基于瞬时频率的双曲调频信号距离估计误差分析

Instantaneous-frequency-based ranging bias analysis of HFM waveforms

双曲调频信号的多普勒不变性可使运动目标匹配滤波输出的能量损失达到最小,从而可对运动目标有很高的检测能力,在运动目标检测与参数估计中具有独特优势,但同时也给目标距离的估计带来一定误差。在双曲调频信号模糊函数、多普勒不变性和匹配滤波特性的基础上,对距离分辨力和测距误差进行了分析,提出了基于瞬时频率的距离误差计算公式,可直接应用于目标距离的补偿以及目标跟踪中量测方程的校正,提高声呐的工作性能。

Hyperbolic-Frequency-Modulated （HFM） waveforms offer the detection performance that is named ＂Doppler invariance＂, which makes a minimal output lossrelatively unaffected by target range rate in matched filtering. In the meantime the Doppler invariance leads a ranging bias in estimating the range of moving targets. In this article, the range resolution and ranging bias based on the HFM ambiguity functions are analyzed based on the Doppler invariance and matched filter properties. And then an instantaneous-frequency-based ranging bias formulas is proposed, which can be utilized to calibrate the measurement equation of precise target tracking and so to improve the performance of sonar detection.