Authorization to use a motor vehicle

Abstract

A method for authorizing the use of a motor vehicle, in particular a two- or four-wheeled vehicle, which has at least a first antenna and a second antenna spatially spaced apart from each other, by means of a portable identification transmitter having an identification transmitter antenna, comprising the following steps: - the first antenna transmits a first signal which is received by the identification transmitter antenna, - the identification transmitter determines at least one of the spatial components of the first electromagnetic field of the received first signal, preferably using an angle-resolving magnetic field sensor, - the second antenna transmits a second signal which is received by the identification transmitter antenna, - the identification transmitter determines at least one of the spatial components of the second electromagnetic field of the received second signal, preferably using an angle-resolving magnetic field sensor,- A first computer, preferably a computer in the identification transmitter, repeatedly determines, after the elapse of a predetermined first time interval, an angle at least between the determined spatial component of the first electromagnetic field of the received first signal and the determined spatial component of the second electromagnetic field of the received second signal; - The identification transmitter repeatedly determines, after the elapse of a predetermined time interval, preferably the predetermined first time interval, a field strength of at least the first electromagnetic field of the received first signal and also repeatedly a field strength of the second electromagnetic field of the received second signal, wherein the determination of the field strengths is preferably carried out with the aid of the first computer.- The identification transmitter sends an authorization signal to the vehicle to authorize its use only if the following conditions are cumulatively met: - the angle repeatedly determined after the elapsed time of the predetermined first time interval exceeds a predetermined threshold, - the repeatedly determined angle increases, i.e., becomes larger, and / or - the repeatedly measured field strength of the first and / or second electromagnetic field also increases, i.e., becomes larger, whereby it is provided that the determined angle transmitted to the vehicle is repeatedly time-stamped and stored in the vehicle to form a reference angle pattern for comparison with subsequently determined angle patterns and only provides an authorization signal to authorize the use of the vehicle if the pattern comparison is positive; and / or whereby it is provided thatthat the measured or determined field strength transmitted to the motor vehicle is repeatedly time-stamped and stored in order to create a reference field strength pattern for comparison with subsequently determined field strength patterns and to provide an authorization signal for the use of the motor vehicle only in the case of a positive pattern comparison.

Description

The invention relates in particular to a method for authorizing the use of a motor vehicle, which has at least a first and a second antenna, wherein the first antenna and the second antenna are spatially spaced apart from one another, by means of a portable identification transmitter, which has an identification transmitter antenna. The motor vehicle is preferably a two- or four-wheeled motor vehicle.In such a known method it is desirable to further improve it against manipulations.DE 10 2011 079 421 A1 describes a method in which at least the first four steps of the method according to the invention are carried out according to claim 1 and in which an angle between two signals which were transmitted from two antennas of a motor vehicle to a portable identification transmitter is measured.DE 10 2010 010 057 A1 describes a method in which field strengths of two signals which were transmitted from two antennas of a motor vehicle to a portable identification transmitter are measured repeatedly.The object of the invention is in particular to provide a method for authorizing the use of a motor vehicle with improved protection against manipulations.This object is achieved in particular by a method for authorizing the use of a motor vehicle having the features of the independent method claim. Advantageous embodiments of the method according to the invention are the subject matter of the dependent method claims.The method according to the invention is based on a method for authorizing the use of an in particular two- or four-wheeled motor vehicle, which has at least a first and a second antenna, wherein the first antenna and the second antenna are spatially spaced apart from one another, by means of a portable identification transmitter, which has an identification transmitter antenna.This known method is further developed according to the invention by the following steps.In a first step, the first antenna emits a first signal which is received by the identification transmitter antenna.In a second step, the identification transmitter determines at least one of the spatial components of the first electromagnetic field of the received first signal, preferably using an angle-resolving magnetic field sensor.In a third step, the second antenna emits a second signal which is received by the identification transmitter antenna.In a fourth step, the identification transmitter determines at least one of the spatial components of the second electromagnetic field of the received second signal, preferably using an angle-resolving magnetic field sensor.In a fifth step, a first computer, preferably a computer in the identification transmitter, repeatedly determines the angle at least between the determined spatial component of the first electromagnetic field of the received first signal and the determined spatial component of the second electromagnetic field of the received second signal after the expiration of a predetermined first time interval.In a sixth step, the identification transmitter repeatedly determines the field strength of at least the first electromagnetic field of the received first signal after a predetermined time interval has elapsed, preferably the predetermined first time interval, and preferably also repeatedly determines the field strength of the second electromagnetic field of the received second signal, wherein the determination of the field strengths is preferably carried out with the aid of the first computer.In a seventh step, the identification transmitter sends an authorization signal for authorizing the use of the motor vehicle to the motor vehicle only if the following requirements are cumulatively fulfilled:the angle repeatedly determined in each case after the expiration of the predetermined first time interval exceeds a predetermined threshold value,the repeatedly determined angle increases or becomes larger, and / orthe repeatedly measured field strength of the first and / or second electromagnetic field likewise increases or increases.In summary, one aspect of the method according to the invention consists in ascertaining whether the identification transmitter is moving towards the motor vehicle. This can be established according to the invention on the one hand by the identification transmitter repeatedly ascertaining the field strength of the signals which are transmitted by the motor vehicle and checking whether the field strength or the field strengths increase or increase. This can be determined according to the invention, on the other hand, by the identification transmitter repeatedly determining the angle between the signals transmitted by the motor vehicle and checking whether the repeatedly determined angles increase.According to the invention, it is provided that in the motor vehicle the angle determined and transmitted to the motor vehicle is repeatedly provided with a corresponding time stamp and stored in order to form a reference angle pattern for comparison with angle patterns determined later and to provide an authorization signal for authorizeing the use of the motor vehicle only in the case of a positive pattern comparison.This measure can further increase the protection against manipulations.According to the invention, in combination therewith or alternatively, it is provided that in the motor vehicle the measured or determined field strength transmitted to the motor vehicle is repeatedly provided with a corresponding time stamp and stored in each case in order to form a reference field strength pattern for comparison with field strength patterns determined later and to provide an authorization signal for authorizeing the use of the motor vehicle only in the case of a positive pattern comparison.The above optional measures can advantageously be used alternatively or in combination to increase the protection of the method according to the invention against manipulations.According to an advantageous embodiment of the method according to the invention, the time interval between the transmission of the first signal by the first antenna and the transmission of the second signal by the second antenna is selected to be so short in time-but different from zero-that the identification transmitter carried by the driver is largely not moved when the driver approaches the motor vehicle. Therefore, the determination of the angle at least between the determined spatial component of the first electromagnetic field of the received first signal and the determined spatial component of the second electromagnetic field of the received second signal is largely not adulterated or not unusable by the movement of the driver or by the movement of the identification transmitter connected therewith.In one embodiment of the method according to the invention, it is provided that the motor vehicle has a further, third antenna which is in each case spatially spaced apart from the first and the second antenna. In an analogous or similar manner, the angle is determined at least between the determined spatial component of the first electromagnetic field of the received first signal and the determined spatial component of the third electromagnetic field of a third signal transmitted by the third antenna and received by the identification transmitter.The above measures make it possible to further improve the security of the method according to the invention against manipulations.In a further development of the method according to the invention, it is provided that the spatial components of the first electromagnetic field of the received first signal determined by the identification transmitter are the x, y and z components of the electromagnetic field of a first Cartesian coordinate system.In one embodiment of the method according to the invention, the spatial components of the second electromagnetic field of the received second signal determined by the identification transmitter are the x, y and z components of the electromagnetic field largely the components with respect to the first Cartesian coordinate system. This is largely because the Cartesian coordinate system or reference system on which the components are ascertained spatially changes only slightly in very short periods of time between the repeated ascertainment of the angles in the case of slight movements of the identification transmitter.According to a further development of the method according to the invention, the spatial components of the third electromagnetic field of the received third signal determined by the identification transmitter are the x, y and z components of the electromagnetic field largely those of the first Cartesian coordinate system.In one embodiment of the method according to the invention, it is provided that at least one first vector is formed by calculation from the x, y and z components of the first electromagnetic field of the received first signal determined by the identification transmitter and a second vector is formed by calculation from the x, y and z components of the second electromagnetic field of the received second signal determined by the identification transmitter and the scalar product thereof is formed by calculation from these two vectors.In a preferred embodiment of the method according to the invention, it is provided that the angle between the two vectors is determined mathematically with the aid of the scalar product.The above measures ensure that only a low processor power is required for calculating the angles.According to a preferred development of the method according to the invention, it is provided that the determined angle exceeds a predetermined threshold value of largely zero degrees. In particular, a threshold value, in particular a threshold value greater than 1 to 10 degrees, preferably 1 to 5 degrees, is provided.In a further embodiment of the method according to the invention, the threshold value, which is greater than zero degrees, is increased with decreasing distance of the identification transmitter from the motor vehicle. The distance is preferably determined by means of a time of flight measurement between the signals which are exchanged between the motor vehicle and the identification transmitter.According to a particularly preferred embodiment of the method according to the invention, it is provided that the first, second and / or third antennas each transmit on an identical or different frequency in the frequency range from 20 kHz to 140 kHz, preferably on approximately 125 kHz, preferably offset in time.The safety of the method according to the invention for authorizing the use of a motor vehicle can be additionally improved by the above measures.The invention additionally proposes an advantageous motor vehicle access system in which the execution of the method according to the invention is provided.According to an advantageous development of the motor vehicle access system according to the invention, the identification transmitter is a radio key or a smartphone, wherein the smartphone is preferably provided with an identification transmitter software application, such as a so-called app.In another advantageous embodiment of the motor vehicle access system according to the invention, it is provided that the identification transmitter is a smartphone provided with a computer chip, a radio motor vehicle key provided with a computer chip or a chip card with a computer chip.Finally, in a further advantageous embodiment of the motor vehicle access system according to the invention, it is provided that the identification transmitter has a sensor for determining or ascertaining an electromagnetic field and / or the components of the electromagnetic field which has been generated by one or more antennas of the motor vehicle in the region of the identification transmitter.The vehicle access system according to the invention is advantageous in particular in that it can be provided cost-effectively and nevertheless reliably against manipulations.Furthermore, a immobilizer according to the invention is proposed, in which the execution of the method according to the invention is provided.In addition, a motor vehicle having a immobilizer according to the invention is proposed, in which the execution of the method according to the invention is provided.Finally, the invention proposes a computer program product for controlling at least one processor, which computer program product brings about the execution of the method according to the invention.

Claims

Method for authorisation of the use of an in particular two- or four-wheeled motor vehicle, which has at least one first antenna and a second antenna, which are spatially spaced apart from one another, by means of a portable identification transmitter, which has an identification transmitter antenna, having the following steps: - the first antenna emits a first signal, which is received by the identification transmitter antenna, - the identification transmitter ascertains at least one of the spatial components of the first electromagnetic field of the received first signal, preferably using an angle-resolving magnetic field sensor, - the second antenna emits a second signal, which is received by the identification transmitter antenna, - the identification transmitter ascertains at least one of the spatial components of the second electromagnetic field of the received second signal, preferably using an angle-resolving magnetic field sensor, - a first computer, Preferably a computer in the identification transmitter repeatedly determines an angle at least between the determined spatial component of the first electromagnetic field of the received first signal and the determined spatial component of the second electromagnetic field of the received second signal after the expiration of a predetermined first time interval, - the identification transmitter repeatedly determines a field strength of at least the first electromagnetic field of the received first signal after the expiration of a predetermined first time interval and also repeatedly determines a field strength of the second electromagnetic field of the received second signal, wherein preferably the determination of the field strengths is performed with the aid of the first computer, - the identification transmitter only sends an authorization signal to authorize the use of the motor vehicle to the motor vehicle if the following requirements are cumulatively fulfilled: - the angle repeatedly determined in each case after the expiration of the predetermined first time interval exceeds a predetermined threshold value, the repeatedly determined angle increases, i.e. becomes larger, and / or the repeatedly measured field strength of the first and / or second electromagnetic field likewise increases, i.e. becomes larger, wherein it is provided that the determined angle transmitted to the motor vehicle is repeatedly provided with a corresponding time stamp and stored in the motor vehicle in each case in order to form a reference angle pattern for comparison with angle patterns determined later and to provide an authorization signal for authorizing the use of the motor vehicle only in the case of a positive pattern comparison; and / or wherein it is provided that in the motor vehicle the measured or determined field strength transmitted to the motor vehicle is repeatedly provided with a corresponding time stamp and stored in each case in order to form a reference field strength pattern for comparison with field strength patterns determined later and to provide an authorization signal for authorizeing the use of the motor vehicle only in the case of a positive pattern comparison.Method for authorisation of the use of a motor vehicle according to claim 1, characterised in that the time interval between the transmission of the first signal by the first antenna and the transmission of the second signal by the second antenna is chosen to be so short in time, but different from zero, that the identification transmitter carried by a driver is largely not moved when the driver approaches the motor vehicle and therefore the determination of the angle is largely not adulterated or unusable by the movement of the driver and / or by the movement of the identification transmitter connected therewith.Method for authorisation of the use of a motor vehicle according to one of the preceding claims, characterised in that the motor vehicle has a further, third antenna which is in each case spatially spaced apart from the first and the second antenna and in that the angle at least between the determined spatial component of the first electromagnetic field of the received first signal and the determined spatial component of the third electromagnetic field of a third signal which is transmitted by the third antenna and received by the identification transmitter is determined in an analogue and / or similar manner.Method for authorisation of the use of a motor vehicle according to one of the preceding claims, characterised in that the spatial components of the first electromagnetic field of the received first signal determined by the identification transmitter are the x, y and z components of the electromagnetic field of a first Cartesian coordinate system.Method for authorisation of the use of a motor vehicle according to claim 4, characterised in that the spatial components of the second electromagnetic field of the received second signal determined by the identification transmitter are the x, y and z components of the electromagnetic field largely the components with respect to the first Cartesian coordinate system.Method for authorisation of the use of a motor vehicle according to one of claims 4 or 5, insofar as it relates back to claim 3, characterised in that the spatial components of the third electromagnetic field of the received third signal determined by the identification transmitter are the x, y and z components of the electromagnetic field largely those of the first Cartesian coordinate system.Method for authorisation of the use of a motor vehicle according to one of the preceding claims, characterised in that at least a first vector is formed by calculation from the x, y and z components of the first electromagnetic field of the received first signal determined by the identification transmitter and a second vector is formed by calculation from the x, y and z components of the second electromagnetic field of the received second signal determined by the identification transmitter and their scalar product is formed by calculation from these two vectors.Method for authorisation of the use of a motor vehicle according to claim 7, characterised in that the angle between the two vectors is determined mathematically with the aid of the scalar product.Method for authorisation to use a motor vehicle according to one of the preceding claims, characterised in that the determined angle exceeds a predetermined threshold value of substantially zero degrees, in particular a threshold value greater than 1 to 10 degrees, preferably 1 to 5 degrees.Method for authorisation of the use of a motor vehicle according to claim 9, characterised in that the threshold value which is greater than zero degrees is increased with decreasing distance of the identification transmitter from the motor vehicle, wherein the distance is preferably determined by means of a transit time measurement between the signals which are exchanged between motor vehicle and identification transmitter.Method for authorisation of the use of a motor vehicle according to one of claims 3 to 10, characterised in that the first, second and third antennas each transmit on an identical or different frequency in the frequency range from 20 kHz to 140 kHz, preferably on approximately 125 kHz, preferably offset in time.Motor vehicle access system for authorisation of the use of a motor vehicle, comprising - a motor vehicle which has at least one first antenna and one second antenna which are spaced apart from one another in space, and - a portable identification transmitter which has an identification transmitter antenna, characterized in that the motor vehicle access system is configured to carry out a method according to one of the preceding claims.Motor vehicle access system according to claim 12, characterised in that the identification transmitter is a radio key or a smartphone, wherein the smartphone is preferably provided with an identification transmitter software application, such as a so-called app.Motor vehicle access system according to Claim 12, characterized in that the identification transmitter is a smartphone provided with a computer chip, a radio motor vehicle key provided with a computer chip or a chip card with a computer chip.Motor vehicle access system according to one of Claims 12 to 14, characterized in that the identification transmitter has a sensor for determining or ascertaining an electromagnetic field and / or the components of the electromagnetic field which has been generated by one or more antennas of the motor vehicle in the region of the identification transmitter.Immobiliser for authorising the use of a motor vehicle, characterised bythe execution of a method according to one of Claims 1 to 11.Motor vehicle having a immobilizer for authorisation of the use of the motor vehicle, characterized bythe execution of a method according to one of the preceding Claims 1 to 11.A computer program product for controlling at least one processor, which computer program product effects the execution of a method according to one of the preceding claims 1 to 11.