基于改进时频脊线的跳频参数盲估计算法

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中图分类号：TN911 文献标志码：A 文章编号：1673-2340（2025）02-0048-08

Blind estimation algorithm for frequency hopping parameters based on enhanced time-frequency ridge extraction

WANKai'，CHANGCheng²，HOUChangbol*，WUXiangyu1 （l.Schoolof Informationand CommunicationEngineering，HarbinEngineering University，Harbinl5Oool，China; 2.China AcademyofLaunchVehicle Technology，BeijinglOo854，China）

Abstract：In existing blindestimation algorithms for frequency-hoppingparameters basedon time-frequencyridges， performance degrades significantly when thesignal-to-noiseratio（SNR）fals below-5dB.Toaddressthis issue，an improvedblindestimationmethod basedontime-frequencyridges isproposed.First，the time-frequencymatrixof the receivedsignal isobtainedusing theshort-time Fourier transform（STFT）.Then，Gaussian filtering isapplied for signal smoothingand noise suppresson.Since the energy distribution offixed-frequency interference differs fromthat of frequency-hopping signals in the time-frequency matrix，an energycancelation method is used to eliminate such interference.Next，OTSU thresholding isapplied tothe matrixafter energycancelltion to further removeresidual fixed-frequency interferenceand noise，yieldingaclearer time-frequencyrepresentation.Time-frequencyridgesare thenextracted from this image，and the least-squares method is employed to fitthe hopping instants along these ridges，enabling accurateestimationof frequency-hopping parameters.Simulation resultsshow that the proposed method efectively produces clean time-frequency images evenat SNR levelsaslowas -5dB in the presence of fixed-frequency interference. The average relative estimation error of each parameter remains below 1% ，and the method demonstrates strong robustness against varying intensity and quantity of interference.

Keywords：frequencyhopping signal;parameter estimation;time-frequencyridges;fixed frequencyinterference; gaussian filtering; blind estimation algorithms; signal to noise

跳频通信作为扩频技术的重要分支，通过伪随机码序列对载波频率实施动态操控，实现快速灵活的跳变机制。（剩余10089字）