Odyssey Space Research proposes to develop a modular navigation software package to provide precise state information for offline analysis and real-time applications. This navigation package will use particle filter methodology to process discrete observation data and maintain an accurate state. This navigation system will leverage several NASA products to rapidly prototype and demonstrate the feasibility of this software during Phase I, including the General Mission Analysis Tool (GMAT) and Trick, taking it from TRL 2 past TRL 3. Phase II will deliver an expanded modular software product integrated into several other software packages demonstrating different estimation capabilities (TRL 5-6). This system will function as a standalone estimation package that can be easily integrated into other software packages, or as the basis for embedded flight software algorithms. This navigation package will be designed to meet the position, velocity, and time estimation requirements for space missions. It will contain an expanded state vector used to estimate non-Gaussian forcing functions perturbing the vehicle's dynamics. This navigator will integrate the measurements from diverse sensors running at different rates. And it will demonstrate accurate estimation of uncertain dynamics parameters that are affecting the vehicle's state such as the gravitation field of small bodies.