Direct non-line-of-sight bias estimation for positioning in digital broadcasting system

Non-line-of-sight (NLOS) conditions pose a major challenge to radio positioning in both indoor and outdoor scenarios. In this paper, the proposed technique using the digital broadcasting signals takes the NLOS bias into consideration and improves the location accuracy of a mobile station (MS), since digital broadcasting signal has some unique advantages for wireless location. A constrained optimization-based location algorithm is proposed to estimate the unknown bias directly by using the sequential quadratic programming (SQP) algorithm. This method does not rely on any prior statistics information, and simulation results show that the proposed method considerably outperforms existing methods.