Research On Weak Signal Detection Method In Offshore Electromagnetic Spectrum

With the increase of frequency equipment,the offshore electromagnetic environment is becoming more and more complex,and it has become a problem to detect weak signals at sea through the electromagnetic spectrum.Combined with the real-time nature of maritime signals,thesis studies the weak signal detection method suitable for offshore electromagnetic spectrum detection from the perspective of signal-to-noise separation and dynamic threshold setting.The main research content of thesis is as follows:Aiming at the problem that the weak signal energy in the electromagnetic spectrum is not high,and it is not easy to be captured and detected,thesis analyzes and tests the electromagnetic wave propagation loss in theth complex environment at sea based on the definition and characteristics of weak signal,so as to guide the detection of weak signal.The frequency domain characteristics of background noise in offshore spectrum monitoring are extracted and analyzed,which paves the way for subsequent research on the influence of these noises in frequency domain signal detection.Aiming at the current situation that the detection accuracy of signal weak energy detection method is not high,an improved frequency domain detection algorithm is designed.The algorithm combines the three core ideas of segmentation processing,smooth filtering and real-time dynamic threshold selection based on historical statistical values,and gives the specific flow of the algorithm.Aiming at the problem that the signal is greatly affected by the real-time nature of the offshore electromagnetic environment,resulting in weak signals that are not easy to detect,the proposed improved algorithm successfully reduces the influence of noise in the received signal by estimating the deviation constant.In addition,the algorithm is more sensitive to signal fluctuations in a short period of time.The experimental results verify the performance superiority of the algorithm at low signal-to-noise ratio,which can solve the real-time and adaptive problems of maritime radio signals,and greatly improve the detection performance of weak signals at sea in the electromagnetic spectrum.