1. A method for grouping object sensor measurements with target objects in an object detection system, said method comprising: providing a list of target objects being tracked by the object detection system, where the list of target objects includes known targets identified by the object detection system in an area ahead of a host vehicle; computing hypothesis locations and orientations for each known target in the list of target objects, where the hypothesis locations and orientations include a prediction of each known target's movement since the list of target objects was previously computed, where computing hypothesis locations and orientations for each known target includes using digital map data to predict a location and orientation of each known target based on road curvature data and target velocity; providing sensor measurement points from at least one object sensing system, where the sensor measurement points designate points at which an object has been detected in the area ahead of the host vehicle; grouping, using a microprocessor, the sensor measurement points with the known targets at the hypothesis locations and orientations; validating the hypothesis locations and orientations based on the grouping; identifying new targets based on any clusters of sensor measurement points which do not correlate to one of the known targets; and updating the list of target objects to include the known targets at the hypothesis locations and orientations, and any new targets identified.