TOPOLOGICAL ANALYSIS OF SATELLITE-BASED DISTRIBUTED SENSOR NETWORKS

A method for evaluating the topological quality of networks for distributed sensor applications is presented. The criteria for evaluation are network survivability and delay. Nodal connectivity is used to characterize survivability, and mean path length is used to characterize delay. To calculate these two quantities, an algorithm is developed to find k shortest node-disjoint paths between a pair of nodes when each link has unit distance. As an example of the use of this type of analysis, the effects of nodal losses in a multiple-node satellite network consisting of a Walker low-orbit sphere and a geosynchronous constellation are examined. The example demonstrates how topological analysis on the basis of connectivity and mean path length may be used to detect, and subsequently address, potential flaws in a network design. The results show that the geosynchronous/low-orbit link assignment protocol should be a primary concern in the design of this network. They also show that the nodal degree of the failed node, and the distribution of links between the Walker sphere and the geosynchronous constellation, are the fundamental determinants of mean path length.