Projectile motion parameter determination device using successive approximation and high measurement angle speed sensor

摘要

The invention relates to an apparatus and method for determining parameters of motion regarding a struck projectile. The invention has particular application to determining the launch parameters of a golf ball struck by a golf club. A Doppler microwave speed sensor measures the apparent speed of a struck golf ball, which is the true speed of the ball subtended onto a radial from the sensor to the ball. The speed sensor is positioned a substantial lateral distance from a straight aim line, and the sensor's microwave beam is wide. As a result of this deployment, and in contrast to the typical usage of microwave speed sensors, the apparent speed measured by the sensor differs significantly from the true speed of the ball. The measured apparent speed results from a complicated interaction of initial ball speed, loft angle, and aim angle. A computer connected to the sensor acquires measured apparent speed data into an array. Within the computer, a trajectory prediction algorithm is capable of predicting an array of apparent speeds which would result from a given set of launch conditions. An error function is capable of ascertaining how well predicted apparent speeds match actual acquired speeds. A search algorithm uses the trajectory prediction algorithm and the error function to try a succession of progressively better guesses of launch parameters. Those launch parameters, comprised of initial ball speed, loft angle, and aim angle, which best account for the acquired apparent speed data are reported by the computer as the actual launch parameters. An impact detection device is configured to detect the impact of club on ball within a window of time in which such impact is plausible. The computer will not report launch parameters if a comparison using the error function indicates that the acquired data was likely the result of interference from an extraneous golf ball.