  In this study, the optimal jammer placement problem is proposed and analyzed
for wireless localization systems. In particular, the optimal location of a
jammer node is obtained by maximizing the minimum of the Cramer-Rao lower
bounds (CRLBs) for a number of target nodes under location related constraints
for the jammer node. For scenarios with more than two target nodes, theoretical
results are derived to specify conditions under which the jammer node is
located as close to a certain target node as possible, or the optimal location
of the jammer node is determined by two of the target nodes. Also, explicit
expressions are provided for the optimal location of the jammer node in the
presence of two target nodes. In addition, in the absence of distance
constraints for the jammer node, it is proved, for scenarios with more than two
target nodes, that the optimal jammer location lies on the convex hull formed
by the locations of the target nodes and is determined by two or three of the
target nodes, which have equalized CRLBs. Numerical examples are presented to
provide illustrations of the theoretical results in different scenarios.
