METHOD FOR DECIDING THE DISTANCE THRESHOLD FOR A PLURAITY OF TRANSPONDERS

Abstract

A temporal optimization of a distance threshold decision for a plurality of transponders is disclosed in which it may be determined as rapidly as possible whether at least one of the transponders falls below a preset distance, particularly to a query node. A decision is to be made regarding the release with high probability, particularly in less than 500 ms, even if a plurality of authorized transponders are present in querying range and the necessary measurements and/or calculations are time-intensive. The disclosure introduces an estimation phase occurring before a first phase. In the estimation phase it is initially estimated with high probability which one or several of the transponders are the one or several with the shortest distance(s). Afterwards, the actual distance determination begins and is executed such that initially the distance is determined for at least one of the transponders having the smallest distance with the greatest probability.

Claims

1. A method for determining at least one distance to at least one transponder of a plurality of transponders and a query node, or to a predetermined point disposed in a geographically fixed manner thereto, said method comprising the following steps transmitting one first query signal from the query node, and transmitting one first response signal by at least two of the plurality of transponders; determining a hierarchy of at least a partial quantity of the plurality of transponders on the basis of the first response signal, wherein places of the plurality of transponders in the hierarchy are determined by an estimated distance, and a highest place in the hierarchy is assigned by a lowest estimated distance, or the places of the plurality of transponders in the hierarchy are assigned by at least one value usable for a distance estimate, and the highest place in the hierarchy is assigned by the value usable for a distance estimate standing for the lowest distance, wherein the value is derived or calculated from the first response signal received at the query node; and transmitting one second query signal from the query node, and transmitting at least one second response signal by at least one of the transponders of the partial quantity of the plurality of transponders, wherein among the at least one transponder transmitting the at least one second response signal, at least one is such that has an upper place in the hierarchy, and using the at least one second response signal, carrying out at least one first distance determination, wherein the first distance determination determines the distance between the query node and the at least one of the transponders of the plurality of transponders from which the second response signal was received and that has the upper place in the hierarchy, wherein the distance determination has a higher precision than the distance estimate or a distance estimate on the basis of the first query signal or on the basis of the first response signal, and wherein the plurality of transponders is equivalent to at least two transponders.

2. The method according to claim 1, wherein following the at least one first distance determination when the determined distance exceeds a predetermined distance, or lies outside of a distance range, at least one additional distance determination is carried out, wherein the at least one additional distance determination determines the distance between the query node or the predetermined point disposed in the geographically fixed manner thereto and the one of the transponders of the plurality which in a consideration in which the highest place in the hierarchy is assigned by the lowest distance, has a lower place than the transponder considered in the first distance determination, and wherein this procedure is repeated until the distances from the query node or the predetermined point disposed in the geographically fixed manner thereto to all transponders of the plurality of transponders or of the hierarchy are determined, or the determined distance to one of the transponders does not exceed the predetermined distance, or lies within the distance range.

3. The method according to claim 1, wherein the hierarchy establishes a sequence of a signal transmission; of the at least one transponder to the query node or a sequence of distance determinations between the query node and the predetermined point disposed in the geographically fixed manner thereto and the plurality of the transponders, or the sequence of calculations necessary for the distance determinations.

4. The method according to claim 1, wherein the second query signal is transmitted from the query node to the transponders from which the hierarchy is to be taken or wherein the transponders included in the hierarchy, depending on the respective place in a sequence of the hierarchy, sequentially transmit a second response or measurement data signal, wherein the sequence defined by the hierarchy is maintained among the transponders in the first response phase or the second response phase, or wherein in a consideration in which the highest place in the hierarchy is assigned by the lowest distance, the transponders transmit in the sequence of decreasing hierarchy place.

5. The method according to the preceding claim 4, wherein the measurement data signal contains at least one phase information or phase correction information or phase deviation information or frequency information or time correction information, wherein the information indicates how the signal received at the transponder from the query node, and the signal transmitted from the transponder to the query node, differ in terms of phase or frequency or time at the query node.

6. The method according to claim 6, wherein all transponders of the plurality of transponders that receive the first query signal respond to the first query signal, or wherein the determination of the hierarchy is based on the first response signal, and coordinations or synchronizations carried out between query node and the plurality of transponders, or wherein calculations carried out for distance estimation or distance determination are predominantly based in the query node or on the basis of the response and measurement data signals transmitted to the query node and measurements of the query node, as well as predetermined characteristics of the transponders or characteristics of the transponders set by the query node.

7. The method according to claim 1, wherein before the distance estimate, a frequency determination, coordination or gain determination or synchronization is carried out on at least two of the plurality of transponders, on signals of at least two of the plurality of transponders, or between the query node and at least two of the plurality of transponders, or insights gained therefrom are used for the distance estimate.

8. The method according to claim 1, wherein the determination of the hierarchy occurs on the basis of signal strengths or RSSI of the first response signals, or wherein the distance determination occurs by means of phase-based distance measurement or time of flight measurement or round-trip time measurement between the query node and the at least one transponder, wherein beforehand phases or times, are collected.

9. The method according to claim 1, wherein the value used for the distance estimate contains at least one RSSI.

10. The method according to claim 1, wherein wireless first or second query signals of the query node or wireless first or second response signals of the transponders are additionally received in a spatially distanced manner from the query node, by at least one antenna spatially distanced from the query node, and wherein the first or second query signals or first or second response signals received in such a manner are taken into account in forming the hierarchy or determining the distance.

11. A distance threshold decision method for deciding whether at least one transponder exceeds a predetermined distance to a query node or to a predetermined point disposed in a spatially fixed manner thereto or lies outside a predetermined distance range, wherein the decision is based on at least one distance determination according to claim 1.

12. A method for deciding on a release, wherein at least one distance between a query node or at least one antenna of the query node, or between a predetermined point, disposed in a spatially fixed manner thereto and an authorized transponder of a plurality of transponders, and wherein the release occurs or is not refused when the at least one determined distance between the query node or at least one antenna of the query node, or the predetermined point does not exceed a predetermined distance or lie within a predetermined distance range, wherein a distance threshold decision occurs according to claim 11, and wherein the authorized transponder is a transponder that was previously registered with the query node or which has an identifier known to the query node.

13. A wireless authorization system having at least one query node with at least one antenna, configured for operating an access restriction means, which is closed or activated in dependence upon the distance of at least one transponder of a plurality of transponders to the query node, or to at least one antenna of the query node, or to a predetermined point, wherein the wireless authorization system is configured for: transmitting one first query signal from the query node and receiving respectively one first response signal from at least two of the plurality of transponders, and determining a hierarchy of at least a partial quantity of the plurality of transponders on the basis of the first response signals, wherein places of the transponders in the hierarchy are determined by an estimated distance and a highest place in the hierarchy is assigned by a lowest estimated distance, or the places of the transponders in the hierarchy are determined by at least one value that can be is used for the distance estimate and the highest place in the hierarchy is assigned by the value that is used for the distance estimate that stands for the lowest distance, wherein the value is derived or calculated, from the one first response signal received at the query node; and transmitting a second query signal from the query node and receiving at least one second response signal from at least one of the transponders of the partial quantity of the plurality of transponders, wherein among the at least one second response signal, at least one is from a transponder that has an upper place in the hierarchy and is configured to carry out at least one first distance determination using the at least one second response signal; wherein the first distance determination determines the distance between the query node or the at least one antenna of the query node or a predetermined point disposed in a spatially fixed manner thereto, and the transponder of the plurality of transponders from which the second response signal was received and that has the upper place, in the hierarchy; wherein the wireless authorization system is configured to carry out the distance determination with a higher precision than the distance estimate or a distance estimate based on the at least one first query signal or based on the at least one first response signal, and wherein the plurality of transponders is equivalent to at least two transponders; and wherein the wireless authorization system is configured to grant or refuse an access, or to operate the access restriction means including to activate, deactivate, to open, to close or to remove the access restriction means, and the wireless authorization system is configured to not refuse the access or grant the access, deactivate, open or remove the access restriction means once a determined distance does not exceed a predetermined distance or lie within a predetermined distance range, or to refuse the access or not grant the access and to activate or close the access restriction means if the at least one determined distance between the query node or the at least one antenna of the query node or the predetermined point exceeds the predetermined distance or lies outside the predetermined distance range.

14. The wireless authorization system according to claim 13, comprising the plurality of transponders.

15. The wireless authorization system according to claim 14, having at least one listening node with at least one listening antenna, said listening node being spaced from the query node or at least one antenna of the query node, wherein the wireless authorization system is configured to receive and to process signals exchanged between the query node and the plurality of transponders, and the wireless authorization system is configured to take into account at least one first response signal received or processed by at least one listening node for the determination of the hierarchy, or to take into account at least one second response signal received or processed by at least one listening node for the determination of the distance.

16. The method according to claim 1, further comprising transmitting a multiplicity of second response signals.

17. The method according to claim 1, wherein among the at least one transponder transmitting the at least one second response signal, at least one is such that has the highest place in the hierarchy.

18. The method according to claim 1, wherein one measurement data signal respectively is transmitted in a first response phase following a second query signal, and respectively one measurement data signal is transmitted in a second response phase following the first response phase.

19. The method according to claim 1, wherein, for the round trip time measurement between the query node and the at least one transponder, beforehand the necessary measurement values including phases or times are collected, based on the first or second query signals or the first or the second response signals.

20. The method according to claim 1, wherein the value used for the distance estimate contains at least one previously determined RSSI, determined on a plurality of frequencies or a plurality of antenna paths, containing such on over which the first or second query signals or the first or second response signals were or will be transmitted.

21. The method according to claim 1, wherein the signal strength, the phase, the cycle time or the RSSI of the first or second query signals or the first or second response signals are taken into account in forming the hierarchy or determining the distance.

Description

[0071] The following, description given purely as an example of the figures, which are purely examples and schematic, contributes toward improved understanding of the invention. They show:

[0072] FIG. 1 an illustration of the invention in the scope of an automotive locking system, and

[0073] FIG. 2 an illustration of the sequence of the signal exchange and of the calculations in the system from FIG. 1

[0074] FIG. 1 shows a view of an automobile 1 from above, antennas 2 are disposed next to the door and trunk latches. Also apparent are additional authorized fobs (transponders) 4, 5, 7, B for opening. Moreover, predetermined distance thresholds 3 around the antennas 2 are shown by dashed circles.

[0075] Below, as a timeline, FIG. 2 shows the time in the query node of the automobile that is connected to all five antennas 2. Above these, timelines of the fobs 4, 5, 7 and 8 are shown. Actions of the query node and the transponder are illustrated in the timelines. If the automobile or electronics contained therein detect, for example by capacitative sensors, an approach, for example, of a hand, at a door latch 6, as indicated by the arrow 10, the query node transmitted a first query signal 11 via one or more of its antennas, from which a time synchronization and particularly a response sequence can advantageously be derived by the transponder. Moreover, preferably an additional signal 12 is transmitted by the query node, particularly with a continuous carrier wave, that enables a certain frequency adjustment for the fobs to the frequency of the query node. This signal is not actually advantageous for the distance estimate, however it is advantageous to transmit this signal already in this phase in order to give the fobs a time period for frequency adjustment before the subsequent distance determination. Thereafter the fobs respectively transmit a first response signal 13 sequentially. Different than the example, additional first query signals and/or first response signals can occur thereafter.

[0076] These response signals are used for distance estimation and hierarchy formation 14 in the query node. Thereafter the query node transmits a second query signal 15, from which preferably the new reply sequence and/or selection is apparent. In this example, the query node has the sequence 5, 8, 7. In this example, the fobs each respond with a second response signal 16 and thereafter with measurement value signals 17.

[0077] Different than in this example, additional second query signals and/or second response signals can follow thereafter.

[0078] Once the data of the first fobs in the hierarchy is available, the determination of the distance 18 to the fob begins. Depending on the embodiment, a part of the determination can even occur as early as following reception of the second response signal 16 of the fob, here fob 5. Additional distance determinations 20 to other fobs can follow the first distance determination. However, to the extent that the first distance is within the predetermined distance threshold 3, which is the case here, the door lock is opened, which is indicated by the arrow 19. The additional determinations 20 can then be dispensed with.

LIST OF REFERENCE SYMBOLS

[0079] 1 automobile [0080] 2 antenna [0081] 3 permissible distance [0082] 4 first fob [0083] 5 second fob [0084] 6 door latch [0085] 7 third fob [0086] 8 fourth fob [0087] 10 beginning of the method/approach [0088] 11 first query signal and time synchronization signal [0089] 12 frequency coordination signal [0090] 13 first response signal [0091] 14 hierarchy determination [0092] 15 second query signal [0093] 16 second response signal [0094] 17 measurement data signal PCT) [0095] 18 calculation of the distance to fob 5 [0096] 19 door lock opening [0097] 20 calculation of the distance to fob 8 [0098] 21 calculation of the distance to fob 7