Radar System With Improved Angle Formation

• US 20110074621A1
• Filed: 07/02/2009
• Published: 03/31/2011
• Est. Priority Date: 07/02/2008
• Status: Active Grant

• Current Assignee: ADC GmbH (TE Connectivity Ltd. (United Kingdom))
• Original Assignee: ADC GmbH (TE Connectivity Ltd. (United Kingdom))
• Inventors: Wintermantel, Markus
• Granted Patent: US 8,665,137 B2
• Time in Patent Office: Days
• US Class Current: 342/70
• 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 13/4454 phase comparisons monopulse, i.e. comparing the echo signals received by an interferometric antenna arrangement
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/462 using multipath signals
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• 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 7/0234 Avoidance by code multiplex
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems
• CPC Class Codes: G01S 7/285 Receivers
• CPC Class Codes: G01S 7/354 Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40

Abstract

The invention relates to a radar system for recording the environment of a motor vehicle, comprising:

• • transmission means for emitting transmission signals using at least two transmitter antennas;
  • receiving means for receiving transmission signals reflected by objects using one or more receiver antennas;
  • and signal processing means for processing the received signals,
    characterized in that
  • a phase center of at least one receiver antenna does not lie, with regard to a spatial direction R, outside phase centers of two transmitter antennas that are offset in said spatial direction,
  • and in that the signals received by said antenna are separated according to the two portions originating from said two transmitter antennas.

Claims

1. A radar system for recording the environment of a motor vehicle, comprising:

transmission means for emitting transmission signals using at least two transmitter antennas;

receiving means for receiving transmission signals reflected by objects using one or more receiver antennas;

and signal processing means for processing the received signals,

characterized in that

a phase center of at least one receiver antenna does not lie, with regard to a spatial direction R, outside phase centers of two transmitter antennas that are offset in said spatial direction,

and in that the signals received by said receiver antenna are separated according to the two portions originating from said two transmitter antennas

2. A radar system according to claim 1, in which the antennas arranged on the outside with regard to the spatial direction R are used for transmission.

14. A radar system according to claim 1, in which the antennas are constructed in planar technology.

15. A radar system according to claim 1, in which at least one antenna is used both for transmission and reception, wherein this at least one antenna works simultaneously as transmitter and receiver antenna or its function changes temporally between transmitter and receiver antennas.

16. A radar system according to claim 1, in which the separation of the received signals into portions originating from different transmitter antennas is realized by temporal multiplexing of these transmitter antennas, i.e. by corresponding switching only one transmitter antenna is active respectively at any one receiving time, wherein for objects moved relative to the radar system the resulting phase offset of received signals, which originate from different transmitter antennas, is considered for the angular measurement.

17. A radar system according to claim 1, in which the separation of the received signals into portions, which originate from different but simultaneously emitting transmitter antennas, is realized by the fact that for these different transmitter antennas at least one parameter for the modulation of amplitude, frequency and/or phase of the emitted signal is different.

18. A radar system according to claim 1, in which a number N_S of transmitter antennas and a number N_E of receiver antennas each have at least approximately the same emission characteristic and with regard to their phase centers in the spatial direction R are each at least arranged approximately equidistantly, wherein in this spatial direction R the distance of these N_S transmitter antennas to each other is larger by an integral factor K≦

N_E than the distance of these N_E receiver antennas to each other, whereby an arrangement with a transmitter antenna and a maximum of N_S·

N_E receiver antennas equidistantly arranged in this spatial direction R is synthesized with an at least approximately identical emission characteristic.

19. A radar system according to claim 18, wherein in the signal processing means the position of objects in the spatial direction R is determined by the fact that for the angle formation with regard to this spatial direction R a digital beam formation or high-resolution methods are used.

20. A radar system according to claim 18, in which

the N_S transmitter antennas and the N_E receiver antennas are realized in planar technology and are arranged on a plane surface and

at least two of the N_S transmitter antennas and of the N_E receiver antennas overlap with regard to the spatial direction R

characterized in that this overlap is realized by at least one of the following arrangements and/or embodiments of the N_S transmitter antennas and the N_E receiver antennas:

a) the antennas are offset to each other with regard to the spatial direction S which is perpendicular to spatial direction R,

b) the transmitter and/or the receiver antennas have an inclined form with regard to the spatial direction R,

c) the antennas are locked into each other with regard to the spatial direction R,

d) emitting and/or receiving elements are jointly used by at least two transmitter and/or receiver antennas, and/or

e) at least one antenna is used both for transmission and reception.

21. A radar system according to claim 20, in which, with regard to the spatial direction R, the width of the N_S transmitter antennas and/or the width of the N_E receiver antennas is larger than the distance of the N_E receiver antennas to each other.

22. A radar system according claim 18, in which

received signals from different combinations of the N_S transmitter antennas and of the N_E receiver antennas are acquired, wherein for each combination a relative phase center is defined as a sum of the two vectors from a reference point to the phase centers of the respective transmitter antenna and of the respective receiver antenna and the relative phase centers of these combinations of transmitter and receiver antennas lie at least approximately equidistant with regard to the spatial direction R,

with regard to the spatial direction S which runs perpendicular to the spatial direction R, the position of the relative phase centers of these combinations of transmitter antennas and receiver antennas varies periodically with the period length P, if a sequence of these combinations of transmitter antennas and receiver antennas is considered, which is arranged in the spatial direction R with regard to the position of the relative phase centers, and

in the signal processing means it is utilized that the received signals of an object dependent on its angular position in the spatial direction S have a phase portion alternating periodically with the period length P over the combinations of transmitter and receiver antennas arranged in such manner, whereby for this spatial direction S assertions regarding the angular position of objects and/or regarding the misalignment of the radar system are possible.

23. A radar system according to claim 22, in which the spatial direction R lies horizontally and the spatial direction S lies vertically, and in the signal processing means, for recognizing in particular stationary objects which can be driven over or under, a measure is used, which utilizes at least one deviation in relation to the proportions resulting with received signals from only one elevation angle, wherein in connection with the reflecting property of road surfaces the size and/or the amount, in particular filtered in each case over the object distance, and/or the distance-related variation of this measure is used for an at least rough estimate of the height of objects above the road surface.

24. A radar system according to claim 1, in which

received signals from different combinations of transmitter and receiver antennas are acquired, wherein for each combination a relative phase center is defined as a sum of the two vectors from a reference point to the phase centers of the respective transmitter antenna and of the respective receiver antenna,

transmitter and receiver antennas used thereby each have at least approximately the same emission characteristic, wherein the emission characteristic of these transmitter antennas can be different from the emission characteristic of these receiver antennas,

with regard to the spatial direction R the position of the relative phase centers of these combinations of transmitter and receiver antennas varies periodically with the period length Q by an equidistant raster, and

in the signal processing means, for determining the position of objects in the spatial direction R, it is utilized that the received signals of an object dependent on its angular position in the spatial direction R apart from a linear phase portion have a phase portion alternating with the period length Q, if a sequence of the combinations of transmitter and receiver antennas ordered in the spatial direction R with regard to the position of the relative phase centers is considered.

3-13. -13. (canceled)