Automatic calculation of electron density profiles from digital ionograms: 2. True height inversion of topside ionograms with the profile‐fitting method

An efficient electron density profile inversion algorithm is developed for use on automatically scaled digital topside ionograms. The profile‐fitting method described here models the topside ionosphere with a single polynomial, a method particularly suited for autoscaled data because it is not too sensitive to a certain amount of scatter in the h ′(ƒ) data and it makes use of ordinary and extraordinary ray echoes. The program was applied to input data consisting of O and X trace segments obtained from automatic scaling of a number of digitized ISIS ionograms. It is shown that fully automatic calculation of the topside electron density profiles from digital topside ionograms can be performed in less than 10 s on a Cyber 71 computer.