1. A method in a computing device for classifying objects, the method comprising: providing a classifier that identifies a class for an object, the classifier inputting a feature vector representing the object and outputting an indication of the class for the object; receiving a signal frame for a detected object, the signal frame representing return signals acquired by receivers based on signals emitted by transmitters operating in multistatic mode, the signal frame including, for each transmitter and receiver pair, a plurality of samples acquired by the receiver at different sampling times for the signal emitted by the transmitter; transforming the samples of the return signal for each transmitter and receiver pair to a return spectrum in the frequency domain; generating singular values from the samples of the return spectrum of each transmitter and receiver pair; generating a feature vector representing the detected object from the generated singular values; and applying the classifier to the generated feature vector to identify the class of the detected object.