SBIR-STTR Award

Real time information of ionospheric parameters has both military and scientific uses. We propose the development of a low cost device that continuously tracks the o- adn x-mode critical ionospheric frequencies With a 1 second time resolution and a 5 khz frequency resolution. The results are displayed in real time in digital format. The critical frequency tracker" (cft) transmits two waves (o- and xx-mode) at adjustable frequencies and determines the highest frequency for which there is an ionospheric echo. Average transmitted power is less than 20 w. A bistatic version of the cft will yield real time readout of the maximum useable frequency (muf) for an ionospheric propagation path. The cft may also yield information on the height of the f2 peak in the ionosphere. We suggest that, when a cft is available, it is possible (by combining its information with data from a vhf polarimeter) to develop a scheme that permits the rapid calculation of ionization profiles useful in the real time correction of radar aiming errors owing to ionospheric refraction.

Simple measurements of ordinary and extraordinary critical frequencies together with information on total electron content may be coupled with a physical (first-principle) model to produce a description of the electron concentration in the ionosphere. Total electron content is routinely measured using satellite-to-ground radio links. We are developing simple, complementary systems, called "ionospheric meaurement systems" (IMS), that accurately measure the ordinary-and extraordinary-mode critical frequencies.