| 摘要 |
PURPOSE: To obtain an image of high quality by deciding the frequency offset of a back scattering ratio factor from the azimuth spectrum of radar crude data, and obtaining phase error from the decided offset, thereby correcting the error due to the atmosphere such as troposphere, ionosphere. CONSTITUTION: Means 201 to 203 in a broken line section 20 decide frequency offsetΔF(i) orΔF(t) by the back scattering element of azimuth spectrum by the correlation of two continuous spectra. Next to means 203 for forming the maximum of correlation K(f, i), difference forming means 21 for forming the difference between the offsetΔF(t) and predetermined valueΔFsoll of the offset is provided. If the forward speed Vv of the carrier is known, predetermined valueΔFsoll is calculated, while if it is not known, the offsetΔF(t) is displayed as predetermined valueΔFsoll , and passed through a low pass filter 22. Next to the means 21, integrating units 231 , 232 for double integrating the obtained difference are provided, constant 2n/Δt is multiplied in a standardizing unit 24 to obtain a phase differenceψe(t).
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