Weighted SPICE Algorithms for Range-Doppler Imaging Using One-Bit Automotive Radar

Abstract

We consider the problem of range-Doppler imaging using one-bit automotive LFMCW 1 or PMCW radar that utilizes one-bit ADC sampling with time-varying thresholds at the receiver. The one-bit sampling technique can significantly reduce the cost as well as the power consumption of automotive radar systems. We formulate the one-bit LFMCW/PMCW radar range-Doppler imaging problem as one-bit sparse parameter estimation. The recently proposed hyperparameter-free (and hence user friendly) weighted SPICE algorithms, including SPICE, LIKES, SLIM and IAA, achieve excellent parameter estimation performance for data sampled with high precision. However, these algorithms cannot be used directly for one-bit data. In this paper we first present a regularized minimization algorithm, referred to as 1bSLIM, for accurate range-Doppler imaging using onebit radar systems. Then, we describe how to extend the SPICE, LIKES and IAA algorithms to the one-bit data case, and refer to these extensions as 1bSPICE, 1bLIKES and 1bIAA. These onebit hyperparameter-free algorithms are unified within the one-bit weighted SPICE framework. Moreover, efficient implementations of the aforementioned algorithms are investigated that rely heavily on the use of FFTs. Finally, both simulated and experimental examples are provided to demonstrate the effectiveness of the proposed algorithms for range-Doppler imaging using one-bit automotive radar systems.Index Terms-One-bit sampling, time-varying threshold, automotive radar, range-Doppler imaging, hyperparameter-free sparse parameter estimation, weighted SPICE for one-bit data. I. INTRODUCTIONM ILLIMETER wave radar is widely used in diverse applications including advanced driver assistance automotive systems and fully autonomous vehicles [1]. Compared with other sensing systems, such as cameras, lidars and ultrasonics, radar systems can provide better performance, especially in poor lighting or adverse weather conditions [2].The most commonly used probing waveform in existing commercial automotive radar systems is the LFMCW waveform, which reduces the system cost by allowing lowrate ADCs at the radar receivers. An LFMCW radar system transmits a series of chirps, which are reflected by the targets