Energy-Efficient Target Tracking in Wireless Sensor Networks: A Quantized Measurement Fusion Framework

Yan Zhou,Tingrui Pei,Yonghong Lan,Dongli Wang

doi:10.1155/2014/682032

Abstract

Optimizing the design of tracking system under energy and bandwidth constraints in wireless sensor networks (WSN) is of paramount importance. In this paper, the problem of collaborative target tracking in WSNs is considered in a framework of quantized measurement fusion. First, the measurement in each local sensor is quantized by probabilistic quantization scheme and transmitted to a fusion center (FC). Then, the quantized messages are fused and sequential importance resampling (SIR) particle filtering is employed to estimate the target state. In the FC, quantized measurement fusion via both augmented approach and weighted approach is investigated. For both approaches, the closed-form solution to the optimization problem of bandwidth scheduling is given, where the total energy consumption is minimized subject to a constraint on the fusion performance. Finally, posterior Cramer-Rao lower bounds (CRLBs) on the tracking accuracy using quantized measurement fusion are derived. Simulation results reveal that both approaches perform very closely to the posterior CRLB while obtaining average communication energy saving up to 72.8% and 45.1%, respectively.

Highlights

Target tracking through wireless sensor networks (WSNs) is a problem with a large spectrum of applications [1, 2], such as surveillance [3], natural disaster relief [4], traffic monitoring [5], and pursuit evasion games
The other approach first combines the quantized measurements based on the BLUE rule, and traditional filtering schemes are employed to estimate the state of the target
It is clear that the augmented approach significantly outperforms the weighted approach since the raw quantized messages are used for the former

Summary

Introduction

Target tracking through wireless sensor networks (WSNs) is a problem with a large spectrum of applications [1, 2], such as surveillance [3], natural disaster relief [4], traffic monitoring [5], and pursuit evasion games. The posterior CRLBs on the mean squared error (MSE) of target tracking in WSNs with quantized range-only measurements are discussed in [15] Both constant velocity (CV) and constant acceleration (CA) models for target dynamics and International Journal of Distributed Sensor Networks general range-only measuring model for local sensors are included, while the sensor nodes are assumed to be randomly distributed. We consider the quantized measurement fusion problem for collaborative target tracking with focus on the energy and bandwidth scheduling strategy. The other is the weighted approach under quasi-best linear unbiased estimation (quasi-BLUE) fusion rule Note that the latter approach has a lower computational load since the observation vector dimension kept unchanged regardless of the number of the sensors deployed [17]. (2) With the focuses on tradeoff between energy/power consumption and fusion accuracy for quantized measurements, we give closed-form solution to the optimization problem for bandwidth scheduling for both approaches. A numerical example is given in Section 7, which is followed by Section 8 that involves the conclusion and future work

Problem Formulation

Two Quantized Measurement Fusion Approaches

Bandwidth Scheduling for Augmented Approach

Bandwidth Scheduling for Weighted Approach

A Simulation Example

Conclusion and Future Work