DE10112573C2 - Method for initializing an anti-theft system for a motor vehicle - Google Patents

Description

The invention relates to a method for initializing a Theft prevention system for a motor vehicle, it relates For example, a method for initializing a path immobilizer or an access control device for a Motor vehicle.

In a known method for initializing a thief Stahlschutzsystems (DE 197 21 286 C1) is the Initialisie for the first time at the end of the vehicle carried out. For this purpose, the anti-theft system in a Initialization brought and then encoding data both in a control unit in the vehicle and in all assigned to the motor vehicle, portable code transmitter stores. When the anti-theft system is initialized, can use the encoders to access and access permissions Use of the motor vehicle can be detected.

If this procedure is applied, then the force vehicle assigned encoder at the end of the tape when vehicle be present physically and be after the initia tion together with the motor vehicle to the wholesale and Sent to retailers. It must be paid attention to that the encoders and motor vehicle always stay together and that the encoders do not use encoders that are driving to others witnesses fit, be reversed.

There is also the danger that during the process simultaneous teach-in (initialize) multiple encoders and possibly confirming the coding done by the Code encoders signal overlays take place, so the signals not be received properly and no clear to order.  

In another known method for initializing ei Anti-theft system for a motor vehicle (DE 197 37 874 C1) is caused by unusual pressing of a key in the Ignition lock the anti-theft system in the initialisie condition. About an immobilizer then finds a bidirectional dialogue with the key instead. If the Dialog is recognized as entitled, he becomes a random number testifies that defines a starting value. This starting value is from the immobilizer via the key to the receiver of the Transfer locking system. This start value is only to generate a switch code and thus to compare used reference codes.

The invention is based on the problem, a method for Initializing an anti-theft system to create with the each assigned to the motor vehicle encoder unique can be initialized. Initial initialization can be during Vehicle manufacturers done, but can also directly at Kun to be possible.

This problem is inventively by a method the features of claim 1 solved. This is the Anti-theft system first in a Initialisierungszu stood spent. If this condition is taken, then sent out an interrogation signal, on which every code transmitter, receiving the interrogation signal generates a random number. With this random number will then charak one for each coder teristic airtime, within which each codege Returned via his response signal and thus the I completed confirmation of the code transmitter and this to the control device in the vehicle can communicate. This process is repeatable until all encoders are recognized and initialized are.

Be flat in later operation of the theft protection system if different transmission times used, it will never  happen that two encoders simultaneously their response signal send out if they both received an interrogation signal. By randomly generated, unterschiedli In the case of sending times, the encoders send their response signal different times.

Advantageous embodiments of the invention are characterized by the Subclaims reproduced.

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

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

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

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

If the user seeks access to his motor vehicle, he can pull the door handle 2 or actuate a switch near the door handle 2 , whereby a control and evaluation unit 3 is caused to send an interrogation signal 6 vehicle side via antennas 4 in the vehicle becomes. If the code transmitter 1 receives the interrogation signal 6 , it sends a coded response signal 7 wirelessly back to a receiver in the motor vehicle. The receiver is formed by the On to 4 together with the central control and Auswerteein unit 3 .

In the control and evaluation unit 3 , the received Ant word signal 7 is demodulated and the Codeeinfor information contained therein evaluated, ie checked for his authorization over. For this purpose, the code information is compared with an expected and stored reference code information (also referred to as coded data).

Each motor vehicle usually has a plurality of keys or encoders 1 assigned. In order for the code transmitter 1 and the control and evaluation unit 3 to be able to "understand" and communicate with each other, the code transmitters 1 must be trained or initialized on the anti-theft system. By an initialization Codierdaten both in the control and off value unit 3 and in the encoder 1 are mutually matched and stored from the outside not readable.

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

The initialization need not be carried out at the vehicle manufacturer, but can be done when selling the vehicle to the end customer. For this purpose, there are not yet individualized universal encoders 1 as "bulk material". As many encoders 1 , as the motor vehicle to be assigned, ge brought into the vicinity or in the motor vehicle. When the encoders 1 are in a detection area 5 , the initialization can be started.

The detection area 5 is defined so that inside half of the detection area 5 signals between the code generator 1 and motor vehicle safely with a sufficiently large power ü can be transmitted. Since the signals for security green the (security against unauthorized tapping of the signals) ei ne relatively small range, the Erffassungsbe rich 5 can be kept small.

In a first exemplary embodiment ( FIG. 2), it should be assumed that none of the present code transmitters 1 has yet been initialized. Are now these codes 1 , which are to be assigned to the driving convincing within the Erffassungsbe range 5 and the theft protection system is already in the initialization state, a Queryig signal 6 is first transmitted via the antennas 4 . The first interrogation signal 4 is designated in Figs. 2 and 3 as a "broadcast message" to which each of the general purpose encoders can respond.

Each code transmitter 1 , which has received an interrogation signal 6 , he testifies for a transmission time (also referred to as time slot or as a time window) according to a random principle. The transmission time represents a start time and a time duration within which the respective code transmitter 1 sends its response signal 7 .

The duration of the transmission time is in each case determined such that within the transmission time, the complete response signal 7 can be sent out safely. The time start (start time) of the transmission time depends on the time of the received interrogation signal. 6 Depending on the random number from the receipt of the interrogation signal 6, a delay time is determined, after the expiration of the respective transmission time of the code generator 1 starts.

If a high-diversity random algorithm (ie, a relatively large pseudorandom sequence) is used, it is very unlikely that two encoders 1 will have the same random number and hence the same transmission time, since the transmission time will be determined from the random number. However, any number of random numbers may not be allowed, so that in normal operation, the total duration between transmission of the interrogation signal 6 and waiting for the last response signal 7 is not too large.

When the transmission time is randomly generated, each encoder 1 transmits a response signal 7 during the designated transmission time (referred to as an answer message in Figs. 2 and 3). In the control and evaluation unit 3 of the motor vehicle then all received Antwortsig signals 7 are evaluated. In the control and evaluation unit 3 is also checked whether all encoders 1 have actually sent to un ferent times. This is example, based on clearly present response signals 7 be made.

If not all response signals 7 unambiguously received, so again an interrogation signal 6 is sent out, so that the personigen code transmitter 1 with the same transmission time different transmission times can be assigned.

Can all code transmitter 1 are clearly distinguished with their response signals 7 , ie all response signals 7 were received at different times (thus have the code 1 because of the small distance to the motor vehicle and thus the very small signal delay also all different transmission times), so in The code information contained in the response signals 7 stored as coding data in the control and evaluation unit 3 . Thus, then all the code transmitter 1 and the control and evaluation unit 3 are trained or initialized.

It can be provided that all code encoders 1 work with the sliding code information or each code generator 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 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 sent out its response signal 7 , should not be too large, so that the user does not have to wait too long in normal operation until he has authenticated with the help of its encoder 1 .

In a second exemplary embodiment ( FIG. 3), it can be provided that all transmission times of all code transmitters 1 which are located 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 vehicle transmission of an erase signal or marker signal.

All encoders 1 that receive the clear signal and thus do not have the mark delete the current airtime. Subsequently, an interrogation signal 6 is sent from the motor vehicle, whereby in each code transmitter 1 , which receives the interrogation signal 6 and which is not marked, again a transmission time is generated at random.

All encoders 1 whose transmission time has been determined in this way and are therefore not marked, now send their Ant word signal 7 during the predetermined transmission time back to the motor vehicle. In the control and evaluation unit 3 , all received response signals 7 are evaluated.

If not all code encoders 1 can be distinguished, since their response signals 7 are for example partly superimposed and therefore not "readable", the control and evaluation unit 3 sends a marking signal to all those Co encoders 1 from which a valid response signal 7 has been received ,

So that the correct code transmitter 1 is addressed, key numbers can be used as addresses that are assigned to each code transmitter 1 . Both in Querstagesig signal 6 and in the response signal 7 , the individual key number may be included.

Subsequently, an interrogation signal 6 is sent out again. If the unmarked encoders 1 receive the interrogation signal 6 , they again generate a random transmission time and send out their response signal 7 within this transmission time. Thus, all encoders 1 whose transmission times previously overlapped with those of other encoders 1 , provided with a new Sen dezeit.

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

If all response signals 7 of the encoder 1 can be clearly distinguished, the response signals 7 are accepted and corresponding coding data is stored in the control and evaluation unit. The anti-theft system is now initialized. Thus, the control and evaluation unit 3 knows all the coding data of all encoders 1 and can then determine the presence of the code generator 1 by comparing the received Co deinformation with this encoding data a present authorization.

The encoders 1 maintain their transmission times until the antitheft system is reinitialized (this is also referred to as reinitialization). Thus, the encoders 1 always send at different transmission times, even in the later normal operation of the anti-theft system. If then, for example, driver and passenger each carry a motor vehicle associated code transmitter 1 with you, then sends everyone who receives an interrogation signal 6 after triggering, his response signal 7 within the respective transmission time back. The evaluation unit can now receive both response signals 7 unambiguously free and unambiguous and check the code information for their authorization.

The evaluation of the received response signals 7 can then be started if, theoretically, the last response signal 7 with the most recent transmission time should have been received. The evaluation can also be started after receiving the first response signal 7 . All other received response signals 7 are then evaluated sequentially o according to a predetermined key priority. A release signal to unlock the doors or Lö sen the immobilizer can be triggered after the first, as justifiable recognized code information.

It can also be personalized settings based on the key numbers are made (seats, mirrors or similar Liche adjustment to the appropriate person a set). If several encoders 1 recognized as authorized, so also other settings for the passenger can be accepted, if in addition it should be known which encoder 1 is approaching from which side of the motor vehicle (this may be due to the location of the receiving antenna or reception strengths of the respective 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 range 5 is only a few meters, so that remote co-encoders 1 are not initialized.

The signals (interrogation signal 6 , response signal 7 , clear signal, marker signal) are usually transmitted wirelessly (optically, acoustically or by radio) between the motor vehicle and the code transmitter 1 .

To put the anti-theft system in the initialization state for example, an external diagnostic device in an authorized workshop to the motor vehicle be closed. By a separate start signal is then  the anti-theft system in the initialization ver puts.

This start signal, for example, only from the Diag If there is proof, as with For example, the vehicle registration document, is present and a chassis number corresponding to the vehicle is entered. An introduction initialization can also be triggered by data from a central database of the vehicle manufacturer Proof of authorization (such as PIN number) requested who the. It can also be provided that first data to the Di must be communicated to the motor vehicle or the motor vehicle, from the database of the vehicle manufacturer. Thus Abuse and initialization by strangers becomes widespread prevented.

To initiate the initialization can also be an unusual Operation of controls are used. For this purpose should te be necessary, however, that access to the motor already legitimately open and also the way lock is released. Such an unusual activity should was clearly different from the usual, to use the force differ and should be used be known only to the rightful user. Such Actuation could for example be a multiple operation of the ignition switch within a very short time.

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

The term "control and evaluation" is a Zent ralsteuergerät to understand, which is connected to a transmitting and Emp catching unit and the antennas 4 . The antennas 4 are used to send out and receive signals. In the control and evaluation unit 3 , the signals are modulated or demodulated and the received signals are checked for their entitlement by comparison with expected and stored data. The antennas 4 are usually ver shares on the motor vehicle outside and inside, so that signals in the entire outdoor space in the immediate environment of the motor vehicle and in the interior including Kof ferraum of the motor vehicle can be sent.

Transmitter and receiver can also be arranged separately in the motor vehicle and outside the control and evaluation unit 3 . It can also be arranged downstream of each antenna own control and evaluation unit.

The term "initialization" is understood to mean a first or repeated storage of data in both the encoders 1 and in the control and evaluation unit 3 if necessary. Only if the data of the code transmitter 1 and the data of the control and evaluation unit 3 , the convincing for each motor and possibly individual for each user, match, access to the motor vehicle and the Benut tion of the motor vehicle can be released.

All signals are coded signals that are transmitted modulated become. If the signals are binary coded, that is the security against misuse or unauthorized access or use of the Motor vehicle, the larger, the greater the bit length of the Sig is nale. Safety is greatest when using the signals Help from crypto algorithms are generated and transmitted.

Each encoder 1 contains its own characteristic identifier (code information) which is different from the code information of other encoders 1 . Only code transmitter 1 , which are all assigned to a motor vehicle, may have the same code information (optionally with different key number). Typically, the driving frame number of the motor vehicle may serve to generate the code information. Likewise, inputs of PIN numbers can serve for the creation of the code information. As a result of these random methods, different code information for the code transmitters 1 is then generally obtained, so that they differ significantly from other code generators 1 .

Due to the different transmission times, the encoders 1 are clearly identified and the initialization can be done with Univer sal-encoders 1 directly at the customer at any time.

Claims (6)

A method of initializing an anti-theft system for a motor vehicle having
a arranged in the motor vehicle transmitting and receiving unit ( 3 , 4 ) which is electrically connected to at least one in or on the vehicle power antenna ( 4 ) via which in each case an interrogation signal ( 6 ) is emitted,
a portable code transmitter ( 1 ) which transmits a response signal ( 7 ) when it has previously received the interrogation signal ( 6 ), wherein in the response signal ( 7 ) code information for proving a permission is included, and
a motor vehicle-side control and evaluation unit ( 3 ), which is connected to the transmitting and receiving unit ( 3 , 4 ) and which evaluates the received response signal ( 7 ),
characterized by the following steps:

• Bringing the anti-theft system into an initialization state,
• Sending an interrogation signal ( 6 ),
• Generating a random number on each code transmitter ( 1 ) which receives the interrogation signal ( 6 ), a transmission time characteristic of the respective code transmitter ( 1 ) being determined as a function of the random number,
• - Sending a response signal ( 7 ) within the transmission time and
• - Evaluating the response signal ( 7 ) in the evaluation unit.

2. Method according to claim 1, characterized in that a code information contained in the response signal ( 7 ) 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 he neuten, random setting of transmission times is sent, if previously at least two response signals ( 7 ) were received at about the same time, with all code transmitter ( 1 ) whose airtime is set properly, as such by a from the transmitting and receiving unit ( 3 , 4 ) emitted mark signal are marked and only the non-markier th code transmitter ( 1 ) to the further interrogation signal ( 6 ) responsi ren. 4. The method according to any one of the preceding claims, characterized in that before the first interrogation signal ( 6 ) an erase signal is sent, by all existing transmission times of the code transmitter ( 1 ) are deleted. 5. The method according to any one of the preceding claims, characterized in that in each response signal ( 7 ) for each code transmitter ( 1 ) characteristic identifier is contained, based on 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 in that the initialization state only at Proof of entitlement is taken.