US Patent 11513208 Method for determining spin of a projectile

A method for estimating a spin of a projectile, the method comprising obtaining from a radar transceiver a first time series comprising observations of a radial velocity of the projectile relative to the radar transceiver, calculating, from the first time series, a center velocity of the projectile, extracting from the first time series a second time series comprising a variation in the first time series around the calculated center velocity estimating a frequency of the second time series, and determining the spin of the projectile WO based on the estimated frequency of the second time series.