초록 ▼

A muzzle velocity chronograph method and apparatus for providing an accurate and precise measurement of the muzzle velocity of a projectile ejected from a gun. A conventional radar Doppler signal is sampled and digitized and arranged in a succession of groups, each group representing a separate time

A muzzle velocity chronograph method and apparatus for providing an accurate and precise measurement of the muzzle velocity of a projectile ejected from a gun. A conventional radar Doppler signal is sampled and digitized and arranged in a succession of groups, each group representing a separate time period. A fast-Fourier transform is then computed for each group of samples, and peak frequency measurements in the transformed data are tracked from one time period to the next. These peaks indicate the velocities of the projectile of interest and any other nearby moving objects. Finally, a least mean square error curve fit and standard regression algorithm are used to deduce the projectile\s initial, muzzle velocity. The invention provides accurate muzzle velocity determinations even in circumstances where the Doppler signal contains substantial interference caused, for example, by random noise and the presence of moving fragments in the direction of the projectile.

대표청구항 ▼

Doppler radar apparatus for determining the initial velocity of a projectile ejected from a muzzle, comprising: radar means for producing a Doppler signal indicative of movement of the projectile relative to the muzzle; Fourier transform means for operating on a predetermined plurality of segments o

Doppler radar apparatus for determining the initial velocity of a projectile ejected from a muzzle, comprising: radar means for producing a Doppler signal indicative of movement of the projectile relative to the muzzle; Fourier transform means for operating on a predetermined plurality of segments of the Doppler signal, each segment representing a separate time period, to produce a corresponding plurality of frequency spectrum signals; detection means, responsive to the plurality of frequency spectrum signals, for measuring the velocity of the projectile during the time period associated with each successive segment of the Doppler signal, wherein the detection means includes comparator means for comparing each of the plurality of frequency spectrum signals with a prescribed threshold that varies with frequency and with the amount of superimposed noise, the comparator means also determining that portions of the signals exceeding the threshold result from one or more moving objects, including the projectile whose initial, muzzle velocity is being estimated; and regression means, responsive to the projectile velocities measured by the detection means for the plurality of successive time periods, for estimating the projectile\s initial, muzzle velocity.