Design And Application Of Receiving Channel For Multichannel Ionospheric Oblique Survey System

The effects of the ionosphere on the reflection and absorption of radio are different with time and space.The detection and research of the ionosphere is of great significance for wireless communication,space meteorology and national defense construction.With the progress of science and technology,ionospheric detection technology has also been rapidly developed,and the study of the ionosphere is also gradually deepened.Ionospheric obliquity detection can be used to study ionospheric characteristics over a long distance and a wide range.Based on the oblique detection method of ionosphere,a multi-channel ionospheric oblique measurement system is designed and developed.In addition to the conventional ionospheric detection function,the system can also use the azimuth of incoming wave signal to realize positioning.The whole structure is more compact,compact and portable.The paper mainly includes the following contents:(1)Based on the ionospheric detector of Wuhan University,A multi-channel ionospheric oblique survey receiver is designed and implemented.In the realization of the receiver,the channel gain adjustable range is larger and the sensitivity is higher by optimizing the analog front end.In the system structure,a channel calibration module is added to make the system more convenient for channel conformance testing and calibration.Select the ADC again and replace the single-channel ADC with the eightchannel ADC;Added a high-speed data transmission module to facilitate the expansion of more channels;The output bandwidth of the frequency source is expanded from 1?200MHz to 10?1200MHz,providing high stability and high precision frequency source for higher working frequency.(2)The receiver and performance index of the multichannel ionospheric oblique survey system are tested,and the test results meet the design requirements.The multichannel active direction finding and passive direction finding experiments,as well as the intersection positioning verification experiment based on azimuth Angle are designed.The experimental results verify the reliability and practicability of the system design.