The Design And Implementation Of Wideband Meteor Radar Hardware System

The technology of meteor radar observations has been developed in the 1930s,and it was mainly used as the meteor astronomy observations.With the continuous development of science and technology,meteor radar systems have been constantly upgrading and their application have gradually expanded from the initial observations to the meteor shower observations,the meteor velocity and meteoric atmospheric dynamics research.The development of foreign meteor has improved a lot,while the radar designed by Australia is the most prominent.It makes use of the latest all-sky meteor radar technology,so that the meteor region of the various parameters of atmospheric dynamics can be obtained.Meteor radars were introduced in some areas of China after 2000,such as Wuhan,Kunming and Sanya.Although meteor astronomy,atmospheric dynamics and some aspects of research results have been acquired,but there is still no domestically developed meteor radar equipment.Therefore,the development of wideband meteor radar is presented in this paper,including theoretical research,overall design and implementation of the transmitting system and receiving system,and the preliminary experimental observations have been made.And the velocity,location and spatial distribution of meteors were analyzed by the observation.Firstly,it is introduced that several frequency synthesis methods commonly used in excitation sources and the Direct Digital Frequency Synthesis(DDS)technology is selected as the excitation source for the transmitting system.The DDS chip AD9958 is used as the core component of the system and its working band is between 3 0MHz and 100MHz.The two-phase coded modulation signal is selected as the transmitting waveform design and the method of the hardware and software implementation is given.The circuit of the DDS output signal is adjusted to make it meet the requirement of the power amplifier module's input power and suppress the signal distortion and harmonic interference.Secondly,the wideband meteor radar receiving system is designed.Compared with several commonly used receiving structures,the system uses a digital IF digitized receiving structure.After analyzing several important index of the system,the whole design and implementation of the system are completed,including the analogy receiving front-end circuit design,analog-digital converter design,digital down-conversion design,data transmission design and channel calibration design.The system's sensitivity,dynamic range,gain and other indicator were tested.And the test results show that the receiving system meets the design targets.Finally,a preliminary experiment,including closed-loop experiment and open-loop experiment,is carried out in combination with the transmitting system and the receiving system.The experimental results prove the correctness and feasibility of the wideband meteor radar.Besides,the open loop experiment has been carried out by using complementary code and Barker code.And some characteristics of the meteor echo have been analyzed from the experiment,such as the speed,the position and typical azimuthal and height distribution.Briefly,the hardware of the meteor radar is designed in this paper,including the implementation of the transmitting system and receiving system.Its working frequency is so wide that it covers the current foreign meteor radar's working band.And the radar parameters can be flexibly configured.The designed wideband meteor radar has been carried out preliminary experiments.In the future,the radar will be operated round the clock in order to obtain the acquisition of the detection results,and the preliminary development of meteor radar still need to be further improved.