Gmsk Frequency Hopping And Blind Detection Algorithm Of Blind Estimation Of Signal Parameters

Frequency-Hopping (FH) is a novel spread spectrum communication technique,which develops very fast in military field due to its LPI/LPD (Low Probability of Intercept / Detection) properties and immunity against interferences,The extensive application of HF (high frequency) frequency-hopping radios in military has greatly enhanced the ability of military equipments against jamming and interception and brought up a new austere challenge for communication countermeasures. So researching the surveillance,interception and classification methods for FH signals has been a difficult and pressing task in communication countermeasure fields.In recent years,the three hot-points of Modern Signal Processing theory - Spectrum Estimation,Higher Order Cumulants,Time-Frequency Analysis have become more and more mature and greatly promoted the research work for communication countermeasure techniques.Nowadays,the research of new surveillance and interception algorithms for FH signals using modern signals processing technique has become a hot topic since the conventional communication countermeasure techniques don't work any more. FH signals are time-variant and non-stationary signals,while time-frequency analysis is a powerful tool to analyze this kind of signals. So how to deal with FH signals using time-frequency analysis technique is a important aspect in the research fields of FH surveillance algorithms. In this paper we will do some efforts in this field.Chapter 1 introduces the extensive application of HF/VHF communication and HF/VHF radios in military field,and points out the significance for promoting the research work of FH communication countermeasure using modern signal processing techniques,especially time-frequency analysis.Chapter 2 introduces the theory of frequency-hopping and OMSK,at the same time gives out a FH-GMSK radio model in High Frequency band under the MATLAB simulink environment.Chapter 3 respectively proposes the parameter blind estimation algorithms for high-speed-hop and low-speed-hop FH signals based on Smoothed Pseudo WVD (SPWVD) . Furthermore,the simulation results are given to demonstrate the algorithms performance.Chapter 4 gives out the blind detection algorithm of unknown FH signal using Multi-Hop Autocorrelation technique and blind signal separation algorithm using Joint Approximate Diagonalisation of Eigen-matrices (JADE) technique. Some elementary simulation results are also presented here.