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 that are 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, - 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.- The identification transmitter transmits a measure or value for the determined at least one spatial component of the first electromagnetic field of the received first signal and a measure or value for the determined at least one spatial component of the second electromagnetic field of the received second signal to the motor vehicle; - A computer, preferably a computer in the motor vehicle, 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; and - The motor vehicle only provides an authorization signal for authorizing the use of the motor vehicle if the determined angle exceeds a predetermined threshold, characterized in that- that the threshold value increases as the distance between the identification device and the vehicle decreases.

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. The motor vehicle is in particular a two- or four-wheeled motor vehicle.In such known methods it is desirable to further improve these against manipulations.DE 10 2011 079 421 A1 describes a method according to the preamble of claim 1.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 a motor vehicle, in particular a 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 the angle-resolving magnetic field sensor.In a fifth step, the identification transmitter transmits a measure or a value for the determined at least one spatial component of the first electromagnetic field of the received first signal and a measure or a value for the determined at least one spatial component of the second electromagnetic field of the received second signal to the motor vehicle.In a sixth step, a computer, preferably a computer in the motor vehicle, 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, andIn a seventh step, the motor vehicle provides an authorization signal for authorizing the use of the motor vehicle only if the ascertained angle exceeds a predetermined threshold value.According to the invention, provision is made for,the threshold value is increased as the distance of the identification transmitter from the motor vehicle decreases.In summary, the position of the receiver or of the identification transmitter can be determined in an angle-resolved manner by the method according to the invention with the aid of at least two spatially separated or spaced transmitters. If the signals of the spaced transmitters are forwarded by a repeater with manipulative intention, the propagation time is extended and the angle information is lost. The angle-resolving method according to the invention can detect such a manipulation of the radio link by the parallelism of the signals being detected by the identification transmitter and / or by the motor vehicle and the latter and / or the latter preventing the transmission of an authorization signal.In one embodiment of the method according to the invention, it is provided that the time interval between the emission of the first signal by the first vehicle antenna and the emission of the second signal by the second vehicle 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 vehicle and 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.By means of the above measures, a particularly reliable determination of the angle and thus a particularly reliable determination of whether the predetermined threshold value is exceeded can be achieved.According to a further embodiment of the method according to the invention, 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 analogous or similar manner.By means of these measures, the reliability in the determination of the angle and thus the determination of whether the predetermined threshold value is exceeded can be further increased.In an advantageous embodiment 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.According to an advantageous development of the method according to the invention, it is provided 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. 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.In one embodiment 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.By means of the above measures, a particularly reliable determination of the angle between the determined spatial components of the first electromagnetic field of the received first signal and the determined spatial components of the second electromagnetic field of the received second signal or the determined spatial components of the third electromagnetic field of the received third signal can be achieved.In an advantageous development 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.According to a particularly advantageous development of the method according to the invention, the angle between the two vectors is determined mathematically with the aid of the scalar product.To calculate the angle between the two vectors with the aid of the scalar product, only a small amount of computing effort or a low processor power is required.According to a particularly preferred embodiment 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 greater than 1 to 10 degrees, preferably 1 to 5 degrees.In an advantageous development of the method according to the invention, the threshold value, which can be greater than zero degrees, is increased with decreasing distance of the identification transmitter from the vehicle. The distance is preferably determined by means of a time of flight measurement between the signals which are exchanged between the vehicle and the identification transmitter.According to a preferred embodiment of the method according to the invention, it is provided 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.The above measures can additionally improve the reliability of the method according to the invention for authorizing the use of a motor vehicle.In addition to the advantageous method according to the invention for authorizing the use of a motor vehicle, the invention makes it possible to provide a vehicle access system for authorizing the use of a motor vehicle, wherein said vehicle access system is involved in the execution of a method according to the invention or executes a method according to the invention.In an advantageous development of the vehicle access system according to the invention, it is provided that the identification transmitter is a radio key or a smartphone, preferably with an identification transmitter software application, such as a so-called app.According to an advantageous embodiment of the vehicle access system according to the invention, the identification transmitter is a smartphone provided with a computer chip, a radio vehicle key provided with a computer chip or a chip card with a computer chip.In one embodiment of the vehicle access system according to the invention, 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 vehicle antennas in the region of the identification transmitter.The above features of the vehicle access system according to the invention make it possible to provide the driver with a particularly comfortable use of the method according to the invention for authorizing the use of a motor vehicle.The invention also proposes a immobilizer for authorisation of the use of a motor vehicle, which is advantageously involved in the execution of a method according to the invention or executes a method according to the invention.Furthermore, a motor vehicle is proposed, in which it is provided that at least one method according to one of Claims 1 to 11 is carried out in the motor vehicle.Finally, the invention proposes a computer program product for controlling at least one processor, which computer program product brings about the execution of a method according to one of Claims 1 to 11.

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, - 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, the identification transmitter transmits a measure or a value for the determined at least one spatial component of the first electromagnetic field of the received first signal and a measure or a value for the determined at least one spatial component of the second electromagnetic field of the received second signal to the motor vehicle, a computer, preferably a computer in the motor vehicle, 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, and the motor vehicle provides an authorization signal for authorizing the use of the motor vehicle only if the determined angle exceeds a predetermined threshold value, characterized in that the threshold value is increased with a decreasing distance of the identification transmitter from the motor vehicle.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 by the movement of the driver or by the movement of the identification transmitter connected thereto is largely not adulterated or unusable.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 emitted by the third antenna and received by the identification transmitter is determined in an analogous 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 greater than 1 to 5 degrees.Method for authorisation of the use of a motor vehicle according to one of the preceding claims, characterised in that the distance is determined by means of a time of flight 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 transmit - in each case on an identical frequency or on different frequencies - in the frequency range from 20 kHz to 140 kHz, preferably on approximately 125 kHz, - preferably offset in time.Vehicle access system for authorisation of the use of a motor vehicle, comprising - a motor vehicle having at least a first and a second antenna which are spatially spaced apart from one another, and - a portable identification transmitter having an identification transmitter antenna, characterised in that the vehicle access system is configured for carrying out a method according to one of the preceding claims.Vehicle access system according to claim 12, characterised in that the identification transmitter is a radio key or a smartphone, preferably with an identification transmitter software application, such as a so-called app.Vehicle access system according to Claim 12, characterized in that the identification transmitter is - a smartphone provided with a computer chip, - a radio vehicle key provided with a computer chip or - a chip card with a computer chip.Vehicle access system according to one of Claims 12 to 14, characterized in that the identification transmitter has a sensor for determining and / or ascertaining an electromagnetic field and / or 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, characterized in that a method according to one of Claims 1 to 11 is carried out in the motor vehicle.A computer program product for controlling at least one processor, which computer program product effects the execution of a method according to one of claims 1 to 11.