Drive support apparatus
A drive support apparatus includes: a reliability determiner determining a reliability of a map matching, an area definer defining a determination area to include a cross point between a self-vehicle predicted path and a nearby vehicle predicted path, an intersection node finder determining an intersection node in a travel direction of the self-vehicle based on a high map matching reliability, and a node determiner determining whether the intersection node is found in the determination area. When no intersection node is found in the determination area, a drive support level is suppressed, and when the reliability is low, drive support is provided depending on whether the cross point between the self-vehicle predicted path and the other vehicle predicted path is found. Thus, lack of the drive support in a support-required situation is prevented, while preventing a provision of an unnecessary drive support.
1. A drive support apparatus for providing an alert in a subject vehicle, the drive support apparatus comprising:
a controller, the controller configured to
continuously determine a current position of the the subject vehicle by continuously obtaining a navigation signal from a navigation satellite of a satellite navigation system;
determine a degree of reliability of a map matching that matches the current position of the subject vehicle onto a road on a map, based on a comparison between a locus of the current position of the subject vehicle and a road shape;
determine a predicted path of the subject vehicle based on the current position and a travel direction of the subject vehicle;
obtain a predicted path of a nearby vehicle from a vehicle-to-vehicle communicator in the subject vehicle;
define a determination area around a cross point of the predicted path of the subject vehicle and the predicted path of the nearby vehicle when the cross point is within an intersection of a road on which the subject vehicle is traveling and a road on which the nearby vehicle is traveling;
determine whether an intersection node of the road on which the subject vehicle is currently traveling is map-matched by at least a preset-degree of reliability; and
determine whether the intersection node is within the determination area, wherein
the controller is further configured to output the alert at different alert levels, and wherein
the controller is further configured to output the alert at a level below a highest alert level when the intersection node is not within the determination area, and wherein the alert based on the cross point when the degree of reliability of the map matching is below the preset-degree of reliability.
2. The drive support apparatus of claim 1 , wherein
the controller is further configured to compute a time difference between an arrival time of the subject vehicle to the cross point and an arrival time between the nearby vehicle to the cross point, and wherein
the controller is further configured to determine the alert level based on the time difference, the cross point, the intersection node, and the reliability of the map matching.
3. The drive support apparatus of claim 1 , wherein
the controller is further configured to determine a state of the map matching, the state at least one of
(i) a matched state that
matches the current position of the subject vehicle to one road on the map, and
(ii) a plurality of match candidates state that matches the current position of the subject vehicle to a plurality of roads on the map, and wherein
the controller is further configured to determine that the degree of reliability of the map matching is the preset-degree of reliability for the matched state, and to determine that the degree of reliability of the map matching is below the preset-degree of reliability for the plurality of match candidates state.
4. The drive support apparatus of claim 1 , wherein
the controller is further configured to determine a state of the map matching, the state at least one of
(i) a matched state that matches the current position of the subject vehicle to one road on the map,
(ii) a not-yet-matched state where the current position of the subject vehicle does not match any roads on the map, and
(iii) a transitions state where the map matching transitions from the matched state to the not-yet-matched state, and wherein
the controller is further configured to determine that the degree of reliability of the map matching is the preset-degree of reliability for the matched state, and to determine that the degree of reliability of the map matching is below the preset-degree of reliability for the not-yet-matched state and the transition state.
5. The drive support apparatus of claim 1 , wherein
the controller is further configured to determine the map matching is lower than the preset-degree of reliability when the controller cannot determine the degree of reliability of the map matching.
6. The drive support apparatus of claim 1 , wherein
wherein the controller is further configured to determine the intersection node as a node closest to the current position of the subject vehicle in the travel direction of the subject vehicle.
7. A drive support system for providing an alert in a subject vehicle, the drive support system comprising:
a plurality of detectors;
a drive support apparatus in communication with the plurality of detectors, the drive support apparatus including:
a receiver configured to receive a navigation signal from a satellite;
a communication device configured to communicate with at least one of another vehicle and a roadside device; and
a controller configured to communicate with the receiver and the communication device, the controller further configured to
continuously determine a current position of the the subject vehicle by continuously obtaining the navigation signal;
determine a degree of reliability of a map matching that matches the current position of the subject vehicle onto a road on a map, based on a comparison between a locus of the current position of the subject vehicle and a road shape;
determine a predicted path of the subject vehicle based on the current position and a travel direction of the subject vehicle;
obtain a predicted path of a nearby vehicle from the communication device;
define a determination area around a cross point of the predicted path of the subject vehicle and the predicted path of the nearby vehicle when the cross point is within an intersection of a road on which the subject vehicle is traveling and a road on which the nearby vehicle is traveling;
determine whether an intersection node of the road on which the subject vehicle is currently traveling is map-matched by at least a preset-degree of reliability; and
determine whether the intersection node is within the determination area, wherein
the controller is further configured to output the alert at different alert levels, and
wherein
the controller is further configured to output the alert at a level below a highest alert level when the intersection node is not within the determination area, and wherein
the controller is further configured to determine the alert level at which to output the alert based on the cross point when the degree of reliability of the map matching is below the preset-degree of reliability.