###### Abstract
When detecting expected station signals, it is necessary to suppress the signals from other stations and reduce their impact on the detection of expected station signals. Simultaneously, noise is received at the same time during the receiving process of the Alpha signal, which affects the accuracy of the expected station detection and signal parameter measurement. In particular, when the signal is weak, noise and mutual interference must be suppressed to improve the quality of Alpha navigation signals. Alpha positioning was realized using hyperbolic positioning technology after calculating the phase difference between the signals received from different stations. The phase difference was measured by detecting the indirect phase difference between the different frequency signals at each station and the reference frequency signals [5, 18]. Phase difference measurements require a highly stable clock and a reference signal of the same order as that of the transmitted signal, which not only imposes high time synchronization requirements on the receiving equipment but also precludes automated phase difference detection. Currently, signal delay correlation and envelope detection methods exist for detecting pulse signals similar to Alpha navigation signals [19, 20, 21]. The signal delay correlation method was used to correlate the two sets of signals before and after obtaining the correlation results. This method requires a high SNR, and the multivalue of the correlation results can lead to large detection errors. The envelope detection method uses the Hilbert variation to obtain the signal envelope and then detects the station signals according to the order of the broadcasting signals. This method generates mutual interference between signal envelopes of different frequencies, which affects the detection performance. In the field of radio timing and navigation signal processing, noise suppression methods include classical bandpass filtering and modern filtering. The classical bandpass filter can either be a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter. Modern filtering methods include wavelet filtering, empirical mode decomposition, kalman filtering, etc. [22, 23]. Although the modern filtering method has the advantage of strong anti-noise ability, it is more complicated to implement on a hardware platform with high digital signal processing timing. The classical bandpass filter is simple to realize and can fulfill the requirements of the receiver, so it is often used in engineering implementation. Therefore, this paper primarily considers the use of a bandpass filter to suppress the noise. To address the detection problems of noise and mutual interference in Alpha navigation signal reception, a multichannel orthogonal correlation detection method is proposed in this study. Upon extracting the three frequency signals of all stations in Alpha, an orthogonal correlation was performed for each frequency signal to obtain the correlation peaks, and station identification was achieved according to the broadcasting order of the three frequency signals of the different stations in the Alpha system. In this study, the performance of the detection method was simulated under noise and mutual interference, and real signals were used to verify the method. The results show that the method not only has the advantage of strong mutual interference resistance but can also achieve the detection of Alpha navigation signals under the condition of a lower signal-to-noise ratio (SNR) and meet the application requirements of the Alpha receiver.