System Description - Software
Functional Overview
The GDGPS System is driven by the RTGx software set (https://www.sciencedirect.com/science/article/pii/S0273117720302532), developed completely in-house at JPL, and possessing many unique features and capabilities. The C++ software evolved from one of the world's leading GPS data processing and analysis software packages, JPL's GIPSY-OASIS and its real-time version RTG (Real Time GIPSY).
RTGx is also the navigation software for the former GPS Operational Control Segment (OCX), and was developed under the strict quality assurance processes as appropriate for its critical mission at the heart of the world's most important infrastructure.
Distinguished Heritage
Used as prototype for the FAA's Wide Area Augmentation System (WAAS)
Awarded NASA Software of the Year 2000
Flew onboard the NTS-3 mission, embedded in the JPL Cion GNSS receiver, performing real-time onboard orbit determination, 2025
Inducted into the Space Technology Hall of Fame, 2004
Usability
Complete Automation
End-to-end automatic operations with minimal human intervention.
Complete Positioning System
The software handles all aspects of a complete real-time global positioning system, including GNSS orbit determination and simultaneous network positioning. Supports real-time applications as well as post-processing and simulations.
Highly Portable
The software is regularly tested on multiple flavors of Linux. Various positioning modules have been ported to several embedded real-time environments, including flight receivers.
Versatile
Works with many types of popular geodetic receivers. Flexible adaptation layer makes it easy to accommodate new receiver types.
Visual aids: Real-time graphic display of performance using network monitoring tools and internal quality control.
Quality Factors
- Object Oriented C++ and Python for portability and maintainability
- Modularity: Highly modular code to support embedded as well as ground applications
- Reliability: Outstanding track record of continuous operations
- Accuracy: All models are sub-cm accurate for the most demanding science applications
- Maintainability: Designed for operations by a third party and for team maintenance. Configuration control management.
Innovation & Creativity
Parallelized architecture (MPI) enables real-time solutions to massive estimation problems, e.g., multiple GNSS constellations
State-space architecture guarantees seamless global uniformity of the differential corrections
Innovative use of the internet to achieve robustness through redundancy
Unique satellite dynamics and signal models developed in-house at JPL
Efficient GNSS data compression
Innovative system for end-to-end redundant operations provides high reliability
Uniquely flexible filter design allows any parameter to have stochastic attributes
Capable of adding satellites/receivers on the fly
Unique dynamics integrator supports very high orbit modeling accuracy
Tropospheric delay model and stochastic estimation capability for users or reference sites
Exploit full information content of phase data
Real-time playback capability