Arithmetic device and arithmetic method

An arithmetic method for a vehicle, the method comprising:

• receiving, by one or more processors, from a sensor, information pertaining to one or more detection targets each being recognized by the sensor;
• grouping, by the one or more processors, a plurality of targets, including the one or more detection targets and one or more tracking targets, into a plurality of groups, based on positional information of the one or more detection targets and the one or more tracking targets, wherein the one or more tracking targets are detected in a previous cycle and are being tracked, and wherein each group of the plurality of groups corresponds to a spatial area of a plurality of spatial areas each having a priority based on a distance between the spatial area and the vehicle, and the plurality of spatial areas are defined with varying granularity based on the positional information and the priority;
• retrieving, by the one or more processors, a second target, of the plurality of targets, to be associated with a first target from a subset of the plurality of groups;
• fusing, by the one or more processors, the first target and the second target that are associated with each other to produce a new tracking target that is either (i) a newly created target or (ii) an updated version of the tracking target;
• and
• outputting a control signal to a vehicle control device to control acceleration, deceleration, or steering of the vehicle based on the new tracking target.