Access device for a vehicle

1. An access device for a vehicle, comprising:

an on-vehicle control device configured to transmit enquiry signals to a mobile identification transmitter to query state of motion thereof;

wherein the on-vehicle control device is further configured to adapt the transmission of the enquiry signals for a response from the mobile identification transmitter containing the state of motion thereof or for the absence of the response;

the mobile identification transmitter, the mobile identification transmitter comprising:

a motion sensor for detecting a movement of the mobile identification transmitter,

an identification-transmitter transmitting/receiving device configured to:

receive the vehicle's enquiry signals, and

transmit a response signal containing the state of motion of the mobile identification transmitter in response to at least one enquiry signal; and

an identification-transmitter control device configured to control the transmission of the response signals;

wherein the on-vehicle control device transmits to the mobile identification transmitter an enquiry signal, containing a request, at any one time or after a specific time interval has elapsed after a specific state of motion of the mobile identification transmitter has been recognized, which enquiry signal forces the mobile identification transmitter to return a response signal in any event.

2. The access device as claimed in claim 1 , wherein the identification-transmitter control device is configured to enable the transmission of a response signal only when a specific state of motion exists.

3. The access device as claimed in claim 1 , wherein the mobile identification transmitter further comprises:

an identification-transmitter timing device for recording the time since a last predetermined movement of the mobile identification transmitter.

4. The access device as claimed in claim 1 , wherein the identification-transmitter control device is further configured to:

recognize the state of motion to be a stationary state of the mobile identification transmitter when detected movement is below a predetermined threshold value, and

recognize the state of motion to be a moving state of the mobile identification transmitter when the detected movement is above a predetermined threshold value.

5. The access device as claimed in claim 3 , wherein the identification-transmitter control device is further configured to recognize the state of motion of the mobile identification transmitter as a moving state when detected movement is above a predetermined threshold value and the time measured by the identification-transmitter timing device is within a predetermined time interval.

6. The access device as claimed in claim 1 , wherein the on-vehicle control device is further configured to reduce frequency of the transmission of the enquiry signals when a stationary state has been received as the state of motion of the mobile identification transmitter.

7. The access device as claimed in claim 1 , wherein the on-vehicle control device is further configured to reduce a data content or signal duration of the enquiry signals when a stationary state has been received as the state of motion of the mobile identification transmitter.

8. The access device as claimed in claim 6 , wherein the on-vehicle control device is further configured to increase the frequency of the transmission of the enquiry signals again when, after a stationary state has been received as the state of motion of the mobile identification transmitter, a moving state has been received again.

9. The access device as claimed in claim 1 , wherein the mobile identification transmitter automatically transmits a notification signal when it changes from a stationary to a moving state.

10. The access device as claimed in claim 1 , wherein the on-vehicle control device is designed to authenticate the mobile identification transmitter by using at least one enquiry signal to transmit a request, and to receive a response signal from the mobile identification transmitter containing an identification code.

11. The access device as claimed in claim 1 , wherein the on-vehicle control device transmits signals configure to determine position of the mobile identification transmitter as the enquiry signals or as separate localization signals.

12. The access device as claimed in claim 11 , wherein localization signals for position determination are transmitted only when a moving state of the mobile identification transmitter is recognized.

13. The access device as claimed in claim 1 , wherein the on-vehicle control device is further configured to trigger a predetermined vehicle function based on reception of a moving state of the mobile identification transmitter or position of the mobile identification transmitter relative to the vehicle or the reception of a valid identification code of the mobile identification transmitter, or if a specific combination of said criteria exists.

14. A vehicle having an access device as claimed in claim 1 .

15. A method for operating an access device of a vehicle, comprising:

at an on-vehicle control device:

transmitting enquiry signals to a mobile identification transmitter to query state of motion thereof;

adapting the transmission of the enquiry signals for a response signal received from the mobile identification transmitter containing the state of motion of the mobile identification transmitter, or based on the absence of the response signal; and

emitting at any one time or after a specific time interval has elapsed after a specific state of motion of the mobile identification transmitter has been recognized an enquiry signal, which enquiry signal; at the mobile identification transmitter, forces the mobile identification transmitter to return a response signal in any event.