Vehicle sensor system and process

1. A process of determining target parameters of an object within a field of detection of an automotive radar system, said process comprising the steps of:

(a) establishing a target range from a sequence of ranges provided by an automotive radar system secured to a vehicle;

(b) dwelling on said target range for an initial dwell time to obtain radar data;

(c) determining if said radar data corresponds to the presence of an object or to the absence of an object at said target range based on probability density distributions of an object being present and being absent at said target range, and if such said determination cannot be made, then repeating steps (b) and (c) until said determination can be made;

(d) if said radar data is determined to correspond to the presence of an object in step (c), then dwelling at said target range for an extended dwell time to obtain additional radar data for determining the target parameters of said object before proceeding to step (e); and

(e) establishing the next of said sequence of ranges as the target range before reiterating steps (b)-(e).

2. The process of claim 1 , wherein, in step (c), said determination is made using a sequential probability ratio test (SPRT).

3. The process of claim 1 , wherein, in step (c), an object is determined present if r<B and an object is determined absent if r>A, wherein,

r

=

f

1

⁡

(

m

⁢

N

)

f

0

⁡

(

m

⁢

N

)

ƒ 0 (m) is the probability density function when an object is actually present at a particular range for a given radar value,

ƒ 1 (m) is the probability density function when no such object is actually present at a particular range for the given radar value,

m N is calculated signal magnitude based on the on-going collection of noisy radar signal observed within N observations,

A

≈

1

-

β

α

,

⁢

B

≈

β

1

-

α

,

1−α is the probability of detection and

β is the probability of a false alarm.

4. The process of claim 3 , wherein 1−α is about 0.95, and β about 0.01.

5. The process of claim 3 , wherein

f

0

⁡

(

m

)

=

1

σ

⁢

2

⁢

π

⁢

exp

⁡

(

-

(

m

-

m

TN

)

2

2

⁢

σ

2

)

,

and

f

1

⁡

(

m

)

=

m

σ

2

⁢

exp

⁡

(

-

m

2

2

⁢

σ

2

)

,

wherein

σ a is the standard deviation of noise present in the radar data,

m N is a calculated signal magnitude based on the on-going collection of noisy radar signal observed within N observations,

m TN is the detection threshold at which performance requirements are to be satisfied.

6. The process of claim 5 , wherein mm is at least 1.5 times larger than σ.

7. The process of claim 1 , further comprising:

(f) determining target parameters based on additional radar data obtained in step (d).

8. The process of claim 7 , wherein said target parameters comprise range, bearing, and Doppler velocity.

9. The process of claim 7 , wherein target parameter data is transmitted to a processor to support a vehicular application selected from at least one of a parking aid, stop & go, or pre-crash detection.

10. The process of claim 7 , wherein said step (f) is performed after step (b) is performed on all ranges in said sequence of ranges.

11. The process of claim 7 , wherein said step (f) is performed after each step (c) is performed.

12. The process of claim 1 , wherein said initial dwell is based on obtaining a fixed number of radar data.

13. The process of claim 1 , wherein, in step (c), if a determination cannot be made whether said data corresponds to the presence of an object or the absence of an object, than increasing said initial dwell time to obtain additional radar data.

14. The process of claim 1 , wherein said initial dwell is terminated once a decision is made in step (c).

15. The process of claim 14 , wherein said extended dwell time begins immediately after a decision is made in step (c) that an object is present.

16. The process of claim 1 , wherein said extended dwell time is fixed.

17. The process of claim 1 , wherein said extended dwell time is based on at least one of object range and estimated signal to noise ratio.

18. The process of claim 1 , wherein the ratio of extended dwell time to initial dwell time of step (b) is greater than two.

19. The process of claim 1 , wherein said radar data is radar data comprising a complex value having in-phase and quadrature components.

20. The process of claim 1 , wherein coherent or noncoherent integration is used in step (b).

21. The process of claim 1 , wherein an FFT is used on the extended dwell time data to estimate target parameters.

22. A system for sensing objects about the perimeter of a vehicle, said system comprising at least one computer being configured to perform the following steps:

(a) establishing a target range from a sequence of ranges provided by an automotive radar system secured to a vehicle;

(b) dwelling on said target range for an initial dwell time to obtain radar data;

(c) determining if said radar data corresponds to the presence of an object or to the absence of an object at said target range based on probability density distributions of an object being present and being absent at said target range, and, if the presence or absence of said object cannot be determined, repeating steps (b)-(c);

(d) if said radar data corresponds to the presence of an object as determined in step (c), then dwelling at said target range for an extended dwell time to obtain additional radar data for determining the target parameters of said object before proceeding to step (e); and

(e) establishing the next of said sequence of ranges as the target range before reiterating steps (b)-(e).

23. A system in combination with a vehicle radar system for sensing objects about the perimeter of a vehicle, said system comprising:

a data processor;

an input for receiving radar data from said vehicle radar system;

memory operatively connected to said data processor, said memory containing instructions comprising at least:

a detection module for establishing a target range from a sequence of ranges, instructing said vehicle radar system to dwell on said target range for an initial dwell time to obtain radar data, and determining if said radar data corresponds to the presence of an object or to the absence of an object at said target range based on probability density distributions of an object being present and being absent at said target range, and repeating the initial dwell time to collect more radar data if the presence or absence of said object cannot be determined;

a collection module for dwelling at said target range for an extended dwell time after said detection module determine an object to be present to obtain additional radar data for determining the target parameters of said object; and

a state estimation module for determining target parameters of said object from said addition radar data.

24. A vehicle comprising:

a vehicle radar system for radar data, said system comprising;

a data processor;

an input for receiving radar data from said vehicle radar system;

memory operatively connected to said data processor, said memory containing instructions comprising at least:

a detection module for establishing a target range from a sequence of ranges, instructing said vehicle radar system to dwell on said target range for an initial dwell time to obtain radar data, and determining if said radar data corresponds to the presence of an object or to the absence of an object at said target range based on probability density distributions of an object being present and being absent at said target range, and repeating the initial dwell time to collect more radar data if the presence or absence of said object cannot be determined;

a collection module for dwelling at said tar get range for an extended dwell time after said detection module determine an object to be present to obtain additional radar data for determining the target parameters of said object; and

a state estimation module for determining target parameters of said object from said addition radar data.