1. A classifier for classifying a given radar track segment obtained from a radar system, the radar system having a primary surveillance radar for providing primary radar data and a secondary surveillance radar for providing secondary radar data, wherein the classifier comprises: a) a pre-processing stage, the preprocessing stage forms the given radar track segment and generates principal data based on the primary radar data or a combination of secondary and primary radar data, and extension data based on the primary radar data; b) a feature extraction stage connected to the pre-processing stage, the feature extraction stage processes at least one of the primary and secondary radar data associated with the given radar track segment to provide a plurality of feature values; c) a classification stage connected to the feature extraction stage, the classification stage generates a principal classification result and an extension classification result for the given radar track segment based on at least a portion of the feature values; or the classification stage generates a combined classification result for combined principal and extension feature values; and, d) a combiner stage connected to the classification stage, the combiner stage combines the extension and principal classification results to provide a classification result for the given radar track segment when the classification stage provides the principal and extension classification results.