Computer simulation of satellite systems

A digital computer program is described that simulates the physical characteristics of the Vela satellite system for the detection of nuclear detonations in space. The program consists of a modular set of subroutines that calculate the output of a nuclear device, the transport of the radiation to each sensor, and the contribution of each sensor output response to the transmitted data word from each satellite. Stochastic elements in the system such as the various event-satellite configurations, background radiation conditions, and data word transmission errors are included in the simulation. The ensemble of data words resulting from a number of replications under statistically identical-system-event conditions yields probabilistic information about the detection capability and false alarm rate of the system. The latter measures of system performance can be investigated by means of a flexible set of decision criteria subroutines that enable the user to investigate the effect of applying to the calculated data various criteria to determine when a sensor can be said to have reported an event and when the system as a whole can be said to have reported an event.