Winner: NASA Software of the Year 2000 Award

GDGPS (Internet-based Global Differential GPS) is a uniquely powerful and flexible C-language software package that provides a complete end-to-end system capability for GPS-based real-time positioning and orbit determination.

Features:

• 10 cm horizontal and 20 cm vertical real time positioing accuracy with dual frequency GPS receivers.

• 5 cm - level real time orbit determination for low Earth satellites carrying dual frequency GPS receivers.

• The most precise and complete set of geodetic, satellite dynamics, and GPS measurement models for uncompromising accuracy.

• Dual mode application: same software used to compute GPS orbit and clock corrections and, embedded, for user positioning/orbit determination.

• Uniformly valid corrections anywhere in the world or in space

• Internet-based correction dissemination

• Software proven operationally in a number of critical real time systems. Complete end-to-end automation

Accomplishments:

• Extensively implemented for real-time and near-real-time user positioning and orbit determination:
  • NASA Shuttle SRTM mission (rapid receiver validation)
  • SNOE (Student Nitric Oxide Experiment) spacecraft
  • NASA X33/RLV mission (onboard navigation demonstration package; payload integration and testing)
  • NASA AirSAR mission (precise positioning and calibration for science data and control)
  • Scheduled to fly on SAC-C GPS receiver, 2000
  • Scheduled to fly on ST-5 Communications and Navigation Transceiver (CCNT), 2003

• Successful implementation for continuous operational control and conversion of NASA Global GPS Network (GGN) data, provided to the International GPS Service (IGS) on an operational basis (since 1/2000)

• Successful implementation in commercial wide-area differential service (SATLOC, 1995-2000)

• Successful implementation in Federal Aviation Administration (FAA) Wide Area Augmentation System (WAAS) proof of concept demonstrations; selected by FAA for implementation by Raytheon in operational system