Conference Paper

Positioning Algorithms for Cellular Networks Using TDOA

Inst. of Commun. & Navigation, German Aerosp. Center, Wessling
DOI: 10.1109/ICASSP.2006.1661018 Conference: Acoustics, Speech and Signal Processing, 2006. ICASSP 2006 Proceedings. 2006 IEEE International Conference on, Volume: 4
Source: IEEE Xplore

ABSTRACT In this paper, we investigate the performance of positioning algorithms in wireless cellular networks based on time difference of arrival (TDoA) measurements provided by the base stations. The localization process of the mobile station results in a non-linear least squares estimation problem which cannot be solved analytically. Therefore, we use iterative algorithms to determine an estimate of the mobile station position. The well-known Gauss-Newton method fails to converge for certain geometric constellations, and thus, it is not suitable for a general solution in cellular networks. Another algorithm is the steepest descent method which has a slow convergence in the final iteration steps. Hence, we apply the Levenberg-Marquardt algorithm as a new approach in the cellular network localization framework. We show that this method meets the best trade-off between accuracy and computational complexity

0 Bookmarks
 · 
126 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we have studied the performance of the AOA (Angle of Arrival) in multi-antenna systems for LBS (Location Based Services) and we also analyzed the performance of the AOA in SISO (Single Input Single Output) in multipath environments and their differences. The adequacy of AOA positioning in new communication environments was determined. Currently used positioning methods in 3G communication environment has been developed based on SISO. However, the accuracy of SISO-based TOA (Time of Arrival), TDOA (Time Difference of Arrival), AOA positioning techniques degraded in multipath environments. The communication system will be changed and developed. According to enhanced positioning techniques are required. Using antenna characteristics and the phase difference between antennas of LTE-Advanced standard's key technique MIMO system AOA positioning, and SISO based AOA positioning performance were analyzed. We found that AOA technique potential for use based on Multiple antenna systems by computer simulations.
    Journal of IEMEK. 01/2013; 8(2).
  • [Show abstract] [Hide abstract]
    ABSTRACT: The linear least squares (LLS) technique is widely used in time-difference-of-arrival based positioning because of its computational efficiency. Two-step weighted least squares (2WLS) and constrained weighted least squares (CWLS) algorithms are two common LLS schemes where an additional variable is introduced to obtain linear equations. However, they both have the same measurement matrix that becomes ill-conditioned when the sensor geometry is a uniform circular array and the source is close to the array center. In this paper, a new CWLS estimator is proposed to circumvent this problem. The main strategy is to separate the source coordinates and the additional variable to different sides of the linear equations where the latter is first solved via a quadratic equation. In doing so, the matrix to be inverted has a smaller condition number than that of the conventional LLS approach. The performance of the proposed method is analyzed in the presence of zero-mean white Gaussian disturbances. Numerical examples are also included to evaluate its localization accuracy by comparing with the existing 2WLS and CWLS algorithms as well as the Cramér–Rao lower bound.
    Signal Processing. 11/2013; 93(11):2872–2878.
  • [Show abstract] [Hide abstract]
    ABSTRACT: A container terminal plays an important logistical role in handling transshipping containers. Therefore, location information regarding vehicles that carry containers in a port is critical to cost- and time-efficient management for harbor automation. In terms of scalability, cost, and energy efficiency, an active radio-frequency-identification (RFID) based real-time locating system (RTLS) is an appropriate technology for obtaining location information. In general, an RTLS estimates locations using the transmission time of wireless signals. Accurate distance measurement depends on not only time measurement but also guaranteed line-of-sight (LOS) communication. However, in a container terminal environment, the performance of existing system can be seriously degraded because of densely deployed obstacles, e.g., containers and vehicles. Furthermore, places that readers can be installed in a terminal are limited, and thus a sufficient number of readers cannot be installed to provide reliable communication. To overcome these problems, this paper presents a novel and practical approach to overcoming non-line-of-sight (NLOS) RF propagation problems in asset tracking systems for container terminals. In proposed system, we have considered practicable methods from unit experimentsin real world as well as theoretical methods: the system tries to reducerange estimates obtained under NLOS conditions, and estimate the tag locations using vehicles’ range estimates and route information. For evaluation, the proposed method has been implemented at a real container terminal in South Korea, and experimental tests demonstrated its validity.
    International Journal of Precision Engineering and Manufacturing 11/2012; 13(11). · 1.59 Impact Factor