Method of and apparatus for determining the relative weight and weapon class of battlefield projectiles insensitive to errors in meteorological data and radar measurements

Abstract

The application measures a projectile velocity and an acceleration from radar track data. The air temperature and an air pressure are measured. The measured air temperature and the measured air pressure are extrapolated to the projectile's location for each instant in time a radar measurement made by the radar. The projectile's drag parameter is estimated at each time in the projectile's flight that the projectile's velocity and acceleration are estimated. The projectile's Mach number is estimated at each time in the projectile's flight. The drag coefficient is estimated. A functionally normalized drag parameter (FNDP) is formed. The FNDP is defined as the ratio of drag parameter of a reference projectile at each Mach number the drag is measured to the in-flight projectile's drag parameter at the corresponding Mach numbers. A weighted average of the resulting FNDP values is performed with respect to Mach number. The most likely of three regions the FNDP parameter lies is statistically determined. The relative weight of the in-flight projectile is inferred as one of light, medium or heavy based on the most likely of the three regions.