| 摘要: |
| 相干线性调频Z变换（Coherent chirp-Z transform，CCZT）测距算法在调频连续波（Frequency Modulation Continuous Wave，FMCW）雷达调制带宽降低时，其相干频谱易出现密集的周期性峰值，使真实谱峰难以准确定位，从而导致算法距离估计精度降低。针对此问题，本文提出一种子载频相干与二次拟合结合（Sub-carrier Frequency Coherence and Quadratic Fitting, SFC-QF）的高精度测距算法。算法首先对不同子载频的拍频信号进行相干处理，通过在相干频谱中引入载频差加权，抑制低带宽条件下相干频谱周期性峰值。然后对相干频谱的估计结果及其邻域进行二次拟合处理，在降低算法性能对频谱细化次数依赖的同时，实现更高的估计精度。仿真结果表明，相比于CCZT及其他对比算法，所提算法在百兆赫兹级低带宽雷达中能够显著提高距离估计精度，为低带宽FMCW雷达的高精度距离测量提供了一种有效的解决方案。 |
| 关键词: 调频连续波雷达 高精度测距 子载频相干 二次拟合 低带宽雷达 |
| DOI： |
| 分类号:TN958.94 |
| 基金项目:国家重点研发计划（2022YFB3200189）；特立学生科技创新团队（2025CX06030） |
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| A High Precision Ranging Algorithm for FMCW Radar Based on Sub-carrier Frequency Coherence and Quadratic Fitting |
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| Abstract: |
| When the modulation bandwidth of frequency modulation continuous wave (FMCW) radar decreases, the coherent spectrum of the coherent chirp-Z transform (CCZT) ranging algorithm tends to exhibit dense periodic peaks, making it difficult to accurately locate the true spectral peak, thereby leading to a reduction in ranging precision. To address this issue, this paper proposes a high precision ranging algorithm that combines sub-carrier frequency coherence and quadratic fitting (SFC-QF). The algorithm first performs coherent processing on the beat signals of different sub-carriers, by introducing carrier frequency difference weighting into the coherent spectrum to suppress periodic peaks under low-bandwidth conditions. Subsequently, applying quadratic fitting to the estimated peak and its neighborhood in the coherent spectrum, thereby reducing the algorithm’s dependence on the number of spectral refinements while achieving higher estimation accuracy. Simulation results demonstrate that, compared with the CCZT and other reference algorithms, the proposed SFC-QF method significantly improves the ranging estimation precision in low-bandwidth radars at the hundred-megahertz level, providing an effective solution for high precision distance measurement with low-bandwidth FMCW radar. |
| Key words: FMCW radar high precision ranging sub-carrier frequency coherence quadratic fitting low-bandwidth radar |