Automotive radar system and method for using same

• US 8,432,309 B2
• Filed: 11/29/2010
• Issued: 04/30/2013
• Est. Priority Date: 11/29/2010
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: MacDonald, James D., Rubin, Lawrence A.
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US12/955,625
• Publication Number:
  US 20120133547A1
• Time in Patent Office: 883 Days
• Field of Search: 342/128, 342/137, 342/136
• US Class Current: 342/137
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/462 using multipath signals
• CPC Class Codes: G01S 2013/9315 Monitoring blind spots
• CPC Class Codes: G01S 2013/93273 on the top of the vehicles
• CPC Class Codes: G01S 2013/93274 on the side of the vehicles
• CPC Class Codes: G01S 2013/93275 in the bumper area

Abstract

A radar system (44) for a vehicle (42) includes a transmit unit (56) and a receive unit (58). The transmit unit (56) includes a single beam antenna (72) for output of a radar signal (74) into a target zone (46). The receive unit (58) includes a single beam antenna (76) for receiving a direct receive signal (78) and an indirect receive signal (80). The receive signals (78, 80) are reflections of the radar signal (74) from an object (34, 36) in the target zone (46). The indirect receive signal (80) is reflected off the object (34, 36) toward a reflective panel (54) of the vehicle (42), and the indirect receive signal (80) is reflected off the reflective panel (54) for receipt at the receive antenna (76). The receive signals (78, 80) are summed to produce a detection signal (81) indicating presence of the object (34, 36) in the target zone (46).

Claims

1. A radar system for a vehicle comprising:

a transmit unit including a single beam transmit antenna for output of a radar signal into a target zone external to said vehicle; and

a receive unit including a single beam receive antenna capable of receiving a direct receive signal and an indirect receive signal, each of said direct and indirect receive signals being reflections of said radar signal from an object in said target zone, and said direct and indirect receive signals being summed to produce a detection signal indicating a presence of said object in said target zone, wherein said target zone includes a first region adjacent to a side of said vehicle and a second region displaced outwardly and backwardly from a rear quarter panel of said vehicle, and said each of said single beam transmit and receive antennas exhibits an antenna pattern having a main lobe directed in said second region and a side lobe reflected from a reflective panel of said vehicle into said first region such that when said object is located in said second region, a first signal strength of said direct receive signal dominates a second signal strength of said indirect receive signal in said detection signal and when said object is located in said first region, said second signal strength of said indirect receive signal dominates said first signal strength of said direct receive signal in said detection signal.

2. A radar system as claimed in claim 1 wherein each of said single beam transmit and receive antennas produces an antenna pattern having a main lobe and first side lobes joined to each side of said main lobe, said first side lobes being shoulder-type side lobes.

3. A radar system as claimed in claim 1 wherein each of said single beam transmit and receive antennas includes a feed antenna having a patch antenna element.

4. A radar system as claimed in claim 3 wherein said feed antenna is mounted proximate a back surface of a dielectric lens.

5. A radar system as claimed in claim 1 wherein each of said single beam transmit and receive antennas is stabilized to produce a free space equivalent antenna pattern.

6. A radar system as claimed in claim 1 wherein each of said single beam transmit and receive antennas exhibits an antenna pattern that is wider in azimuth than in elevation.

7. A radar system as claimed in claim 1 wherein said radar signal is an indirect transmit signal reflected off said reflective panel of said vehicle toward said object in said target zone, and said indirect receive signal is reflected off said reflective panel for receipt at said receive antenna.

8. A radar system as claimed in claim 1 further comprising:

a first housing in which said transmit unit is located; and

a second housing separate from said first housing in which said receive unit is located so that said single beam transmit antenna is separate and isolated from said single beam receive antenna.

9. A radar system as claimed in claim 1 wherein said transmit unit and said receive unit are configured to be mounted to an outside mirror of said vehicle with respective transmit and receive antennas aimed toward said target zone.

10. A radar system as claimed in claim 1 wherein said receive unit provides said detection signal for alerting an operator of said vehicle of said presence of said object in said target zone.

11. A method for detecting an object in a target zone external to a vehicle comprising:

defining said target zone to include a first region adjacent to a side of said vehicle and a second region displaced outwardly and backwardly from a rear quarter panel of said vehicle;

transmitting a radar signal from a single beam transmit antenna of a transmit unit into said target zone;

receiving a direct receive signal and an indirect receive signal at a single beam receive antenna of a receive unit, each of said direct and indirect receive signals being reflections of said radar signal from said object;

directing a main lobe of an antenna pattern for each of said single beam transmit and receive antennas into said second region such that a side lobe of said antenna pattern is reflected from a reflective panel of said vehicle into said first region, wherein when said object is located in said second region, a first signal strength of said direct receive signal dominates a second signal strength of said indirect receive signal in said detection signal and when said object is located in said first region, said second signal strength of said indirect receive signal dominates said first signal strength of said direct receive signal in said detection signal; and

summing said direct and indirect receive signals to produce a detection signal indicative of a presence of said object in said target zone.

12. A method as claimed in claim 11 further comprising selecting each of said single beam transmit and receive antennas that produce an antenna pattern having a main lobe and first side lobes joined to each side of said main lobe.

13. A method as claimed in claim 11 further comprising selecting each of said single beam transmit and receive antennas that produce an antenna pattern that is wider in azimuth than in elevation.

14. A method as claimed in claim 11 wherein said indirect receive signal is reflected off said object in said target zone toward said reflective panel of said vehicle, and said indirect receive signal is subsequently reflected off said reflective panel for receipt at said receive antenna.

15. A method as claimed in claim 11 further comprising alerting an operator of said vehicle of said presence of said object in said target zone in response to said detection signal.

16. A radar system for a vehicle comprising:

a transmit unit including a single beam transmit antenna for output of a radar signal into a target zone external to said vehicle; and

a receive unit including a single beam receive antenna capable of receiving a direct receive signal and an indirect receive signal, each of said direct and indirect receive signals being reflections of said radar signal from an object in said target zone, each of said single beam transmit and receive antennas producing an antenna pattern having a main lobe and first side lobes joined to each side of said main lobe, said first side lobes being shoulder-type side lobes, and said antenna pattern being wider in azimuth than in elevation, and said direct and indirect receive signals being summed to produce a detection signal indicating a presence of said object in said target zone, wherein said target zone includes a first region adjacent to a side of said vehicle and a second region displaced outwardly and backwardly from a rear quarter panel of said vehicle, and said each of said single beam transmit and receive antennas exhibits an antenna pattern having said main lobe directed in said second region and one of said first side lobes reflected from a reflective panel of said vehicle into said first region such that when said object is located in said second region, a first signal strength of said direct receive signal dominates a second signal strength of said indirect receive signal in said detection signal and when said object is located in said first region, said second signal strength of said indirect receive signal dominates said first signal strength of said direct receive signal in said detection signal.

17. A radar system as claimed in claim 16 wherein each of said single beam transmit and receive antennas comprises a feed antenna having a single patch antenna element mounted proximate a back surface of a dielectric lens, said feed antenna being stabilized to produce a free space equivalent antenna pattern.