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A Decorrelation Technique for Direction-of-Arrival Estimation of Coherent Signals

Coherent 신호의 입사방향 추정을 위한 상관관계 제거 기법

  • Park, Geun-Ho (Department of Electronics Engineering, Pusan National University) ;
  • Shin, Jong-Woo (Department of Electronics Engineering, Pusan National University) ;
  • Kim, Hyoung-Nam (Department of Electronics Engineering, Pusan National University)
  • Received : 2015.10.13
  • Accepted : 2016.07.27
  • Published : 2016.08.25

Abstract

Subspace-based direction-of-arrival (DOA) estimation algorithms have a difficulty in dealing with coherent signals caused by multi-path environment. As one of attempts to solve this problem, a spatial differencing method is known to be useful for not only estimating DOAs of the coherent signals but also improving the number of resolvable wavefronts even more than the number of antenna elements. However, since the conventional spatial differencing method uses only the partial statistics of the observed data, this method suffers from the performance degradation in estimation accuracy caused by the residual correlation between the uncorrelated signals. To cope with this problem, in this paper, a generalized spatial differencing method is proposed. Unlike the conventional method, the proposed method utilizes the entire statistics of the received signals. Therefore, the additional performance enhancement in both estimation accuracy and the number of resolvable wavefronts can be achieved. The performance analyses with computer simulations show that the proposed method outperforms the conventional method in terms of the estimation accuracy and the number of resolvable wavefronts.

배열 안테나를 이용한 부공간 (subspace) 기반의 도래각 추정 알고리즘은 다중 경로에 의해 나타나는 coherent 신호가 입사하는 경우 원 신호 공분산 행렬의 특이성 (singularity)으로 인해 도래각 추정 정확도가 급격히 감소한다. Coherent 신호에 의한 도래각 추정 알고리즘의 성능 저하를 극복하기 위해 제안된 공간 차이 기법 (spatial differencing method)은 coherent 신호의 도래각 추정뿐만 아니라 안테나 개수 이상의 신호원을 추정하는 기법으로 주목받았다. 그러나, 공간 차이 기법은 수신 신호의 유한한 표본 수에 의해 발생하는 uncorrelated 신호 간의 상관관계 (correlation)에 따라 도래각 추정 성능이 크게 영향을 받는 구조적 문제가 존재한다. 이러한 문제를 극복하기 위해, 본 논문에서는 획득한 수신 신호의 정보를 최대한 활용하여 uncorrelated 신호간의 상관관계를 효과적으로 제거하는 일반화된 공간 차이 기법을 제안한다. 그리고 모의실험을 통해 도래각 추정 정확도와 추정 가능 신호원의 수의 관점에서 성능을 평가하여 제안한 기법의 우수성을 입증한다.

Keywords

References

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