Environmental Reference Map Building Based on Occupancy Grid

Disclosed is a method for building a reference map. The method includes accumulating perception sensor data for a vehicle moving through an environment. The method includes generating an occupancy grid from the accumulated sensor data as the vehicle moves. The cells in the occupancy grid have a status and a confidence characteristic associated with the respective cell status determined based on the accumulated data. The method includes building a reference map for the environment by recording reference map cell states based on the confidence characteristics of respective cell statuses in the occupancy grid. In response to the recording reference map cell states, each reference map cell is assigned a single state based on the confidence characteristics associated with the respective cell. The step of building the reference map further includes recording a weight associated with each assigned reference map cell state.