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Azimuth Estimation For Radio Frequency Signal Based On Microwave Photonics

Posted on:2020-12-16Degree:MasterType:Thesis
Country:ChinaCandidate:X C ShaoFull Text:PDF
GTID:2428330602952190Subject:Engineering
Abstract/Summary:PDF Full Text Request
Passive direction finding technology is to measure the angle of arrival from the target signal only by receiving the information of the target signal without exposing itself.AOA plays an important role in electronic reconnaissance system.With the rapid development of modern electronic warfare,the frequency of signals such as radar and communication increasing,the traditional AOA technology in electric domain cannot meet the requirements and suffer from electronic bottlenecks such as bandwidth,loss and electromagnetic interference,which cannot adapt to the modern electronic reconnaissance system.The AOA technology based on microwave photonic can overcome the above disadvantages,have the unique advantages of microwave photonic system,such as high frequency,large bandwidth,low loss,etc.It could achieve high precision direction finding by combining the above advantages.However,many of schemes based on microwave photonic also have obvious disadvantages.The most of modulators have the phenomenon of offset point drift,which increase the measurement error.It is too hard to realize precise direction finding to meet the requirements of electronic reconnaissance system when the incoming signal is very small.The problems mentioned above are common problems in the AOA schemes based on microwave photonic.In order to solve these problems,the direction finding technology based on microwave photonics is deeply studied in this paper.The proposed schemes are theoretically analyzed,mathematically deduced and simulated.The contents of specific research are as follows:1.A direction finding scheme based on polarization multiplexing maher zendle modulator(PDM-MZM)is proposed.The scheme combines the phase difference measurement technique of microwave photonics with the direction finding principle of phase interferometer.And the scheme is verified by simulation.It has the advantages such as using the integrated PDM-MZM modulator,system stability.The simulation result shows that,within the scope of 0-180 ° phase difference high precision phase achieved.Combined with the fuzzy algorithm of discontinuous baselines constituting a two baseline direction-finding system,the precision of direction finding system is very good.2.A direction finding scheme based on polarization multiplexing orthogonal frequency shift keying(DP-QPSK)modulator is proposed and simulated.This scheme uses an integrated modulator to carry out all-optical direction finding without filter or photoelectric conversion.The working frequency of the direction finding system is unconstrained and the measurement precision is high.Simulation: the measured signal 10 GHz,power 0 d Bm,phase difference between the two way signal within-180 ° to 180 °,the simulation results show that the scheme can keep the good direction finding precision under small signal.3.The Sagnac ring based microwave photonic direction finding scheme is proposed and simulated.The scheme using Sagnac ring,the output of the ring can achieve the completely suppressed optical carrier without adding a notch filter to filter residual light carrier.The simulation results show that the proposed scheme can achieve high precision measurement of phase difference with small signal,the range of phase difference for-180 ° to 180 ° can realize the phase error 1.1 °.
Keywords/Search Tags:microwave photonic, electro-optic modulator, angle of arrival, microwave photonic phase detection, microwave photonic direction finding
PDF Full Text Request
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