Optimization of array geometry for direction-of-arrival estimation using a priori information

[摘要] This paper focuses on the estimation of the direction-of-arrival (DOA) ofsignals impinging on a sensor array. A novel method of array geometryoptimization is presented that improves the DOA estimation performancecompared to the standard uniform linear array (ULA) with half wavelengthelement spacing. Typically, array optimization only affects the beam patternof a specific steering direction. In this work, the proposed objectivefunction incorporates, on the one hand, a priori knowledge about the signal'sDOA in terms of a probability density function. By this means, the array canbe adjusted to external conditions. On the other hand, a modified beampattern expression that is valid for all possible signal directions is takeninto account. By controlling the side lobe level and the beam width of thisnew function, DOA ambiguities, which lead to large DOA estimation errors, canbe avoided. In addition, the DOA fine error variance is minimized. Using aglobally convergent evolution strategy, the geometry optimization providesarray geometries that significantly outperform the standard ULA with respectto DOA estimation performance. To show the quality of the algorithm, fouroptimum geometries are presented. Their DOA mean squared error is evaluatedusing the well known deterministic Maximum Likelihood estimator and comparedto the standard ULA and theoretical lower bounds.

[学科分类] 电子、光学、磁材料