Off-board navigation system for vehicles

• US 20070299600A1
• Filed: 05/29/2007
• Published: 12/27/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: C.R.F. Societa Consortile Per Azioni
• Original Assignee: C.R.F. Societa Consortile Per Azioni
• Inventors: Liberto, Carlo, Lilli, Francesco
• Granted Patent: US 8,068,981 B2
• Time in Patent Office: Days
• US Class Current: 701/201
• CPC Class Codes: G01C 21/3415 Dynamic re-routing, e.g. recalculating the route when the user deviates from calculated route or after detecting real-time traffic data or accidents
• CPC Class Codes: G08G 1/096811 where the route is computed offboard
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data

Abstract

Described herein is an off-board navigation system for vehicles, comprising at least one operating center and at least one on-board navigation unit installed on board a vehicle, in which the operating center is provided with monitoring means configured for detecting events that modify the road conditions of stretches of road forming part of a road network, and processing means designed to determine, following upon detection of an event, whether said event has occurred on a stretch of road forming part of a route supplied to a user and, in this case, to request an alternative route and determine a point of no return (PNR) that is set along the route supplied to a user and beyond which the vehicle is no longer able to avoid the event and a point of influence (AR), in which the practicability of the route starts to be affected by the onset of the event and beyond which the user is still in time to request and receive an alternative route that will enable him to avoid the event in the case where the point of no return (PNR) has not yet been exceeded.

Claims

1. An off-board navigation system for vehicles, comprising at least one operating center and at least one on-board navigation unit installed on board a vehicle, which communicates with said operating center and can be used by a user for setting target destinations;

said operating center comprising;

a calculating unit, which receives a user request and is designed to calculate, in response, a route on the basis of the information regarding the position of said vehicle and on the basis of geographical data present in the operating center itself;

transceiver means designed to transmit said route to said on-board navigation unit; and

monitoring means designed to monitor constantly the traffic and road conditions of a road network of a portion of territory and to detect events that modify the road conditions of stretches of road forming part of said road network;

wherein said operating center is provided with processing means designed to determine, following detection of an event, whether said event has occurred on a stretch of road forming part of said route supplied to said user and, in this case, to determine;

a point of no return (PNR) that is set along said route and beyond which said vehicle is no longer able to avoid said event; and

a point of influence (AR) in which the practicability of said route starts to be affected by the onset of said event and beyond which said user is still in time to request to and to receive from said operating center an alternative route designed to avoid said event in the case where said point of no return (PNR) has not yet been exceeded.

2. The system according to claim 1, in which said processing means is moreover configured for:

estimating the current position of said vehicle;

determining on the basis of the estimated current position of said vehicle a temporal distance of said vehicle from said event; and

verifying whether said temporal distance satisfies a pre-set relation with a pre-set threshold value.

3. The system according to claim 2, where said temporal distance satisfies said pre-set relation, said processing means is moreover configured for:

determining on the basis of the estimated current position of said vehicle a spatial distance of said vehicle from said event; and

verifying whether said spatial distance satisfies a pre-set relation with a pre-set threshold value.

4. The system according to claim 3, where said spatial distance satisfies said pre-set relation, said processing means are moreover configured for:

asking the route-calculating unit to calculate on the basis of said estimated current position a route alternative to said route supplied to the user, which enables said user to avoid said event.

5. The system according to claim 4, in which said processing means is moreover configured for calculating said point of influence (AR) and said point of no return (PNR) in the case where said route-calculating unit is able to calculate an alternative route.

6. The system according to claim 1, in which said processing means is configured for determining said point of influence (AR) on the basis of a pre-set time (t_est) of extinction of said event.

7. The system according to claim 6, in which said processing means is configured for determining said point of influence (AR) on the basis of a distance (d) that said vehicle would cover in said time (t_est) of extinction of the event if it were to cover said route in the opposite direction starting from the position of the event and if it were to travel at a pre-set speed for covering said route.

8. The system according to claim 7, in which said processing means is configured for determining said distance (d) on the basis of a degree of practicability of each stretch of road forming part of a portion of said route comprised between the estimated position of said vehicle and the point in which said event has occurred.

9. The system according to claim 8, in which said processing means is configured for associating to each of the stretches of road comprised between the estimated position of the vehicle and the point in which the event has occurred a weight that indicates the evolution of the degree of practicability of the stretch of road with respect to a pre-set threshold value.

10. The system according to claim 9, in which said processing means is configured for modifying said time (t_est) of extinction of the event on the basis of the evolution of the degree of practicability of said stretches of road.

11. The system according to claim 10, in which said processing means is configured for reducing said time (t_est) of extinction of the event in the case where at least half of said stretches of road presents a weight that indicates an improvement of the degree of practicability with respect to a pre-set threshold value.

12. The system according to claim 10, in which said processing means is configured for prolonging said time (t_est) of extinction of the event in the case where at least half of said stretches of road presents a weight that indicates a worsening of the degree of practicability with respect to a pre-set threshold value.

13. The system according to claim 11, in which said processing means is configured for calculating said distance (d) on the basis of said reduced time (t_est) of extinction of the event.

14. The system according to claim 12, in which said processing means is configured for calculating said distance (d) on the basis of said prolonged time (t_est) of extinction of the event.

15. The system according to claim 1, in which in order to determine said point of no return (PNR) of said processing means is configured for:

calculating a new route, assuming as starting position of the vehicle a point that is located at a pre-set temporal distance from said event; and

repeating said step of calculation, displacing said starting position of the vehicle until said new route presents a deviation with respect to said route supplied to said user.

16. The system according to claim 1, in which said monitoring means is configured for determining a weight that indicates the degree of seriousness of said event and said processing means is configured for determining said point of influence (AR) and said point of no return (PNR) in the case where said weight associated to said event will exceed a pre-set threshold value.

17. The system according to claim 16, in which said processing means is configured for sending to said on-board navigation unit a message containing:

information that signals the presence of said event on said route supplied to the user and said weight of said event;

information that signals the geo-referenced position of said event;

information that signals the availability of said alternative route;

information that signals said point of influence (AR); and

information that signals said point of no return (PNR).

18. The system according to claim 17, in which said on-board navigation unit is configured for evaluating whether said information received is of interest to the user.

19. The system according to claim 18, in which said on-board navigation unit is configured for:

verifying on the basis of the current position of the vehicle whether the vehicle has already exceeded said point of influence (AR) and/or said point of no return (PNR) and, on the basis of said verification,

deciding whether to display a message for the user.

20. The system according to claim 19, in which said on-board navigation unit is configured for displaying a message containing:

information that signals the presence of said event on said route supplied to the user and said weight of said event;

information that signals the geo-referenced position of said event;

information that signals the availability of said alternative route;

information that signals said point of influence (AR); and

information that signals said point of no return (PNR);

in the case where the vehicle has exceeded the point of influence (AR) but has not yet exceeded the point of no return (PNR).

21. The system according to claim 1, in which said on-board navigation unit is configured for sending to the operating center a request for said alternative route.

22. An off-board-navigation method for a vehicle comprising the steps of:

determining a point of no return (PNR) that is set along a route supplied to a user and beyond which said vehicle is no longer able to avoid an event that affects the practicability of said route; and

determining a point of influence (AR), in which the practicability of said route starts to be affected by the onset of said event and beyond which said user is still in time to request and to receive an alternative route designed to avoid said event in the case where said point of no return (PNR) has not yet been exceeded.

23. The method according to claim 22, further comprising the steps of:

estimating the current position of said vehicle;

determining on the basis of the estimated current position of said vehicle a temporal distance of said vehicle from said event; and

verifying whether said temporal distance satisfies a pre-set relation with a pre-set threshold value.

24. The method according to claim 23, further comprising the steps of:

determining on the basis of the estimated current position of said vehicle a spatial distance of said vehicle from said event; and

verifying whether said spatial distance satisfies a pre-set relation with a pre-set threshold value;

in the case where said temporal distance satisfies said pre-set relation.

25. The method according to claim 24, further comprising, in the case where said spatial distance satisfies said pre-set relation:

calculating on the basis of said estimated current position an alternative route to said route supplied to the user, which enables said user to avoid said event.

26. The method according to claim 25, further comprising:

calculating said point of influence (AR) and said point of no return (PNR) in the case where the alternative route enables said user to avoid said event.

27. The method according to claim 22 comprising the additional step of:

determining said point of influence (AR) on the basis of a pre-set time (t_est) of extinction of said event.

28. The method according to claim 27, in which said point of influence (AR) is determined on the basis of a distance (d) that said vehicle would cover in said time (t_est) of extinction of the event if it were to cover said route in the opposite direction starting from the position of the event and if it were to travel at a pre-set speed for covering said route.

29. The method according to claim 28, in which said distance (d) is determined on the basis of a degree of practicability of each stretch of road forming part of a portion of said route comprised between the estimated position of said vehicle and the point in which said event has occurred.

30. The method according to claim 29, comprising the additional step of:

associating to each of the stretches of road comprised between the estimated position of the vehicle and the point in which the event has occurred a weight that indicates the evolution of the degree of practicability of the stretch of road with respect to a pre-set threshold value.

31. The method according to claim 30, comprising:

modifying said time (t_est) of extinction of the event on the basis of the evolution of the degree of practicability of said stretches of road.

32. The method according to claim 31, comprising:

reducing said time (t_est) of extinction of the event in the case where at least half of said stretches of road presents a weight that indicates an improvement of the degree of practicability with respect to a pre-set threshold value.

33. The method according to claim 31, comprising:

prolonging said time (t_est) of extinction of the event in the case where at least half of said stretches of road presents a weight that indicates a worsening of the degree of practicability with respect to a pre-set threshold value.

34. The method according to claim 32, in which said distance (d) is calculated on the basis of said reduced time (t_est) of extinction of the event.

35. The method according to claim 33, in which said distance (d) is calculated on the basis of said prolonged time (t_est) of extinction of the event.

36. The method according to claim 22, in which determining said point of no return (PNR) comprises:

calculating a new route assuming as starting position of the vehicle a point that is found at a pre-set temporal distance from said event; and

repeating said step of calculation, displacing said starting position of the vehicle until said new route presents a deviation with respect to said route supplied to said user.

37. The method according claim 22, further comprising:

determining a weight that indicates the degree of seriousness of said event; and

determining said point of influence (AR) and said point of no return (PNR) in the case where said weight exceeds a pre-set threshold value.

38. The method according to claim 37, further comprising sending to an on-board navigation unit (4) of said vehicle a message containing:

information that signals the presence of said event on said route supplied to the user and said weight of said event;

information that signals the geo-referenced position of said event;

information that signals the availability of said alternative route;

information that signals said point of influence (AR); and

information that signals said point of no return (PNR).

39. The method according to claim 38, further comprising:

evaluating at said on-board navigation unit if said information received is of interest to the user.

40. The method according to claim 39, comprising:

verifying on the basis of the current position of the vehicle whether the vehicle has already exceeded said point of influence (AR) and/or said point of no return (PNR) and, on the basis of said verification,

deciding whether to display a message for the user.

41. The method according to claim 40, comprising displaying on said on-board navigation unit a message containing:

information that signals the presence of said event on said route supplied to the user and said weight of said event;

information that signals the geo-referenced position of said event;

information that signals the availability of said alternative route;

information that signals said point of influence (AR); and

information that signals said point of no return (PNR);

in the case where the vehicle has exceeded the point of influence (AR) but has not yet exceeded the point of no return (PNR).

42. The method according to claim 22, further comprising sending a request for said alternative route to the operating center.

43. A computer product that can be loaded into the memory of a digital processor, said computer product comprising portions of software code that are able to implement the method according to claim 22 when said computer product is run on said digital processor.