Peri, Frank, Jr. | Search NASA

NASA NTRS1992

A real time data acquisition system using the MIL-STD-1553B bus

A flight digital data acquisition system that uses the MIL-STD-1553B bus for transmission of data to a host computer for control law processing is described. The instrument, the Remote Interface Unit (RIU), can accommodate up to 16 input channels and eight output channels. The RIU employs a digital signal processor to perform local digital filtering before sending data to the host. The system allows flexible sensor and actuator data organization to facilitate quick control law computations on the host computer. The instrument can also run simple control laws autonomously without host intervention. The RIU and host computer together have replaced a similar larger, ground minicomputer system with favorable results.

Peri, Frank, Jr.↗

NASA NTRS1986

Surface control system for the 15 meter hoop-column antenna

The 15-meter hoop-column antenna fabricated by the Harris Corporation under contract to the NASA Langley Research Center is described. The antenna is a deployable and restowable structure consisting of a central telescoping column, a 15-meter-diameter folding hoop, and a mesh reflector surface. The hoop is supported and positioned by 48 quartz cords attached to the column above the hoop, and by 24 graphite cords from the base of the antenna column. The RF reflective surface is a gold plated molybdenum wire mesh supported on a graphite cord truss structure which is attached between the hoop and the column. The surface contour is controlled by 96 graphite cords from the antenna base to the rear of the truss assembly. The antenna is actually a quadaperture reflector with each quadrant of the surface mesh shaped to produce an offset parabolic reflector. Results of near-field and structural tests are given. Controls structures and electromagnetics interaction, surface control system requirements, mesh control adjustment, surface control system actuator assembly, surface control system electronics, the system interface unit, and control stations are discussed.

Miller, James B.↗