In this paper, we propose a new channel estimation algorithm for low earth orbit satellite digital communications. Low earth orbit satellite channels impart severe spreading in delay and Doppler on the transmitted signal. We model the channel as a tapped-delay-line lter with time-varying complex coe cients. The time evolution of the taps is described by an auto-regressive model. A coupled lter ...

In this paper, we propose a new channel estimation algorithm for low earth orbit satellite digital communications. Low earth orbit satellite channels impart severe spreading in delay and Doppler on the transmitted signal. We model the channel as a tapped-delay-line lter with time-varying complex coeecients. The time evolution of the taps is described by an auto-regressive model. A coupled lter ...

The Space Weather and Terrestrial Hazards (SWATH) experiment is a small, lightweight and inexpensive payload designed to place into 10wearth orbit a set of instruments for measurement and study of local space hazards. The SWATH instrumentation is designed to utilize the bus being developed for the Miniature Sensor Technology Integration program. The mission has three major scientific objectives...

As the Earth revolves around the Sun, it orbits through planetary debris left from the formation of the solar system. Many of the debris objects are asteroids and comets in orbits bringing them close to the Earth and are referred to as Near-Earth-Objects (or NEOs). Of the total NEO population, some portion are in orbits actually intersecting or crossing the orbit of the Earth. The asteroids of ...

Over the last few years, new Global Navigation Satellite System (GNSS) applications have emerged that go far beyond the original objectives of GNSS which was providing position, velocity and timing (PVT) services for land, maritime, and air applications. Indeed, today, GNSS is used in Low Earth Orbit (LEO) for a wide range of applications such as real-time navigation, formation flying, precise ...

The operation of satellites in very low Earth orbit (VLEO) has been linked to a variety benefits both the spacecraft platform and mission design. Critically, for observation (EO) missions reduction altitude can enable smaller less powerful payloads achieve same performance as larger instruments or sensors at higher altitude, with significant As result, renewed interest exploitation these orbits...