Patent ID: 8106814

Claim:
A method for determining an angle of elevation of a projectile following a ballistic trajectory, comprising the steps of: estimating, at a predetermined time a first derivative and a second derivative with respect to time of a Doppler velocity of the projectile; estimating the radial component of an acceleration of the projectile, the radial component being determined in accordance with the following approximate relationship: d ¨ ≈ - 2 · ⅆ Γ ρ ⅆ t ; estimating a speed of the projectile at the predetermined time, the estimated speed being determined in accordance with the following relationship: {circumflex over ( V )}=( d 2 −{dot over (d)}·R−{circumflex over (Γ)} ρ ·R ) 1/2 ; estimating an angle of elevation of the projectile at the predetermined time, the angle of elevation being estimated in accordance with the following relationship: ⅆ E ^ ⅆ t = 1 R · ( V ^ 2 - d 2 ) 1 / 2 , wherein: d is the Doppler velocity of the projectile; {dot over (d)} is the first derivative with respect to time of the Doppler velocity; {umlaut over (d)} is the second derivative with respect to time of the Doppler velocity; R is a radial distance measured; Γ ρ is the acceleration of the projectile; V is the speed of the projectile; E is the angle of elevation of the projectile; and ^ indicates an estimation of a respective parameter.