Research On Signal Detection Technology Based On Interferometry

Interferometric techniques originated from radio astronomy have the advantages of high angular accuracy and passive measurement,and are gradually being promoted and applied in the field of non-cooperative measurements.It is important to carry out signal detection for non-cooperative satellites,which can detect non-cooperative satellite signals in time and carry out non-cooperative signal monitoring.The main work and results of the thesis,which is based on interferometry to carry out signal detection technology research,are as follows:1.The signal detection algorithm based on interference phase stability judgment was designed,and the algorithm was optimized considering the motion of the satellite relative to the station.The optimal value of the detection threshold was estimated by simulation to be 1.20 rad,and the corresponding false alarm rate simulation result was 0.001%,and the algorithm was verified with the cooperative signal with known frequency information,and the results showed that the satellite signal detection accuracy reached 95%;2.The influence of the parameters on the detection results during the data processing was comprehensively analyzed,including the number of FFT points,integration time,etc.:the processing time and detection effect corresponding to different FFT points were analyzed,and the value of FFT points was determined;the detection effect of different integration time was analyzed,and the results showed that the signal could be detected when the integration time reached 10s;the experiment was carried out with the help of interferometric system,simulated the effect of measurement point positioning error on antenna addressing error,and the three 1.5m mesh parabolic antennas in the interferometric system were calibrated for addressing,and the results showed that the addressing accuracy of the three antennas were within 0.01m;3.The interferometric system was used to carry out the real measurement experiments in the airspace to be measured to verify the effect of the research results in the actual detection.The results showed that a total of 11 signals were detected from the measured data in the airspace;the 11 signals were homologated and found to belong to 3 satellites,of which 3 signals belong to one satellite,5 signals belong to another satellite and the remaining 3 signals belong to a third satellite.In summary,the signal detection algorithm based on interferometric phase stability judgment can detect satellite signals without any a priori knowledge,and can be used for non-cooperative signal monitoring and target source screening.