Motor vehicle with a satellite-based navigation device for position determination and with an anti-theft device

0001The invention relates to a motor vehicle with the features of the preamble of patent claim 1.

0002It is known to provide both a satellite-based navigation device and an anti-theft device (ADE) in a motor vehicle. It is also known to transmit a radio signal when the ADE responds, which allows a conclusion to be drawn about the current position of the motor vehicle. In this way it should be possible to find the motor vehicle again. The navigation device therefore only has the intended function within the framework of the ADE, to provide information about the current position of the motor vehicle. The ADE must be addressed before theft can be recognized. This is not guaranteed with a relatively common form of theft. This is the case of the unauthorized relocation, for example by towing or moving the motor vehicle after charging beforehand.

0003The invention has for its object to provide a motor vehicle of the type mentioned, in which the ADE also addresses the particular form of theft mentioned.

0004The invention solves this problem by the characterizing features of patent claim 1.

0005In addition to its intended use, the navigation device now serves to provide comparison data for the ADE. If these data do not match, it inevitably results from the fact that the motor vehicle was brought from the place it was in when the motor vehicle was parked. The position of the motor vehicle can be determined with sufficient accuracy with the aid of the navigation device. Already a change of the location by a few meters results in a difference in the position data, which can be easily determined with the ADE and which allow the ADE to take the measures provided in the event of theft. These include acoustic or visual warning messages which are triggered by the motor vehicle and which are immediately recognizable to outsiders. A silent alarm can also be triggered by sending a radio signal or a telephone message. It is also possible to have an ADE that works with or is identical to an electronic immobilizer to maintain the electronic immobilizer.

0006Within the scope of the invention there are many possible applications. On the one hand, it is about the possibility of determining possible changes in the position of the motor vehicle. To do this, it is possible to determine the current position several times in succession. This chronological sequence can, for example, be at a regular interval or also dependent on external or internal conditions. For example, the frequency with which the current position is determined may be higher at night, corresponding to the greater theft probability. For example, there is also a higher theft probability if the motor vehicle is a convertible vehicle that is parked openly. The vehicle user himself can also increase the sampling frequency for the position determination, for example with the aid of a switch. He will do this, for example, if he is forced to park the vehicle unlocked and he suspects that the theft is more likely. In such a case, the frequency of the position determination can of course also be increased automatically.

0007It may be sufficient or else be provided to determine the current position when the motor vehicle is started up again. As a rule, this is the last possible time for this determination. This measure in itself is characterized by low energy consumption.

0008Another aspect of the invention is concerned with the improvement of the ADE itself. In this way, the path is chosen to limit the utility of the possibly stolen motor vehicle for the unauthorized user. Generally, these measures consist in switching off user-relevant functions. First and foremost is the high-quality and expensive navigation device itself, which is switched off when the ADE responds. In addition to the loss of comfort, there is a danger for the unauthorized user to be recognized, since the lack of functionality of the navigation device for the unauthorized user entails the danger on the latter <img file="EP0758738A2_D0001.tif" />Defect "to be addressed and to suspect theft.

0009In the event of a relocation of the motor vehicle caused by the legitimate user, for example by a car train, the positional deviation would be recognized when restarting. However, since the user is identified as authorized, for example by activating the electronic immobilizer, the ADE does not respond.

0010This results in an expansion of known anti-theft devices, since the navigation device triggers the anti-theft device and at the same time can provide an indication of theft.