Method of estimating target elevation utilizing radar data fusion

• US 20090002222A1
• Filed: 06/27/2007
• Published: 01/01/2009
• Est. Priority Date: 06/27/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Hsu, Hui-Pin, Colburn, Joseph S., Altan, Osman D., Geary, Kevin
• Granted Patent: US 7,592,945 B2
• Time in Patent Office: Days
• US Class Current: 342/145
• CPC Class Codes: G01C 9/00 Measuring inclination, e.g. by clinometers, by levels
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles

Abstract

A collision avoidance system for reducing false alerts by estimating the elevation of a target, includes short and long range single-dimensional scanning radar sensors having differing ranges and beam angles of inclination, and a digital fusion processor, and preferably includes a locator device, an inclinometer, and a memory storage device cooperatively configured to further perform trend analysis, and target tracking.

Claims

1. A system for estimating the elevation of at least one target utilizing single-dimensional scanning radar and data fusion, said system comprising:

a first single-dimensional radar sensor having a first operable range and first beam angle of inclination, and configured to generate a first return signal based on the relative distance between the first sensor and each of said at least one target, the operable range, and the angle of inclination;

a second single-dimensional radar sensor having a second operable range and a second beam angle of inclination, and configured to generate a second return signal based on the relative distance between the second sensor and each of said at least one target, the operable range, and the angle of inclination; and

at least one digital fusion processor communicatively coupled to the first and second sensors, and configured to determine a relative signal value based on the first and second return signals,

said processor being further configured to estimate the elevation of said each of said at least one target based on the relative signal value.

2. The system as claimed in claim 1, wherein the digital fusion processor is configured to determine the relative signal value based on a simple ratio of the first return signal to the second return signal.

3. The system as claimed in claim 1, wherein the digital fusion processor is configured to determine the relative signal value based on the difference between the first and second return signals.

4. The system as claimed in claim 1, wherein a plurality of digital fusion processors inter-communicate and cooperatively configured to determine the relative signal value as a neural network.

5. The system as claimed in claim 1, wherein the digital fusion processor includes a Kalman filter and is configured to determine the relative signal value by applying the filter to the first and second return signals.

6. The system as claimed in claim 1, further comprising:

a memory storage device communicatively coupled to the processor, and operable to store data,

said sensors and processor being cooperatively configured to sequentially determine a plurality of relative return signal values for each of said at least one target over a period, so as to track each of said at least one target,

said processor being configured to deliver to and retrieve from the storage device the plurality of relative return signal values, and to estimate the elevation of said each of said at least one target based on an aggregate of the relative signal values.

7. The system as claimed in claim 6, further comprising:

a locator device configured to generally determine the current position coordinates of the sensors,

each of said sensors and processor being cooperatively configured to determine a target range between the sensor and target and generally determine the absolute position coordinates of the target based on the current position coordinates of the sensor and target range.

8. The system as claimed in claim 1, further comprising:

a memory storage device communicatively coupled to the processor, and operable to store data,

said sensor utilizing radar technology and being configured to detect the target over a period, so as to determine a plurality of return signal strengths from the detection of the target,

said processor being configured to determine a trend in the difference between successive strengths, wherein the preceding strength is subtracted from the succeeding strength, and to determine the relative signal value only when the trend is positive.

9. The system as claimed in claim 1, further comprising:

at least one inclinometer configured to measure first and second vertical angles of operation for the first and second sensors,

said processor being communicatively coupled to the inclinometer and configured to determine the relative signal value based on the angle of operation.

10. The system as claimed in claim 9, wherein the first and second operable ranges and the first and second beam angles of inclination are congruent, and the first and second vertical angles of operation are non-congruent.

11. The system as claimed in claim 9, further comprising:

a memory storage device further communicatively coupled to the processor, and operable to store data,

said inclinometer, sensors and processor being cooperatively configured to sequentially determine a plurality of correlative angles of operation and relative return signal values for each target over a period,

said processor being configured to deliver to and retrieve from the device the plurality of correlative angles of operation and relative return signal values,

said processor being further configured to estimate the elevation of said each of said at least one target based on the correlative angles of operation and relative signal values.

12. The system as claimed in claim 11, wherein the processor is further configured to estimate the elevation of said target only when the rate of change in successive angles of operation do not exceed a pre-determined threshold.

13. A system for estimating the elevation of at least one target utilizing single-dimensional scanning radar and data fusion, said system comprising:

a first single-dimensional radar sensor having a first operable range and first beam angle of inclination, and configured to generate a first return signal based on the relative distance between the first sensor and each of said at least one target, the operable range, and the angle of inclination;

a second single-dimensional radar sensor having a second operable range different from the first range and second beam angle of inclination different from the first angle of inclination, and configured to generate a second return signal based on the relative distance between the second sensor and each of said at least one target, the operable range, and the angle of inclination;

a digital fusion processor communicatively coupled to the first and second sensors, including a Kalman filter, and configured to determine a relative signal value based on the first and second return signals;

a locator device communicatively coupled to the processor and configured to generally determine current position coordinates for the sensors; and

a memory storage device communicatively coupled to the processor, and operable to store data,

said locator device and processor being cooperatively configured to determine the absolute position coordinates of the target,

said sensors and processor being cooperatively configured to sequentially determine and deliver to the device a plurality of relative return signal values for each of said at least one target over a period, so as to track each of said at least one target,

said processor being configured to retrieve from the storage device the plurality of relative return signal values, and estimate the elevation of said each of said at least one target based on an aggregate of the relative signal values.

14. A method of estimating the elevation of at least one target utilizing single-dimensional scanning radar and data fusion, said system comprising the steps of:

a) directing a single-dimension short range radar beam having a first angle of inclination and a first range, from a first height of operation and towards a target;

b) directing a single-dimension longer range radar beam having a second angle of inclination less than the first angle of inclination and a second range longer than the first range, from a second height of operation and towards the target;

c) receiving return signals from said short and longer range beams when the target is within both of the first and second ranges;

d) autonomously fusing target elevation information provided by the return signals and based on the beam angles of inclination to determine a relative return signal value or combined pattern, based on the first and second return signals; and

e) comparing the relative return signal value or combined pattern with a plurality of predetermined target elevation identification categories, so as to determine a matching category.

15. The method as claimed in claim 14, wherein the method is performed by a host vehicle having an operator, the categories include overpass, and at-grade target determinations, and further comprises the step of:

f) autonomously notifying the operator of the matching category by generating an output when the vehicle is outside of a predetermined minimum range from the target.

16. The method as claimed in claim 14, wherein the first and second heights of operation are 45 cm, the first angle of inclination is 16 degrees, the first range is 30 m, the second angle of inclination is 3 degrees, and the second range is 150 m.