AdaIC News Winter 1995

European Space Agency Using Ada for Global Positioning System

This is one of a series of Ada success stories produced in cooperation with the AdaIC, the Ada Resource Association, and ACM SIGAda. For copies, and for information on other Ada success stories, contact the AdaIC.

Ada is in space, as well as everywhere else. One case in particular is a global positioning system (GPS) receiver for space applications under development by the European Space Agency (ESA) and Alcatel-Sel (D). It will be used on-board the ESA's future low-earth-orbit spacecraft, Hermes, the manned European space shuttle, and the Colombus Free-Flier Laboratory. The receiver is a 5-channel parallel receiver. In 1993, a specially qualified version of this unit flew on the German Astropas platform, on-board the shuttle STS-59 mission.

As 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. Alcatel-Sel was selected due to the experience they already had on GPS civil receivers.

The Ada system

The aim of this contract was to procure 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 rendezvous, 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.

For further information, please contact:

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


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