Research On Reconnaissance And Recognition Method Of UAV Signal

Unmanned aerial vehicle(UAV)originated from the military field,and then quickly gained favor in the civil field because of its miniaturization characteristics.In recent years,with the increasing of the “flying illegally” incident of small UAV,the application of frequency hopping communication countermeasure technology to the small UAV counter-reaction field is a hot spot at present.The jamming technology for small unmanned aerial vehicles has been mature,and it is a hot research topic in technology and products to realize the signal reconnaissance and passive location of UAVs in complex electromagnetic environment.Therefore,in view of the problem of signal reconnaissance,research on reconnaissance and recognition method of UAV signal is of great significance and impetus to the field of UAV anti-system.The specific work arrangement of this thesis is as follows:(1)The principle and model of frequency hopping communication system and UAV signal analysis are studied,which provides a theoretical basis for subsequent detection and identification and parameter estimation algorithms.(2)The detection method of small unmanned aerial vehicle remote control signal is mainly studied.Although the detection method based on multi-hop autocorrelation has good detection performance,it is easy to be affected by the fixed frequency signal(map transmission,WiFi),the detection method based on power spectrum estimation utilizes the difference between the power spectrum of remote control signal and the power spectrum of fixed-frequency signal over time,it can eliminate the fixed frequency signal and obtain the target signal.Finally,aiming at the non-stationary characteristics of remote control signal,a spectrum-based remote control signal extraction method is researched,which extracts the target signal according the prior information(hop duration)of the remote control signal.Compared with the spectrum-based detection method for eliminating interference signals,the method not only reduces the calculation amount,but also can extract the target signal more accurately when there are multiple frequency hopping signals and the hop duration is different,and does not need the subsequent sorting process.(3)The main research of small UAV signal(remote control and map transmission)feature parameter estimation and identification methods,first researched the spectrum based feature parameter extraction method,including according to the maximum and time-frequency ridge line to estimate parameters,and considering the frequency collision solution.In the case of processing the measured remote control signal data of small unmanned aerial vehicle,the estimation method based on multi-window overlapping spectrum is researched,and the algorithm verification of the measured data of small unmanned aerial vehicle is carried out.Then the method of signal recognition is studied.Finally,utilize higher order cumulant and cyclic spectrum,the method of modulation recognition and parameter estimation of real-time signal of small unmanned aerial vehicle is studied.