| 摘要: |
| 阵列分子阵后由于子阵存在方向性，导致子阵输出噪声相关系数以及相关半径难以准确估计，从而严重影响阵列性能。针对这一问题，提出了共线子阵在空间各向同性均匀噪声场中输出噪声相关系数的解析计算方法。将噪声相关性计算公式中的波束响应项用子阵加权向量表示，再利用共线子阵的对称性对双重积分进行化简，最终得到不含积分项的解析解。利用该方法，分析了子阵不同参数对输出噪声相关性以及子阵波束形成的影响，结果表明，子阵阵元数、子阵的波束指向角以及子阵中心间距的对输出噪声相关性有重要影响，而子阵波束的旁瓣对噪声相关性的影响较小。数值仿真验证了噪声相关性计算方法的有效性以及相关结论的正确性。 |
| 关键词: 线列子阵 各向同性均匀噪声场；噪声相关系数 |
| DOI： |
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| 基金项目: |
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| Spatial coherence of output noise for sub-arrays in spherically isotropic noise |
| LEI Zhixiong,CHEN Peng |
| (Southwest China Institute of Electronic Technology,Chengdu 610036,China;School of Information Engineering,Changan University,Xian 710064,China) |
| Abstract: |
| The subarray-based beamforming requires noise covariance matrix of output noise generated by sub-arrays.By using beam patterns as inputs,traditional calculation requires several double integrations which bring high computational load,and the computational error caused by numerical integration will degrade the performance of the array.For above problems,an analytical solution of spatial coherence for collinear sub-arrays in spherically isotropic noise is proposed.Without loss of generality,the path differences and beam patterns will only depend on the elevation angle due to linear array symmetry,when the array is assumed placed on the z-axis.Firstly,beam patterns of sub-array can be expressed in a combination of sub-array weight vectors and sub-array manifolds.Then the formulations of the power spectrum densities and cross-power spectrum density of two sub-arrays will be simplified to ones with summations instead of integrals,which can be analytically computed.This solution indicates different parameters such as sub-array element numbers,beam steering directions and distances have great influences on spatial coherence of sub-arrays.In contrast to the parameters mentioned above,sub-array side-lobes have limited effects on spatial coherence of sub-arrays.Numerical simulations demonstrate the accuracy of the analytical solution and the validity of the related theoretical analysis. |
| Key words: linear sub-arrays spherically isotropic noise field noise coherence |
