DE10040480A1 - Locking system for motor vehicle has device in electronic key for adjusting allowable distance value between key and control device - Google Patents

Abstract

The system includes a control device (4) for locking or unlocking car doors (6), ignition, steering lock etc. An electronic key (5) is also provided. After positive evaluation of the transmitted operation signal (7), if the key is authorized and the distance between the key and control device is allowable, the state of the control device is changed. A device for adjusting the allowable distance value is arranged in the key. The distance value is detected from the propagation time of the signals.

Description

The invention relates to a locking system according to the preamble of patent claim 1.

Electronic locking systems are used for increased security requirements work for example by means of electromagnetic waves. Especially at Such locking systems are used in motor vehicles as door locking systems, ignition lock systems, Steering wheel locks or the like used.

Such locking systems are known from DE 43 40 260 A1. The locking system exists from a control device having at least two states for the removal and / or Locking the car doors, the ignition lock, the steering wheel lock or the like, and one associated electronic key. The control device and the key have too their intended operation means for sending and / or receiving signals. In normal operation is between the key and the control device at least one signal can be transmitted as a coded operating signal, so that after positive Evaluation of the transmitted operating signal and thus one with an authorized key Change in the state of the control device can be effected.

Such locking systems are also so-called "keyless entry" functionality further developed, with a manual actuation of the electronic key by the User is no longer necessary. It is sufficient for the user to have the key with them leads, the operating signal between the control device and the key is automatically transmitted when the user is in a, near the  Motor vehicle located effective area and there, for example, the door handle on the Car door operated.

Cases are conceivable here in which unauthorized users wait until the authorized user User after locking the door locking system of the motor vehicle the actual one Has left the effective range for the locking system. The unauthorized users then initiate a transmission of the operating signal by the key of the authorized User, with the help of transparent electronics for the key and / or the Control device, the operating signal is transmitted to the motor vehicle. This is done unlocking the door locking system, which the authorized user no longer notices because he is already at a considerable distance from the motor vehicle, outside the effective range for the locking system. This gives unauthorized users access to the motor vehicle.

To such access from unauthorized users to the motor vehicle prevent, the locking system is proposed in DE 199 41 428 A1 with a means for determining the distance between the control device and the To equip the key with the appropriate distance value. With the help of this remedy checks whether the operating signal is out of the effective range or outside the effective range arises. A change in the state of the control device can only be effected if in addition to the positive evaluation of the transmitted operating signal, a permissible one Distance value is present. However, it still seems possible using the transparent Electronics the determination of the distance value by unauthorized users manipulate, with which the subsequent transmission of the operating signal from outside the Effective range is not recognized. The security against theft and theft suffers from this Locking system.

The invention is based on the problem of theft protection of the locking system continue to improve.

This task is performed in a generic locking system by the characterizing Features of claim 1 solved.  

The invention is based on the idea that in the key a means for adjustable Change in the distance value is arranged. This means changes that between the Control device as the first device and the key as the second device for Measuring the distance exchanged signal by an arbitrary amount so that a Manipulation is recognized by transparent electronics. In this case there is no Change in state of the control device. Further refinements of the invention are Subject of the subclaims.

The means for determining the distance value can be based on the principle of Run time measurement work. For this purpose, the runtime of a signal is Range signal determined. The range signal expediently consists of two Partial signals. The first partial signal is from the first device to the second device transfer. The first partial signal is then changed in the second device. Subsequently, the second partial signal from the second device, which changed the contains the first partial signal, retransmitted to the first device. For the actual determination of the distance value, the phase offset between the second partial signal and the Use the first partial signal, the one carried out in the second device Change must be taken into account accordingly. It can still offer that Means for changing the distance value as an adjustable delay element in the train second facility.

The first partial signal can be an electromagnetic signal in the inductive one Act area. The first partial signal preferably has a frequency of 20 kHz on. At the same time, the first partial signal can serve as a wake-up signal for the second device. With the help of the wake-up signal, the second device also comes out of an idle state reduced energy requirements transferred to the intended operation. In which second partial signal can be an electromagnetic signal in the high-frequency range act, the second partial signal in particular a frequency of 315 or 868 MHz having. It then lends itself to the frequency of the first partial signal on the second To modulate partial signal. Furthermore, it can then offer that the coded Operating signal also as an electromagnetic signal in the high frequency range between  is transferred to the two institutions. In particular, the coded Operating signal are transmitted on the transmission path for the second partial signal.

To further increase manipulation security for the locking system, a changing change of the distance value made in the second facility become. This change in the change in the distance value is then in the first Facility to take into account accordingly. The change in the change of Distance value is particularly important in the subsequent determination of the Distance value made. The change in the distance value is then corresponding to calculate the same algorithm in both facilities. As a baseline for the The current change code can be used to calculate the change in the distance value can be used for the coded operating signal.

The advantages achieved with the invention are in particular that an unauthorized Actuation of the locking system is recognized with certainty and therefore also effective can prevent. Effective protection against manipulation of the Locking system, especially against attacks by means of transparent electronics unauthorized persons. In addition, incorrect operation of the locking system locked out. The locking system according to the invention therefore increases security against theft further.

An embodiment of the invention with various developments is in the Drawings shown and will be described in more detail below. Show it

Fig. 1 is a motor vehicle equipped with a locking system and

Fig. 2 is a block diagram for the locking system.

A motor vehicle 1 with the authorized user 2 can be seen in FIG. 1. The motor vehicle 1 is provided with a locking system 3 as a door locking system, which comprises a first device 4 designed as a control device and a second device 5 designed as an associated electronic key. The electronic key 5 is in the possession of the authorized user 2 , with which the latter has access to the motor vehicle 1 within an effective range 8 .

The control device 4 has at least two states, with the car doors 6 being locked in the first state and unlocking in the second state. The two devices 4 , 5 have means for transmitting and / or receiving signals for their intended operation. At least one of these signals transmitted between the key 5 and the control device 4 is a coded operating signal 7 . If the key 5 is authorized, the state of the control device 4 can be changed after the transmitted operating signal 7 has been positively evaluated. The coded operating signal 7 is transmitted when the authorized user 2 actuates the door handle 28 on the car door 6 . This unlocks the car doors 6 in accordance with the keyless entry functionality. Just as the transfer of the coded operating signal 7 can also be done automatically without user 2 as soon as it enters the active region 8, which is not considered in more detail below. If the user leaves the effective area 8 , the car doors 6 are automatically locked.

In FIG. 1, a situation is further demonstrated wish to gain in the two unauthorized persons 9, 10 access to the motor vehicle 1 after the authorized user 2 'the active region 8 has left. For this purpose, the first person 9 with a prepared electronic key 11 is in the vicinity of the motor vehicle 1 , while the second person 1.0 with a prepared control device 12 is in the vicinity of the authorized user 2 '. The prepared key 11 and the prepared control device 12 of course do not know the coded operating signal 7 , but the prepared key 11 and the prepared control device 12 , if appropriate with appropriate amplification, build a transmission path 13 for the coded operating signal 7 between the control device 4 and the outside of the Effective area 8 located key 5 . The first person 9 actuates the door handle 28 on the car door 6 , whereupon the operating signal 7 is forwarded via the transmission path 13 , so that the state of the control device 4 can be changed without the user 2 'noticing this.

In order to prevent such access by unauthorized users 9 , 10 to the motor vehicle 1 , it is determined whether the signal transmitted between the two devices 4 , 5 originates from the effective range 8 or outside the effective range 8 . For this purpose, the locking system 3 contains means for determining the distance value corresponding to the distance between the two devices 4 , 5 . If the determined distance value is permissible, with which the key 5 is located within the effective range 8 , a change in state of the control device 4 can then be carried out after a positive evaluation of the transmitted operating signal 7 . If, on the other hand, the determined distance is inadmissible, with which the key 5 is not in the effective range 8, there is no change in the state of the control device 4 even with an authorized key 5 .

However, there is now the possibility here of designing the prepared key 11 such that only the coded operating signal 7 is passed on via the transmission path 13 , but the distance value is determined between the control device 4 and the prepared key 11 . Since the person 9 is in the effective area 8 with the prepared key 11 , it is then incorrectly assumed that the distance value is permissible. In order to prevent such a possibility of manipulation of the locking system 3 , it is proposed to arrange a means for the adjustable change of the distance value in the key 5 representing the second device. The locking system 3 takes this change into account in order to determine the actual distance between the control device 4 and the key 5 . On the other hand, the prepared key 11 does not know this arbitrary change in the distance value, so that the presence of the prepared key 11 is recognized by the locking system 3 and the determined distance value is declared as not permissible. A change of state of the control device 4 is therefore not carried out.

The more detailed configuration of the locking system 3 can be seen as a block diagram in FIG. 2. The control device 4 in the motor vehicle 1 has a low-frequency LF transmitter 15 with associated coil 18 , a high-frequency FM transceiver 16 with antenna 19 and a phase detector 17 , these components being controlled as intended by a microprocessor 14 . The key 5 also contains a microprocessor 20 for the intended control of its components. These components essentially consist of an LF receiver 21 with associated coil 22 , an FM transceiver 23 with antenna 24 and a delay element 25 . The designation of the other components of the key 5 can be found in FIG. 2.

If the authorized user 2 approaches the motor vehicle 1 , as can be seen in FIG. 1, and actuates the door handle 28 on the car door 6 , the means for determining the distance value are first activated. The distance value results from the determination of the transit time of a signal in the manner of a range signal, which in turn can consist of two partial signals 26 , 27 , as can also be seen in FIG. 2. For this purpose, the microprocessor 14 controls the LF transmitter 15 to emit the first partial signal 26 via the coil 18 . The first partial signal 26 is now transmitted from the first device 4 to the second device 5 and is picked up there by the coil 22 of the LF receiver 21 . Then, the first partial signal in the second device S is changed by means of control by the microprocessor 20 with regard to the distance value. For this purpose, the means for changing the distance value is preferably designed as an adjustable delay element 25 in the second device 5 , the microprocessor 20 actuating the delay element 25 accordingly. Subsequently, the second partial signal 27 , which contains the modified first partial signal 26 , is retransmitted from the second device 5 to the first device 4 by means of the FM transceivers 23 , 16 and associated antennas 24 , 19 .

In the device 4 there is a phase detector 17 which forms the phase offset between the second partial signal 27 and the first partial signal 26 . From the phase displacement of the microprocessor 14 5 determined in consideration of the change made in the second device 5 the distance value between the two bodies 4. If the distance value is permissible, then the coded operating signal 7 , which can for example consist of a bidirectionally transmitted change code, is transmitted between the two devices 4 , 5 by means of the FM transceivers 16 , 23 .

The first partial signal 26 can be an electromagnetic signal in the inductive range. In particular, the partial signal 26 can have a frequency of 20 kHz. Since the inductive partial signal 26 is transmitted by means of the coils 18 , 22 , it has a limited range and is only effective in the effective area 8 , so that the activation of the locking system 3 is limited to the effective area 8 . The first partial signal 26 can expediently serve as a wake-up signal for the second device 5 . When the first partial signal 26 is received, the second device 5 is then transferred from an idle state with a reduced energy requirement to the intended operation.

The second partial signal 27 can be an electromagnetic signal in the high-frequency range. In particular, the partial signal 27 can have a frequency of 3.15 or 868 MHz. In order to determine the distance value, the frequency of the first partial signal 26 is expediently modulated onto the second partial signal 27 . The coded operating signal 7 is preferably also transmitted as an electromagnetic signal in the high-frequency range between the two devices 4 , 5 . The transmission path for the second partial signal 27 with the FM transceivers 16 , 23 and antennas 19 , 24 is suitable for this.

In order to further increase security against manipulations of the locking system 3 by unauthorized persons 9 , 10 , the change in the distance value can change in the second device 5 . The respective other value can expediently be set for change in the subsequent determination of the distance value. The change in the change in the distance value is then taken into account in the first device 4 when the microprocessor 14 evaluates the phase offset present in the phase detector 17 . The respective value that is set by the microprocessor 20 to change the distance value in the delay element 25 is calculated in accordance with the same algorithm in both devices 4 , S. The current change code for the coded operating signal 7 can be used as the starting value for this calculation.

The invention is not based on the described and illustrated embodiment limited. Rather, it also includes all professional training within the framework of the  The inventive concept. Such a locking system can be used to operate the Door locking system also for locking and / or unlocking the ignition lock, the Steering wheel lock or the like can be used in the motor vehicle. Otherwise there is also one Use for another door lock, for example on a property is possible.  

Reference numeral list

1

motor vehicle

2

.

2

'(authorized) user

3

locking system

4

Control device / first device

5

electronic key / second device

6

car door

7

operating signal

8th

effective range

9

.

10

unauthorized user,

11

prepared key

12

prepared control device

13

Transmission path (if not authorized)

14

Microprocessor (in control unit)

15

LF-transmitters

16

FM transceiver (in control device)

17

phase detector

18

Coil (from LF transmitter in control device)

19

Antenna (from FM transceiver in control device)

20

Microprocessor (in key)

21

LF receiver

22

Coil (for LF receiver)

23

FM transceiver (in key)

24

Antenna (from FM transceiver in key)

25

delay

26

first partial signal

27

second partial signal

28

Door handle (on car door)

Claims (9)

1. Locking system, in particular for a motor vehicle ( 1 ), with a first device ( 4 ) having at least two states and designed as a control device, such as a control device ( 4 ) for unlocking and / or locking the car doors ( 6 ) and the ignition lock, the steering wheel lock or the like, and with an associated second device ( 5 ) designed as an electronic key, and with a means for determining the distance value corresponding to the distance between the two devices ( 4 , 5 ), the two devices ( 4 , 5 ) have means for transmitting and / or receiving signals for their intended operation, and in particular at least one of the signals transmitted between the second device ( 5 ) and the first device ( 4 ) is a coded operating signal ( 7 ) , so that after a positive evaluation of the transmitted operating signal ( 7 ) at an authorized second device ( 5 ) and casual distance value a change in the state of the first device ( 4 ) can be effected, characterized in that a means for adjustable change of the distance value is arranged in the second device ( 5 ). 2. Locking system according to claim 1, characterized in that the means for determining the distance value determines the transit time of a signal in the manner of a range signal, preferably the range signal from a from the first device ( 4 ) to the second device ( 5 ) transmitted first partial signal ( 26 ), which is then changed in the second device ( 5 ), and then one of the second. Device ( 5 ) for retransmitting the first device ( 4 ), which contains the modified first partial signal ( 26 ), second partial signal ( 27 ). 3. Locking system according to claim 1 or 2, characterized in that the distance value from the phase offset between the second partial signal ( 27 ) and the first partial signal ( 26 ) is determined taking into account the change made in the second device ( 5 ). 4. Locking system according to claim 1, 2 or 3, characterized in that the means for changing the distance value is designed as an adjustable delay element ( 25 ) in the second device ( 5 ). 5. Locking system according to one of claims 1 to 4, characterized in that the first partial signal ( 26 ) is an electromagnetic signal in the inductive range, which in particular has a frequency of 20 kHz, and that preferably the first partial signal ( 26 ) serves as a wake-up signal for the second device ( 5 ), so that the second device ( 5 ) is converted from an idle state with reduced energy consumption into the intended operation. 6. Locking system according to one of claims 1 to 5, characterized in that it is in the second partial signal ( 27 ) is an electromagnetic signal in the high frequency range, which in particular has a frequency of 315 or 868 MHz, and that preferably the frequency of the first Partial signal ( 26 ) is modulated onto the second partial signal ( 27 ). 7. Locking system according to one of claims 1 to 6, characterized in that the coded operating signal ( 7 ) is transmitted as an electromagnetic signal in the high frequency range, in particular on the transmission path for the second partial signal ( 27 ), between the two devices ( 4 , 5 ) , 8. Locking system according to one of claims 1 to 7, characterized in that the change in the distance value in the second device ( 5 ), in particular in a subsequent determination of the distance value, changes, the change in the change in the distance value in the first device ( 4 ) is taken into account accordingly. 9. Locking system according to one of claims 1 to 8, characterized in that the change in the distance value is calculated in accordance with the same algorithm in both devices ( 4 , 5 ), in particular as the output value for the calculation of the current change code for the coded operating signal ( 7 ) is used.