Analysis of stand-alone GPS for relative location discovery in wireless sensor networks

In this paper, we use experiments to examine the accuracy of standalone Global positioning System (GPS) for relative location discovery in wireless sensor networks. The relative locations are obtained by comparison of stand-alone global GPS position fixes. We seek to find out if stand-alone GPS measurements from inexpensive GPS receivers can result in the relative positioning accuracies desired. Various sensor deployment scenarios are used that are representative of the real operational conditions of wireless sensor network applications. The ground truth sensor node locations are estimated by measuring the internode distances between all the sensor node and applying the multidimensional Scaling (MDS) technique. The analysis is based on the approach of Procrustes analysis. An optimal rigid transformation is obtained using a least squares method to estimate the root mean square errors of the GPS relative positions. Based on the results, conclusions and discussions are made about the suitability of stand-alone GPS as a localization tool in wireless sensor networks.