Automobile radar antenna alignment system using transponder and lasers

• US 6,329,952 B1
• Filed: 06/01/2000
• Issued: 12/11/2001
• Est. Priority Date: 02/17/1999
• Status: Expired due to Fees

• Current Assignee: Anritsu Co (Anritsu Corporation)
• Original Assignee: Anritsu Co (Anritsu Corporation)
• Inventors: Grace, Martin I.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): NGUYEN, HOANG V
• Application Number:
  US09/587,539
• Time in Patent Office: 558 Days
• Field of Search: 343/703, 343/713, 340/903, 342/174, 356/385
• US Class Current: 343/703
• CPC Class Codes: G01S 7/4017 of HF systems
• CPC Class Codes: G01S 7/4026 Antenna boresight
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/4034 in elevation, i.e. in the vertical plane
• CPC Class Codes: G01S 7/4052 by simulation of echoes
• CPC Class Codes: G01S 7/4065 involving a delay line
• CPC Class Codes: G01S 7/4086 in a calibrating environment, e.g. anechoic chamber
• CPC Class Codes: G01S 7/4095 the external reference signals being modulated, e.g. rotating a dihedral reflector or modulating a transponder for simulation of a Doppler echo
• 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 21/061 Two dimensional planar arrays

Abstract

A transponder (200) is attached to a laser alignment fixture (210) and used to align an automobile collision avoidance radar antenna boresite with the thrust vector of the vehicle. The alignment fixture (210) has attached reflectors for alignment with two laser beams. To align the collision avoidance radar, the transponder (200) is positioned along the thrust vector of the automobile using a first laser beam (203) aligned perpendicular to a wheel axle. The first laser beam (203) is aligned when transmitted from the wheel axle onto a first piece of reflective material attached to the alignment fixture (210). A second laser (216) is provided parallel to the centerline of the collision avoidance radar antenna to remove azimuth and elevation translation errors between the transponder antenna centerline and the collision avoidance radar antenna centerline. The second laser beam (216) is aligned when transmitted from the automobile onto a second piece of reflective material attached to the alignment fixture (210). The transponder (200) is then used to zero an angle (α) between the electrical boresite of the collision avoidance radar antenna and the boresite of the transponder antenna. The angle (α) is set to zero by adjusting the automobile collision avoidance radar antenna until a processor in the collision avoidance radar indicates the angle a is zero.

Claims

1. A method of aligning an automotive radar antenna of a collision avoidance radar system installed in an automobile comprising the steps of:

providing a first laser beam approximately perpendicular to an axle of the automobile;

moving a transponder and determining when the light from the first laser beam is reflected from a first reflective material on an alignment fixture supporting the transponder;

providing a second laser beam from the automobile aligned approximately parallel with the centerline of the radar antenna;

removing translation errors by moving the alignment fixture and determining when light from the second laser beam is reflected from a second reflective material on the alignment fixture;

transmitting a first RF signal from the radar antenna to a transponder antenna;

transmitting a return RF signal from the transponder antenna in response to the first RF signal; and

adjusting the boresite position of the radar antenna until a processor indicates, based on the receipt of the return RF signal, that the boresite of the radar antenna is aligned with the boresite of the transponder antenna.

2. The method of claim 1, further comprising the steps of:

downconverting the first RF signal to provide an intermediate frequency signal;

delaying the intermediate frequency signal; and

upconverting the frequency of the intermediate frequency signal to provide the return RF signal.

3. The method of claim 2, wherein a Doppler shift is provided to the return RF signal during the step of upconverting.

4. A method of testing an automobile collision avoidance radar system installed in an automobile comprising the steps of:

positioning a transponder antenna of a transponder approximately along a mechanical reference line from the automobile;

removing translation errors by moving the transponder antenna so that the transponder antenna centerline is approximately aligned with a centerline of an automotive radar antenna of the collision avoidance radar system;

transmitting a first signal from the radar antenna to the transponder antenna;

transmitting a return signal from the transponder antenna in response to the first signal;

adjusting the boresite position of the radar antenna until the collision avoidance radar system indicates, based on the receipt of the return signal, that the electrical boresite of the radar antenna is aligned with the electrical boresite of the transponder antenna.

5. The method of claim 4, wherein the step of removing translation errors is performed using the following steps:

providing a laser beam from the automobile aligned approximately parallel with a centerline of the transponder antenna; and

moving the alignment fixture until the laser beam is reflected from a reflective material on the alignment fixture.

6. The method of claim 4, wherein the step of removing translation errors is performed using the following steps:

providing a laser beam from an alignment fixture aligned approximately parallel with a centerline of the transponder antenna; and

removing translation errors by moving the alignment fixture until the laser beam is reflected back from a reflective material on the automobile.

7. The method of claim 4, further comprising the steps of:

downconverting the first signal from the collision avoidance radar system to provide an intermediate frequency signal;

delaying the intermediate frequency signal; and

upconverting frequency of the intermediate frequency signal to provide the return signal.

8. The method of claim 7, wherein a Doppler shift is provided to the conditioned signal during the step of upconverting.

9. An automobile collision avoidance radar antenna alignment system comprising:

a transponder alignment fixture;

a transponder attached to the alignment fixture, said transponder having a transponder antenna;

a first reflective material positioned on the alignment fixture so that a laser beam aligned approximately perpendicular to the automobile wheel axle, when reflected from the first reflective material, will position the transponder antenna approximately along the thrust vector of the vehicle; and

a second reflective material positioned on the transponder alignment fixture so that a laser beam aligned approximately parallel to a centerline of an automotive radar antenna of the collision avoidance radar system, when reflected from the second reflective material, will remove translation errors between the centerline of the automotive radar antenna and a centerline of the transponder antenna.

10. The system of claim 9, wherein the transponder comprises:

a transponder antenna;

a first local oscillator;

a first downconverter having a first input coupled to the output of the antenna, a second input coupled to the first local oscillator, and having an output;

switches for selectively coupling one of at least two delay elements from the output of the second down converter with a first node;

a second local oscillator; and

an upconverter having a first input coupled to the first node, a second output coupled to the second local oscillator, and an output coupled to the antenna.

11. The system of claim 10, wherein one of the delay elements comprises a bulk acoustic wave delay line.

12. The system of claim 10, wherein one of the delay elements comprises a through line.

13. The system of claim 10, wherein the first and second local oscillators are phase locked, and the second local oscillator is controlled to have a frequency offset from the first local oscillator to provide a desired Doppler shift in the conditioned signal.

14. The system of claim 10, wherein the transponder alignment fixture includes a narrow slot positioned so that the transponder will be positioned along the thrust vector of the automobile when the laser beam passes through the narrow slot and is reflected from the first reflective material.