In view of the shortcomings of the existing method of identification of radiant sources

a novel feature extraction method based on I/Q mismatch is proposed

which can be detected

reproducible and invariable by using the I/Q mismatch fingerprint of the source. This method is a fingerprint feature extraction method based on signal space. It needs to estimate the signal-to-noise ratio of the signal. Through comprehensive consideration

the SNR estimation method based on eigenvalue decomposition is adopted. The experimental simulation results show that

under the same signal to noise ratio

the radio frequency fingerprint feature extraction method based on I/Q mismatch is superior to the dual spectrum and Hilbert-Huang transform signal feature extraction methods.