航空磁异常探测中的自适应高阶过零检测器

传统航空磁异常探测方法依赖目标信号特性或噪声统计特性的先验知识，造成检测概率低、探测距离短。为了提高航空磁异常信号检测器性能，综合考虑目标信号特征和噪声统计特性，提出一种基于高阶过零法的自适应磁异常探测方法。根据铁磁性潜艇目标信号模型、实测目标高空信号以及稳定无磁环境和复杂磁环境中长时间采集的实测磁噪声，分析目标信号和噪声的特征，研究二者之间的高阶过零统计特性。基于信号的前5阶高阶过零序列构造检测器的检验统计量，设计适用于复杂环境下航空磁异常目标探测的自适应高阶过零（AHOC）检测器。理论性能分析和实测数据验证表明：铁磁性目标信号和磁噪声信号的高阶过零特性存在显著差异，前5阶高阶过零率有明显的区分度；在相同的输入幅度信噪比条件下，AHOC检测器输出的幅度信噪比大于5，抗噪能力更强，且具有良好的弱信号检测能力；AHOC检测器的检测效果优于常规的高阶过零检测器和标准正交基函数检测器，适用于复杂磁环境下的低信噪比探测。

Adaptive High-order Zero-crossing Detector for Airborne Magnetic Anomaly

Traditional airborne magnetic anomaly detection methods rely on prior knowledge of target signal characteristics or noise statistical characteristics，resulting in poor detection probability and short detection distance.In order to improve the performance of airborne magnetic anomaly detectors，an adaptive magnetic anomaly detection method based on the high-order zero-crossing method is proposed, in which the characteristics of the target signal and the statistical characteristics of noise are considered.The characteristics of target signal and noise are analyzed based on the target signal model of ferromagnetic submarine，the measured high-altitude signal of target，and the measured magnetic noises collected over a long period in stable non-magnetic and complex magnetic environments.The high-order zero-crossing statistic characteristics of target signal and noise are researched.Then the test statistic is proposed based on the first five orders of the high-order zero-crossing sequence of signals，and an adaptive high-order zero-crossing detector suitable for detection in complex environment was designed. Theoretical performance analysis and measured data verification show that the magnetic noises collected in stable non-magnetic and complex magnetic environments are quite different， and the noise cannot be simply regarded as a Gaussian distribution. The high-order zero-crossing characteristics of the ferromagnetic and magnetic noise signals are obviously different， and the first five orders of high-order zero-crossing rate are clearly distinguishable. Under the condition of the same input amplitude signal-to-noise ratio， the amplitude of output signal-to-noise ratio of adaptive high-order zero-crossing detector is greater than 5. The anti-noise capability of the adaptive high-order zero-crossing detector is stronger and has good weak signal detection capacity. The detection performance of adaptive high-order zero-crossing detector is better than that of conventional high-order zero-crossing detector and orthonormal basis functions detector. The adaptive high-order zero-crossing detector is suitable for low signal-to-noise ratio detection.