Passive keyless entry system

• US 20010033222A1
• Filed: 03/16/2001
• Published: 10/25/2001
• Est. Priority Date: 03/20/2000
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Nowottnick, Juergen, Boeh, Frank
• Granted Patent: US 6,747,545 B2
• Time in Patent Office: Days
• US Class Current: 340/5.61
• CPC Class Codes: G07C 2009/00396 starting with prompting the keyless data carrier
• CPC Class Codes: G07C 2009/00412 the transmitted data signal being encrypted
• CPC Class Codes: G07C 2009/00555 comprising means to detect or avoid relay attacks
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/122 Counter-measures against attacks; Protection against rogue devices
• CPC Class Codes: H04W 4/021 Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds

Abstract

The configuration of an entry security system, hereinafter also referred to as passive keyless entry system (PKE), is described, having a greatly improved resistance against external attacks. The system according to the invention can be used in the field of motor vehicle entry systems and is also suitable for realizing chip card-based secure entry systems in the field of security for buildings.

It is an object of the invention to provide an arrangement of the type described above making a “relay attack” at least essentially more difficult or even impossible.

The invention provides an improved passive keyless entry system in which additional information is gained about the relative orientation and positioning between a data carrier (PKE card) and a base station which is preferably arranged in a vehicle. This information, denoted as position information, is used to verify the origin of data during the authentication process in the entry system. The data carrier comprises M antenna coils which are orthogonally arranged with respect to each other, as well as a UHF transmitter stage. The base station comprises N antenna coils which, in an arrangement of the entry system according to the invention, are arranged in the vehicle. Additionally, the base station is provided with a further number—typically but not necessarily equal to N—of UHF receiver stages. In a first step, the data carrier (PKE card) measures and computes its own orientation relative to the antenna coils of the base station. In a second step, the position information thus obtained is transmitted, preferably in an encrypted form, from the data carrier to the base station. The base station measures and computes the orientation of the data carrier from the phase or amplitude differences in the UHF signal received by the UHF receiver stages of the base station. The two position information components thus obtained independently of each other are compared and access is granted only when they correspond within predetermined measuring tolerances.

Claims

1. An arrangement for a passive keyless entry system comprising a base station arranged on an object to be secured against unauthorized access, for example, a vehicle, and a data carrier (“

PKE card”

) particularly a chip card which can be carried preferably by an authorized user, and, together with the base station, is adapted to determine authorized access and corresponding control of the base station for exchanging signals with the base station, a signal transmission from the base station to the data carrier being preferably performed by low-frequency, magnetic alternating fields and a signal transmission from the data carrier to the base station being preferably performed by high-frequency, electromagnetic alternating fields (UHF range), in which

the base station comprises a first number (N) of LF transmitter stages and an antenna coil associated with each LF transmitter stage for transmitting low-frequency, magnetic alternating fields, and a second number of UHF receiver stages,

the data carrier comprises a second number (M) of orthogonally aligned antenna coils each being coupled to an LF receiver stage for receiving low-frequency, magnetic alternating fields,

the data carrier further comprises a UHF transmitter stage for transmitting a UHF signal,

the base station comprises a third number of UHF receiver stages for receiving the UHF signal transmitted by the UHF transmitter stage of the data carrier,

the base station and the data carrier comprise a control stage each for controlling the LF and UHF transmitter and receiver stages and for generating signals to be transmitted and evaluating received signals,

first position information about the relative position of the data carrier with respect to the antenna coils of the base station is gained from a measurement of the low-frequency, magnetic alternating fields transmitted by the LF transmitter stages of the base station to the data carrier via the antenna coils of the data carrier in the control stage of the data carrier, which information is transmitted in a preferably encrypted form in the UHF signal from the data carrier to the base station,

second position information about the relative position of the data carrier with respect to the UHF receiver stages of the base station is gained from a subsequent measurement of the UHF signal transmitted by the UHF transmitter stage of the data carrier to the base station via the UHF receiver stages of the base station in the control stage of the base station,

a signal representing authorized access is generated by comparing both position information components in the control stage of the base station, which signal is only generated when both position information components differ by less than a predetermined extent.

2. An arrangement as claimed in

claim 1

, characterized in that the two position information components are determined by measuring the field strengths and/or the phase differences of the magnetic alternating fields at the locations of the antenna coils of the data carrier coupled to the respective LF receiver stages, or by measuring the UHF signal at the locations of the UHF receiver stages of the base station.

3. A base station for an arrangement as claimed in

claim 1

or

2

.

4. A data carrier for an arrangement as claimed in

claim 1

or

2

.