Direct Positioning Estimation Beyond the Constellation Using Falcon Gold Data Collected on Highly Elliptical Orbit

The long-term objective of this research is to develop methods to navigate through cis-lunar space while not relying on the limited availability of the DSN. Such methods would utilize the weak signals from the antenna sidelobes of the well-established GNSS constellation. Prior work in utilizing weak GNSS signals in the urban environment within Direct Positioning Estimation (DPE) methods inform our research as we process real data collected on board a satellite on a highly elliptical orbit (HEO) reaching altitudes beyond those of the GPS constellation. We use the techniques that we have implemented and developed in the GNSS degraded environment of the urban canyon to further investigate the use of these limited and weak signals for navigation beyond the constellation. Specifically, we will be implementing direct positioning estimation or collective detection technique to make use of these limited and weak signals. To test our techniques we use real data collected from the Falcon Gold satellite which collected data above the constellation on a HEO orbit.