Device for transmitting data in a motor vehicle

• US 20030142004A1
• Filed: 12/13/2002
• Published: 07/31/2003
• Est. Priority Date: 02/09/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Gaier, Stefan, Gottwald, Frank, Voigtlaender, Klaus, Giehler, Elmar, Crowhurst, Peter, Tihovsky, Slava
• Granted Patent: US 6,693,581 B2
• Time in Patent Office: Days
• US Class Current: 342/42
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9329 cooperating with reflectors or transponders
• CPC Class Codes: G01S 7/006 using shared front-end circuitry, e.g. antennas G01S13/765, G01S13/825 take precedence
• CPC Class Codes: G01S 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/61 Signal comprising different frequencies, e.g. frequency hopping
• 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: H01Q 1/3208 characterised by the application wherein the antenna is used

Abstract

A device for data transmission in a motor vehicle and/or from a motor vehicle in its vicinity has a first transceiver unit (1) in or on the motor vehicle and a second transceiver unit (2) which is provided in at least one transponder unit whose spatial position relative to the vehicle may be variable or any desired position; it is characterized in that the first transceiver unit (1) is a radar unit equipped for distance measurement, expanded by adding a two-channel data transmission system; the second transceiver unit (2) is also a two-channel data transmission unit, and the microwave frequencies (f₁, f₂) for two-channel communication of the data transmission system are selected so that their difference |f₁-f₂| yields an intermediate frequency (f_IF) which is processable using conventional components in a heterodyne receiver in the reception part of each of the first and second transceiver units (1, 2).

Claims

1. A device for data transmission in a motor vehicle and/or from a motor vehicle in its vicinity, comprising a first transceiver unit (1) in or on the motor vehicle and a second transceiver unit (2) which is provided in at least one transponder unit whose spatial position relative to the vehicle may be arbitrary or variable,

wherein the first transceiver unit (1) is a radar unit equipped for distance measurement, which is expanded by adding a two-channel data transmission system;

the second transceiver unit (2) is also a two-channel data transmission unit; and

the microwave frequencies (f₁, f₂) for two-channel communication of the data transmission system are selected such that their difference |f₁-f₂| yields an intermediate frequency (f_IF) which is processable using conventional components in a heterodyne receiver in the reception part of each of the first and second transceiver units (1, 2).

2. A data transmission device according to claim 1, wherein the transmitting or receiving antenna(s) (15, 16;

26, 25) is/are circularly polarized on the side of the first or second transceiver unit (1 or 2), and the respective receiving or transmitting antenna(s) (26, 25;

15, 16) is/are linearly polarized on the side of the respective other transceiver unit (2, 1).

3. The data transmission device according to claim 2, wherein the antenna(s) is/are circularly polarized on the transponder side.

4. The data transmission device according to claim 2 or 3, wherein the antenna(s) has/have a spherical directional characteristic on the transponder side.

5. The data transmission device according to one of the preceding claims, wherein the transponder unit is part of a vehicle key.

6. The data transmission device according to claim 5, wherein the vehicle key is set up for “

keyless access”

to the motor vehicle on the basis of an identification signal transmitted by data transmission between the vehicle and the transponder.

7. The data transmission device according to one of the preceding claims, wherein at least one transponder unit is also provided in an installation for acquisition of fees or for telematic applications or for remote control applications.

8. The data transmission device according to one of the preceding claims, wherein the transmitter and receiver of both transceiver units (1, 2) are set up so that their transmission frequency (f₁, f₂) is simultaneously used as the local oscillator frequency for a mixer (12, 22) which downmixes the receiving frequency in the reception case.

9. The data transmission device according to one of the preceding claims, wherein the transmission and receiving frequencies (f₁, f₂) of both transceiver units (1, 2) are selected so that their frequency shift conforms to the band limits of the frequency band used.

10. The data transmission device according to one of the preceding claims, wherein each microwave oscillator (10, 20) of both transceiver units (1, 2) has a dielectric resonant oscillator (DRO).

11. The data transmission device according to one of claims 1 through 9, wherein each microwave oscillator of both transceiver units (1, 2) has a voltage-controlled oscillator (VCO).

12. The data transmission device according to one of the preceding claims, wherein a frequency drift is corrected by an AFC circuit (27) in only one of the transceiver units, and thus the intermediate frequency (f_IF) is kept constant.

13. The data transmission device according to one of the preceding claims, wherein a fluctuation in the intermediate frequency (f_IF) caused by a frequency drift is compensated in only one of the transceiver units (1, 2);

the intermediate frequency is downmixed with a variable local oscillator signal (f_LO) to a lower constant intermediate frequency (f_IF2).

14. The data transmission device according to claim 12 or 13, wherein the AFC circuit for correcting frequency drift or a circuit for generating the variable local oscillator signal for downmixing the intermediate frequency is provided only in the second transceiver unit (2) in the transponder.

15. The data transmission device according to one of claims 1 through 14, wherein at least one of the transceiver units (1, 2) has a transmitting antenna and a separate receiving antenna.

16. The data transmission device according to one of claims 1 through 14, wherein at least one of the transceiver units (1, 2) has a common antenna and a directional coupler for the transmitting/receiving branch.

17. The data transmission device according to one of the preceding claims, wherein a frequency shift keying modulator (FSK-M) is provided in the first and second transceiver units (1, 2).

18. The data transmission device according to one of claims 1 through 16, wherein an amplitude shift keying modulator (ASKM) is provided in the first and second transceiver units (1, 2).

19. The data transmission device according to one of claims 1 through 16, wherein a phase shift keying modulator (PSK-M) is provided in the first and second transceiver units (1, 2).