Publications

Featured ebook: Navigation from Low Earth Orbit

Part of: Mobile Satellite Communications Handbook

Compiled by Tyler G.R. Reid, Todd Walter, Per K. Enge, David Lawrence, H. Stewart Cobb, Greg Gutt, Michael O'Conner, David Whelan

This chapter focuses on navigation from low earth orbit (LEO). It opens with a brief history of early US and Russian satellite navigation systems in LEO. The chapter discusses satellites in LEO today, their role in navigation, and LEO constellations on the horizon. It provides the needed mathematical background and discusses the role of LEO in satellite navigation today, showcasing the performance of the Satelles Iridium‐based GPS augmentation system and demonstrating the benefit of stronger signals. The chapter looks to the future of LEO in navigation and demonstrates that the scale of the proposed Broadband LEO constellations, coupled with the more benign LEO radiation environment, can deliver the positioning performance of GPS with commercial‐off‐the‐shelf components. It provides an analysis of the LEO radiation environment compared to medium Earth orbit.

Click here to access this chapter from Position, Navigation, and Timing Technologies in the 21st Century: Integrated Satellite Navigation, Sensor Systems, and Civil Applications

Featured ebook: Non-Geostationary Satellite Systems

Part of: Satellite Communications Payload and System

Compiled by Teresa M. Braun and Walter R. Braun

This chapter focuses on communication satellite constellations in medium earth orbits and low earth orbits (LEO). It distinguishes two different categories of non‐geostationary orbit (NGSO) satellite systems, as they are called by International Telecommunication Union: the early systems were designed to provide voice and/or low‐rate data services. The first operational system was Iridium, which started service in 1998. The second, more recently introduced category of NGSO constellations provides broadband services, so these systems are in competition with high‐throughput satellites. O3b system provides communication services to the underserved “other three billion” people in the equatorial regions of the earth to whom low‐priced high‐speed fiber, microwave, or satellite connections are unavailable. The satellites are manufactured by OneWeb Satellites, a joint venture of OneWeb and Airbus. Telesat LEO is a satellite constellation the Canadian operator Telesat is planning to launch and operate.

Click here to access this chapter from Satellite Communications Payload and System , IEEE, 2021