Sensor placement for reliable observability: A structured systems approach

This paper addresses the problem of reliable sensor placement in large scale linear systems with potentially faulty components. The failure probabilities of individual system components are assumed to be known, and the goal is to place sensor outputs so that the network remains observable with high probability. Two different kinds of system component failures are considered in this paper: 1) the failure of arbitrary sensor devices and 2) the failure of arbitrary connections between pairs of state variables (referred to as a link). In addition, we focus on the design from an economic point of view; thus, we aim to identify the minimum number of state variables that need to be measured to meet desired reliability criteria. We recast this problem as an integer program. Although the integer programming problem is known to be NP-complete, we propose a greedy algorithm and characterize its performance with respect to the optimal solution. Consequently, the proposed approach provides an approximate solution to the problem of minimal sensor placement in the presence of stochastic component failure. Finally, we illustrate the obtained results with an example and simulation analysis.