敏捷数字电离层测高仪系统研制及初步观测

Development of Agile Digital Ionosonde and Its Preliminary Observation

在小型天线和低发射功率条件下,保证电离层测高仪观测数据质量和提高观测速度一直是电离层垂测的技术难点.针对这一问题,基于新近发展的高速数字芯片和射频器件,采用窄带跟踪滤波、脉冲压缩、编码复用和天线均衡匹配等技术,设计和研制一种敏捷数字电离层测高仪.该系统采用数米高的小型收发天线和便携式主机系统,配置任意频率扫描方式频高图、高分辨率多普勒频高图和斜向探测等多种工作模式,具有可流动观测布站、系统参数灵活捷变及适合快速电离层扰动探测等能力.敏捷数字电离层测高仪为组网观测获得大范围电离层时空变化和电离层快速扰动及传播提供了一种有效的探测手段.

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.