Identification system and method of determining motion information

• US 20060197939A1
• Filed: 03/07/2006
• Published: 09/07/2006
• Est. Priority Date: 03/07/2005
• Status: Active Grant

• Current Assignee: Schweizerische Bundesbahnen Sbb
• Original Assignee: Schweizerische Bundesbahnen Sbb
• Inventors: Baiker, Stefan, Ruhl, Martin
• Granted Patent: US 7,825,802 B2
• Time in Patent Office: Days
• US Class Current: 356/72
• CPC Class Codes: B61L 1/10 actuated by electromagnetic radiation; actuated by particle radiation
• CPC Class Codes: B61L 25/04 Indicating or recording train identities
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G08G 1/042 using inductive or magnetic detectors
• CPC Class Codes: H01Q 1/3225 Cooperation with the rails or the road
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/45 Transponders
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

An identification system which may be employed in a transport or monitoring system has at least one stationary and at least one mobile transmission unit which are each provided with an antenna, which antennas in turn are coupled inductively or capacitively to each other during the transmission of data. At least one of the antennas is designed such that in response to a mutual displacement of the coupled antennas a direction-dependent modulation of the transmitted signals occurs which is demodulated and evaluated in at least one of the transmission units, for example, by a demodulation unit and a processor, optionally a signal processor, in order to obtain information relating to the relative motion of the two transmission units. In addition to known identification functions, the identification system may perform additional important functions without requiring any significant additional expense.

Claims

1. Identification system, in particular, for a transport system, a means of transportation, and/or a freight conveyance system, or to monitor persons, comprising at least one stationary and at least one mobile transmission unit which are each provided with an antenna which during the transmission of data are coupled to each other inductively or by an electric field,

wherein at least one of the antennas is designed or arranged such that during mutual displacement of the inductively coupled antennas a directionally dependent modulation of the transmitted signals occurs, and

in at least one of the transmission units a demodulation unit, optionally provided with a processor, is provided by which the direction-dependently modulated signals are able to be demodulated, and the direction of motion and/or speed of motion and/or acceleration is able to be determined.

2. Identification system according to claim 1, wherein the at least one antenna has at least one loop winding which encloses a surface or a body which has no axis of symmetry running vertically to the direction of travel, or that the at least one antenna is installed such that it does not have an axis of symmetry running vertically to the direction of travel, or that the at least one antenna has multiple antenna segments which have differing coupling properties.

3. Identification system according to claim 2, wherein the at least one antenna has multiple loop windings, of which one or more loop windings enclose different areas or bodies such that symmetrical or asymmetrical surface segments or body segments lying adjacent in the direction of displacement are defined which are enclosed by different numbers of loop windings, and/or the antenna area enclosed by loop windings is divided into areas, in or on which materials of differing permeability are located.

4. Identification system according to claim 2, wherein the surface has the shape of a triangle or trapezoid, and/or that the antenna is installed obliquely relative to the direction of motion, and/or that materials of different permeability and/or materials of identical permeability and different density are located in areas.

5. Identification system according to claim 1, wherein one or more antenna segments are provided with fixedly defined diameters, based on which the speed or acceleration can be determined.

6. Identification system according to claim 1, wherein a coupling device is provided with a loop-shaped first and with a loop-shaped second coupling element which are coupled to each other by at least one conductive or inductive third coupling element, and of which the first coupling element is inductively coupled to a coupling element of the stationary or the mobile transmission unit, and of which the second coupling element serves as an antenna of the given stationary or mobile transmission unit and serves only to effect transmission of signals, or transmission and direction-dependent modulation of signals.

7. Method of operating an identification system according to claim 1, wherein during the coupling of the antennas and during the mutual displacement of the stationary and mobile transmission unit signals are transmitted from the stationary to the mobile transmission unit, or signals are transmitted from the mobile to the stationary transmission unit, which signals are direction-dependently modulated by at least one of the antennas, and demodulated in the receiving transmission unit, after which the direction of motion and/or speed of motion is able to be determined based on the demodulated signals.

8. Method of operating an identification system according to claim 7, wherein the demodulated signals are compared with signal patterns which are characteristic of the directions of motion, or at least one fixed threshold value is provided, or based on the received signals at least one variable threshold value is generated that is used to determine whether the first or second signal half lies above the threshold value.

9. Method of operating an identification system according to claim 7, wherein the modulation is implemented by appropriately shaped, appropriately installed, or segmented modulation antennas.

10. Method of operating an identification system according to claim 9, wherein one or more antenna segments are provided with fixedly defined diameters for which, preferably based on significant changes in amplitude, corresponding intervals are determined in a signal pattern, the speed and/or acceleration being determined therefrom.

11. Method of operating an identification system according to claim 7, wherein the signals implementing the information transfer or power supply are demodulated in order to determine the directional information and/or the speed information.

12. Method of operating an identification system according to claim 7, wherein the directional information and/or the speed information is obtained in the mobile transmission unit and transmitted to the stationary transmission unit.

13. Method of operating an identification system according to claim 7, wherein after the determination of motion information the control devices implementing traffic management are actuated, and/or the signals, reports or warnings are issued.

14. Method of operating an identification system according to claim 7, wherein the signal transmission is implemented inductively or capacitively.