Goddard Enhanced Onboard Navigation System (GEONS) V3.1(GSC-19476-1)

Goddard Enhanced Onboard Navigation System (GEONS) is an enterprise, multi-mission, flight software library with associated tools that provides high-accuracy solutions for spacecraft position, velocity, and time. GEONS can be used for onboard autonomous navigation, ground-based operational navigation, and ground-based simulation and analysis of navigation systems. For flight applications, the GEONS flight software can be integrated either within a Global Positioning System (GPS) receiver, a communications receiver, or a spacecraft onboard computer. GEONS processes data from GPS receivers, ground stations, spacecraft crosslinks, cameras, LiDAR, accelerometers, and attitude sensors to produceaccurate absolute and relative navigation solutions in real time. GEONS is written in ANSI standard C, uses a UD-factorized Extended Kalman Filter (EKF) architecture, and includes fault detection capabilities. The software includes high-fidelity dynamics models, including non-spherical gravity, third body gravitational perturbations, solar radiation pressure, atmospheric drag, process noise models, and clock error models. The user must configure GEONS for their specific application. The configurability of GEONS allows it to support a wide variety of missions and enables the user to optimally balance GEONS computation time, memory, and navigation accuracy for the considered application.GEONS has over 20 years of flight heritage from previous versions of the software that have flown on multiple missions. GEONS has been baselined to provide onboard, autonomous navigation for multiple upcoming missions. Although GEONS has only flown for Earth orbiting missions to date, it can support a wide range of orbit regimes including cislunar/lunar space and beyond.