An inertial measurement system for a spinning projectile comprising: first (roll), second and third gyros with axes arranged such that they define a three dimensional coordinate system; at least a first linear accelerometer; a controller, arranged to: compute a current projectile attitude comprising a roll angle, a pitch angle and a yaw angle; compute a current velocity vector from the accelerometer; combine a magnitude of said velocity vector with an expected direction for said vector to form a pseudo-velocity vector; provide the velocity vector and the pseudo-velocity vector to a Kalman filter that outputs a roll gyro scale factor error calculated as a function of the difference between the velocity vector and the pseudo-velocity vector; and apply the roll gyro scale factor error from the Kalman filter as a correction to the output of the roll gyro.

A non-lethal projectile having a shear-thinning fluid within an interior cavity. The shear-thinning fluid having a greater apparent viscosity at low shear rates to spin-stabilize the non-lethal projectile during flight and a lower apparent viscosity at a high shear rate corresponding with the shear-thinning fluid shearing against the frangible cap upon the non-lethal projectile striking the target, with the low viscosity of the shear-thinning fluid allowing proper dispersal upon impact with the target. The shear-thinning fluid can comprise a marking media and be in the form of an emulsion with less than about 50% liquid by volume to effectively disperse upon impact with the target.

A non-lethal projectile having a shear-thinning fluid within an interior cavity. The shear-thinning fluid having a greater apparent viscosity at low shear rates to spin-stabilize the non-lethal projectile during flight and a lower apparent viscosity at a high shear rate corresponding with the shear-thinning fluid shearing against the frangible cap upon the non-lethal projectile striking the target, with the low viscosity of the shear-thinning fluid allowing proper dispersal upon impact with the target. The shear-thinning fluid can comprise a marking media and be in the form of an emulsion with less than about 50% liquid by volume to effectively disperse upon impact with the target.

This invention relates to a non-lethal projectile to be fired using a paintball gun, and more particularly, but not exclusively, to an aerodynamic non-lethal projectile which is used for marking, inhibiting or administering medicinal or other chemical substances to live targets. According to a first aspect of the invention, there is provided a projectile comprising a body shaped to receive a capsule containing a substance, the body having a stabilizing member connected thereto for stabilizing the projectile in flight when the projectile is discharged from a weapon, and an annular member connected to the stabilising member at a rear end of the projectile for positioning the projectile relative to the weapon and relative to other projectiles to be discharged by the weapon.

This invention relates to a non-lethal projectile to be fired using a paintball gun, and more particularly, but not exclusively, to an aerodynamic non-lethal projectile which is used for marking, inhibiting or administering medicinal or other chemical substances to live targets. According to a first aspect of the invention, there is provided a projectile comprising a body shaped to receive a capsule containing a substance, the body having a stabilizing member connected thereto for stabilizing the projectile in flight when the projectile is discharged from a weapon, and an annular member connected to the stabilising member at a rear end of the projectile for positioning the projectile relative to the weapon and relative to other projectiles to be discharged by the weapon.

The present invention relates to increasing the flight stability of a bullet in subsonic flight. The bullet may incorporate features that impart additional angular momentum during flight. Helical fins may be configured such that laminar airflow over the bullet during flight causes the bullet to rotate, increasing the angular momentum of the bullet and stabilizing it during flight. The fins may be self-forming during the use of the bullet or may be formed during manufacturing.

The present invention relates to increasing the flight stability of a bullet in subsonic flight. The bullet may incorporate features that impart additional angular momentum during flight. Helical fins may be configured such that laminar airflow over the bullet during flight causes the bullet to rotate, increasing the angular momentum of the bullet and stabilizing it during flight. The fins may be self-forming during the use of the bullet or may be formed during manufacturing.

A crowd control projectile includes a payload carrier, an incapacitating agent inside the payload carrier, and an activating mechanism for activating the incapacitating agent. The activating mechanism includes a sensor and a timer. The timer delays the activation until a predetermined delay after the sensor senses that the projectile has been launched. Alternatively, the activating mechanism includes a receiver for receiving an activation signal after the projectile has been launched. Preferably, the projectile has the shape of a clay pigeon. A launcher of such a projectile includes a communication mechanism for transmitting a timing signal or an activation signal to the projectile and an arm for launching the projectile by direct contact. To control a crowd, the projectile is launched over the crowd by direct contact with a solid arm and the activating mechanism is used to activate the incapacitating agent when the projectile is above the crowd.

A crowd control projectile includes a payload carrier, an incapacitating agent inside the payload carrier, and an activating mechanism for activating the incapacitating agent. The activating mechanism includes a sensor and a timer. The timer delays the activation until a predetermined delay after the sensor senses that the projectile has been launched. Alternatively, the activating mechanism includes a receiver for receiving an activation signal after the projectile has been launched. Preferably, the projectile has the shape of a clay pigeon. A launcher of such a projectile includes a communication mechanism for transmitting a timing signal or an activation signal to the projectile and an arm for launching the projectile by direct contact. To control a crowd, the projectile is launched over the crowd by direct contact with a solid arm and the activating mechanism is used to activate the incapacitating agent when the projectile is above the crowd.

A projectile has a front portion, a divider and a cylindrical portion. The front portion has a wall defining an interior cavity, which is closed by the divider. The cylindrical portion comprises a cylindrical sidewall having an outer surface and an inner surface. The projectile also has a plurality of depressions in the cylindrical sidewall. The depressions have an outlet adjacent the second end, an inlet toward the first end and a neck area between the inlet and the outlet. A width of the inlet is smaller than a width of the outlet. The depressions at the neck area have a curved sidewall, but a generally straight sidewall between the neck area and the outlet. The surface of the depression extends at a ramp angle from the outer surface of the sidewall at the inlet of the depression toward the inner surface of the sidewall at the outlet.