Sub-Peaks Suppression for DTMB Signal Based Passive Detection Systems

Abstract

Passive detection is an effective way to monitor the security of the low-altitude airspace. Tsinghua University’s independently developed Digital Television Terrestrial Multimedia Broadcasting (DTMB) signal enjoys a high coverage in China, whereas few studies have addressed the passive detection based on this kind of signal in detail. Ambiguity function is utilized to detect the targets, however there exists sub-peaks caused by the frame format of the DTMB signal. In this paper, we propose a sub-peaks suppression scheme based on DTMB. The influence of the repeated PN sequence and the power difference on sub-peaks generation are analyzed. To tackle the sub-peaks problem, sampled Linear Frequency Modulation signal with the same power of the frame body is adopted to replace the original PN sequence in DTMB reconstruction. The experimental results show that our proposed method can effectively mitigate the sub-peaks problem.