A Signal Processing Algorithm of Two-Phase Staggered PRI and Slow Time Signal Integration for MTI Triangular FMCW Multi-Target Tracking Radars.

Taiwen Tang,Janaka Elangage,Chen Wu

doi:10.3390/s21072296

Taiwen Tang, Janaka Elangage + Show 1 more

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https://doi.org/10.3390/s21072296

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Abstract

In this paper, a novel signal processing algorithm for mitigating the radar blind speed problem of moving target indication (MTI) for frequency modulated continuous wave (FMCW) multi-target tracking radars is proposed. A two-phase staggered pulse repetition interval (PRI) solution is introduced to the FMCW radar system. It is implemented as a time-varying MTI filter using twice the hardware resources as compared to a uniform PRI MTI filter. The two-phase staggered PRI FMCW waveform is still periodic with a little more than twice the period of the uniform PRI radar. We also propose a slow time signal integration scheme for the radar detector using the post-fast Fourier transformation Doppler tracking loop. This scheme introduces dB of extra signal processing gain to the signal before the radar detector compared with the original uniform PRI FMCW radar. The validation of the algorithm is done on the field programmable logic array in the loop test bed, which accurately models and emulates the target movement, line of sight propagation and radar signal processing. A simulation run of tracking s of the target movement near or at the radar blind speed shows that the total degradation from the raw post-fast Fourier transformation received signal to noise ratio is about dB. With a dB post-processing signal to noise ratio of the proposed algorithm for the moving target at around a km range and with about a dB m2 radar cross section at a GHz carrier frequency, the tracking errors of the two-dimensional angles with a digital phased array are less than degree. The range tracking error is about m.

Highlights

Advanced radar sensors that feature multiple functions, multiple modes, multiple channels, multiple waveforms and multiple targets have been researched in recent decades [1,2,3]
With the uniform pulse repetition interval (PRI) moving target indication (MTI) filter, the signal to noise ratio (SNR) drops near any integer multiples of the blind speed
This solution is more effective than using a uniform PRI Frequency modulated continuous wave (FMCW) waveform and relying on the range extrapolation solution in [27] because there is a major post-Fourier transformation (FFT) SNR improvement of the proposed solution in the blind speed zone compared with the uniform PRI waveform

Summary

Introduction

Advanced radar sensors that feature multiple functions, multiple modes, multiple channels, multiple waveforms and multiple targets have been researched in recent decades [1,2,3]. These advanced radars are equipped with “smart” processors that adapt to the sensing environments and sensing requirements. In recent years, this technology trend of advanced radars has been realized primarily because of the combination of advanced signal processing, advanced radio frequency (RF) and integrated circuit technology and artificial intelligence. The radar is designed for L band (1–2 GHz) with a narrow bandwidth and potentially frequency hopping capability if the radio frequency front-end permits

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