3 research outputs found
Anthropogenic Space Weather
Anthropogenic effects on the space environment started in the late 19th
century and reached their peak in the 1960s when high-altitude nuclear
explosions were carried out by the USA and the Soviet Union. These explosions
created artificial radiation belts near Earth that resulted in major damages to
several satellites. Another, unexpected impact of the high-altitude nuclear
tests was the electromagnetic pulse (EMP) that can have devastating effects
over a large geographic area (as large as the continental United States). Other
anthropogenic impacts on the space environment include chemical release ex-
periments, high-frequency wave heating of the ionosphere and the interaction of
VLF waves with the radiation belts. This paper reviews the fundamental physical
process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure
Introduction to GNSS
This chapter is a primer on global navigation satellite
systems (GNSSs). It assumes no prior knowledge
of the systems or how theywork. All of the key concepts
of satellite-based positioning, navigation,
and timing (PNT) are introduced with pointers to
subsequent chapters for further details. The chapter
begins with a history of PNT using satellites and
then introduces the concept of positioning using
measured ranges between a receiver and satellites.
The basic observation equations are then
described along with the associated error budgets.
Subsequently, the various GNSSs now in operation
and in development are briefly overviewed. The
chapter concludes with a discussion of the relevance
and importance of GNSS for science and
society at large