Techniques for remote sensing of ionospheric electron density from a spacecraft

Techniques for the remote sensing of ionospheric electron density from a satellite platform were examined. Techniques by which a more general areal survey is made to determine the electron density in three dimensions are considered. Existing techniques are reexamined for additional potential, and the feasibility of new techniques is considered. Topside sounders currently offer the best areal survey capability with the ISIS satellites. A spacecraft version of the Digisonde sounder offers enhanced measurements. Thomson scatter radars are useful in ground based installations but would be cumbersome on a satellite. Numerous optical or chemiluminescent methods are possible. They often use relatively simple equipment and, are easy to include with other detectors on a satellite system.