Research On Sensitivity Of Synthetic Aperture Radiometer Based On Delay Correlation

The synthetic aperture radiometer imaging system based on delay correlation has the advantage of less correlation calculation,but at the same time the sensitivity performance is reduced.With the development and application of remote sensing technology,the performance requirements for microwave radiometers are getting higher and higher.Sensitivity is one of the important indicators of microwave radiometer performance evaluation,so it is also very valuable to study the sensitivity of synthetic aperture radiometer based on delay correlation.The application of the principle of delay correlation makes the system based on delay correlation different from the conventional synthetic aperture in the acquisition of visibility.Based on this difference,this paper studies the sensitivity based on delay correlation.Derive the autocorrelation function based on the delay correlation,modify and verify the normalized auto(cross)correlation function of the individual antenna pairs;derive the visibility function based on delay correlation,and obtain the relationship?_p between delay correlation visibility and regular visibility.Imitate the conventional sensitivity derivation process,the sensitivity based on the delay correlation in the one-dimensional case is derived,and the relationship?_p between the variance of the delay correlation visibility and the variance of the conventional visibility is derived,and the sensitivity based on the delay correlation in the two-dimensional case is derived in this way,and the ratio relationship between the two is obtained by comparing with the conventional sensitivity.Finally,this paper verifies the accuracy of the sensitivity formula based on delay correlation by calculating the sampled data of the simulation system and the actual system.Then discusses the delay time and the number of antennas based on the ratio relationship.It is known from the analysis that the application of delay correlation theory reduces the sensitivity performance of synthetic aperture radiometer imaging based on delay correlation;then the quantization error existing in the AD sampling process is studied,the sensitivity formula based on delay correlation with quantization error is derived,and some influencing factors of the quantization error are discussed and analyzed.It can be seen from the analysis that the quantization error will further reduce the sensitivity performance based on delay correlation,but as the number of quantization bits increases,the decrease is greatly reduced,or even has no effect.