Development of Agile Digital Ionosonde and Its Preliminary Observation

Ionosonde, as one of the most important instruments for ionospheric observation, is usually deployed at permanent stations because of its large size antennas and main machine. Owing to the increasing spatial and temporal resolution requirements of ionosonde observations, the development trend of ionosonde is toward agile in field site setup and ionospheric disturbance detection. In recent years, some important achievements have been made in lowering the transmitting power and reducing the size of the main machine. However, it is still a standing technical issue to perform fast ionospheric sounding and produce high quality ionogram under small antennas and low transmitting power condition. In regards to this issue, based on the newly developed high speed digital circuits and RF devices, an agile digital ionosonde is designed and developed by using the narrow band tracking filtering, pulse compression, code multiplexing and antenna matching techniques. The agile digital ionosonde uses small transmitting and receiving antennas with several meters height and portable main machine. Its main characteristics include mobile observation, system parameters agility and fast ionospheric disturbance detecting. It is configured with arbitrary frequency sweeping vertical sounding, high Doppler resolution vertical sounding and oblique sounding observation mode. The observations performed at several stations in China indicate that the agile digital ionosonde can be well employed to make fast measurements with high quality ionogram and is suitable for permanent and temporary stations. The agile digital ionosonde will provide an important way to sense ionospheric temporal and spatial variations, especially the fast disturbance and its propagation in a large area.