Abstract: A method of determining the location of a candidate object in an environment, the method including the steps of: (a) capturing a 3D point cloud scan of the object and its surrounds; (b) forming a surface geometry model of the candidate object. (c) forming a range hypothesis test comparing an expected range from the geometry model of the candidate object in comparison with the measured range of points in the Lidar point cloud scan and deriving an error measure there between; (d) testing the range hypothesis for a series of expected locations for the surface geometry model of the candidate object and determining a likely lowest error measure.