NOVA AND GEOSAT COMPUTERS

Abstract

Two computers, utilized on-board the Navy satellites NOVA, launched in May 1981, and GEOSAT, to be launched in early 1984, are reviewed. The NOVA computer is an extension of the TRIAD design presented at the 1972 Government Microcircuit Applications Conference. The NOVA computer is the third generation digital data handling system for the Navy Transit Navigation Satellites. Covered in this paper is the computer architecture, hardware design, and relation to other satellite systems. The design of the NOVA computer software and its in-orbit performance is covered in a companion paper. The NOVA computer is an integral part of the on-board data handling system. It formats the Transit navigation message, stores and analyzes telemetry, and executes commands to extend the autonomous operation time of the satellite. The GEOSAT computer is a signal processor for a satellite born radar altimeter. It is an extension of the SEASAT-A design presented at the 1977 JBIS Symposium on Computer Techniques for Satellite Control and Data Processing. Its principal design feature is the incorporation of a microprocessor. The GEOSAT computer performs return signal acquisition, range tracking, receiver gain control, calibration, ocean wave height estimation, telemetry formatting, and command decoding. This paper gives a brief description of the GEOSAT computer functional performance, hardware, and software.