In order for the information provided by networks of unattended ground sensors (UGS) to be of use to the tactical planner, the location of each sensor must often be known. Sensor localization is typically achieved by careful hand emplacement, or facilitated by anchor nodes whose position is precisely known. Nova Engineering and Army Research Laboratory are currently designing a new sensor network architecture to meet the growing need for UGS networks that can self-localize using anchor nodes with imprecise prior location information. In this paper we present an overview of a prototype sensor network and an analysis of its capability. We also present new results on the effects of network deployment parameters on sensor localization error, such as the level of network connectivity and the number of GPS-enabled nodes on the network. We compare time of arrival (TOA) and time difference of arrival (TDOA) ranging algorithms for sensor localization, and we consider the benefits of including available direction of arrival (DOA) estimates. Selected scenarios of UGS deployments are provided for comparison.