Abstract:

It is convenient to use frequency domain methods to deal with flight test data. The frequency domain maximum likelihood method is a very efficient method, the advantages of which are simple in computing, un biased and consistent. Since the flight test data are of time domain, it needs to be converted into frequency domain by FFT method. Then it can be used to identify the system. This method has got good results in identifying the parameters of military aircraft equivalent systems.

Key words: fr equency domain maximum likelihood method, FFT, aircra ft equivalent syst ems