Systems and methods for detecting bifurcations

1. A method of detecting, by a navigation system, a bifurcation in a navigable feature, the method comprising:

first determining, by the navigation system, a first possible segment (PS 1 ) and a second possible segment (PS 2 ) of the navigable feature (NV), on which a navigation device is located, based on location measurements along the navigable feature (NV), the location measurements representing a heading vector (V heading ) pointing to an estimated direction in which the navigation device is travelling, and the location measurements having a higher probability of being on the first possible segment than on the second possible segment;

second determining, by the navigation system, an angle (θ) based on the heading vector (V heading ) and a vector (V h-s ) between the second possible segment (PS 2 ) and one of the location measurements; and

detecting, by the navigation system, a bifurcation based on the angle (θ).

2. The method of claim 1 , wherein the second determining includes,

determining a navigation device based location (N L ) based on the location measurements, and

determining the vector between the second possible segment and the heading vector, the vector (V h-s ) between the second possible segment (PS 2 ) and the one of the location measurements is a vector (V h-s ) from the navigation device based location (N L ) to the second possible segment (PS 2 ).

3. The method of claim 1 , further comprising:

selecting the first possible segment (PS 1 ) or the second possible segment (PS 2 ) as the segment of the location measurements based on the detecting.

4. The method of claim 3 , further comprising:

displaying a position on a navigation device, the position on the navigation device corresponding to the selected segment of the location measurements.

5. The method of claim 3 , wherein the selecting includes a first selecting algorithm if the angle (θ) is less than 70 degrees.

6. The method of claim 3 , wherein the selecting includes a second algorithm if the angle (θ) is greater than 70 degrees.

7. The method of claim 3 , wherein the detecting detects a bifurcation if the angle (θ) is greater than a threshold.

8. The method of claim 1 , wherein the second determining includes,

determining a dot product of the heading vector (V heading ) and the vector (V h-s ) between the second possible segment (PS 2 ) and the one of the location measurements,

determining a cosine of the angle (θ) based on the dot product.

9. The method of claim 1 , wherein the first determining includes,

matching the location measurements to at least one position on a map, and

matching the location measurements to an orientation on the map, the position and orientation representing the heading vector (V heading ).

10. The method of claim 9 , wherein the first determining includes,

determining a plurality of possible segments based on the at least one position and the orientation, each of the plurality of possible segments having a rating, wherein

the first possible segment (PS 1 ) has the highest rating and the second possible segment (PS 2 ) has the second highest rating.

11. The method claim 1 , wherein the navigable feature (NV) includes at least one of a same road, a same path, a same highway and a same transportation segment.

12. The method of claim 1 , wherein the location measurements are collected by a navigation device.

13. The method of claim 12 , wherein the navigation device is any one of a map creation device, a personal navigation device, a mobile phone, a personal digital assistant and an in vehicle device.

14. The method of claim 1 , wherein the first determining determines the first possible segment (PS 1 ) and the second possible segment (PS 2 ) of the navigable feature (NV) based on the location measurements along the navigable feature (NV) and map data.

15. A non-transitory computer readable medium including program segments for, when executed on a computer, causing the computer to implement the method claim 1 .

16. Computer software comprising one or more software modules stored on non-transitory storage medium, said one or more software modules being operable, when executed in an execution environment, to cause a computer to:

determine a first possible segment (PS 1 ) and a second possible segment (PS 2 ) of the navigable feature (NV), on which a navigation device is located, based on location measurements along the navigable feature (NV), the location measurements representing a heading vector (V heading ) pointing to an estimated direction in which the navigation device is travelling, and the location measurements having a higher probability of being on the first possible segment than on the second possible segment;

determine an angle (θ) based on the heading vector (V heading ) and a vector (V h-s ) between the second possible segment (PS 2 ) and one of the location measurements; and

detect a bifurcation based on the angle.

17. A navigation device comprising:

a memory; and

a processor coupled to the memory, wherein the processor is operative to,

determine a first possible segment (PS 1 ) and a second possible segment (PS 2 ) of the navigable feature (NV), on which a navigation device is located, based on location measurements along the navigable feature (NV), the location measurements representing a heading vector (V heading ) pointing to an estimated direction in which the navigation device is travelling, and the location measurements having a higher probability of being on the first possible segment than on the second possible segment,

determine an angle (θ) based on the heading vector (V heading ) and a vector (V h-s ) between the second possible segment (PS 2 ) and one of the location measurements, and

detect a bifurcation based on the angle.

18. The navigation device of claim 17 , wherein the navigation device is portable.

19. The navigation device of claim 17 , wherein the navigation device is an in vehicle device.