Use of a Commercial Visual Programming Language to Simulate, Decommutate, Test and Display a Telemetry Stream

Abstract

The advantages of using visual programming to create, modify, test and display a telemetry stream are presented. The failure to fully deploy the high-gain antenna of the Galileo spacecraft has resulted in a software redesign of the computer systems onboard the spacecraft to support the low-gain antenna mission. Visual programming software is being used to test new algorithms as part of the ground support for the spacecraft Test Bed. It is very important that any new software algorithms be thoroughly tested on the ground before any modifications are made to the spacecraft. The advantage of using a visual programming language (LabVIEW, National Instruments) is that it provides easy visibility into the decommutation process that is being modified by the Galileo programming support team. In addition, utilities were written using visual programming to allow real-time data display and error detection. A data acquisition board is used to clock in the actual synchronous telemetry signal from the Test Bed at rates below 10 kHz. The time to write and modify the code using visual programming is significantly less (by a factor of 4 to 10) than using text-based code. The gains in productivity are attributed to the communication among the customer, developer, and computer that are facilitated by the visual syntax of the language.