Method for detecting the time of the earliest reception of a signal change, in particular for measuring delay time or for defence against relay attacks

A method for securing an access system having an authorization means and an access control means, wherein at least one first plurality of symbols or chips is transmitted by means of a transmission system between the authorization means and access control means, electrically, magnetically, or electromagnetically from a first of the authorization means and access control means to a second of the authorization means and access control means, at a first symbol or chip rate, encoded in at least one first analog signal (NF), or is transmitted from a first of the authorization means and access control means to a second of the authorization means and access control means in at least one second analog signal (HF) generated based on the first analog signal;

• wherein the time of the earliest reception of the signal change or signal edge is determined and when a predetermined time deviation of a point in time of a data reception from the point in time of the earliest reception is exceeded or if the earliest reception deviates from a predetermined time window or one calculated using other methods, access, entry, activation, or opening is denied by the access control means, or a signal propagation time or signal round-trip time or a distance is determined based on the time of the earliest reception and when a predetermined signal propagation time or signal round-trip time or a predetermined distance is exceeded or when a predetermined deviation from the signal propagation time or signal round-trip time or distance determined in another way or by means of another method is exceeded, the access, entry, or opening is denied by the access control means.

An access control system having an authorization means and an access control means, wherein the access control system has a transmission system configured between the authorization means and the access control means to transfer at least one first plurality of symbols or chips electrically, magnetically, or electromagnetically from a first of the authorization means and access control means to a second of the authorization means and access control means, at a first symbol or chip rate, encoded in at least one first analog signal (NF), or to transfer from the first of the authorization means and access control means to the second of the authorization means and access control means, encoded in at least one second analog signal (HF) generated based on the first analog signal, wherein the access control system is configured to determine a point in time of an earliest reception of a signal change or a signal edge and, when a predetermined time deviation of a time of a data reception from the time of the earliest reception is exceeded, or if the earliest reception deviates from a predetermined timespan or a timespan calculated using other methods, to deny access, entry, activation, deactivation, or opening, or to determine a signal propagation time or signal round-trip time or a distance based on the time of the earliest reception, and if a predetermined signal propagation time or signal round-trip time or a predetermined distance is exceeded or if a predetermined deviation from the signal propagation time or signal round-trip time or distance determined by means of another method is exceeded, to deny access, entry, activation, or opening.

A use of a point in time of an earliest reception of a signal change or a signal edge for access control, authentication, distance measurement, synchronization, or for detection of or for defense against relay attacks, wherein at least one first plurality of symbols or chips is transmitted from a first object to a second object by means of a transmission system, at a first symbol or chip rate, encoded in at least one first analog signal (NF), or is transferred from the first object to the second object in at least one second analog signal (HF), generated based on the first analog signal, and a second plurality of sampling values of the transmitted symbols or chips of the at least one first analog signal or second analog signal at the second object is used to detect the earliest reception of the signal change or the signal edge of a symbol or chip that has been changed as compared to the previous symbol or chip, wherein, the time of the earliest reception is selected to be the time at which the earliest, of the second plurality of sampling values or the earliest aggregated group from the second plurality of sampling values shows a statistically significant change or exceeds or falls below a value determined from a fourth plurality of sampling values of the at least one first analog signal or second analog signal or goes beyond a value range determined from the fourth plurality of sampling values of the at least one first analog signal and the second analog signal, wherein the second plurality of sampling values of the third plurality of the transmitted symbols or chips is chosen so that their sampling values are taken on symbols or chips transmitted at different times and are situated on at least five different first points in time in the symbol or chip period which are offset by at least two percent of the symbol or chip period or which are framing at least ten percent of the first points in time in the symbol or chip period.

A transmission system having at least two objects, each having at least one antenna and having a total of at least one transmitter and one receiver and a computing or control unit and at least one memory and being designed to transmit a first plurality of symbols or chips, at a first symbol or chip rate, encoded in at least one first analog signal (NF), from a first of the at least two objects to a second of the at least two objects or in at least one second analog signal (HF) generated on the basis of the first analog signal, from the first of the at least two objects to the second of the at least two objects, and designed to determine a point in time of an earliest reception of a signal change or a signal edge, for measuring the propagation time, for measuring distance or for synchronization, in a symbol-synchronized or digital transmission system;

• wherein the system is designed to use a second plurality of sampling values of a third plurality of the transmitted symbols or chips of the at least one first analog signal or second analog signal on the second object, in order to detect the earliest reception of the signal change or the signal edge of a symbol or chip that deviates from the preceding symbol or chip, wherein, the time of the earliest reception is selected to be the time at which the earliest of the second plurality of sampling values or the earliest aggregated group from the second plurality of sampling values which shows a statistically significant change lies, or the time at which the earliest of the second plurality of sampling values or the earliest aggregated group of the second plurality of sampling values lies, which exceeds or falls below a value determined from a fourth plurality of sampling values of the at least one first analog signal or second analog signal or which goes beyond a value range determined from the fourth plurality of sampling values of the first and of the second analog signal, wherein the second plurality of sampling values of the third plurality of the transmitted symbols or chips is chosen so that their sampling values are taken on symbols or chips transmitted at different times and are situated on at least five different first points in time in the symbol or chip period which are offset by at least two percent of the symbol or chip period or which are framing at least ten percent of the first points in time in the symbol or chip period.