Abstract: A system for precisely measuring muzzle exit velocity of a “muzzle loaded” mortar projectile fired from a mortar tube using two back-biased Hall effect sensors for projectile gas ring channel detection. The system includes a back-biased Hall effect sensor block, a digital resolver electronic circuit and a computer software interface. The back-biased Hall effect sensors are located in a calibrated sensor block attached to a mortar tube. As the projectile metal casing passes a face of the sensors, the sensors trigger and release, providing two electronic pulses. The pulse edges are captured in the resolver electronics, containing a discriminator circuit for filtering all input pulses to distinguish between a projectile loading event and a projectile firing event. Once a valid firing event is detected, an output of precision timers is presented serially to a computer where it is processed and displayed by a computer software interface.

Abstract: An isolation system for a sensitive component or apparatus affixed to a mortar tube comprising a barrel mount assembly which supports two parallel shafts. A plate parallel with each axis of the two shafts positions four bearing carrier blocks, two each containing a sleeve bearing which rides on each of the shafts to allow the plate assembly to slide freely along the length of the shafts and support an isolated cage. During firing, the travel vector is decoupled from the cage by the shafts as they move with the barrel through the bearings leaving the cage assembly in free space. The cage then accelerates under the force of gravity over the distance of the displaced travel of the shafts back to its rest position landing on steel springs or dampers, each on a shaft and seated against the lower flange end of the barrel mount assembly.

Abstract: A method and apparatus using ultrasonic sensors for determination of the pointing vector described by two points separated in space in the coordinate frame of the measuring system. For measurement, acoustic signals are transmitted from two emitters whose spatially separated coordinates form the desired pointing vector. Three detectors, associated receiver electronics and software are required to compute six distinct spheres from the time of flight measurements. The intersection of the three spheres, associated with each emitter, describe the desired location in the detector coordinate system of that emitter. With the coordinates of each emitter, the pointing vector is computed using standard geometry. A reference is required to determine the time of flight of the signals to each detector. Another embodiment uses an active reflective technique, where the timing is obtained through round trip transmission and reception of the signal with a known fixed delay at the vector points.

Abstract: A method and apparatus using ultrasonic sensors for determination of the pointing vector described by two points separated in space in the coordinate frame of the measuring system. For measurement, acoustic signals are transmitted from two emitters whose spatially separated coordinates form the desired pointing vector. Three detectors, associated receiver electronics and software are required to compute six distinct spheres from the time of flight measurements. The intersection of the three spheres, associated with each emitter, describe the desired location in the detector coordinate system of that emitter. With the coordinates of each emitter, the pointing vector is computed using standard geometry. A reference is required to determine the time of flight of the signals to each detector. Another embodiment uses an active reflective technique, where the timing is obtained through round trip transmission and reception of the signal with a known fixed delay at the vector points.