Design Of Wideband Signal 3D Direction Finding System Based On USRP X310

In recent years,with the continuous development of software radio technology,the pre-research and application of software radio platform in radar is also in full swing.The traditional radio service is very limited in terms of monitoring frequency band range and monitoring angle due to technical limitations,and the radio spectrum monitoring and direction finding system based on software radio can overcome the above problems well,thus attracting more scientific research and technology The personnel invest in the research on the direction finding system based on software radio.This subject mainly relies on the "Spaceborne Radio Plasma Detection System" project to design a three-dimensional direction finding system for broadband signals based on software radio."Spaceborne Radio Plasma Detection System",as a major national scientific research instrument development project,aims to develop a multi-functional spaceborne radio instrument and signal processing software platform.The prototype of the system has the advantages of low weight,low power consumption and strong flexibility.Its main functions can be used to detect the distribution and structure of space plasma density in key regions of the ionosphere,as well as extract and analyze space plasma trajectory information in space.The plasma density distribution in the ionospheric space is uneven.In order to enable the radar to image the space plasma in different regions,the detection range of the space plasma should cover 30 k Hz～3MHz.Receiving and spatial positioning of incoming wave signals is also an urgent problem to be solved.So this paper designs a three-dimensional direction finding system based on USRP X310 broadband signal based on the technical direction of receiving and direction finding of incoming wave signals.Active exploration has been carried out to determine the azimuth of the incoming wave signal,which is of great significance for the detection and imaging of space plasma.The research content and results of this paper mainly include the following aspects:First of all,due to the high cost and inflexible operability of traditional radio direction finding system equipment,this paper uses a general software radio hardware platform and GNU Radio software to design a radio direction finding system,and uses the MUSIC algorithm to achieve it.The function of performing direction finding on incoming wave signals.Secondly,this paper designs a wideband signal transceiver system through GNU Radio software combined with custom modules.This system can realize the frequency sweep step transceiver function of the signal source.Combined with the radio direction finding system,it can realize the frequency sweep step method.The receiving of the incoming wave signal broadens the monitoring frequency range of the incoming wave signal.Finally,the USRP X310 device is equipped with two Twin RX daughter boards,and four glue stick antennas are connected to form an antenna array as a signal receiver.After the phase correction of the antenna array is performed,the direction finding is started,and then the incoming wave direction of the received signal is estimated.After repeated experimental results,it is shown that by manipulating the antenna direction of the transmitter to change the orientation of the signal source,the receiver can distinguish and display the direction of the incoming wave in real time.The system can effectively estimate the incoming wave direction of the signal in space,which is effective and practical.