Method for monitoring a parameter of a tire of a vehicle

Abstract

The present invention discloses a method for monitoring a parameter of a tire of a vehicle using a wheel unit assigned to the tire, wherein the wheel unit comprises a sensor device for detecting a phy

Description

The invention relates to a method for monitoring a parameter of a tire of a vehicle using a wheel unit assigned to the tire, wherein the wheel unit comprises a sensor device for detecting a physical variable of the tire, and wherein the wheel unit generates a data packet and transmits the data packet wirelessly to a processing device of the vehicle. The invention further relates to a wheel unit for a tire parameter monitoring system of a vehicle for monitoring a parameter of a tire of the vehicle, and further relates to a corresponding tire parameter monitoring system. Nowadays, vehicles comprise a vast number of monitoring and information systems that monitor the condition of the motor vehicle and individual motor vehicle components and, for example, provide a driver of the motor vehicle with information about the motor vehicle. Some of these systems serve merely for information purposes, for example for the driver, but sometimes they also serve for warning purposes. One of these systems is a tire parameter monitoring system or tire pressure monitoring system (TPMS) which typically comprises a wheel unit arranged in or at the wheels of the motor vehicle, in particular in or at the tires or the rims of the wheels, which particularly measures or detects one or more current physical variables such as temperature, acceleration and pressure, for example an internal air pressure of the corresponding tire, i.e. a corresponding tire pressure, by means of respective sensor devices of the wheel unit, such as a temperature sensor, a acceleration sensor and a pressure sensor arranged in the wheel unit. The detected physical variable data or an information on the detected physical variables, together with other relevant information such as an identifier characteristic of the wheel unit, a battery status of a battery of the wheel unit and an operating status of the assigned wheel, are transmitted wirelessly, for example by means of high-band frequencies (typically 315 MHz or 433 MHz or 2.4 GHz), via a data packet from the wheel unit to a processing device or a so-called receiver of the tire parameter monitoring system and is then evaluated by the processing device. For example, if an evaluation indicates that the tire pressure is below a predetermined threshold, a warning signal is triggered. Typically, today’s tire parameter monitoring systems are exposed to security threat due to lack of security in communication and data transmission between the wheel units and the processing device. In these systems, typically unencrypted data or data packets are sent from the wheel units to the processing device. There is therefore a need for a new generation of wheel units which use data encryption to remove or reduce security vulnerability. However, most of today's tire parameter monitoring systems still use a processing device which cannot process encrypted data, so no backward compatibility can be provided for such a new generation of wheel units. It is therefore an object of the present invention to provide an improved method for monitoring a parameter of a tire of a vehicle using a wheel unit assigned to the tire and a corresponding wheel unit and a corresponding tire parameter monitoring system which enables a reliable and secure and at the same time cost-effective monitoring of the parameter, in particular a backward compatibility, wherein also a current or existing processing device of a vehicle which cannot process encrypted data can still or nevertheless be used for the monitoring, even when an encrypted data transmission is used, i.e. even when a wheel unit is used that use data encryption, without having to replace this processing unit or make any amendments to the processing unit. The foregoing object is solved by the entire teaching of claim 1 and claims 8 and 9. Further embodiments and advantageous further developments of the present invention are indicated in the dependent claims and the description below. According to one aspect of the invention, a method for monitoring a parameter of a tire of a vehicle using a wheel unit assigned to the tire is provided, wherein the wheel unit comprises a sensor device for detecting a physical variable of the tire, wherein the wheel unit generates a data packet and transmits the data packet wirelessly to a processing device of the vehicle, wherein the data packet comprises an, in particular predetermined, unencrypted data set which comprises information on the detected physical variable, and an encrypted authentication identifier arranged after the unencrypted data set for authentication of the data set towards the processing device. A core idea here is, without affecting or altering the (unencrypted) data set, to add an additional data or information, namely an encrypted authentication identifier, after the data set. In this way, a method is provided which in particular has an anti-spoofing mechanism and also a backward compatibility, wherein a processing device of a vehicle, particularly of a tire parameter monitoring system of the vehicle, can always a reliably used for the monitoring the parameter, regardless of using unencrypted or encrypted data transmission, i.e. regardless of whether or not wheel units are used that use data encryption. Thus, in accordance with the present invention, an improved method for monitoring a parameter of a tire of a vehicle using a wheel unit assigned to the tire is provided which enables a reliable and secure and at the same time cost-effective monitoring of the parameter, in particular a backward compatibility, wherein also a current or existing processing device of a vehicle which cannot process encrypted data can still or nevertheless be used for the monitoring, even when an encrypted data transmission is used, i.e. even when a wheel unit is used that use data encryption. Advantageously, the physical variable is a pressure, in particular an internal air pressure of the tire, or an acceleration, in particular a radial acceleration of the tire or the wheel unit, or a temperature, in particular an internal air temperature of the tire or a temperature of the tire. In particular, the parameter of the tire can directly be the detected physical variable of the tire, i.e. the physical variable can directly represent the parameter of the tire or the physical variable can be identical to the parameter of the tire. However, the parameter of the tire can also be, in particular, a parameter determined on the basis of the detected physical variable, for example a tread depth of a tire profile or a mileage of the tire, so the parameter can be or have been determined on the basis of the physical variable. The information on the detected physical variable can, for example, be designed as a measured value of the detected physical variable. The wheel unit is arranged in particular on the wheel of the tire of the vehicle, and can advantageously be arranged, preferably fixed, on a rim of the wheel or on the tire. Advantageously, the wheel unit also comprises a radio or wireless interface, in particular designed as a transmitting and receiving unit, which transmits or sends the data packet to the processing device, and / or a control and data processing unit, which is preferably designed to control the sensor device and at least to preprocess the sensor data of the sensor device, and which in particular comprises a microprocessor or microcontroller. The wheel unit generates both the unencrypted data set and the encrypted authentication identifier as a common data packet, wherein the encrypted authentication identifier is added, in particular directly, after the unencrypted data set within the data packet, in particular, the authentication identifier is arranged or located at the end of the data packet. Advantageously, for generating the encrypted authentication identifier a cryptological method is used. Preferably, the generation of the encrypted authentication identifier can also be deactivated, for example by an external programming or handheld device. Preferably, the data packet is designed as a data telegram. The processing device is advantageously designed as an electronic control unit (ECU). For example, the processing device may be permanently and solely assigned to the tire parameter monitoring system as a separate electronic control unit, in particular a stand-alone electronic control unit, or it may be part of another electronic control unit of the vehicle, such as a body control unit. Advantageously, the processing device is configured to process the received data packet, preferably wherein the received data packet is evaluated as part of the processing, an wherein the information on the detected physical variable is evaluated as part of the evaluation, for example the information on the detected physical variable is compared with a predetermined threshold, ora value of the parameter of the tire first is determined based on the information on the detected physical variable and then the determined value of the parameter is compared with a predetermined threshold. According to an advantageous embodiment, the unencrypted data set comprises a, in particular predetermined and / or fixed, number of sections for information, and wherein the encrypted authentication identifier is arranged, in particular directly, after the last section of the unencrypted data set. Thereby, the information on the detected physical variable is provided or included in one of the sections. According to a further advantageous embodiment, the authentication serves to verify or prove an origin of the unencrypted data set. In particular, the authentication serves to verify or prove whether or that the data set originates from the wheel unit. According to a further advantageous embodiment, the processing device is not designed to verify or check the authenticity of the unencrypted data set by means of the encrypted authentication identifier, and wherein the processing device receives the data packet transmitted by the wheel unit and evaluates the unencrypted data set. Since, despite the encryption of the data package, the data set remains unaltered and, above all, unencrypted, the data set can (still) be used, particularly processed and evaluated, by such a processing device. According to a further advantageous embodiment, the processing device is designed to verify or check the authenticity of the unencrypted data set using the encrypted authentication identifier, wherein the processing device receives the data packet transmitted by the wheel unit and performs a check or verification of the authenticity of the received unencrypted data set (2) using the encrypted authentication identifier, and wherein the processing device evaluates the unencrypted data set only after a successful authentication, i.e. if the processing device authenticates the data set. As a result of verifying or checking the authenticity of the received unencrypted data set, the data set is thus either evaluated or not evaluated, wherein the data set is evaluated if the processing device authenticates the data set, and wherein the data set is not evaluated, in particular discarded without evaluation, if the processing device does not authenticate the data set. A processing device which is designed to verify or check the authenticity of the unencrypted data set using the encrypted authentication identifier can therefore verify or check the encrypted authentication identifier thereby increasing security of the method or of a respective tire parameter monitoring system. As part of verifying or checking the authenticity of the data set, for example, the authentication identifier of the received data packet is compared with a reference authentication identifier stored or generated in the processing device. According to a further advantageous embodiment, the encrypted authentication identifier is designed as a digital signature. Thus, the encrypted authentication identifier is designed or configured as a digital signature for authentication of the data set. According to a further advantageous embodiment, the unencrypted data set further comprises an identifier characteristic of the wheel unit, a localization information and / or a checksum for integrity protection of the unencrypted data set. The identifier characteristic of the wheel unit can be designed in particular as a fixed ID or individual identification number. The localization information can in particular indicate a tire position of the tire assigned to the wheel unit or a position of the wheel unit in relation to the vehicle body, for example front-left, front-right, rear-left or rear-right. In an advantageous embodiment, in which the unencrypted data set comprises a number, in particular a predetermined and / or fixed number, of sections for information, wherein the encrypted authentication identifier is arranged after the last section of the unencrypted data set, and wherein the unencrypted data set also contains an identifier characteristic of the wheel unit, localization information and a checksum for integrity protection of the unencrypted data set, the information on the detected physical variable is contained in one of the sections and the identifier characteristic of the wheel unit, the localization information and the checksum are contained in respective sections. According to another aspect of the invention, a wheel unit for a tire parameter monitoring system for monitoring a parameter of a tire of a vehicle is provided, wherein the wheel unit comprises a sensor device for detecting a physical variable of an assigned tire of the vehicle, wherein the wheel unit is configured to generate a data packet and to transmit the data packet wirelessly to a processing device of the tire parameter monitoring system, an wherein the data packet comprises an, in particular predetermined, unencrypted data set which comprises information on the detected physical variable, and an encrypted authentication identifier arranged after the unencrypted data set for authentication of the data set towards the processing device. The advantages and the specific and preferred embodiments described for the method according to the invention also apply accordingly to the wheel unit according to the invention. According to another aspect of the invention, a tire parameter monitoring system for a vehicle for monitoring a parameter of a tire of the vehicle is provided, which comprises a wheel unit assigned to the tire and a processing device, wherein the wheel unit comprises a sensor device for detecting a physical variable of the tire, wherein the wheel unit is configured to generate a data packet and to transmit the data packet wirelessly to the processing device, and wherein the data packet comprises an, in particular predetermined, unencrypted data set which comprises information on the detected physical variable, and an encrypted authentication identifier arranged after the unencrypted data set for authentication of the data set towards the processing device. The advantages and the specific and preferred embodiments described for the method according to the invention also apply accordingly to the tire parameter monitoring system according to the invention. The drawings described herein are used to provide a further understanding for the present invention, and constitute a part of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation to the present invention. In the drawings the only FIG. shows a data packet 1 generated by a wheel unit of a tire parameter monitoring system according to a preferred embodiment of the invention. The data packet 1 comprises an unencrypted data set 2, wherein the unencrypted data set 2 comprises a predetermined number of sections 2a, 2b, ..., 2n for (unencrypted) information. Thereby, for example, the first section 2a of the data set 2 contains an ID of the wheel unit, the second section 2b of the data set 2 contains a localization information regarding the wheel unit, the third section 2c of the data set 2 contains information on a detected first physical variable, e.g. a tire pressure, the fourth section 2d of the data set 2 contains information on a detected second physical variable, e.g. a tire temperature, the fifth section 2e of the data set 2 contains information on a detected third physical variable, e.g. a radial acceleration, and the last section 2n of the data set 2 contains a checksum for integrity protection of the unencrypted data set 2. The data packet 1 also comprises an encrypted authentication identifier 3, designed as a digital signature, for authentication of the data set 2 towards a processing device of the tire parameter monitoring system, wherein the encrypted authentication identifier 3 is, without effecting or altering the (unencrypted) data set 2, added or arranged after the last section 2n of the unencrypted data set 2.

Claims

claims1. Method for monitoring a parameter of a tire of a vehicle using a wheel unit assigned to the tire, wherein the wheel unit comprises a sensor device for detecting 5 a physical variable of the tire, wherein the wheel unit generates a data packet (1) and transmits the data packet (1) wirelessly to a processing device of the vehicle, wherein the data packet (1) comprises an unencrypted data set (2) which comprises information on the detected physical variable, and an encrypted authentication identifier (3) arranged after the unencrypted data set (2) for authentication of the 10 data set towards the processing device, wherein the processing device is notdesigned to verify or check the authenticity of the unencrypted data set (2) by means of the encrypted authentication identifier (3), and wherein the processing device receives the data packet (1) transmitted by the wheel unit and evaluates the unencrypted data set (2).

152. Method according to claim 1, wherein the unencrypted data set (2) comprises a, in particular predetermined and / or fixed, number of sections (2a, 2b,..., 2n)for information, and wherein the encrypted authentication identifier (3) is arranged after the last section (2n) of the unencrypted data set (2).

203. Method according to one of claims 1 to 2, wherein the authentication serves to verify or prove an origin of the unencrypted data set (2).

4. Method according to one of the preceding claims, wherein the processing device 25 is designed to verify or check the authenticity of the unencrypted data set (2) using the encrypted authentication identifier (3), wherein the processing device receives the data packet (1) transmitted by the wheel unit and performs a check or verification of the authenticity of the received unencrypted data set (2) using the encrypted authentication identifier (3), and wherein the processing device30 evaluates the unencrypted data set (2) only after a successful authentication.28 08 255. Method according to one of the preceding claims, wherein the encrypted authentication identifier (3) is designed as a digital signature.

6. Method according to one of the preceding claims, wherein the unencrypted data 5 set (2) further comprises an identifier characteristic of the wheel unit, localization information and / or a checksum for integrity protection of the unencrypted data set.

7. Wheel unit for a tire parameter monitoring system for monitoring a parameter of a tire of a vehicle, wherein the wheel unit comprises a sensor device for detecting a10 physical variable of an assigned tire of the vehicle, wherein the wheel unit is configured to generate a data packet (1) and to transmit the data packet (1) wirelessly to a processing device of the tire parameter monitoring system, an wherein the data packet (1) comprises an unencrypted data set (2) which comprises information on the detected physical variable, and an encrypted authentication15 identifier (3) arranged after the unencrypted data set (2) for authentication of the data set (2) towards the processing device, wherein the processing device is not designed to verify or check the authenticity of the unencrypted data set (2) by means of the encrypted authentication identifier (3), and wherein the processing device is configured to receive the data packet (1) transmitted by the wheel unit and to20 evaluate the unencrypted data set (2).

8. Tire parameter monitoring system for a vehicle for monitoring a parameter of a tire of the vehicle, which comprises a wheel unit assigned to the tire and a processing device, wherein the wheel unit comprises a sensor device for detecting a physical25 variable of the tire, wherein the wheel unit is configured to generate a data packet (1) and to transmit the data packet (1) wirelessly to the processing device, and wherein the data packet (1) comprises an unencrypted data set (2) which comprises information on the detected physical variable, and an encrypted authentication identifier (3) arranged after the unencrypted data set (2) for authentication of the30 data set (2) towards the processing device, wherein the processing device is not designed to verify or check the authenticity of the unencrypted data set (2) by means of the encrypted authentication identifier (3), and wherein the processing device isconfigured to receive the data packet (1) transmitted by the wheel unit and to evaluate the unencrypted data set (2).28 08 25s

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