Patent ID: 8767193

Claim:
A method for tracking the relative velocity between a vehicle and a target; comprising: a) determining a velocity of the vehicle based on inertial measurements acquired for the vehicle; b) determining a velocity vector signal of the vehicle along a line of sight of a laser vibrometer on the vehicle, wherein the laser vibrometer has a nominal window in the frequency domain centered around an operating frequency of the laser vibrometer; c) converting the velocity vector signal to a Doppler frequency velocity estimate; d) subtracting a Doppler frequency velocity error from the Doppler frequency velocity estimate to create a corrected Doppler frequency velocity estimate; e) creating an updated window by shifting the nominal window's center frequency by the corrected Doppler frequency velocity estimate of step d); f) acquiring velocity measurements of the vehicle relative to the target using the laser vibrometer on the vehicle; g) converting the laser vibrometer velocity measurements to frequency data; h) overlaying the updated window from step e) onto the frequency data from step g); i) determining from step h) which frequency within the updated window has the largest magnitude signal; and j) determining the Doppler frequency velocity error by subtracting the corrected Doppler frequency velocity estimate of step d) from the frequency within the updated window having the largest magnitude signal of step i).