DE10112573A1 - Method for initializing an anti-theft system for a motor vehicle - Google Patents

Abstract

The anti-theft system is first put into an initialization state. Then an interrogation signal (6) is sent out. In each code transmitter (1) which receives the interrogation signal (6), a transmission time characteristic of the respective code transmitter (1) is generated with the aid of a random principle. A response signal (7) is then transmitted within this transmission time. All received response signals (7) are then evaluated in the motor vehicle. Due to the different transmission times, the code transmitters (1) are clearly recognized and the initialization can be carried out directly at the customer with universal code transmitters (1).

Description

The invention relates to a method for initializing a Anti-theft system for a motor vehicle, it concerns for example a method of initializing a route immobilizer or an access control device for one Motor vehicle.

In a known method of initializing a thief steel protection system (DE 197 21 286 C1) is the initial for the first time at the end of the line at the vehicle manufacturer carried out. For this, the anti-theft system is divided into one Initialization state brought and then coding data both in a control unit in the motor vehicle and in all portable code transmitter assigned to the motor vehicle stores. When the anti-theft system is initialized can use the code transmitters to grant access and Use of the motor vehicle can be demonstrated.

If this procedure is used, the force vehicle-assigned code transmitter at the end of the line at the vehicle be physically present and will be after the initia lization together with the motor vehicle to the wholesale and Mailed to retailers. Care must be taken to ensure that the code transmitter and motor vehicle always stay together and that the encoders are not with encoders that drive to other witness fit, be exchanged.

With this procedure there is also the risk that the Simultaneous teaching (initialization) of several code transmitters and if the coding has been confirmed by the The encoder signals overlays take place, so the signals not properly received and no clear to order is present.

The invention is based on the problem of a method for Initialize to create an anti-theft system with that each code transmitter assigned to the motor vehicle clearly can be initialized. The initialization can be done at Vehicle manufacturers take place, but can also directly at the customer be possible.

According to the invention, this problem is solved by a method solved the features of claim 1. It will Anti-theft system first in an initialization stood spent. When this state is reached, it will an interrogation signal is sent, upon which each code transmitter, who receives the interrogation signal generates a random number. With this random number then becomes one for each code transmitter Teristic airtime set within each code sends back via its response signal and thus the I Confirm the nitialization of the code transmitter and the tax device in the motor vehicle. This process is repeatable until all code encoders are recognized and initialized are.

Are even in the later operation of the anti-theft system if different broadcast times are used, it never will occur that two coders send their response signal at the same time send if both of you have received a query signal. Due to the randomly generated, differ The transmitters send their response signal different times.

Advantageous embodiments of the invention are the Sub-claims reproduced.

Embodiments of the invention are described below the schematic drawings explained in more detail. Show it:  

Fig. 1 is a block diagram of an anti-theft system egg nes motor vehicle and

Fig. 2 and 3 are flowcharts of methods for Initiali Sieren of the anti-theft system of FIG. 1.

An anti-theft system for a motor vehicle can prevent the intended use of a motor vehicle or access to the motor vehicle by an unauthorized user. In order to prove an authorization (this is also referred to as authentication), a user needs at least one electronic key or a code transmitter 1 ( FIG. 1).

If the user is looking for access to his motor vehicle, he can pull the door handle 2 or operate a switch in the vicinity of the door handle 2 , whereby a control and evaluation unit 3 causes a query signal 6 to be transmitted from the vehicle via antennas 4 in the motor vehicle becomes. If the encoder 1 receives the interrogation signal 6, it sends a coded response signal back 6 wirelessly to a receiver in the motor vehicle. The receiver is formed by the antennas 4 together with the central control and evaluation unit 3 .

In the control and evaluation unit 3 , the received response signal 6 is demodulated and the code information contained therein is evaluated, ie checked for its authorization. For this purpose, the code information is compared with an expected and stored reference code information (also referred to as code data).

Several keys or code transmitters 1 are usually assigned to each motor vehicle. So that the code transmitter 1 and the control and evaluation unit 3 “understand each other” and can communicate with one another, the code transmitter 1 must be trained or initialized on the theft protection system. By initiating coding data in the control and evaluation unit 3 as well as in the code transmitter 1 are determined to match each other and not readable from the outside.

This happens during a so-called initialization process status, in which the anti-theft protection system only upon proof an authorization or by an unusual, pre-determined put actuation of actuators is spent.

The initialization does not have to be carried out by the vehicle manufacturer, but can be done when the vehicle is sold to the end customer. To this end, there have not yet been any individualized, universal code transmitters 1 as "bulk goods". As many code transmitters 1 as are to be assigned to the motor vehicle are brought into the vicinity or into the motor vehicle. If the code transmitter 1 is in a detection area 5 , the initialization can be started.

The detection area 5 is defined in such a way that within the detection area 5 signals between the code transmitter 1 and the motor vehicle can be transmitted safely with a sufficiently high power. Since the signals for security reasons (security against unauthorized eavesdropping of the signals) have a relatively short range, the coverage area 5 can also be kept small.

In a first exemplary embodiment ( FIG. 2), it is assumed that none of the present code transmitters 1 has yet been initialized. There are now these code transmitters 1 , which are to be assigned to the vehicle, within the detection area 5 and the anti-theft system is already in the initialization state, so a query signal 6 is first transmitted via the antennas 4 . The first interrogation signal 4 is referred to in FIGS. 2 and 3 as a "broadcast message" to which each of the universal coders can respond.

Each code transmitter 1 , which has received an interrogation signal 6 , generates a transmission time (also referred to as a time slot or time window) according to a random principle. The transmission time represents a start time and a time period within which the respective code transmitter 1 sends its response signal 6 .

The duration of the transmission time is determined in such a way that the complete response signal 6 can be transmitted reliably within the transmission time. The starting time (start time) of the transmission time depends on the time of the received interrogation signal 6 . Depending on the random number, a delay time is defined from the receipt of the query signal 6 , after which the respective transmission time of the code transmitter 1 starts.

If a random algorithm with high diversity (ie a relatively large pseudo random sequence) is used, it is very unlikely that two code transmitters 1 have the same random number and thus the same transmission time, since the transmission time is determined depending on the random number. However, any number of random numbers must not be allowed, so that the total time between sending the query signal 6 and waiting for the last response signal 7 does not become too long in normal operation.

If the transmission time is generated at random, each code transmitter 1 sends out a response signal 6 (is referred to in FIGS . 2 and 3 as a response message) during the specified transmission time. All received response signals 7 are then evaluated in the control and evaluation unit 3 of the motor vehicle. In the control and evaluation unit 3 , it is also checked whether all code transmitters 1 have actually sent at different times. This is accomplished, for example, on the basis of clearly available response signals 7 .

If not all response signals 7 are received uniquely, a query signal 6 is sent out again, so that different ones can also be assigned to those code transmitters 1 with the same transmission time.

If all of the code transmitters 1 with their response signals 7 can be clearly differentiated, ie if all the response signals 7 were received at different times (thus the code transmitters 1 have different transmission times due to the short distance to the motor vehicle and thus the very short signal transit time), then the in the response signals 7 contained code information stored as coding data in the control and evaluation unit 3 . All code transmitters 1 and the control and evaluation unit 3 are then learned or initialized.

It can be provided that all code transmitters 1 work with the same code information or that each code transmitter 1 has its own code information. It is important for the invention that each code transmitter 1 is "understood" by the control and evaluation unit 3 as soon as it is initialized and thus assigned to the anti-theft protection system.

The number of possible transmission times is variable and can be determined depending on the number of code transmitters 1 to be initialized. However, the total time until the last code transmitter 1 has also sent its response signal 6 should not be too long, so that the user does not have to wait too long in normal operation until he has authenticated himself using his code transmitter 1 .

In a second exemplary embodiment ( FIG. 3) it can be provided that all transmission times of all code transmitters 1 which are in the detection area 5 during initialization are deleted first. With the deletion, a marking on the code transmitter 1 is deleted. This can be done by sending a delete signal or marker signal on the vehicle side.

All code transmitters 1 that receive the delete signal and thus do not have the marking delete the current transmission time. Subsequently, an interrogation signal 6 is sent from the motor vehicle, which in turn generates a transmission time at random in each code transmitter 1 which receives the interrogation signal 6 and which is not marked.

All code transmitters 1 whose transmission time was determined in this way and which are therefore not marked, now send their response signal 6 back to the motor vehicle during the previously determined transmission time. All received response signals 7 are evaluated in the control and evaluation unit 3 .

If it is not possible to distinguish all of the code transmitters 1 , since their response signals 7, for example, were partially superimposed and were therefore not “readable”, the control and evaluation unit 3 sends a marking signal to all those code transmitters 1 from whom a valid response signal 6 was received ,

So that the correct code transmitter 1 is addressed, key numbers can be used as addresses which are assigned to each code transmitter 1 . Both in Abfragesig nal 6 and in response signal 6, the individual key number may be included.

An interrogation signal 6 is then sent out again. If the unmarked code transmitter 1 receives the interrogation signal 6 , it generates a random transmission time again and sends out its response signal 6 within this transmission time. Thus, all code transmitters 1 , whose transmission times previously overlapped with those of other code transmitters 1 , are provided with a new transmission time.

The process is repeated until all code transmitters 1 have different transmission times.

If all response signals 7 of the code transmitter 1 can be clearly distinguished, the response signals 7 are accepted and corresponding coding data are stored in the control and evaluation unit. The anti-theft system is now initialized. The control and evaluation unit 3 thus knows all the coding data of all the code transmitters 1 and can then determine the present calculation when the code transmitter 1 is used later by comparing the received code information with these coding data.

The code transmitters 1 maintain their transmission times until the theft protection system is reinitialized (this is also referred to as reinitialization). Thus, the code transmitters 1 always send at different transmission times, even in later normal operation of the anti-theft protection system. If then, for example, a driver and passenger, respectively the motor vehicle associated code encoder 1 carry with him, each receiving an interrogation signal after triggering 6 transmits its response signal 6 back within the respective transmission time. The evaluation unit can now doubtlessly receive both response signals 7 freely and unambiguously and check the authorization of the code information.

The evaluation of the received response signals 7 can then begin when theoretically the last response signal 6 with the latest transmission time should have been received. The evaluation can also be started after receiving the first response signal 7 . All further received response signals 7 are then evaluated one after the other in accordance with a predetermined key priority. A release signal for unlocking the doors or releasing the immobilizer can be triggered after the first code information recognized as being authorized.

Individual settings can also be made using the key numbers (adjust seats, mirrors or similar adjustment devices to the appropriate person). If several code transmitters 1 are recognized as authorized, further settings can also be made for the front passenger, should it also be known which code transmitter 1 approaches the motor vehicle from which side (this can be due to the location of the receiving antenna or the reception strengths of the respective one Antennas 4 are determined).

For the initialization of the code generator 1, all the code generator 1, in a detection region 5 also be arranged in the motor vehicle outside the motor vehicle or the like. The detection area 5 is only a few meters, so that more distant co degeber 1 are not initialized.

The signals (query signal 6 , response signal 6 , delete signal, marking signal) are usually transmitted wirelessly (optically, acoustically or by radio) between the motor vehicle and the code transmitter 1 .

To the theft protection system in the initialization state An external diagnostic device can be used, for example in an authorized workshop to the vehicle be closed. With a separate start signal ver theft protection system in the initialization state puts.

This start signal can only be received from the Diag, for example be sent out if proof, as with for example the vehicle registration document and a chassis number is entered to match the vehicle. An introduction initialization can also be triggered by data, from a central database of the vehicle manufacturer Proof of authorization (such as PIN number) is requested the. Provision can also be made for data to be sent to the Di device or the motor vehicle must be communicated, that come from the database of the vehicle manufacturer. Consequently  abuse and initialization by strangers is largely prevented.

To initiate the initialization can also be an unusual one Operating controls can be used. To do this However, access to motor vehicles may be necessary is already legitimately open and also the way is locked. Such an unusual activity is said to clearly differed from the usual ones for using the power Actuations used in the vehicle differ and should be known only to the legitimate user. Such For example, actuation could be a multiple actuation the ignition switch within a very short time.

The term "code transmitter" is to be understood as an electronic unit which is arranged on a handle of a conventional mechanical door or ignition key. Data is stored in the electronic unit. The code transmitter 1 can both receive data and send it out. The code transmitter 1 can also be in the form of a credit card o which is arranged in other suitable, small portable housings.

The term “control and evaluation unit” is to be understood as a central control device which is connected to a transmitting and receiving unit and its antennas 4 . On the antennas 4 signals are sent and received. The signals are modulated or demodulated in the control and evaluation unit 3 and the received signals are checked for their justification by comparison with expected and stored data. The antennas 4 are usually arranged vertically on the outside and inside of the motor vehicle, so that signals can be sent to the entire outside space in the immediate vicinity of the motor vehicle and to the interior including the trunk of the motor vehicle.

The transmitter and receiver can also be arranged separately from one another in the motor vehicle and outside the control and evaluation unit 3 . Each antenna can also have its own control and evaluation unit.

The term “initialization” is to be understood as a first-time or, if necessary, repeated storage of data both in the code transmitters 1 and in the control and evaluation unit 3 . Only if the data of the code transmitter 1 and the data of the control and evaluation unit 3 , which are witness to each motor vehicle and possibly individual for each user, match, can access to the motor vehicle and the use of the motor vehicle be released.

All signals are coded signals that transmit modulated become. If the signals are binary coded, then security is from misuse or unauthorized access or use of the Motor vehicle the larger, the larger the bit length of the Sig nale is. Security is greatest when the signals are with Generated and transmitted with the help of crypto algorithms.

Each code transmitter 1 contains its own characteristic characteristic (code information), which differs from the code information of other code transmitters 1 . Only code transmitter 1 , all of which are assigned to a motor vehicle, can have the same code information (possibly with a different key number). Typically, the chassis number of the motor vehicle can be used to generate the code information. Entering PIN numbers can also be used to create the code information. As a rule, these random methods then also obtain different code information for the code transmitter 1 , so that they differ significantly from other code transmitters 1 .

Due to the different transmission times, the code transmitter 1 is clearly recognized and the initialization can be carried out at any time directly at the customer with universal code transmitter 1 .

Claims (6)

1. Method for initializing an anti-theft system for a motor vehicle, which has
a transmission and reception unit ( 3 , 4 ) arranged in the motor vehicle, which is electrically connected to at least one antenna ( 4 ) arranged in or on the motor vehicle, via which an interrogation signal ( 6 ) is respectively transmitted,
a portable code transmitter (1) which emits a response signal (6) when it has received the interrogation signal (6) above, wherein in the response signal (6) a code information is contained for the detection of an authorization, and
a motor vehicle control and evaluation unit ( 3 ) which is connected to the transmitting and receiving unit ( 3 , 4 ) and which evaluates the received response signal ( 6 ),
characterized by the following steps:

• - bringing the theft protection system into an initialization state,
• - sending out an interrogation signal ( 6 ),
• - generating a random number on each code transmitter ( 1 ) which receives the query signal ( 6 ), a transmission time which is characteristic of the respective code transmitter ( 1 ) being determined as a function of the random number,
• - Sending a response signal ( 6 ) within the transmission time and
• - Evaluation of the response signal ( 6 ) in the evaluation unit.

2. The method according to claim 1, characterized in that a code information contained in the response signal ( 6 ) is stored as reference code information for the respective code transmitter ( 1 ) in the control and evaluation unit ( 3 ) during the initialization state. 3. The method according to any one of the preceding claims, characterized in that a further interrogation signal ( 6 ) for the new, random setting of transmission times is transmitted if at least two response signals ( 7 ) were previously received approximately at the same time, all code transmitters ( 1 ) being previously , whose transmission time is set correctly, are marked as such by a transmission signal from the transmitting and receiving unit ( 3 , 4 ) and only the unmarked code transmitter ( 1 ) react to the further interrogation signal ( 6 ). 4. The method according to any one of the preceding claims, characterized in that before the first interrogation signal ( 6 ) a delete signal is sent out by all available transmission times of the code transmitter ( 1 ) are deleted. 5. The method according to any one of the preceding claims, characterized in that each response signal ( 6 ) contains an identifier characteristic of the respective code transmitter ( 1 ), by means of which the control and evaluation unit ( 3 ) identifies the respective code transmitter ( 1 ) , 6. The method according to any one of the preceding claims, characterized characterized that the initialization state only at Proof of authorization is taken.