A Range-angle Joint Imaging Algorithm for Automotive Radar Systems Based on Doppler Domain Compensation
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摘要: 高性能、高分辨率单快拍前视成像技术是赋能车载雷达发展的关键,但距离/多普勒走动问题会限制相干积分的实施,同时系统分辨率也往往受限于硬件参数难以提高。根据车载毫米波雷达时分多输入多输出(TDM-MIMO)的前视成像体制,该文提出多普勒域补偿和点对点回波校正方法,完成多域信号解耦合,同时完成距离多普勒走动校正和多普勒解模糊。由于有限阵元数及强噪声干扰限制了传统单维度距离角度成像准确性,因此,该文提出一种基于改进贝叶斯匹配追踪方法(IBMP)的多域联合估计算法。该方法基于伯努利-高斯(BG)模型,在最大后验(MAP)准则约束下迭代更新估计参数和支撑域,实现了多维联合信号的高精度重构。仿真和实测结果表明该文方法能够有效解决距离走动问题,并提高雷达前视成像的角度分辨率,具有较强噪声鲁棒性。
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关键词:
- 毫米波雷达 /
- 距离走动 /
- 多普勒域补偿 /
- 多域联合估计 /
- 改进贝叶斯匹配追踪(IBMP)算法
Abstract: Single snapshot forward-looking imaging technology with high performance and resolution is crucial for enabling the development of automotive radars. However, range migration issues can limit the implementation of coherent integration methods, and improving system resolution is generally difficult due to hardware parameter limitations. Based on the Time-Division Multiplexing Multiple-Input-Multiple-Output (TDM-MIMO) forward-looking imaging systems of automotive millimeter wave radar, this paper proposes Doppler domain compensation and point-to-point echo correction measures for achieving multidomain signal decoupling. However, the accuracy of traditional single-dimension range and angle imaging is limited by the number of finite array elements and significant noise interference. Therefore, this paper proposes a multidomain joint estimation algorithm based on the Improved Bayesian Matching Pursuit (IBMP) method. The Bayesian method is based on the Bernoulli-Gaussian (BG) model, and the estimated parameters and support domain are iteratively updated in this method while adhering to the Maximum a Posteriori (MAP) criterion constraint to achieve the high-precision reconstruction of multidimensional joint signals. The final set of simulation and actual measurement results demonstrate that the proposed method can effectively solve the problem of range migration and improve the angle resolution of radar forward-looking imaging while exhibiting excellent noise robustness. -
1 基于MAP的贝叶斯匹配追踪方法
1. The Bayesian Matching Pursuit (BMP) based on MAP
初始化:
$\partial \left( {\mathbf{0} } \right) = \left( { - M{\text{In} }\;\pi - M{\text{In} } \;{\sigma ^2} - \dfrac{1}{ { {\sigma ^2} } }\left\| { {\boldsymbol{Y} } } \right\|_2^2} \right) + Q{\text{In} }\left( {1 - {p_1} } \right)$${ { {\boldsymbol{c} } }_q} = \dfrac{ { { { {\boldsymbol{a} } }_q} } }{ { {\sigma ^2} } },{\beta _q} = \sigma _1^2{\left( {1 + \sigma _1^2{ {\boldsymbol{a} } }_q^{\text{H} }{ { {\boldsymbol{c} } }_q} } \right)^{ - 1} }$ ${\partial _q} = \partial \left( {\mathbf{0} } \right) + {\text{In} }\dfrac{ { {\beta _q} } }{ { \sigma _1^2} } + {\beta _q}\left\| {\left( { { { {\boldsymbol{Y} } }^{\text{H} } }{ { {\boldsymbol{c} } }_q} } \right)} \right\|_2^2 + {\text{In} }\left( {\dfrac{ { {p_1} } }{ {1 - {p_1} } } } \right)$ $\varOmega = [\;],\;{ { {\boldsymbol{s} } }^{\left( 0 \right)} } = {\mathbf{0} }$ 更新迭代过程: ${q^*} = {{{\rm{max}}\_{\rm{index}}} }\left( { {\partial _q} } \right)$ $\varOmega = \varOmega \cup {q^*},{ { {\boldsymbol{s} } }^{\left( { {d} } \right)} } = { { {\boldsymbol{s} } }^{\left( { { {d} } - 1} \right)} } + \delta \left[ { {q^*} } \right],{\partial ^{\left( d \right)} } = {\partial _{ {q^*} } }$ ${ { {\boldsymbol{c} } }_q} = { { {\boldsymbol{c} } }_q} - {\beta _{ {q^*} } }{ { {\boldsymbol{c} } }_{ {q^*} } }({ {\boldsymbol{c} } }_{ {q} })^{\text{H} }{ { {\boldsymbol{a} } }_q}$ ${\beta _q} = \sigma _1^2{\left( {1 + \sigma _1^2({ {\boldsymbol{a} } }_q)^{ {\rm{H} } }{ { {\boldsymbol{c} } }_q} } \right)^{ - 1} }$ ${\partial _q} = {\partial ^{\left( d \right)} } + {\rm{In} }\dfrac{ { {\beta _q} } }{ {\sigma _\Delta ^2} } + {\beta _q}\left\| { { { {\boldsymbol{Y} } }^{\text{H} } }{ { {\boldsymbol{c} } }_q} } \right\|_2^2 + {\text{In} }\left( {\dfrac{ { {p_1} } }{ {1 - {p_1} } } } \right)$ 输出: ${\hat { {\boldsymbol{x} } }_{ {\text{map} } } } = \sigma _1^2 \displaystyle\sum\limits_{i \in \varOmega } { {\delta _i}{ {\left( { {\boldsymbol{c} }_i^{} } \right)}^{\text{H} } }{ {\boldsymbol{Y} } } }$ 表 1 仿真实验雷达参数
Table 1. Radar parameters for simulation experiment
雷达参数 数值 载频(GHz) 77 带宽(MHz) 1500 MIMO天线配置 2T × 4R 脉冲宽度(μs) 55 脉冲采样点数K 256 脉冲个数L 256 角度分辨率(°) 15.7 距离分辨率(m) 0.1 最大不模糊速度(m/s) 8.85 表 2 AWR1642雷达关键参数
Table 2. Radar parameters of AWR1642
雷达参数 值 载频(GHz) 77 带宽(MHz) 1500 MIMO天线配置 2T × 4R 脉冲宽度(μs) 160 脉冲采样点数K 128 脉冲个数L 15.7 角度分辨率(°) 0.1 距离分辨率(m) 0.095 -
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