| Remote positioning and localization techniques have emerging applications in defense, security, and law enforcement. Many remote positioning systems are under development to address special needs of advanced military systems and battle field situation awareness, such as multi-robot collaboration, and battle field central command and control. Examples are RFID, Radar, and more recently, wireless local positioning systems (WLPS). WLPS are equipped with antenna arrays capable of joint time-of-arrival (TOA) and direction-of-arrival (DOA) estimation. In these systems, each node in a mobile adhoc network (MANET) is capable of positioning other nodes located in its coverage area.
In this paper, we consider the problem of data fusion via sensors capable of DOA and TOA estimation in multi-sensor environments. Here, each sensor is capable of localizing other sensors; however, whenever multiple sensors are available, their estimated TOA/DOA is optimally fused to enhance the localization performance. Assuming a target is located in the coverage area of multiple sensors, the localization circular-error-probability (CEP) is computed theoretically. CEP refers to the probability that the two-dimensional positioning error radius is less than a maximum value, Rmax.
A novel two-dimensional optimization fusion technique is introduced and mathematically evaluated. The minimization outcome is incorporated to calculate Rmax as a function of: (1) the statistical TOA and DOA mean calculated by each sensor, (2) DOA and TOA estimation error; and, (3) the maximum tolerable CEP. The theoretical results are compared with simulations in two situations: (i) zero, and, (ii) non zero inter-sensor positioning error. It is observed that there is a tradeoff between positioning via DOA, TOA, or both, as the relative distance of sensors and target changes.
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| Zhonghai Wang was born in Jilin, P.R.China, on Sep.18, 1974. He received his B.S degree in electrical engineering from Tianjin University, Tianjin, P.R.China, in 1998.
From 1998 to 2005, he was working for China Aerospace Science and Industry Corporation (CASIC). He is now a Ph.D student in the Department of Electrical and Computer Engineering in Michigan Technological University, Michigan, USA. His research interests include Data Fusion and Beam Forming. |