Accession Number : AD0723977

Title :   Collision Geometry Formulae and Application to Collision Warning Techniques.

Descriptive Note : Research and development technical rept.,

Corporate Author : ARMY ELECTRONICS COMMAND FORT MONMOUTH N J

Personal Author(s) : Musillo,Anthony

Report Date : MAR 1971

Pagination or Media Count : 39

Abstract : The paper discusses two dimensional collision geometry in which straight and nonaccelerated flight paths are assumed. A derivation of the time dependence of the range (R), relative velocity (dR/dt), and relative acceleration (2nd dR/dt) will be presented and the quantities expressed as a function of R. The time to collision (tau) will be discussed, also. These quantities are applied to realistic collision geometries based on present Army aircraft operations. Also, a discussion of relative velocity versus range curves with reference to tau min (where tau = dR/(dR/dt)) and constant range warning lines is given. These parameters are incorporated in present state-of-the-art techniques such as the Doppler and range increment techniques. The former technique attempts to detect any change in the Doppler frequency when tau = tau min ( in this case, 15 seconds). A change in the Doppler frequency indicates a noncollision course. The range increment technique measures differences in ranges over small constant time intervals and uses these range changes to obtain tau. A sample error measurement analysis in one of the low range rate change situations gives an indication of the magnitude of the range error measurement. (Author)

Descriptors :   (*ARMY AIRCRAFT, FLIGHT PATHS), (*FLIGHT PATHS, *AVIATION SAFETY), WARNING SYSTEMS, AVIATION ACCIDENTS, MISS DISTANCE, DOPPLER RADAR, RANGE FINDING, DIFFERENTIAL EQUATIONS, NUMERICAL ANALYSIS, NUMERICAL INTEGRATION, CURVE FITTING

Subject Categories : Aircraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE