Experimental study of passive detection of underwater targets across ice

•As a major method of polar detection, the passive detection of the narrowband components of cross-ice underwater target signals has never been studied before.•The results of processing of the experimental data show that the α comparative detector based on the simplified 1D Kalman filter proposed in this paper can smoothen the noisy frequency domain to reduce interference and improve detection performance.•This manuscript is applied to the narrowband signals generated by ships in the Arctic to verify the proposed method. Provide prior knowledge for the application of the detection method in this paper to passive detection of polar narrowband signals in the future.