Engineering topics
Publications and source records attributed to Jackson, J. E..
Earth orbits spacecraft whose apogees are well below geostationary altitude and whose primary purpose is to conduct investigations in the near-Earth environment are considered.
The paper outlines the techniques used to obtain topside ionograms and reduce them to electron profiles, indicating the most important differences between ground-based and satellite-based ionograms. The theory of the total reflection sounding technique at vertical incidence is outlined and the features of the satellite instrumentation are discussed. Finally, topside sounder data are analyzed with reference to the problems encountered in the conversion of the sounder data to N(h) profiles.
Scientific results from OGO-5 and OGO-6 experiments are summarized and approximately 200 citations are included to update the 1975 OGO bibliography. Personal author, subject, and corporate source indexes are included. The supplement follows the same format as that of the OGO Program Summary; it does not repeat the finalized information in the original publication, which should be consulted for indexes of experiments, experimenters, institutions, and the glossary of abbreviations and acronyms.
An overview of the OGO program is presented. Brief descriptions of the six OGO spacecraft, and the experiments on each are included.
A general review is given of the inversion techniques used to derive the ionospheric electron density N as a function of altitude h from group path P versus frequency f measurements obtained by vertical incidence ionospheric sounders. The paper discusses the medium under investigation, the experimental techniques used to obtain the P(f) data, the theoretical considerations leading to the integral equation relating P(f) to N(h), and the assumptions made in the inversion process. The lamination inversion technique is then presented, with special attention given to mathematical difficulties arising from discontinuities in the P(f) function, infinities in the integrand, and in some cases unknown integration limits. Methods outlined for minimizing the uncertainties due to discontinuities include the use of redundant information - that is the two distinct P(f) functions available for a given N(h) profile - and the use of models based on statistical data. Mathematical procedures are discussed that increase significantly the efficiency and accuracy of the required numerical integrations. The accuracy of the inversion technique is deduced by comparing the resulting N(h) profile with N(h) data obtained by simultaneous but independent observations.
Deriving ionospheric electron density as function of altitude from group path versus frequency measurements by vertical ionospheric sounders
Theoretical analysis of 24.5/73.6 MHz rocket-to-ground CW propagation experiment for in situ electron density measurements
Variation of ionospheric electron density during solar eclipse
Ionospheric satellites objectives and development resulting from topside sounder and ISIS programs
Topside ionogram reduction for ionospheric electron density determination, using geomagnetic strength at all heights, iteration and change of variables
Electron density profiles from topside ionograms compared to ground based sounding results, discussing error corrections
Comparison and analysis between topside and ground based measurements of ionospheric electron density profiles
Satellite ionosonde techniques and method for reducing topside ionograms to electron density profiles
Charged-particle profiles of upper ionosphere from alouette topside satellite sounding, compared with rocket- & ground-based backscatter measurements
Topside ionosphere measurements, estimating relative concentrations of oxygen, helium and hydrogen ions
Topside sounder program - upper ionospheric sounding
Payload designed to measure the electron density of the ionosphere