  This article aims to develop novel path planning algorithms required to
deploy multiple unmanned vehicles in Global Positioning System (GPS) denied
environments. Unmanned vehicles (ground or aerial) are ideal platforms for
executing monitoring and data gathering tasks in civil infrastructure
management, agriculture, public safety, law enforcement, disaster relief and
transportation. Significant advancement in the area of path planning for
unmanned vehicles over the last decade has resulted in a suite of algorithms
that can handle heterogeneity, motion and other on-board resource constraints
for these vehicles. However, most of these routing and path planning algorithms
rely on the availability of the GPS information. Unintentional and intentional
interference and design errors can cause GPS service outages, which in turn,
can crucially affect all the systems that depend on GPS information. This
article addresses a multiple vehicle path planning problem that arises while
deploying a team of unmanned vehicles for monitoring applications in GPS-denied
environments and presents a mathematical formulation and algorithms for solving
the problem. Simulation results are also presented to corroborate the
performance of the proposed algorithms.
