Adaptive Radiolocation for Mobile Sensor Networks

无线电、传感器、致动器和嵌入式计算技术的进步使无线传感网络得以迅速发展。这些网络提供了一种负担得起的方式，可以为看似无限的一组应用程序执行分布式侦听。准确的定位是许多传感器应用的关键使能，包括监视网络、机器人传感器、无线自组织传感器网络中基于位置的路由、智能空间和移动传感器的环境监测。虽然GPS可以潜在地提供精确的定位，但对于廉价的传感器节点来说，所需接收器的复杂性可能过于昂贵。此外，GPS信号非常弱，在建筑物内或茂密的树叶下定位可能不可靠。GPS定位的这些缺点引起了人们对无线传感器系统中GPS较少的分布式无线电定位方法的越来越大的兴趣。该项目主要研究在ISM频段无线电(例如802.11b)上使用到达时间的无GPS协作无线电定位技术。传感器网络中的自适应无线电定位有许多问题需要解决。如果多个传感器同时传输确认，则会发生多路访问干扰。多径的存在会掩盖和干扰对到达时间的正确估计，从而导致距离误差。射频功率放大器是一种主要的能源消耗，因此必须以最少的通信进行定位估计。该项目通过以下方式解决这些问题：1)分析和开发多用户估计算法，可以联合估计来自多个传感器的到达时间(TOA)。2)创建可重配置的计算核心，为嵌入式系统提供自适应无线定位平台。该核心将被设计成能够在不同的系统参数之间进行权衡，包括功率/能量、延迟和定位算法的精度。3)开发新的传感器网络分布式估计算法。4)在2.4 GHz ISM频段的试验床上实现了协同无线定位算法。5)无线定位网络的天线阵设计和感知算法

Advances in radios, sensors, actuators and embedded computing technology have enabled a proliferation of wireless sensing networks. These networks offer an affordable way of performing distributed sensing for a seemingly unbounded set of applications. Accurate positioning is a key enabler for many sensor applications including surveillance networks, robotic sensors, location-based routing in wireless ad-hoc sensor networks, smart spaces and environmental monitoring by mobile sensors. Although GPS can potentially provide accurate positioning, the complexity of the required receivers may be too costly for inexpensive sensor nodes. Furthermore, the GPS signal is extremely weak and positioning can be unreliable inside buildings or under dense foliage. These drawbacks to GPS positioning have led to increasing interest in GPS-less distributed radiolocation methods for wireless sensor systems. This project focuses on techniques GPS-less cooperative radiolocation using time-of-arrival over ISM-band radios (e.g. 802.11b)There are numerous problems that must be solved for adaptive radiolocation in sensor networks. Multiaccess interference occurs if multiple sensors transmit acknowledgements at the same time. The presence of multipath can obscure and interfere with correct estimation of the time-of-arrival causing range errors. The RF power amplifier is a major energy consumer; therefore positioning estimates must be made with minimal communication. The project addresses these problems through: 1) Analysis and development of multiuser estimation algorithms that can jointly estimate times of arrival (TOAs) from multiple sensors. 2) Creation of a reconfigurable computational core, which enables an adaptive radiolocation platform for embedded systems. The core will be designed to enable tradeoffs between different system parameters, including power/energy, latency and accuracy of the positioning algorithms. 3) Development of new distributed estimation algorithms for sensor networks. 4) Implementation of cooperative radiolocation algorithms in a testbed operating in the 2.4 GHz ISM band. 5) Design of antenna arrays and sensing algorithms for the radiolocation network