The New Ingv Digital Ionosonde Design Report

THE NEW INGV DIGITAL IONOSONDE DESIGN REPORT
J. Baskaradas Arokiasamy, C.Bianchi, U. Sciacca, G. Tutone, E. Zuccheretti

Abstract
The ionosonde is a system which exploits the radar technique: it applies electromagnetic waves with variable frequency in the HF band to measure the ionospheric layers electron density, height and other parameters. This paper is a technical report on the new digital ionosonde (AIS-INGV), which was designed both for research purposes and for the routine service of the HF radiowave propagation forecast. It has been developed almost completely within the Laboratorio di Geofisica Ambientale (LGA) at the Istituto Nazionale di Geofisica e Vulcanologia (INGV). It exploits advanced techniques for the signal analysis, recent technological devices and PC resources. The report is divided into two parts; the first is a general description of the design development, the second is a more detailed description of the blocks and circuits actually built and tested, directed to a specialist reader.

1. INTRODUCTION 1.1 The needs of sounding the ionosphere
Traditionally it is called ionosphere those part of the atmosphere that shows a conspicuous ionisation of the medium, i.e. there is a concentration of electrons and ions much greater than outside of it, this ionisation being due mainly to the X and UV radiation coming from the Sun. Even though the most relevant interest in the study of the ionosphere lies in the applications on the radio propagation, other topics are investigated, such as the relationships with the earth magnetic field and the climatology. Historically the term “ionosphere” was adopted to highlight the fact that the ionisation was sufficient to influence the propagation of radio waves in such a way to make possible long distance links on the Earth. Almost every electromagnetic wave is influenced by the ionosphere, but those which are deviated in such a way to make possible the above mentioned links are only those with a frequency...