Localization tasks using two-way ranging (TWR) are making headway in modern daynavigation applications as an alternative to legacy global navigation satellite systems (GNSS) such as GPS. There is not currently literature that provides a closed-form expression for estimation performance bounds on position and attitude when a TWR system is employed. A Cramer-Rao Lower Bounds (CRLB) is derived for position and orientation estimation using both 2-D and 3-D geometries. A literature review is performed to give background and detail on the tools needed for a thorough analysis of this problem. Popular Least Squares techniques and solutions to Wahba’s problem are compared to the derived bounds as proof of correctness using Monte Carlo simulations. A brief exploration on estimation performance using an Extended Kalman Filter for non-stationary users is also looked at as an introduction to future extensions to this work. The literature Applications like the CHP2 system are discussed as well to show how secure, inexpensive and robust implementation of TWR is highly feasible. i