System software provided with the 1A Processor simplifies the task of using input/output devices, manages a portion of system time and memory resources, provides control over program interfaces, and provides an interactive facility that permits examination of system behavior. The impact of this software has been to simplify initial development of switching systems using the 1A Processor, to facilitate software maintenance, and to provide flexibility in adding system features. This article describes the capability and organization of the 1A Processor control, administrative, and utility software.

Let the location of a source of power be given by its polar coordinates. The bearing of the source is the polar angle of its location. Let a set of directional receiving patterns, or beams, be located at the origin of the coordinate system. Each beam is pointed in a different direction. The total power received on each beam is due to the source and noise. Models are presented to describe the dependence of the received powers and their estimates on the source power and bearing. The effect of randomness (noise), such as variation in the medium, is included. Based on these models, we first consider bearing estimation in the absence of randomness but including all sidelobe information. The concept of “virtual source power” is introduced for this purpose. It is then used for bearing estimation when randomness is present giving rise to several nonclassical estimation methods as well as a method using confidence intervals. A variety of squared error techniques are presented, along with comments concerning practical methods of computation.