Research On Electromagnetic Spectrum Detection Method For Complex Offshore Environment

Electromagnetic spectrum resources are extremely important and scarce resources for any country,and they are non-renewable.Maritime electromagnetic spectrum resources are the basis of maritime wireless communication technology.The rapid and stable development of maritime wireless communication technology is inseparable from the reasonable development and efficient management and control of maritime electromagnetic spectrum resources.Based on the signal detection method of maritime electromagnetic spectrum sensing.This thesis is based on the signal detection method of electromagnetic spectrum sensing at sea.Research on electromagnetic spectrum collaborative detection for complex marine environments,estimation of background noise in marine environments,prediction of maritime electromagnetic spectrum distribution,and construction methods of lightweight distributed electromagnetic spectrum databases.The main research contents are as follows.Aiming at the problem of low detection probability of electromagnetic spectrum in complex marine environment.Based on the distributed electromagnetic spectrum detection system,research on the collaborative detection method of radio frequency signals at sea.Combining with the characteristics of sea wave propagation loss,the boundary of propagation loss is proposed.Estimating the electromagnetic spectrum distribution of radio frequency signals in complex maritime environments from the perspective of signal sources.A method for locating radio frequency signal source based on Monte Carlo algorithm is proposed,which improves the blind positioning accuracy of radio frequency signal source.To improve the accuracy of collaborative detection in cognitive wireless networks.Combined with radio signal direction finding,a minimum average distance method is proposed.Aiming at the complex and changeable maritime environment,it is difficult to accurately estimate the electromagnetic spectrum at sea.Study the estimation method of the background noise of the electromagnetic spectrum at sea.Exploring the impact of rough seas on the offshore electromagnetic spectrum.Combined with the loss characteristics of the energy and phase of electromagnetic waves in the complex environment at sea.Study the frequency domain feature detection method of marine radio frequency signal and background noise.Combined with sea surface characteristic parameters and distributed electromagnetic spectrum detection node data.Study the influence of different marine electromagnetic environments on background noise,and extract the background noise envelope in real time.The test results show that the method can effectively estimate the background noise of the electromagnetic spectrum at sea and improve the detection probability of effective signals.Aiming at the problem of dynamic distribution of electromagnetic spectrum at sea caused by the continuous change of antenna attitude in complex maritime environment.Static and dynamic models of rough sea surface are constructed,and a prediction method of electromagnetic spectrum distribution at sea based on ray tracing algorithm is proposed.The influence of marine environmental factors and antenna attitude changes on the fluctuation of received signal strength is studied.Construct the direct and reflected ray propagation model of electromagnetic waves at sea.Combining ocean wave spectrum and antenna tilt angle,a ray-tracing-based acceleration model quickly and efficiently estimates the spatial distribution of the large-scale maritime electromagnetic spectrum.Aiming at the problem of high sparsity of electromagnetic spectrum data in complex maritime environment.Combining the propagation loss characteristics of sea waves and the signal source direction finding data of distributed detection node.Research on signal source cooperative detection and propagation loss parameter estimation method.Construct a distributed electromagnetic spectrum database based on blockchain structure.Reduced redundancy of distributed electromagnetic spectrum data volume.Based on the electromagnetic spectrum collaborative detection consensus mechanism,a distributed electromagnetic spectrum database independently maintained by detection nodes is constructed.In order to improve the utilization rate of electromagnetic spectrum resources and reduce the probability of spectrum collision.An electromagnetic spectrum resource currency is proposed to measure the priority of secondary users’ dynamic spectrum access.When a spectrum conflict event occurs between secondary users.Spectrum time slice resources can be allocated according to the electromagnetic spectrum resource currency.Based on the distributed electromagnetic spectrum database to reproduce the occupancy of space electromagnetic spectrum resources.Realize the visualization of electromagnetic spectrum resource data.The utilization rate of electromagnetic spectrum resources is improved,and the dynamic spectrum access mechanism for secondary users is guaranteed.