DE10040480B4 - Locking system, in particular for a motor vehicle - Google Patents

Abstract

Locking system for a motor vehicle (1) with a first device (4) having at least two states and designed as a control device, and with an associated second device (5) designed as an electronic key, and with a means for determining the distance between the two Devices (4, 5) corresponding distance value, the two devices (4, 5) for their intended operation having means for transmitting and / or receiving signals, and wherein at least one of the between the second device (5) and the signals transmitted to the first device (4) is a coded operating signal (7), so that after a positive evaluation of the transmitted operating signal (7) with an authorized second device (5) and permissible distance value, a change in the state of the first device (4) can be effected, wherein a means for the adjustable change of the distance value is arranged in the second device (5) , characterized in that the change in the distance value in the second device (5) changes when the distance value is subsequently determined, the change in the change in the distance value in the first device (4) being taken into account accordingly.

Description

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

In the case of increased security requirements, electronic locking systems are used that work, for example, by means of electromagnetic waves. In motor vehicles in particular, such locking systems are used as door locking systems, ignition lock systems, steering wheel locks or the like.

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

Such locking systems have also been further developed with so-called "keyless entry" functionality, whereby manual actuation of the electronic key by the user is no longer necessary. It is sufficient for the user to carry the key with him, the operating signal being automatically transmitted between the control device and the key when the user is in an effective area in the vicinity of the motor vehicle and there, for example, actuates the door handle on the car door.

Cases are conceivable here in which unauthorized users wait until the authorized user has left the actual effective range for the locking system after locking the door locking system of the motor vehicle. The unauthorized users then cause the operating signal to be sent by the key of the authorized user, the operating signal being transmitted to the motor vehicle with the aid of transparent electronics for the key and / or the control device. This unlocks the door locking system, which the authorized user no longer notices, since 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.

In order to prevent such access by unauthorized users to the motor vehicle, the DE 199 41 428 A1 proposed to equip the locking system with a means for determining the distance value corresponding to the distance between the control device and the key. With the aid of this means it is checked whether the operating signal originates from the effective range or outside the effective range. The state of the control device can only be changed if, in addition to the positive evaluation of the transmitted operating signal, there is a permissible distance value. However, it still seems possible to manipulate the determination of the distance value by unauthorized users with the help of the transparent electronics, so that the subsequent transmission of the operating signal from outside the effective range is not recognized. This affects the security and theft security of the locking system.

Another locking system, which is equipped with a means for determining the distance between the control device and the key, is in the DE 198 02 526 A1 described. Finally, the shows DE 198 27 586 A1 a locking system that works with signals in the low-frequency and high-frequency range.

The invention has for its object to further improve the theft security of the locking system.

This object is achieved in a generic locking system by the characterizing features of claim 1.

The invention is based on the idea that in order to further increase the security against manipulation for the locking system, a means for the adjustable change of the distance value is arranged in the key, this means exchanging the distance between the control device as the first device and the key as the second device for measuring the distance Signal changed by an arbitrary amount. For this purpose, the distance value is changed in the second device. This change in the change in the distance value must then be taken into account accordingly in the first device. The change in the change in the distance value is still carried out in the subsequent determination of the distance value, so that manipulation by transparent electronics is recognized. In this case there is no change in the state of the control device. Further embodiments of the invention are the subject of the dependent claims.

The means for determining the distance value can work on the principle of the transit time measurement. For this purpose, the transit time of a signal is determined in the manner of a range signal. The range signal expediently consists of two partial signals. The first partial signal is transmitted from the first device to the second device. The first partial signal is then changed in the second device. The second partial signal, which contains the changed first partial signal, is then retransmitted from the second device to the first device. For the actual determination of the distance value, the phase offset between the second partial signal and the first partial signal can be used, the change made in the second device having to be taken into account accordingly. It may also be possible to design the means for changing the distance value as an adjustable delay element in the second device.

The first partial signal can be an electromagnetic signal in the inductive range. The first partial signal preferably has a frequency of 20 kHz. At the same time, the first partial signal can serve as a wake-up signal for the second device. With the aid of the wake-up signal, the second device is converted from an idle state with a reduced energy requirement into the intended operation. The second partial signal can be an electromagnetic signal in the high-frequency range, the second partial signal in particular having a frequency of 315 or 868 MHz. It then makes sense to modulate the frequency of the first partial signal onto the second partial signal. Furthermore, it can then be appropriate that the coded operating signal is also transmitted as an electromagnetic signal in the high-frequency range between the two devices. In particular, the coded operating signal can then be transmitted on the transmission path for the second partial signal.

The change in the distance value is to be calculated according to the same algorithm in both devices. The current change code for the coded operating signal can be used as the starting value for calculating the change in the distance value.

The advantages achieved with the invention consist in particular in that an unauthorized actuation of the locking system is recognized with certainty and can therefore also be effectively prevented. Effective protection against manipulation of the locking system, in particular against attacks by means of transparent electronics by unauthorized persons, is also achieved. Incorrect operation of the locking system is also excluded. The locking system according to the invention therefore further increases the security against theft.

• 1 ein mit einem Schließsystem ausgestattetes Kraftfahrzeug und
• 2 ein Blockschaltbild für das Schließsystem.

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

• 1 a motor vehicle equipped with a locking system and
• 2nd a block diagram for the locking system.

In 1 is a motor vehicle 1 with the authorized user 2nd to see. The car 1 is with a locking system 3rd provided as a door locking system, the first device designed as a control device 4th and a second device designed as an associated electronic key 5 includes. The electronic key 5 is owned by the authorized user 2nd , with which this is within an effective range 8th Access to the motor vehicle 1 owns.

The control device 4th has at least two states, with a lock in the first state and an unlocking of the car doors in the second state 6 is present. The two institutions 4th , 5 have means for sending and / or receiving signals for their intended operation. With at least one of these between the key 5 and the control device 4th transmitted signals is a coded operating signal 7 . With an authorized key 5 is after a positive evaluation of the transmitted operating signal 7 a change in the state of the control device 4th feasible. The transmission of the coded operating signal 7 occurs when the authorized user 2nd the door handle 28 on the car door 6 operated. This will unlock the car doors 6 triggered according to the keyless entry functionality. The transmission of the coded operating signal can just as well 7 also automatically without user involvement 2nd take place as soon as this the effective range 8th enters, which is not considered in the following. The user leaves the effective range 8th , the car doors lock automatically 6 .

In 1 a situation is shown in which there are two unauthorized persons 9 , 10th Access to the motor vehicle 1 want to procure after the authorized user 2 ' the effective range 8th has left. The first person is there 9 with a prepared electronic key 11 near the motor vehicle 1 while the second person 10th with a prepared control device 12th near the authorized user 2 ' stops. The prepared key 11 and the prepared control device 12th know of course the coded operating signal 7 not, however build the prepared key 11 and the prepared control device 12th , if necessary with appropriate amplification, a transmission path 13 for the coded operating signal 7 between the control device 4th and that outside the effective range 8th located key 5 on. The first person 9 operates the door handle 28 on the car door 6 , whereupon the operating signal 7 over the transmission link 13 is forwarded so that the change in state of the control device 4th can be done without this by the user 2 ' would be perceived.

To such access by unauthorized users 9 , 10th to the motor vehicle 1 to prevent it is determined whether that is between the two facilities 4th , 5 transmitted signal from the effective range 8th or outside the effective range 8th comes from. For this purpose the locking system contains 3rd Means for determining the distance between the two devices 4th , 5 corresponding distance value. If the determined distance value is permissible, the key 5 within the effective range 8th is located, then after positive evaluation of the transmitted operating signal 7 a change in state of the control device 4th feasible. On the other hand, if the determined distance is inadmissible, the key 5 not in the effective range 8th is done, even with an authorized key 5 no change of state of the control device 4th .

However, you can now use the prepared key 11 to design such that only the coded operating signal 7 over the transmission link 13 is forwarded, however, the determination of the distance value between the control device 4th and the prepared key 11 he follows. Because the person 9 with the prepared key 11 in the effective range 8th then it is erroneously assumed that the distance value is permissible. To prevent such a possibility of manipulation of the locking system 3rd is proposed in the key representing the second device 5 to arrange a means for the adjustable change of the distance value. The locking system 3rd takes this change into account, in order to take into account the actual distance between the control device 4th and the key 5 ascertain. On the other hand, the prepared key knows 11 this arbitrary change in the distance value does not, so that the presence of the prepared key 11 from the locking system 3rd recognized and the determined distance value is declared as not permissible. A change of state of the control device 4th is therefore not carried out.

The closer design of the locking system 3rd is a block diagram in 2nd to see. The control device 4th in the motor vehicle 1 has a low frequency LF transmitter 15 with associated coil 18th , a high frequency FM transceiver 16 with antenna 19th and a phase detector 17th , these components from a microprocessor 14 controlled as intended. 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 24th and a delay element 25th . The name of the other components of the key 5 is the 2nd refer to.

The authorized user kicks in 2nd to the motor vehicle 1 approach as in 1 can be seen and operates the door handle 28 on the car door 6 , the means for determining the distance value are activated first. The distance value results from the determination of the transit time of a signal in the manner of a range signal, which in turn consists of two partial signals 26 , 27 can exist like that 2nd can be seen further. The microprocessor controls this 14 the LF transmitter 15 to deliver the first partial signal 26 over the coil 18th on. The first partial signal 26 is now from the first facility 4th to the second facility 5 transferred and there from the coil 22 of the LF receiver 21 added. Then the first partial signal in the second device 5 by means of control by the microprocessor 20 changed with regard to the distance value. For this purpose, the means for changing the distance value is preferably an adjustable delay element 25th in the second facility 5 trained, the microprocessor 20 the delay element 25th controls accordingly. Then the second facility 5 the second partial signal 27 that the changed first partial signal 26 contains, for the first setup 4th using the FM transceiver 23 , 16 and associated antennas 24th , 19th retransfer.

In the facility 4th there is a phase detector 17th , which is the phase offset between the second partial signal 27 and the first partial signal 26 forms. The microprocessor determines from the phase shift 14 taking into account that in the second facility 5 change made the distance value between the two facilities 4th , 5 .

If the distance value is permissible, the coded operating signal 7 , which can consist, for example, of a bidirectionally transmitted change code, using the FM transceiver 16 , 23 between the two facilities 4th , 5 transfer.

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

With the second partial signal 27 it can be an electromagnetic signal in the high frequency range. In particular, the partial signal 27 have a frequency of 315 or 868 MHz. The frequency of the first partial signal is expediently used to determine the distance value 26 to the second partial signal 27 modulated on. The coded operating signal is preferably used 7 also as an electromagnetic signal in the high frequency range between the two devices 4th , 5 transfer. The transmission path for the second partial signal is suitable for this 27 with the FM transceivers 16 , 23 and antennas 19th , 24th on.

To further increase security against manipulation of the locking system 3rd by unauthorized persons 9 , 10th can change the distance value in the second device 5 switch. 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 in the first facility 4th when evaluating the in the phase detector 17th present phase shift by the microprocessor 14 considered accordingly. The respective value that is used to change the distance value in the delay element 25th through the microprocessor 20 is set according to the same algorithm in both. Facilities 4th , 5 calculated. The current change code for the coded operating signal can be used as the starting value for this calculation 7 be used.

In addition to actuating the door locking system, such a locking system can also be used to lock and / or unlock the ignition lock, the steering wheel lock or the like in a motor vehicle. Otherwise, it can also be used for any other door lock that is located on a property, for example.

Reference 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 route (if not authorized)

14:

Microprocessor (in control unit)

15:

LF transmitter

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 element

26:

first partial signal

27:

second partial signal

28:

Door handle (on car door)

Claims (10)

Locking system for a motor vehicle (1) with a first device (4) having at least two states and designed as a control device, and with an associated second device (5) designed as an electronic key, and with a means for determining the distance between the two Devices (4, 5) corresponding distance value, the two devices (4, 5) for their intended operation have means for transmitting and / or receiving signals, and wherein at least one of the between the second device (5) and the signals transmitted to the first device (4) is a coded operating signal (7), so that after a positive evaluation of the transmitted operating signal (7) with an authorized second device (5) and permissible distance value, a change in the state of the first device (4) can be effected, wherein in the second device (5) a means for adjustable change of the distance value is arranged, characterized in that the change in the distance value in the second device (5) at a the subsequent determination of the distance value changes, the change in the change in the distance value in the first device (4) being taken into account accordingly. Locking system after 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, the range signal consisting of a first partial signal (26) transmitted from the first device (4) to the second device (5), which then in the second device (5) is changed, and consists of a second partial signal (27) which is subsequently retransmitted from the second device (5) to the first device (4) and contains the modified first partial signal (26). Locking system after Claim 2 , characterized in that the distance value is determined from the phase offset between the second partial signal (27) and the first partial signal (26) taking into account the change made in the second device (5). Locking system after Claim 1 , 2nd or 3rd , characterized in that the means for changing the distance value is designed as an adjustable delay element (25) in the second device (5). Locking system after Claim 2 or 3rd , characterized in that the first partial signal (26) is an electromagnetic signal in the inductive range. Locking system after Claim 2 or 3rd or 5 , characterized in that 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 a reduced energy requirement to its intended operation. Locking system according to one of the Claims 2 to 3rd or 5 to 6 , characterized in that the second partial signal (27) is an electromagnetic signal in the high-frequency range. Locking system after Claim 7 , characterized in that the frequency of the first partial signal (26) is modulated onto the second partial signal (27). Locking system according to one of the Claims 1 to 8th , characterized in that the coded operating signal (7) is transmitted as an electromagnetic signal in the high-frequency range between the two devices (4, 5). Locking system according to one of the Claims 1 to 9 , characterized in that the change in the distance value is calculated in accordance with the same algorithm in both devices (4, 5), the current change code for the coded operating signal (7) being used as the starting value for the calculation.

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