke Ag Automobile antitheft device - uses defined time slot for reception of response code signal at stationary transponder within vehicle
WO1994006988A1 (en) * 1992-09-17 1994-03-31 Rockwell International Corporation Remote vehicle access featuring high security
DE4409167C1 (en) * 1994-03-17 1995-06-29 Siemens Ag Remote-controlled centralised locking system for automobile
GB2288261A (en) * 1994-04-06 1995-10-11 Michael Doxas Remote control radio key
GB2310300A (en) * 1996-02-17 1997-08-20 Rover Group Vehicle security system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0218251A1 (en) 1985-10-11 1987-04-15 Bayerische Motoren Werke Aktiengesellschaft, Patentabteilung AJ-3 Safety device for motor vehicles
DE4020445A1 (en) 1990-02-03 1992-01-02 Bayerische Motoren Werke Ag Automobile antitheft device - uses defined time slot for reception of response code signal at stationary transponder within vehicle
WO1994006988A1 (en) * 1992-09-17 1994-03-31 Rockwell International Corporation Remote vehicle access featuring high security
DE4409167C1 (en) * 1994-03-17 1995-06-29 Siemens Ag Remote-controlled centralised locking system for automobile
GB2288261A (en) * 1994-04-06 1995-10-11 Michael Doxas Remote control radio key
GB2310300A (en) * 1996-02-17 1997-08-20 Rover Group Vehicle security system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003060835A2 (en) * 2002-01-17 2003-07-24 Philips Intellectual Property & Standards Gmbh Method of operating an access control system
WO2003060835A3 (en) * 2002-01-17 2003-11-20 Philips Intellectual Property Method of operating an access control system
WO2017067892A1 (en) * 2015-10-19 2017-04-27 Valeo Comfort And Driving Assistance Method for estimating a distance and electronic unit for a vehicle
FR3044100A1 (en) * 2015-10-19 2017-05-26 Valeo Comfort & Driving Assistance METHOD FOR ESTIMATING DISTANCE AND ELECTRONIC UNIT FOR VEHICLE
US10692318B2 (en) 2015-10-19 2020-06-23 Valeo Comfort And Driving Assistance Method for estimating a distance and electronic unit for a vehicle

Also Published As

Publication number Publication date
GB9816409D0 (en) 1998-09-23
DE69920233T2 (en) 2005-11-24
AU4519099A (en) 2000-02-21
EP1101005B1 (en) 2004-09-15
DE69920233D1 (en) 2004-10-21
EP1101005A1 (en) 2001-05-23

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