METHOD FOR DETERMINING A MOTION STATE OF A PORTABLE TRANSCEIVER DEVICE, METHOD FOR REMOTELY UNLOCKING A DOOR AND PORTABLE TRANSCEIVER DEVICE FOR UNLOCKING A DOOR

Abstract

In a method for determining a motion state of a portable transceiver device for unlocking a door, especially a vehicle door, a radio signal is received at the portable transceiver device. Moreover, a signal strength of the received radio signal is determined. Furthermore, a signal strength variation is determined by comparing the determined signal strength to a previously determined signal strength or by comparing the determined signal strength to a predefined signal strength. Subsequently, it is established that the portable transceiver device is in motion if the amount of signal strength variation exceeds a preset threshold. Alternatively, it is established that the portable transceiver device is at rest if the amount of signal strength variation is equal or lower than the preset threshold. Moreover, a method for remotely unlocking a door, especially a vehicle door, is presented. Also, a portable transceiver device for unlocking a door, especially a vehicle door, is described.

Claims

1. (canceled)

2. (canceled)

3. A method for remotely unlocking a door, comprising: a) emitting a radio signal from the door or an object including the door, the radio signal being a request signal, b) receiving the request signal at a portable transceiver device, c) determining a signal strength of the received request signal, d) determining a signal strength variation by comparing the determined signal strength to a previously determined signal strength or by comparing the determined signal strength to a predefined signal strength, e) emitting a radio signal from the portable transceiver device as an answer signal only if the amount of signal strength variation exceeds a preset threshold, and f) receiving the answer signal at the door or at the object including the door and performing an unlocking activity.

4. The method according to claim 3, wherein the signal strength variation is only determined if the determined signal strength of the received request signal is above a predefined threshold.

5. The method according to claim 3, wherein the answer signal is only emitted if the determined signal strength is bigger than the previously determined signal strength or the predefined signal strength.

6. The method according to claim 3, wherein the request signal is emitted periodically.

7. The method according to claim 3, wherein the door is a vehicle door and the request signal is only emitted if an engine of the vehicle is off.

8. The method according to claim 3, wherein the request signal is only emitted if the door is closed and locked.

9. The method according to claim 3, wherein an identification value in the received answer signal is checked and the unlocking activity only is performed if the identification value is an authorized identification value.

10. The method according to claim 3, wherein the request signal is only emitted if the portable transceiver device is detected to be in an outside region of the door.

11. A portable transceiver device for unlocking a door, comprising a transceiver unit and a controller unit, wherein the transceiver unit and the controller unit are adapted for performing a method according to claim 3.

12. The method according to claim 6, wherein the request signal is emitted every 0.2 to 0.7 seconds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 schematically shows a vehicle and a portable transceiver device according to the invention, wherein the vehicle and the portable transceiver device can be used for performing a method for determining a motion state of the portable transceiver device according to the invention and for performing a method for remotely unlocking a door according to the invention,

[0043] FIG. 2 shows detailed steps of the method for determining a motion state of the portable transceiver device, and

[0044] FIG. 3 shows detailed steps of the method for remotely unlocking the door.

DETAILED DESCRIPTION

[0045] FIG. 1 shows a vehicle 10 and a portable transceiver device 12.

[0046] The portable transceiver device 12 is a key fob for unlocking a door 14 of the vehicle. In the following explanations, a driver door 14 of the vehicle 10 will be used as an illustrative example. However, it is understood that the explanations also apply to any other door of the vehicle 10.

[0047] The vehicle 10 comprises a first antenna device 16 which is arranged inside the door 14.

[0048] The first antenna device 16 is configured for emitting a radio signal which is a low frequency (LF) signal in the present example.

[0049] Moreover, the vehicle 10 comprises a second antenna device 18 which configured for receiving a radio signal sent from the portable transceiver device 12.

[0050] The second antenna device 18 is configured for receiving a high frequency (HF) signal, i.e. the first antenna device 16 and the second antenna device 18 operate on different frequency bands.

[0051] The vehicle 10 further comprises a control unit 20 configured for controlling the first antenna device 16 and the second antenna device 18. Additionally, the control unit 20 is configured for sending a signal for unlocking to the door 14.

[0052] The portable transceiver device 12 comprises a transceiver unit 22.

[0053] The transceiver unit 22 has a third antenna device 24 which is adapted for receiving the radio signal sent by the first antenna device 16. Consequently, the third antenna device 24 is adapted for receiving LF signals.

[0054] The transceiver unit 22 additionally comprises a fourth antenna device 26 which is configured for sending a radio signal which is a HF signal. Thus, this signal can be received by the second antenna device 18 if the portable transceiver device 12 is in the vicinity of the vehicle 10.

[0055] Moreover, a controller unit 28 and a storage unit 30 are provided.

[0056] The storage unit 30 is adapted for storing information relevant for the operation of the portable transceiver device 12. The controller unit 28 is configured for controlling both the storage unit 30 and the transceiver unit 22.

[0057] The controller unit 28 and the transceiver unit 22 are adapted for performing a method for determining a motion state of the portable transceiver device 12 (cf. FIG. 2). This means that it can be determined if the portable transceiver device 12 is in motion or at rest.

[0058] To this end, in a first step S1, a radio signal is received at the portable transceiver device 12. In the example shown, this radio signal is emitted by the first antenna device 16 of the vehicle 10.

[0059] Thereafter, in a step S2, a signal strength of the received radio signal is determined.

[0060] If the signal strength is found to be equal or below a predefined threshold, the received radio signal is considered to be noise and the method is abandoned.

[0061] The threshold is stored on the storage unit 30.

[0062] However, if the determined signal strength of the received radio signal is above the predefined threshold, the method is continued.

[0063] In this case, a signal strength variation is determined in a step S3.

[0064] This is done by comparing the determined signal strength to a previously determined signal strength or by comparing the determined signal strength to a predefined signal strength.

[0065] The previously determined signal strength and the predefined signal strength can be stored on the storage unit 30 such that they are easily accessible for performing step S3.

[0066] On the basis of the signal strength variation it is established that the portable transceiver device 12 is in motion if the amount of signal strength variation exceeds a preset threshold (cf. step S4).

[0067] Alternatively, if the amount of signal strength variation is equal or lower than the preset threshold, it is established that the portable transceiver device 12 is at rest (cf. step S5).

[0068] Also the preset threshold for the signal strength variation can be stored on the storage unit 30.

[0069] The controller unit 28 and the transceiver unit 22 are also adapted for performing a method for remotely unlocking the door 14 of the vehicle 10 (cf. FIG. 3).

[0070] To this end, in a first step S11, a radio signal is emitted from the door 14, more precisely from the first antenna device 16.

[0071] This radio signal is a request signal, which is emitted periodically, in the present example every 0.5 seconds.

[0072] In the present example, the request signal is only sent if an engine of the vehicle 10 is off and the door 14 is closed and locked. Otherwise, the method is abandoned.

[0073] A further condition for emitting the request signal is that the portable transceiver device 12 is detected to be in an outside region of the door 14, i.e. the request signal is only emitted if the portable transceiver device 12 is not inside the vehicle 10.

[0074] In a subsequent step S12, the request signal is received at the portable transceiver device 12, more precisely at the third antenna device 24.

[0075] Thereafter, in a third step S13, a signal strength of the received request signal is determined.

[0076] If the determined signal strength is equal or below a predefined threshold, the method is abandoned.

[0077] Otherwise, i.e. if the determined signal strength of the received request signal is above the predefined threshold, the method is continued.

[0078] In this context, the predefined threshold can be stored on the storage unit 30.

[0079] Subsequently, in a step S14, a signal strength variation is determined by comparing the determined signal strength to a previously determined signal strength or by comparing the determined signal strength to a predefined signal strength.

[0080] Again, the previously determined signal strength and the predefined signal strength can be stored on the storage unit 30.

[0081] Furthermore, a check is performed for establishing whether the determined signal strength is bigger than the previously determined signal strength or the predefined signal strength. In this case, the method is continued since the fact that the determined signal strength is increased with respect to the previously determined signal strength or the predefined signal strength is interpreted as an approaching motion of the portable transceiver device 12 towards the vehicle 10.

[0082] Otherwise, i.e. if the determined signal strength is equal or smaller than the previously determined signal strength or the predefined signal strength, the method is abandoned.

[0083] Moreover, in a step S15, a radio signal is emitted from the portable transceiver device 12 as an answer signal, if the amount of signal strength variation exceeds a preset threshold.

[0084] As before, the preset threshold is stored on the storage unit 30.

[0085] Since the portable transceiver device 12 carries an identification, an identification value is comprised by the answer signal.

[0086] In an additional step S16, the answer signal is received at the door 14 of the vehicle and the identification value is checked, i.e. it is determined if the identification value is an authorized identification value. In other words, it is determined if the portable transceiver device 12 is authorized for unlocking the door 14.

[0087] In the positive case, an unlocking activity is performed by the control unit 20, i.e. at least an unlocking signal is sent to the door 14 in a step S17.

[0088] If the identification value is not an authorized identification value, no unlocking activity is performed (cf. step S18).