Radar system having arrangements and methods for the decoupling of transmitting and receiving signals and for the suppression of interference radiation

• US 9,182,476 B2
• Filed: 04/01/2010
• Issued: 11/10/2015
• Est. Priority Date: 04/06/2009
• Status: Active Grant

• Current Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Original Assignee: Conti Temic Microelectronic GmbH (Continental AG)
• Inventors: Wintermantel, Markus
• Primary Examiner(s): Barker, Matthew M
• Application Number:
  US13/256,488
• Publication Number:
  US 20120001791A1
• Time in Patent Office: 2,049 Days
• Field of Search: 342 70- 72
• US Class Current: 1/1
• CPC Class Codes: G01S 13/26 wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
• CPC Class Codes: G01S 13/343 using sawtooth modulation
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/0233 Avoidance by phase multiplex
• CPC Class Codes: G01S 7/038 Feedthrough nulling circuits
• CPC Class Codes: G01S 7/2926 by integration
• CPC Class Codes: G01S 7/2928 Random or non-synchronous interference pulse cancellers
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing

Abstract

Using a radar system in a motor vehicle, high frequency individual signal pulses are transmitted from at least one transmitting antenna, and at least one receiving antenna receives reception signals formed by reflection of the transmitted signal pulses from objects in the surroundings. The reception signals are mixed with the high-frequency signal to produce low-frequency mixed signals representing the sequence of individual signal pulses. The phase angle of the mixed signals is varied over successive individual signal pulses thereof by varying the phase angle of: the successive individual transmitted signal pulses, the high-frequency signals used for the mixing, and/or the mixed signals. In further processing of the mixed signals to determine the distance and the relative velocity of detected objects, an interference component can be separated and/or suppressed from a useful signal component because the useful signal component has the known phase angle variation but the interference component does not.

Claims

1. A method of operating a radar system in a motor vehicle, wherein said radar system comprises a high frequency oscillator, at least one transmitting antenna, at least one receiving antenna, a mixer and a signal processing arrangement, and wherein said method comprises the steps:

a) with said oscillator, producing a high frequency signal comprising a succession of individual signal pulses;

b) with said at least one transmitting antenna, transmitting said succession of individual signal pulses as transmitted signal pulses into an environment outside said motor vehicle;

c) with said at least one receiving antenna, receiving received signal pulses formed by reflections of said transmitted signal pulses from at least one object in said environment, and producing a received signal comprising said received signal pulses;

d) providing a high frequency secondary signal from said oscillator to said mixer, providing said received signal to said mixer, and with said mixer mixing said received signal and said high frequency secondary signal and thereby producing a low frequency mixed signal comprising low frequency pulses representing said received signal pulses;

e) imposing a phase angle variation on a phase angle of at least some of said low frequency pulses in said low frequency mixed signal by at least one of;

a substep e1) of varying a phase angle of at least some of said individual signal pulses of said high frequency signal before said transmitting, a substep e2) of varying a phase angle of said high frequency secondary signal before said providing thereof to said mixer, and a substep e3) of varying said phase angle of said at least some of said low frequency pulses directly in said low frequency mixed signal after said producing of said low frequency mixed signal;

f) processing said low frequency mixed signal in said signal processing arrangement, comprising performing at least one Fourier transformation on said low frequency mixed signal, including a first Fourier transformation to determine a distance of said at least one object relative to said motor vehicle, or including first and second Fourier transformations to determine a relative velocity of said at least one object relative to said motor vehicle; and

g) during said processing, at least partially eliminating or suppressing an interference component that is further included in said low frequency mixed signal, based on said interference component not exhibiting said phase angle variation that was imposed on said phase angle of at least some of said low frequency pulses in said low frequency mixed signal, wherein said at least partial eliminating or suppressing of said interference component comprises reversing said phase angle variation imposed on said phase angle of at least some of said low frequency pulses by imposing, after said first Fourier transformation, a reverse phase angle variation on said phase angle of those of said low frequency pulses onto which said phase angle variation had been imposed.

2. The method according to claim 1, wherein said individual signal pulses comprise pulses of an amplitude of said high frequency signal over time, and wherein said step e) comprises said substep e1), which comprises varying said phase angle of said individual signal pulses respectively from pulse to pulse.

3. The method according to claim 1, wherein said individual signal pulses each respectively comprise a frequency ramp with a linearly varying frequency of said high frequency signal, and wherein said step e) comprises said substep e1), which comprises varying said phase angle of said individual signal pulses respectively from pulse to pulse.

4. The method according to claim 1, wherein said phase angle variation comprises varying said phase angle of said low frequency pulses from pulse to pulse and not during each respective one of said low frequency pulses.

5. The method according to claim 1, wherein said phase angle variation in said step e) comprises a 180°

phase inversion of said phase angle of at least some of said low frequency pulses.

6. The method according to claim 1, wherein said phase angle variation in said step e) is imposed on alternate ones of said low frequency pulses.

7. The method according to claim 1, wherein said phase angle variation in said step e) is imposed on randomly or pseudo-randomly selected successive ones of said low frequency pulses.

8. The method according to claim 1, wherein said step e) comprises said substep e1).

9. The method according to claim 1, wherein said step e) comprises said substep e2).

10. The method according to claim 1, wherein said step e) comprises said substep e3).

11. The method according to claim 1, wherein said phase angle variation in said step e) is a fixed predetermined variation.

12. The method according to claim 1, wherein said phase angle variation in said step e) is a random variation or a pseudo-random variation.

13. The method according to claim 1, wherein said interference component is caused by said radar system or is imposed from outside of said radar system, and said interference component has a frequency in a high frequency range of said transmitted signal pulses or in a low frequency range of said low frequency pulses.

14. The method according to claim 1, wherein said at least one Fourier transformation performed in said processing in said step f) comprises said first and second Fourier transformations and a further third Fourier transformation performed in succession after one another, and wherein said imposing of said reverse phase angle variation is performed before said second Fourier transformation.

15. The method according to claim 1, wherein said transmitted signal pulses are transmitted from said at least one transmitting antenna simultaneously with said received signal pulses being received by said at least one receiving antenna, and said interference component comprises pulses caused by unintentional radiation from said at least one receiving antenna.

16. The method according to claim 1, wherein said at least one transmitting antenna comprises plural antennas or said at least one receiving antenna comprises plural antennas, said transmitting or said receiving is carried out with successive ones of said transmitted or received signal pulses respectively via said plural antennas operated in series or in parallel with one another, and said processing is further carried out to determine an angular direction of said at least one object.

17. The method according to claim 1, wherein said at least one transmitting antenna comprises plural antennas or said at least one receiving antenna comprises plural antennas, and said imposing of said phase angle variation comprises selecting and applying said phase angle variation so as to achieve a more-uniform detection sensitivity over all angular regions of detection by said at least one receiving antenna as compared to a less-uniform detection sensitivity achieved without said phase angle variation being imposed.

18. The method according to claim 1, wherein said processing comprises integrating said low frequency pulses, such that said interference component results in merely incoherent noise which has thereby been at least partially eliminated or suppressed in said step g).

19. The method according to claim 1, wherein said at least one receiving antenna comprises plural receiving antennas, said receiving of said received signal pulses is performed simultaneously with said plural receiving antennas to respectively produce a plurality of said received signals, said method further comprises summing said plural received signals before said mixing or summing a plurality of said low frequency mixed signal after said mixing, and said processing comprises at least partly separating from one another said plural received signals after said summing.

20. The method according to claim 1, wherein said at least one Fourier transformation performed in said step f) comprises only said first Fourier transformation to determine said distance.

21. The method according to claim 1, wherein said at least one Fourier transformation performed in said step f) comprises said first and second Fourier transformations to determine said relative velocity.

22. A method of operating a radar system in a motor vehicle, wherein said radar system comprises a high frequency oscillator, plural transmitting antennas, at least one receiving antenna, a mixer and a signal processing arrangement, and wherein said method comprises the steps:

a) with said oscillator, producing a high frequency signal comprising a succession of individual signal pulses;

b) simultaneously from said plural transmitting antennas, transmitting said succession of individual signal pulses as transmitted signal pulses into an environment outside said motor vehicle;

c) with said at least one receiving antenna, receiving received signal pulses formed by reflections of said transmitted signal pulses from at least one object in said environment, and producing a received signal comprising said received signal pulses;

d) providing a high frequency secondary signal from said oscillator to said mixer, providing said received signal to said mixer, and with said mixer mixing said received signal and said high frequency secondary signal and thereby producing a low frequency mixed signal comprising low frequency pulses representing said received signal pulses;

e) imposing a phase angle variation on a phase angle of at least some of said low frequency pulses in said low frequency mixed signal by at least varying a phase angle of at least some of said individual signal pulses of said high frequency signal before said transmitting, whereby said phase angles of said individual signal pulses transmitted from different ones of said plural transmitting antennas are respectively different relative to one another on an antenna-by-antenna basis;

f) processing said low frequency mixed signal in said signal processing arrangement to determine at least one of a distance and a relative velocity of said at least one object relative to said motor vehicle, wherein said processing comprises at least partly separating from one another said individual signal pulses transmitted respectively from different ones of said plural transmitting antennas as represented in said received signal produced by a single said receiving antenna; and

g) during said processing, distinguishing between a useful signal component and an interference component that are both included in said low frequency mixed signal, in that said interference component does not exhibit said phase angle variation that was imposed on said phase angle of at least some of said low frequency pulses in said low frequency mixed signal.

23. The method according to claim 22, wherein said processing comprises integrating said low frequency pulses, such that said interference component results in merely incoherent noise which is thereby at least partially eliminated or suppressed.

24. A method of operating a radar system in a motor vehicle, wherein said radar system comprises a high frequency oscillator, two transmitting antennas, at least one receiving antenna, a mixer and a signal processing arrangement, and wherein said method comprises the steps:

a) with said oscillator, producing a high frequency signal comprising a succession of individual signal pulses;

b) simultaneously from said two transmitting antennas, transmitting said succession of individual signal pulses as transmitted signal pulses into an environment outside said motor vehicle;

c) with said at least one receiving antenna, receiving received signal pulses formed by reflections of said transmitted signal pulses from at least one object in said environment, and producing a received signal comprising said received signal pulses;

d) providing a high frequency secondary signal from said oscillator to said mixer, providing said received signal to said mixer, and with said mixer mixing said received signal and said high frequency secondary signal and thereby producing a low frequency mixed signal comprising low frequency pulses representing said received signal pulses;

e) imposing a phase angle variation on a phase angle of at least some of said low frequency pulses in said low frequency mixed signal by at least varying a phase angle of at least some of said individual signal pulses of said high frequency signal before said transmitting, whereby said phase angles of said individual signal pulses respectively transmitted from said two antennas are respectively different from one another;

f) processing said low frequency mixed signal in said signal processing arrangement to determine at least one of a distance and a relative velocity of said at least one object relative to said motor vehicle; and

g) during said processing, distinguishing between a useful signal component and an interference component that are both included in said low frequency mixed signal, in that said interference component does not exhibit said phase angle variation that was imposed on said phase angle of at least some of said low frequency pulses in said low frequency mixed signal.

25. The method according to claim 24, wherein said processing comprises integrating said low frequency pulses, such that said interference component results in merely incoherent noise which is thereby at least partially eliminated or suppressed.