Frequency-Hopping Signal’s Detection

The frequency-hopping (FH) communication technology has been widely used inthe countries of the wireless communication field, especially in the militarycommunications. So the reconnaissance, receiving and interference to FH signal hasbecome an important and key technology in communication countermeasure, and thedetection of FH signal is the most key technology.Based on the frequency-hopping communication principle and time-frequencyanalysis theory, this dissertation designs a FH signal detection algorithm mainly onSmooth Pseudo Wigner-Ville Distribution (SPWVD) time-frequency analysis, andpredicts the signal frequency-hopping pattern. Time-frequency distribution of aunknown fast FH signal in VHF is gained by the smooth pseudo WVD distribution(SPWVD) time-frequency analysis algorithm. According to the FH signalcharacteristics in time-frequency distribution, this dissertation designs a FH signalextraction method based on two-dimension image processing by adoption ofimproved morphological image processing technology. The hopping-speed,frequency-hopping pattern information is extracted and estimated after getting a cleartime-frequency distribution diagram, and the frequency-hopping pattern predict iscompleted. It is shown that this detection method can get a good focus time-frequencydiagram and a high detection rate in-2dB SNR.