利用S变换的X射线脉冲星信号恒虚警率检测算法

针对传统的X射线脉冲星信号检测算法计算量大及在低信噪比下检测性能差的问题，提出了一种结合S变换的恒虚警率检测算法。首先，根据高斯白噪声的S变换域功率谱分布特性对累积信号的时频功率谱进行阀值滤波；然后累加阀值滤波后的信号功率谱作为检测统计量，从理论上对检测统计量的分布特性进行分析，得出检测统计量服从高斯分布，并用蒙特卡罗方法进行了验证。在此基础上，利用检测统计量的概率密度函数计算判决门限，从而实现了恒虚警率检测。理论分析和实验结果表明，本文算法的检测性能优于同类基于高斯分布的恒虚警率检测算法，并且具有较低的复杂度。

A Constant False Alarm Rate Detection Algorithm for X ray Pulsar SignalBased on S transform

In order to overcome shortcomings of traditional X ray pulsar signal detection algorithm，such as large computing, poor detection performance in low signal to noise ratio (SNR), etc, a novel constant false alarm rate (CFAR) detection algorithm is proposed based on S transform (ST). Firstly, threshold filtering is operated on the S transform power spectrum of cumulative signal according to distribution character of S transform power spectrum of Gaussian white noise. Then the sum of the time frequency power spectrum after threshold filtering is used as a test statistic and its distribution characteristic is analyzed theoretically. It is concluded that the test statistic obeys Gaussian distribution, which is also verified by Monte Carle method. And on this basis, the probability density function (pdf) of the test statistic is used to calculate the decision threshold so as to realize the CFAR detection. Theoretical analysis and simulation results indicate that the proposed method has better detection accuracy than a similar CFAR detection algorithm based on the Gaussian distribution, and it also has lower complexity.