Collision Geometry Formulae and Application to Collision Warning Techniques.
Research and development technical rept.,
ARMY ELECTRONICS COMMAND FORT MONMOUTH N J
Pagination or Media Count:
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 dRdt, and relative acceleration 2nd dRdt 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 dRdRdt 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