| Summary: | 碩士 === 國立中央大學 === 通訊工程學系 === 107 === We studied the target localization method for quantized wireless sensor networks(WSN) in the mixed Line Of Sight (LOS) and Non-Line Of Sight (NLOS) signal environments. Owing to the influence of NLOS signals, the accuracy of conventional localization methods are degraded. And, considering limited power resources of sensors,
the Received Signal Strength (RSS) data is usually quantized to several bits. The fusion center can only employ the quantized signals to localize the target position. Due to the effect of non-line of sight signals, we model the measurement noise as a Gaussian mixture distribution and assume that the mixture model parameters are completely unknown. Therefore, the Expectation Maximization (EM) method is used to approximate the Maximum Likelihood Estimation (MLE) target position and the mixed model parameters. The proposed method modifies the Least Squares Estimation (LSE) condition in which the measurement error belongs to a Gaussian mixture distribution.
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