Vehicle obstacle warning radar

• US 20060022866A1
• Filed: 10/19/2004
• Published: 02/02/2006
• Est. Priority Date: 01/17/2002
• Status: Active Grant

• Current Assignee: Ohio State Innovation Foundation (Ohio State University)
• Original Assignee: Ohio State University
• Inventors: Walton, Eric K., Chen, Chi-Chih
• Granted Patent: US 7,295,154 B2
• Time in Patent Office: Days
• US Class Current: 342/194
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: G01S 2013/0254 Active array antenna
• CPC Class Codes: G01S 2013/9315 Monitoring blind spots
• CPC Class Codes: G01S 2013/93271 in the front 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
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: G01S 7/352 Receivers
• CPC Class Codes: G01S 7/358 using I/Q processing
• CPC Class Codes: G01S 7/4086 in a calibrating environment, e.g. anechoic chamber
• 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 1/3283 side-mounted antennas, e.g. bumper-mounted, door-mounted mounted on windscreens H01Q1/1271
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• 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 present invention is a radar system for detecting the presence of obstacles. The radar system includes at least one transmitting antenna and at least one receiving antenna. The transmitting antenna receives an input signal and transmits an electromagnetic wave. The electromagnetic wave reflects off an obstacle back to the receiving antenna. The receiving antenna captures the reflected electromagnetic wave and produces an output signal. The output signal is then combined with the local reference signal in a quadrature mixer. The resulting in-phase (I) and quadrature (Q) signals may be further processed and then transmitted to a processing system. The processing system uses a suitable algorithm, e.g., a back projection algorithm, to estimate the type and location of obstacles that reflected the electromagnetic wave. In an exemplary embodiment, the algorithm is adapted to discriminate between different sizes and locations of obstacles in order to determine if there is a hazard. Based on this information, the processing system then communicates with a visual and/or audible warning system in order to alert the driver about the obstacle if it has been determined to be a hazard.

Claims

1. A method for detecting an object, said method comprising:

providing a transmitting antenna;

providing a first array of receiving antennas;

transmitting from said transmitting antenna;

measuring the magnitude and phase of a respective received signal at each of said receiving antennas;

determining the magnitude of the sum of respective phase-compensated signals related to each of said receiving antennas;

comparing the magnitude of the sum against a first predetermined threshold value; and

comparing the magnitude of the sum against a second predetermined threshold value.

2. The method of claim 1 further comprising the step of determining a warning based on the relationship of the sum to said first predetermined threshold value and said second predetermined threshold value.

3. The method of claim 2 further comprising:

providing a first type of said warning if the sum exceeds said first predetermined threshold value but not said second predetermined threshold value; and

providing a second type of said warning if the sum exceeds said first predetermined threshold value and said second predetermined threshold value

4. The method of claim 1 further comprising:

providing a second array of receiving antennas;

measuring the magnitude and phase of a respective received signal at each of said receiving antennas of said second array;

determining the magnitude of the sum of respective phase-compensated signals related to each of said receiving antennas of said second array;

comparing the magnitude of the sum of said respective phase-compensated signals of said second array against said first predetermined threshold value; and

comparing the magnitude of the sum of said respective phase-compensated signals of said second array against said second predetermined threshold value.

5. The method of claim 4 further comprising the step of determining a warning based on the relationship of the sum of said first array and the sum of said second array to said first predetermined threshold value and said second predetermined threshold value.

6. The method of claim 5 wherein said warning is based on the sum of said first array if the sum of said first array at least exceeds said first predetermined threshold value but the sum of said second array does not exceed said first predetermined threshold value.

7. The method of claim 6 wherein the sum of said first array at least exceeds said first predetermined threshold value but the sum of said second array does not exceed said first predetermined threshold value, the method further comprising:

providing a first type of said warning if the sum of said first array exceeds said first predetermined threshold value but not said second predetermined threshold value; and

providing a second type of said warning if the sum of said first array exceeds said first predetermined threshold value and said second predetermined threshold value.

8. The method of claim 4 further comprising:

performing position triangulation if the sum of said first array and the sum of said second array both at least exceed said first predetermined threshold value;

wherein said second predetermined threshold value is higher than said first predetermined threshold value.

9. The method of claim 8 further comprising the step of providing a warning based on the position of the object.

10. A method for determining the location of an object, said method comprising:

providing a transmitting antenna;

providing a first array of receiving antennas and a second array of receiving antennas;

transmitting from said transmitting antenna;

measuring the magnitude and phase of a respective received signal at each of said receiving antennas of said first array and said second array;

determining the sum of the magnitudes of said first array;

determining the sum of the magnitudes of said second array;

comparing the sum of said first array and the sum of said second array against a predetermined threshold value; and

performing position triangulation if at least one peak of the sum of said first array and at least one peak of the sum of said second array both at least exceed said first predetermined threshold value.

11. The method of claim 10 wherein the step of performing position triangulation considers only interceptions that involve a peak of the sum of said first array and a peak of the sum of said second array.

12. A radar system for detecting an obstacle, said radar system comprising:

a signal source adapted to produce a single frequency, continuous wave input signal;

at least one transmitting antenna adapted to receive said input signal and transmit at least one electromagnetic wave, said at least one electromagnetic wave adapted to reflect off said obstacle to produce at least one reflected electromagnetic wave;

a first array of receiving antennas adapted to receive said at least one reflected electromagnetic wave and produce output signals;

a second array of receiving antennas adapted to receive said at least one reflected electromagnetic wave and produce output signals;

a quadrature mixer adapted to combine said input signal with said output signals of said first and second array of receiving antennas to produce in-phase (I) signals and quadrature (Q) signals; and

a processor adapted to use said I signals and said Q signals to estimate the location of said obstacle.

13. The radar system of claim 12 wherein one transmitting antenna is situated approximately between said first array and said second array of receiving antennas.

14. The radar system of claim 12 wherein:

a first transmitting antenna is situated in an intermediate position among said receiving antennas of said first array; and

a second transmitting antenna is situated in an intermediate position among said receiving antennas of said second array.

15. The radar system of claim 12 wherein:

a first transmitting antenna is situated at an end of said first array of receiving antennas; and

a second transmitting antenna is situated at an end of said second array of receiving antennas.

16. The radar system of claim 12 wherein said at least one transmitting antenna and said first array and said second array of receiving antennas are secured to a vehicle.

17. The radar system of claim 12 wherein said processor is adapted to estimate the angle and range location of said obstacle.

18. The radar system of claim 12 wherein said processor is adapted to use a near field back projection algorithm or a far field angle of arrival algorithm to estimate the location of said obstacle.

19. The radar system of claim 12 further comprising at least one switch in electrical communication with said quadrature mixer such that said at least one switch is adapted to facilitate scanning of said receiving antennas of said first array and said second array.

20. The radar system of claim 19 further comprising a controller in electrical communication with said processor and said at least one switch, whereby said controller is adapted to control the scanning of said receiving antennas.