Efficient Propagators and Gravity Models in non-Cartesian Coordinate Systems

Accurate and timely surveillance of objects in the near-Earth space environment is becoming increasingly critical to US national security. One of the main difficulties in this domain is efficiently and accurately modeling trajectories of the vast number of objects in orbit around the Earth. The orbital trajectory of a single object is typically modeled as a second-order system of equations which includes a force term. The force term incorporates Newton''s laws of motion, the gravity force model, and any other external forces such as atmospheric drag, solar wind or plasma forces, etc. Even if the forces are modeled to the accuracy desired, the system of equations must still be solved numerically. The choice of algorithms and representation of the relevant digital information affects the efficiency and accuracy of such computations. The proposed research will explore using a novel combination of ODE solvers, gravity models, and coordinate systems to improve computational efficiency without loss of accuracy over existing technology. BENEFIT: Currently, the market for the technology is primarily government-based, as no private entities have the sensor resources available to adequately monitor tens of thousands of space objects in Earth orbit. The United States government is one of the few which actively tracks and monitors such objects, through the Air Force Space Command (AFSPC) space surveillance effort and related efforts. As such, US government customers such as AFSPC form the main audience for the technology. The basic research conducted under this proposed effort will identify robust candidate technology that can then be further developed through additional research and engineering to provide enhanced computational efficiency for orbital calculation, allowing higher fidelity and/or lower computational resources for computing the trajectories of tens of thousands of objects in real-time. The software components that will eventually result from this research will be adapted for integration into existing US DOD and civilian systems. As part of a potential Phase II effort, Numerica will seek out appropriate government customers and prime contractors that make up the core market for the technology.