A GPS Receiver Upgrade for the Space Shuttle - Rationale and Considerations

Abstract

PS revolutionized the field of navigation in the 1990s, and made precise navigation available to a wide array of users. Integration of GPS technology into the Shuttle avionics system also occurred in the 1990s. The planned use of GPS during Shuttle missions is not as extensive as some might expect, given the widespread use and success of GPS technology, and the availability of ~$100 receivers to the general public. The rationale behind the current planned use of GPS by the Shuttle Program is discussed along with some history and lessons learned. For the Shuttle Program to fully obtain the benefits of this technology, and to meet any future automation and autonomy requirements, a new GPS receiver with more advanced capabilities than the legacy unit may be needed. 1 II. Why GPS?As far back as the mid 1970s, the Shuttle Program seriously considered using GPS technology on the orbiters. 2 GPS technology had the potential to reduce the number of different types of navigation aids on the orbiter, and to make the orbiter more autonomous by providing self contained navigation on-orbit (reduce or eliminate the need for ground radar and Tracking and Data Relay Satellite (TDRS) tracking). However, the developmental nature of GPS technology, adequate performance of the existing Shuttle on-board and ground navigation systems and cost of GPS xx Copyright © 2004 by United Space Alliance, LLC. Published by the American Institute of Aeronautics and Astronautics with permission. These materials are sponsored by the National Aeronautics and Space Administration under Contract NAS9-20000. The U.S. Government retains a paidup, nonexclusive, irrevocable worldwide license in such materials to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the U.S. Government. All other rights are reserved by the copyright owner. * Technical Staff, Flight Design and Dynamics, USH-485L, 600 Gemini Ave. Member AIAA. A GPS Receiver Upgrade For The Space ShuttleRationale And ConsiderationsJohn L. Goodman * United Space Alliance LLC, Houston, TX 77058 In the mid 1990s, a 5 channel Global Positioning System (GPS) receiver was integrated into the Space Shuttle avionics system due to the anticipated start of Tactical Air Control and Navigation (TACAN) phase-out in the year 2000. While the early 1990s technology level receiver adds redundancy and flexibility to the navigation process, and improves safety at emergency landing sites, new capabilities in modern GPS receivers would further enhance Shuttle navigation. All-in-view satellite tracking, new GPS signals and ground and space based augmentation systems would provide a more robust GPS navigation solution for the orbiters, particularly if future missions call for automated landings, or on-board precision orbit determination. G integration and certification compared to the operational costs of the proven legacy systems drove the Shuttle Program to not incorporate GPS in the 1980s.By the early 1990s, with the GPS satellite...