Navigation Above the GPS Constellation
ACSER is developing a range of satellite navigation receivers to operate in space. Most commonly, those receivers are used in low earth orbit, i.e. at heights of 100s of km, well below the 26000km high GPS satellites. This project looks at how satellites in higher orbits can use Global Navigation Satellite Systems (GNSS) for navigation. Many missions such as satellite communications use orbits that are above the orbits of existing GNSS such as GPS, Glonass, Galileo and Beidou. There are some satellites that are part of, or augment, these systems that operate at the height of geostationary orbits (GEO). The types of topic that may be explored in this area include how well a high-orbit satellite can utilise these satellites, how much can be achieved using “spill-over” of the GNSS satellites on the opposite side of the earth to the receiver, how much can be expected from sidelobes transmitting backwards from satellites on the same side of the earth, and what other sensors can contribute.