Inventors:
James R. Jordan - Boulder CO
Richard J. Lataitis - Highlands Ranch CO
Assignee:
National Oceanic & Atmos Admin - Boulder CO
International Classification:
G01S 1395
Abstract:
The present invention provides an apparatus and method for correcting buoy motion in Doppler moment estimates. In the present invention, it is assumed that the buoy is stationary over short periods of time, 0. 5 seconds for example. The average pitch and roll angles are measured for the 0. 5 second period. A short-term Doppler spectrum for a particular beam is computed and stored along with the corresponding average pointing angle. This short-term Doppler spectrum must be averaged with many others to be able to detect the clear air signal. To correct for motion broadening, the present invention shifts each short Doppler spectrum some number of velocity bins before averaging them together. This shifting scales the measured radial velocity at some measured pointing angle to the radial velocity that would have been measured if the antenna was pointing at some initial pointing angle, typically the steering angle if the antenna was level. The wind velocity derived from the average 30 second Doppler spectrum without shifting is used as a first guess.