Ada in Global Positioning Satellite System

Form U148-0794 ALCATEL.TXT

Ada Information Clearinghouse, 1-800/AdaIC-11, 703/685-1477

Special features introduced with future space applications and qualifications in mind required that the Receiver software be programmed in Ada for reliable and safe software development.

Ada Used to Develop a Global Positioning System for Future Spacecraft

The Project

The European Space Agency (ESA) has been developing with ALCATEL-SEL (D) a GPS Receiver for Space applications. It will be used on-board the future ESA's low Earth Orbit Spacecraft, namely HERMES, the manned European space shuttle and the COLOMBUS Free-Flier Laboratory. The receiver is a 5-channel C/A code and carrier tracking, parallel receiver. A specially qualified version of this unit flied on the German ASTROPAS platform, on-board the shuttle STS-59 mission (1993).

As a preparation for the use of GPS on future spacecraft, ESA contacted ALCATEL-SEL for the manufacturing of a GPS receiver Elegant breadboard Unit following functional, performance and interface requirements applicable to the projects HERMES and COLUMBUS. This company was selected due to the experience that they already had on GPS civil receivers.

The Ada System

The aim of this contract was to procure an equipment that would be used for laboratory testing of the GPS Absolute (stand-alone) navigation accuracy performance when applied to Low Earth Orbit (LEO) vehicles with re-entry capabilities. In addition, the equipment had to be designed for high accuracy GPS applications; Relative Navigation in support of In-orbit Proximity Operations and Rendez-Vous, and Automatic Landing. Finally, the receiver had to be conceived with its future space application and qualification in mind, and a number of special features were introduced for this purpose. One of these features required that the Receiver software be programmed in Ada for reliable and safe software development. This is an ESA software general requirement.

The Development of the Application

The development has been done with the Alsys Ada development environment, AdaWorld for Sun3 to Motorola 80385. Alsys also provided Alcatel-Sel with the Alsys Real Time Kernel (ARTK), which supports Ada features and provides real-time extension to the language for embedded systems. The need of such extensions has been increasingly bigger within the entire Ada community. This is why most of the ARTK's real-time capacities are now going to be offered to all Ada programmers by the new standard, Ada 9X.

For further information, please contact:

Ann Trib
Alsys GMBH & Co.KG
Kleinoberfeld 7 
D-76135 Karlsruhe 
Tel: + 49 721 985 530 
Fax: + 49 49 721 985 5398


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