摘要
The Global Positioning System(GPS)is expected to play an integral role in the development of digital earth;however,the GPS cannot provide positioning information in regions where a majority of the population spends their time,that is,in urban and indoor environments.Hence,alternate positioning systems that work in indoor and urban environments should be developed to achieve the vision of digital earth.Wi-Fi-based positioning systems(WPS)stand out because of the near-ubiquitous presence of the associated infrastructure and signals in indoor environments.The WPS-based fingerprinting is the most widely adopted technique for position determination,but its accuracy is lower than that of techniques such as time of arrival and angle of arrival.Improving the accuracy is still a challenging task because of the complex nature of the propagation of Wi-Fi signals.Here,a novel server-based,genetic-algorithm-optimized,cascading artificial neural network-based positioning model is presented.The model is tested in 2D and 3D indoor environments under varying conditions.The model is thoroughly investigated on a real Wi-Fi network,and its accuracy is found to be better than that of other well-known techniques.A mean accuracy of 1.9 m is achieved with 87%of the distance error within the range of 0-3 m.
