Vehicle navigation system

1. A vehicle navigation system, comprising:

a database configured to store map data having links corresponding to road segments and attributes associated with the links, the map data having at least some links associated with a curvature attribute and a mean absolute curvature ( κ ) stored for the curvature attribute for corresponding links, the mean absolute curvature ( κ ) being determined from a normalized sum or integral of absolute curvature values along the road segment corresponding to the link; and

a processing unit configured to estimate an energy consumption cost factor of the vehicle for a link using the curvature attribute retrieved from the database for the link, and using at least one of (i) vehicle velocity (ii) driver vehicle operating behavior (iii) vehicle fuel consumption (iv) vehicle coefficient of drag or (v) vehicle rolling resistance coefficient or (vi) grade resistance coefficient,

where the sum or the integral are a weighted sum or a weighted integral in which the curvature values are weighted by a weighting factor, and

where the weighting factor is configured to consider the influence of the curvature on energy consumption.

2. The vehicle navigation system of claim 1 where the weighting factor depends on the respective curvature value.

3. The vehicle navigation system of claim 1 , where the processing unit is configured to use a model which determines an additional energy consumption (ΔB) for the link caused by the curvatures along the corresponding road segment from the absolute mean curvature attribute associated with the link.

4. A method of estimating an energy consumption of a vehicle for a link of a route, the method comprising:

retrieving at least one link corresponding to a road segment from a database of map data;

retrieving a curvature attribute associated with the retrieved link from the database, the curvature attribute for the link storing a mean absolute curvature ( κ ) determined from a normalized sum or integral of absolute curvature values along the road segment corresponding to the link; and

estimating an energy consumption cost factor of the vehicle for the link using the retrieved curvature attribute, and using at least one of (i) vehicle velocity (ii) driver vehicle operating behavior (iii) vehicle fuel consumption (iv) vehicle coefficient of drag or (v) vehicle rolling resistance coefficient or (vi) grade resistance coefficient,

where the sum or the integral are a weighted sum or a weighted integral in which the curvature values are weighted by a weighting factor, and

where the weighting factor is configured to consider the influence of the curvature on energy consumption.

5. A method of claim 4 where the weighting factor is one of a multiplier or a multiplicand.

6. A vehicle navigation system comprising:

a processing unit;

a database of map data having links corresponding to road segments and attributes associated with the links, the map data having at least some links associated with a curvature attribute; and

a memory for storing software components configured to perform, when executed by the processor, the following:

retrieving at least one link corresponding to a road segment from the database of map data;

retrieving a curvature attribute associated with the retrieved link from the database, the curvature attribute for the link storing a mean absolute curvature ( κ ) determined from a normalized sum or integral of absolute curvature values along the road segment corresponding to the link; and

estimating an energy consumption cost factor of the vehicle for the link using the retrieved curvature attribute, and using at least one of (i) vehicle velocity (ii) driver vehicle operating behavior (iii) vehicle fuel consumption (iv) vehicle coefficient of drag or (v) vehicle rolling resistance coefficient or (vi) grade resistance coefficient,

where the sum or the integral are a weighted sum or a weighted integral in which the curvature values are weighted by a weighting factor, and

where the weighting factor is configured to consider the influence of the curvature on energy consumption.

7. A vehicle navigation system of claim 6 where the weighting factor is one of a multiplier or a multiplicand.

8. A computer-readable storage medium having computer programs configured to perform, when executed by a processor, the following:

retrieving at least one link corresponding to a road segment from the database of map data having links corresponding to road segments and attributes associated with the links, the map data having at least some links associated with a curvature attribute;

retrieving a curvature attribute associated with the retrieved link from the database, the curvature attribute for the link storing a mean absolute curvature ( κ ) determined from a normalized sum or integral of absolute curvature values along the road segment corresponding to the link; and

estimating an energy consumption cost factor of the vehicle for the link using the retrieved curvature attribute, and using at least one of (i) vehicle velocity (ii) driver vehicle operating behavior (iii) vehicle fuel consumption (iv) vehicle coefficient of drag or (v) vehicle rolling resistance coefficient or (vi) grade resistance coefficient,

where the sum or the integral are a weighted sum or a weighted integral in which the curvature values are weighted by a weighting factor, and

where the weighting factor is configured to consider the influence of the curvature on energy consumption.

9. A method of generating a database comprising map data for a navigation system, the method comprising:

for a link of the map data, retrieving curvature values giving information on the curvature along a road segment corresponding to the link;

determining a mean absolute curvature for the link by determining a normalized sum or integral of the absolute curvature values along the road segment corresponding to the link; and

storing the mean absolute curvature as a curvature attribute in association with the link in the database,

where the sum or the integral are a weighted sum or a weighted integral in which the curvature values are weighted by a weighting factor, and

where the weighting factor is configured to consider the influence of the curvature on energy consumption cost factor along with using at least one of (i) vehicle velocity (ii) driver vehicle operating behavior (iii) vehicle fuel consumption (iv) vehicle coefficient of drag or (v) vehicle rolling resistance coefficient or (vi) grade resistance coefficient.

10. The method of claim 9 , further comprising:

splitting the link into link segments;

determining for each of the link segments the curvature, rolling resistance and/or drag resistance attribute; and

storing the link segments in the database in association with the attribute determined for the respective link segment.