This paper proposes a desirable method to detect different kinds of low probability of intercept (LPI) radar signals, targeted at the main intra-pulse modulation method of LPI radar signals including the signals of li...This paper proposes a desirable method to detect different kinds of low probability of intercept (LPI) radar signals, targeted at the main intra-pulse modulation method of LPI radar signals including the signals of linear frequency modulation, phase code, and frequency code. Firstly, it improves the coherent integration of LPI radar signals by adding the periodicity of the ambiguity function. Then, it develops a frequency domain detection method based on fast Fourier transform (FFT) and segmented autocorrelation function to detect signals without features of linear frequency modulation by virtue of the distribution characteristics of noise signals in the frequency domain. Finally, this paper gives a verification of the performance of the method for different signal-to-noise ratios by conducting simulation experiments, and compares the method with existing ones. Additionally, this method is characterized by the straightforward calculation and high real-time performance, which is conducive to better detecting all kinds of LPI radar signals.展开更多
In this paper,the equivalent radius of radioactive sources in each segment is determined by analyzing the different responses of the two identical detectors,and an improved segmented gamma scanning is used to assay wa...In this paper,the equivalent radius of radioactive sources in each segment is determined by analyzing the different responses of the two identical detectors,and an improved segmented gamma scanning is used to assay waste drums containing mainly organic materials,and proved by an established simulation model.The simulated radioactivity distributions in homogenous waste drum and an experimental heterogeneous waste drum were compared with those of traditional segmented gamma scanning.The results show that our method is good in performance and can be used for analyzing the waste drums.展开更多
基金supported by the National Natural Science Foundation of China(61571462)Weapons and Equipment Exploration Research Project(7131464)
文摘This paper proposes a desirable method to detect different kinds of low probability of intercept (LPI) radar signals, targeted at the main intra-pulse modulation method of LPI radar signals including the signals of linear frequency modulation, phase code, and frequency code. Firstly, it improves the coherent integration of LPI radar signals by adding the periodicity of the ambiguity function. Then, it develops a frequency domain detection method based on fast Fourier transform (FFT) and segmented autocorrelation function to detect signals without features of linear frequency modulation by virtue of the distribution characteristics of noise signals in the frequency domain. Finally, this paper gives a verification of the performance of the method for different signal-to-noise ratios by conducting simulation experiments, and compares the method with existing ones. Additionally, this method is characterized by the straightforward calculation and high real-time performance, which is conducive to better detecting all kinds of LPI radar signals.
基金Supported by National Natural Science Foundation of China(No.10675084)
文摘In this paper,the equivalent radius of radioactive sources in each segment is determined by analyzing the different responses of the two identical detectors,and an improved segmented gamma scanning is used to assay waste drums containing mainly organic materials,and proved by an established simulation model.The simulated radioactivity distributions in homogenous waste drum and an experimental heterogeneous waste drum were compared with those of traditional segmented gamma scanning.The results show that our method is good in performance and can be used for analyzing the waste drums.
