The Application of Speech Recognition Techniques to Radar Target Doppler Recognition: A Case Study

This paper reports some preliminary results of an examination into the feasibility of recognising the Doppler signatures of targets using speech recognition processing techniques. The rationale is that human operators typically listen to the Doppler audio output from the surveillance radar to detect and possibly identify targets. A feature of speech recognition is that pre-processing is used that takes account of the voice mechanisms that produce speech and the characteristics of the human ear. Three different recognition techniques, with identical pre-processing, were implemented. After validating the recognition algorithms with speech the recognisers were retrained with Doppler signals from a number of sources. It was found that the best of the speech recognisers, HMM-GMM, was also the best of the Doppler recognisers with 88% recognition. The work has been compared with that of others using a similar technique and a good agreement has been found. Some recent discoveries in neuroimaging are quoted that suggest that the human brain and that of several other mammals performs visual recognition in a manner common in speech recognition..