Most of our knowledge of the ionosphere comes from remote sensing by radio waves. Single-frequency techniques for remotely measuring time of flight, amplitude, phase, polarization, and angles of arrival include reflection by refractive bending and by so-called coherent and incoherent scatter. The sweep frequency ionosonde technique was developed to probe the vertical structure of the ionosphere. Moving transmitters and/or receivers (on satellites) have been used to investigate the horizontal structure of the ionosphere. We discuss some of these techniques later in this chapter but first we consider the principles underlying the measurement of wave features.

Inspec keywords: ionospheric techniques; ionospheric measuring apparatus; radiowave propagation; ionospheric electromagnetic wave propagation; remote sensing

Other keywords: worldwide sounding; single frequency techniques; remote sensing; phase measurement; ionosondes; group height; amplitude measurement; ionogram interpretation; ionospheric radio soundings; arrival angle measurement; incoherent scatter; ionogram scaling; real height; moving receivers; polarization measurement; ionospheric horizontal structure; wave feature measurement; artificial satellites; ionospheric vertical structure; moving transmitters; refractive bending; time of flight measurement; sweep frequency ionosonde technique; radiowave reflection

Subjects: Radiowave and rocket soundings of the ionosphere