Accession Number : AD0767534

Title :   An Improved Time of Flight Approximator for Trajectory Estimation.

Descriptive Note : Technical note,

Corporate Author : FRANKFORD ARSENAL PHILADELPHIA PA

Personal Author(s) : Wenocur,Brian D.

Report Date : JAN 1973

Pagination or Media Count : 73

Abstract : The problem of numerical processor selection for use in a time of flight submodel has been examined. A one-step method of evaluation for time of flight as a function of range has been formulated which maintains accuracy to within 1% over the range zero to 2000 meters for the M246 projectile. This computerized method runs about 38 times as fast as the more widely applicable differential equation solver, while explicitly accounting for ballistic parameters not present in the inaccurate one-step submodel which it replaces. Statistical variation in times of flight are also considered. Several methods of evaluating the drag coefficient and its statistical variation as functions of velocity from doppler radar data have been explored. The most successful one treated involves obtaining a least square fit for velocity data as a function of time. A rootfinder then evaluates the analytic derivative at a tabular velocity value. (Author)

Descriptors :   (*PROJECTILE TRAJECTORIES, MATHEMATICAL PREDICTION), FIRE CONTROL COMPUTERS, LEAD ANGLE, EXTERIOR BALLISTICS, MATHEMATICAL MODELS, IMPACT PREDICTION, LEAST SQUARES METHOD, COMPUTER PROGRAMS

Subject Categories : Ballistics

Distribution Statement : APPROVED FOR PUBLIC RELEASE