GB2296804A

GB2296804A - Electronic security system

Info

Publication number: GB2296804A
Application number: GB9519022A
Authority: GB
Inventors: Nigel Janson
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-09-17
Filing date: 1995-09-18
Publication date: 1996-07-10
Also published as: GB9519022D0

Abstract

An electronic security system for a vehicle in which a key 11 has electronic storage means 15 for storing coded information which can be detected upon approach or insertion of the key into a lock, or transmitted to the lock from a remote location, has code verification means 17, 18 for comparing the detected code with a lock code stored therein, data coupling means for transferring encrypted enable signals from a first part 17 of the said code verification mean via an optical wave guide 28 to a second part 18 thereof spatially separated therefrom and operable, when enabled, to allow the operation of one or more of the vehicles' essential or auxiliary electrically energised or controlled systems. Second part 18 sends encrypted signals to first part 17 via an optical wave guide 36 to change the encryption code for the next transmission. Presentation of a wrong key gives an alarm 37 and disables vehicle systems. <IMAGE>

Description

AN ELECTRONIC SECURITY SYSTEM The present invention relates generally to an electronic security system and particularly, although not exclusively to a security system for a vehicle. The present invention may be put into effect with beneficial effect in a system of the type in which a "key" (by which term is included a remote transmitter) is provided with electronic storage means for storing information electronically in addition to the information coded mechanically by its shape. Indeed, the present invention may rely entirely on electronic code storage means and the key may be in the form of a card or may be provided with no more than a guide blade for locating and orienting it within the opening of the lock.

Considerable attention has recently been given to increasing the level of security of motor vehicles as a result of the continuing increase in motor vehicle crime, especially the so-called "joy-riding" in which thieves having little regard to the damage they may do to a vehicle, manage to start up the engine and drive away for a short period of time. During this time the vehicle is driven recklessly, even dangerously, and may be used in the pursuance of other criminal activities. As a result considerable damage may be done to the vehicle so that even if the legitimate owner is able to regain possession of the vehicle the cost of reinstating it to its normal condition is considerable.

Original equipment manufacturers have recently introduced additional security provisions, especially in vehicles having electronic engine management systems since these are frequently embedded or encased at inaccessible locations and can exercise control on essential engine functions. Such systems are referred to as "immobilisers". Immobilisers generally require the transmission of signals from an ignition lock or like such authorisation system; in the absence of such signals the engine will not run.

Several disadvantages have been encountered in these known immobilisers, the most significant of which is the ability of criminals to establish how such security systems may be bypassed in order to start up the engine and drive the vehicle away. Extremely sensitive units may suffer from the further disadvantage that spurious activation, for example by the natural radiation always present in the environment, may cause corruption of the system resulting in its refusal to activate the engine even upon introduction of a legitimate authorisation code via the key or other system.

Although it is known to provide keys for motor vehicles with small batteries to power electronic components, the present invention seeks to provide an electronic storage means for the key which will require no power supply in the key. This makes it possible for the key to be made to substantially the same size as conventional keys for motor vehicle ignition locks.

According to one aspect of the present invention, therefore, there is provided an electronic security system for a vehicle of the type in which a key is provided with electronic storage means for storing information in the form of an electronically readable code which can be detected upon approach or insertion of the key into a lock, or transmitted to the lock from a remote location, code verification means at or associated with the lock for comparing the detected code with a lock code stored therein, data coupling means for transferring encrypted enable signals from a first part of the said code verification means to a second part thereof spatially separated therefrom and operable, when enabled, to allow the operation of one or more of the vehicles' essential or auxiliary electrically energised or controlled systems, in which the said second part of the code verification means is linked to the said first part thereof by at least one optical wave guide, and the said enable signals are transmitted from the said first part of the code verification means to the second part thereof as optical signals.

By separating the code verification means into two parts it is possible to locate one part close to the lock, and one part remote from the lock since. It may be provided with some additional form of physical security such as embedding of the components in resin, encasement in a strong steel casing or the like, since the part close to the lock may be subject to physical attack; it is however possible to embed the second part deeply within the engine or its components to make it inaccessible.

Encryption of the signals transferred from one part to the other elevate the level of security making it difficult if not impossible for a criminal to interrupt the transmission lines and energise the motor by providing a false indication that the decoder has detected the presence of an authorised ignition key.

This security is enhanced in an immobiliser of the present invention by forming the said data coupling means to allow bi-directional transfer of the said encrypted signals since this makes it possible to incorporate means for changing the encryption code periodically, in response to given events, or even each time the key is inserted and/or withdrawn from the lock using a code changer of random or pseudo random codes. This is sometimes referred to loosely as a "rolling code " system.

Communications between the two parts of the verification means are therefore highly secure.

The means by which the encryption code is changed may include one-time programmable memory units operable to transmit, from the said second part of the code verification means, to the said first part thereof, encryption-control signals for changing the encryption code to be used for the next transmission of signals from the said first part of the code verification means to the said second part thereof.

The optical wave guide provided for the transfer of encrypted signals between the said first and second parts of the code verification means may act to transfer signals in each of two opposite directions to and from the said second part of the code verification means, in which case coupling means at each end of the wave guide may be provided for coupling the optical signals appropriately to transmitter or receiver elements respectively.

The use of optical wave guides is even more secure than the use of electrical conductors since even if the code verification could be corrupted it is difficult for criminals to transmit signals along the wave guide and unlikely that they would have the necessary equipment available to generate an optical coded signal. Moreover, by adopting a further contrivance, namely the transmission of encrypted digital signals in one direction and encrypted analogue signals in the other direction between the said first and second parts of the code verification means, an additional hurdle is put in the path of any unauthorised person seeking to start the engine without the legitimate authorised key.Of course, it is by no means essential to transmit signals via only a single wave guide, and respective wave guides may be provided for the transmission of signals in each of the said two opposite directions. As well as providing for immobilisation of the engine by the control of its essential systems such as the fuel system, ignition system and the like, the security system of the present invention may also include means for generating a visual and/or an audible alarm indication if the same code verification means detects the presence of an unauthorised code, or the absence of an authorised code, upon operation or attempted operation of the said lock.

The means by which the lock detects the presence of an authorised key are also important. Typically a coil antenna may be provided in the lock, and supplied with an oscillating signal at a given frequency, for example by a Colpitts oscillator, and the electronic code storage means in the key may be an RF transponder or like inductively coupled element operable to generate a given pattern of variation in the inductance which can be detected by the influence this has on the coil antenna in the lock. The coil antenna therefore effectively "interrogates" an approaching object by radiating an RF signal into the space immediately surrounding the lock, and senses the presence of an authorised key to generate a particular code in response thereto.

Although the technology exists to allow the code detected by the antenna to be changed from time to time, it is considered appropriate for the key to have a single code which remains unchanged, and for the security or secrecy of this code to be maintained at a high level by the means described hereinabove in which internal changes are made to prevent corruption.

In order to obtain maximum sensitivity from the coil antenna this is preferably oriented such that its axis is substantially parallel to the direction of movement of the key as it is introduced or removed from the lock.

In place of an RF transponder a so-called "smart card" may be used, which may be of the contactless or contactbearing type; other programmable electronic units capable of interacting with a transmitted radiation field, however, may also be utilised.

According to another aspect of the present invention there is provided an electronic security system for a vehicle, as claimed in any preceding claim, in which the electronic storage means in the key is an RF transponder or a so-called "smart card" of the contactless or contactbearing type, or other programmable electronic unit capable of interacting with a transmitted radiation field whereby to provide a programmed variable inductance to which the antenna is responsive.

Various embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a block schematic diagram of the major components of an immobiliser system formed in accordance with the principles of the present invention; Figures 2A to 2D are block diagrams of the general arrangement of several alternative configurations formed as embodiments of the invention; Figure 3 is a block diagram of a more comprehensive system; Figure 4 is a block diagram illustrating one example of a first part of the code verification means defined above; and Figure 5 is a block diagram of an alternative arrangement having a wider range of application than the system of Figure 4.

Referring now to the drawings, in Figure 1 there is shown schematically an ignition lock and key arrangement in which a key 11, which may be of conventional type having a blade 12 with shaped notches 13 defining a mechanical code effectively matched by a corresponding physical shape within the lock, which according to known technology may be defined by a plurality of pins or tumblers which are aligned in a single unique release position upon insertion of the key into a lock opening 14. Such mechanical arrangements of the lock are well known and will not be described hereinafter.It should be noted that, although described in relation to a known mechanically operable lock, the electronic coderecognition system of the present invention is not in any way dependent on the mechanical interaction of the key and the lock, and indeed could be applied to a "lock" in which the lock release is achieved entirely electronically without any mechanical interaction. For example, the lock opening 14 may be a slot to receive a credit-card type "key" provided with the appropriate code storage means.

The key 11 illustrated in the drawing is provided with an electronic code storage component 15 comprising an electronic circuit having an associated coil which is energised when in the presence of a radio frequency signal of appropriate frequency. This unit will be hereinafter described as an identity tag. The property of the identity tag is that, when energised by an RF signal the coil to which it is connected forms an LC circuit with the tag, which oscillates at a frequency varied by the operation of the circuit itself. In the present case a coil antenna 16 is provided around the lock passage 14 and orientated such that the lock blade 12 passes substantially parallel to the axis of the coil as it is introduced into the lock passage 14.The coil antenna 16 is energised by a first part 17 of code verification means formed two parts, the second part 18 of which is spatially separated from the first part 17.

The first part 17 of the code verification means 17,18 comprises a decoder 19 electrically connected to the coil antenna 16, and includes (although not shown) a suitable oscillator such as a Colpitts oscillator for supplying a given frequency signal to the coil 16.

By orientating the coil 16 in the manner described above it is ensured that the greatest sensitivity to the inductive effect of the identity tag 15 is experienced so that the decoder 19 can determine, with the greatest possible sensitivity, the presence of the identity tag 15 as it approaches the lock. The lock, identified with the reference numeral 20, is in this embodiment, preferably an ignition lock mounted in a suitable part of the instrument panel 21 of a motor vehicle, and acting when the key 11 is introduced and turned, to close a switch to complete a circuit in a line 22 from a positive pole 23 of a battery 24 to a line 25 leading to the second part 18 of the code verification means 17,18. The lines 22 and 23 may be conventional electrical conductors and act to carry the 12 volt signal for energisation of both the parts 17,18 of the code verification means.

The first part 17 of the code verification means 17,18 also includes a controller 26 which is internally connected to the decoder 19 and energised, when the decoder 19 issues a signal indicating recognition of the presence of the identity tag 15. The controller 26 acts to encrypt a verification signal which is transmitted via a transmitter 27 to an optical wave guide 28 in the form of an optical fibre which leads to a receiver 29 in the second part 18 of the verification means 17,18. The signal transmitted by the transmitter 27 onto the fibre optic wave guide 28 is encrypted by the controller 26 in accordance with an encryption pattern determined by the software. When the receiver 29 passes this signal to the controller 30 it acts to perform two functions: the first is to energise a driver unit 31 which supplies power to the engine fuel system 32, and to a driver 33 which supplies power to the vehicle ignition system 34; the second is to generate a different encryption code which is transmitted via a transmitter 35 to a fibre optic wave guide 36 leading back to a receiver 37 which passes the encrypted signal to the controller 26 and, thereby change the encryption code for the next transmission. The fuel system 32 and ignition system 34 may be energised via relays, electronic switches, triac or the like (such as FET) and may include energisation of the vehicle starter motor.

If the decoder 19 detects a responding unit affecting the oscillations of the coil 16, in a pattern which does not match that stored by the decoder 19, the controller 26 is energised to transmit a coded signal via transmitter 27 to the fibre optic wave guide 28 which, upon reception at the receiver 29 triggers the control of 30 to issue an alarm condition signal to an alarm system 37. The alarm system 37 is connected by a line 38 to the ignition system 34 and operates to switch this off when the alarm system is triggered. likewise, the alarm system 37 is connected by a line 39 to the fuel system 32 and likewise switches off the fuel system when an alarm condition is detected.

Additional security is provided by the programme resident in the central control unit 30. Upon manufacture the central control unit 30 is provided with no stored codes and has no pre-programmed relationship with any authorisation codes or keys. this provides the manufacturer with the greatest flexibility and security.

The user is provided with two keys bearing different codes, and the manufacturer of the OTP chips can provide chips having a very large number of unique codes so that no two keys produced ever have the same identity code.

Either of the two keys supplied to the user may be introduced into the lock opening 14 first, and upon doing so the code transmitted by the decoder 19 is recognised by the control unit 30 and stored as a "master" authorisation code. The user may then place the master key in a safe place as a reserve for future use. The second key is then introduced into the lock opening 14 and the signal generated by its OTP chip, decoded by the decoder unit 19, is recognised by the central control unit 30 as the "working" authorisation code.

Referring now to Figure 2, the first arrangement shown in Figure 2A shows the various components of the system in generalised block diagram form. In this drawing is shown a transponder 50 which with a coil antenna 51 the signal from which is fed to a controller/receiver unit generally indicated 53. This is connected directly to the wire harness generally indicated 54, of the electrical unit (not shown) to be controlled, and via an optical wave guide link 55 to a disabler unit 56 having both receiver and transmitter functions to allow bidirectional communication along the wave guide link 55. This is a generalised view of the system more particularly described in relation to Figure 1.

The system shown in Figure 2B is similar to that shown in Figure 2A and common components will be identified with the same reference numerals. This system differs only in that the passive transponder 50 is replaced by an active signal transmitter 57 and the coil antenna 51 is replaced with a receiver 58. Likewise the system of Figure 2C differs only by the replacement of the passive transponder 50 with a read/write transceiver 59 and the coil antenna 51 with a read/write head 60.

The system shown in Figure 2D is a further development in which the controller 53 is formed as a master controller linked to a plurality of disabler units 61, 62, 63, 64 (in this case four) in a so-called "daisy chain" configuration drawing each to control the enablement of a separate electrical unit such as the fuel pump, ignition system, starter motor and door lock release solenoid. Each of the units 61-64 may communicate with the master controller using a different code thereby making it even more difficult for the unauthorised user to circumvent the security system and apply by pay power to the engine to start it.

Figure 3 shows the arrangement of such a multiple protection unit in more detail.

In this unit an ignition key 65 is provided with a radio frequency transponder 66 which responds to signals from a coil antenna 69 located at the ignition lock 67. The coil antenna 69 forms part of a code verification system 68 having a radio frequency receiver 70 the output from which is connected to a micro-controller 71 which reads the stored authorisation code from a EEPROM 72. The radio frequency receiver 70 acts simply to demodulate the signal generated by the transponder 66 in response to the signal transmitted to it from the coil antenna via a transmission signal generator (not shown).

The micro-controller 71 is connected to an alarm sounder 73 and has outputs connected to power drivers 75 and optical transmitters 76. Although only one box representing the power drivers 75 is shown and, likewise, only one box is shown representing the optical transmitters 76, there may be a plurality of such. The power drivers 75 provide output to the wire harness generally indicated 78 the status of which may be monitored by sensors 74 which provide signals back to the micro-controller identifying the status of various parts of the wire harness.

The optical transmitters 76 transmit in coded or encrypted signals two optical receivers 83 the output from which is fed to a separate micro-controller 86 which controls power drivers 82 in response to the outcome of the dialogue with an EEPROM 85 containing the stored authorisation code. Again, sensors 81 may detect the status of the wire harness 78 and supply signals to the micro-controller 86. Two-way communication between the second part 68B of the code verification unit and the first part 68A thereof by way of a second optical transmitter 84 transmitting along an optical waveguide 95 to an optical receiver 77 in the first part 68A of the code verification unit. The optical receiver 77 passes electrical signals to the micro-controller 71.

The wire harness 78 may be connected directly to a number of individual electrical units such as the door lock and/or window system 87, the lighting system 88, the engine control unit (the engine management computer) 89 the ignition system 90, the fuel injectors 91, the fuel pump 92, the starter solenoid 93 and/or the starter switch 94 which may also be directly connected to the ignition lock 67.

Power to the wire harness may be provided from vehicle battery 80 which also powers an alarm system 79 connected (by means not shown) to the micro-controller 71 and 86 to receive output signals if anonymles indicating an attempted unauthorised use of the vehicle are detected.

A specific embodiment of the first part 68A of the code verification system is shown in slightly more detail in Figure 4. The radio frequency receiver comprises an oscillator 97 receiving signals from the coil antenna 69 and passing them to a signal detector 98 which acts in a known way to demodulate the signals, typically applied to a carrier wave by amplitude modulation at the transponder 66. The demodulation is completed by a high pass filter 99 and low pass filter 100 and the thus demodulated signal fed via a comparator 101 to the micro-controller 71. The micro-controller 71 has connections to a EEPROM 72, optical transmitter 76, optical receiver 77 and power driver 75 as in the embodiment of Figure 3, but also has a serial data highway 110 as a potential alternative, which may be of the standard RS232 type or an I squared C database.

The embodiment of Figure 5 illustrates how the microcontroller 71 generates signals applied to the transmitting coil 102 via a transmitter chain comprising a crystal oscilator 107, a divider 106, an intermediate oscilator 105 and a power amplifier 104. The received signal on coil antenna 103 is supplied, in a similar manner to that already described, via an AM receiver 108, a low pass filter 109, an amplifier 111 and from there via a comparitor 112 to the micro-controller 71. Such a system may be formed as a modular unit and resin encapsulated for security.

Claims

1. An electronic security system for a vehicle of the type in which a key is provided with electronic storage means for storing information in the form of an electronically readable code which can be detected upon approach or insertion of the key into a lock, or transmitted to the lock from a remote location, code verification means at or associated with the lock for comparing the detected code with a lock code stored therein, data coupling means for transferring encrypted enable signals from a first part of the said code verification means to a second part thereof spatially separated therefrom and operable, when enabled, to allow the operation of one or more of the vehicles' essential or auxiliary electrically energised or controlled systems, in which the said second part of the code verification means is linked to the said first part thereof by at least one optical wave guide, and the said enable signals are transmitted from the said first part of the code verification means to the second part thereof as optical signals.

2. An electronic security system for a vehicle, as claimed in Claim 1, in which the said data coupling means for transferring the said enable signals allow bidirectional transfer of signals and there are means for changing the code each time the key is inserted and/or withdrawn from the lock.

3. An electronic security system for a vehicle, as claimed in Claim 2, in which the means by which the encryption code is changed include one time programmable memory units operable to transmit, from the said second part of the code verification means, to the said first part thereof, encryption-control signals for changing the encryption code to be used for the next transmission of signals from the said first part of the code verification means to the said second part thereof.

4. An electronic security system for a vehicle, as claimed in any of Claims 1 to 3, in which a single optical wave guide is provided for the transfer of encrypted signals in each of two opposite directions to and from the said second part of the code verification means, there being coupling means at each end of the wave guide for coupling the optical signals appropriately to transmitter or receiver elements respectively.

5. An electronic security system for a vehicle, as claimed in any of Claims 2 to 5, in which the code verification means act to transmit encrypted digital signals in one direction and digital and/or encrypted analogue signals in the other direction between the said first and second parts thereof.

6. An electronic security system for a vehicle as claimed in Claim 4 or Claim 5, when dependent on either of Claim 4 or Claim 5, in which there are provided respective wave guides for the transmission of signals in each of the said two opposite directions.

7. An electronic security system for a vehicle, as claimed in any preceding claim, in which there are provided respective disabler units for each of a plurality of electrically supplied or controlled systems, each communication with a common first part of the code verification means via a respective optical name guide and utilising respective different codes for transmission of information between them.

8. An electronic security system as claimed in Claim 7, in which the said plurality of disabler units are connected together sequentially in a sol-called "daisy chain" configuration.

9. An electronic security system for a vehicle, as claimed in any preceding claim, in which there are further provided means for generating a visual and/or an audible alarm indicator if the said code verification means detects the presence of an unauthorised code (or the absence of an authorised code) upon operation or attempted operation of the said lock.

10. An electronic security sensor for a vehicle, as claimed in any preceding claim, in which the essential electrically energised system of the vehicle is an engine management system, fuel delivery or injection system, fuel pump, fuel shut-off valve, ignition system or any combination thereof.

11. An electronic security system for a vehicle, as claimed in any preceding claim, in which the lock is provided with a coil antenna oriented such that its axis is substantially parallel to the direction of movement of the key as it is introduced or removed from the lock.

12. An electronic security system for a vehicle, as claimed in any preceding claim, in which the electronic storage means in the key is an RF transponder or a socalled "smart card" of the contact less or contact-bearing type, or other programmable electronic unit capable of interacting with a transmitted radiation field whereby to provide a programmed variable inductance to which the antenna is responsive.

13. An electronic security system for a vehicle, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

14. An electronic locking system having at least one lock operable by a key or other release means provided with means by which the authenticity of the key or other release means can be verified by verification means forming part of or being otherwise associated with the lock in such a way that authenticity verification takes place upon an attempt at releasing the lock, and upon verification an enable signal is generated to enable operation of a device or component the operation of which is consequent on the slate of the lock, in which at least two parts of the said verification means are spatially separated and signals are transmitted in at least one direction from one part to the other along at least one optical wave guide.

15. An electronic locking system as claimed in Claim 14, in which the verification means include means for encrypting the signals.

Amendments to the claims have been filed as follows CLAIMS 1. An electronic security system for a vehicle of the type in which a key is provided with electronic storage means for storing information in the form of an electronically readable code which can be detected upon approach or insertion of the key into a lock, or transmitted to the lock from a remote location, code verification means at or associated with the lock for comparing the detected code with a lock code stored therein, data coupling means for transferring encrypted enable signals from a first part of the said code verification means to a second part thereof spatially separated therefrom and operable, when enabled, to allow the operation of one or more of the vehicles' essential or auxiliary electrically energised or controlled systems, in which the said second part of the code verification means is linked to the said first part thereof by at least one optical wave guide, and the said enable signals are transmitted from the said first part of the code verification means to the second part thereof as optical signals.

2. An electronic security system for a vehicle, as claimed in Claim 1, in which the said data coupling means for transferring the said enable signals allow bi-directional transfer of signals and there are means for changing the code each time the key is inserted and/or withdrawn from the lock.

4. An electronic security system for a vehicle, as claimed in any of Claims 1 to 3, in which a single optical wave guide is provided for the transfer of encrypted signals in each of two opposite directions to arid from the said second part of the code verification means, there being coupling means at each end of the wave guide for coupling the optical signals appropriately to transmitter or receiver elements respectively.

7. An electronic security system for a vehicle, as claimed in any preceding claim, in which there are provided respective disabler units for each of a plurality of electrically supplied or controlled systems, each communication with a common first part of the code verification means via a respective optical wave guide and utilising respective different codes for transmission of information between them.

8. An electronic security system as claimed in Claim 7, in which the said plurality of disabler units are connected together sequentially in a so-called "daisy chain" configuration.

10. An electronic security system for a vehicle, as claimed in any preceding claim, in which the essential electrically energised system of the vehicle is an engine management system, fuel delivery or injection system, fuel pump, fuel shut-offvalve, ignition system or any combination thereof.

12. An electronic security system for a vehicle, as claimed in any preceding claim, in which the electronic storage means in the key is an RF transponder or a so-called "smart card" of the contactless or contact-bearing type, or other programmable electronic unit capable of interacting with a transmitted radiation field whereby to provide a programmed variable inductance to which the antenna is responsive.

13. An electronic security system for a vehicle, substantially as herein before described with reference to, and as shown in, the accompanying drawings.