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Radon-Ambiguity变换是一种检测低信噪比下线性调频信号的有力工具。但在多信号环境下,强线性调频信号分量的Radon-Ambiguity变换对弱线性调频信号分量的Radon-Ambiguity变换有较强的抑制作用。同时Radon-Ambiguity变换对具有相同调频斜率和不同初始频率的线性调频信号分量不能实现识别与区分。提出了一种基于逐次滤波Radon-Ambiguity变换的时频表示方法可以有效地检测出多种情况下的多个线性调频信号。仿真试验证明了此方法可以有效地去除噪声、多信号之间交叉项的影响,在低信噪比下也十分有效。
The Radon-Ambiguity Transform is a powerful tool for detecting chirp signals at low signal-to-noise ratios. However, under multi-signal environment, the Radon-Ambiguity transform of the strong linear FM signal component has a strong inhibitory effect on the Radon-Ambiguity transform of the weak linear FM signal component. At the same time, the Radon-Ambiguity transform can not identify and distinguish the chirp signal components with the same chirp rate and different initial frequencies. A time-frequency representation method based on successive filtered Radon-Ambiguity transform is proposed to effectively detect multiple chirp signals in many situations. Simulation results show that this method can effectively remove the noise and the influence of the cross term between multiple signals is very effective at low SNR.