| 摘要 |
PROBLEM TO BE SOLVED: To enhance the performance of topographic echo cancellation processing, and compute a Doppler speed with high precision. SOLUTION: After A/D conversion of a received signal received by an antenna is performed, its quadrature detection is performed. A signal processing part finds speed spectra at each predetermined time duration by converting the quadraturely detected I/Q signals in a time region into a frequency region, by applying FFT processing to them. From the individual speed spectra found at each predetermined time duration, components appearing near zero speed are removed respectively as topographic echoes. The speed spectra from which the topographic echoes have been removed are integrated, and based on the integrated speed spectra the Doppler speed is computed. COPYRIGHT: (C)2008,JPO&INPIT
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