Study on timing jitter in clutter mitigation of through-wall human indication

Ultra-wide band (UWB) through wall radar (TWR) is considered as one of the preferred techniques for through-wall human indication due to its good penetration and high range resolution. UWB TWR benefits from its large bandwidth, but the large bandwidth inadvertently results in an issue not substantial in narrowband radars — high timing jitter effect. In typical impulse TWR, timing jitter is mainly caused by the non-ideal sampling clock at the receiver. The fact that impulse TWR employs pulses with very narrow width makes little jitter inaccuracy large enough to degrade the system performance. However, very few studies about the timing jitter in the UWB TWR applications can be found. In this paper, we focus on the impact of timing jitter on the clutter suppression in through-wall human indication. We first model and analyze the timing jitter in impulse TWR. Then, we introduce a simple jitter compensation method based on interpolation and cross correlation with a specified pulse to align the sampled pulses and combat the timing jitter. Finally, we adopt the exponential average background subtraction (EABS) method to suppress clutters. The proposed method is effective to remove the jitter distortion in clutter mitigation, and applicable for real-time applications. Through-wall experiments are presented to verify the proposed method.