140A-B: Differential GPS I & II

This course is for engineers and system integrators who require enhanced accuracy and integrity capabilities from GPS. The course provides an overview of differential GPS, describes DGPS error sources, and details the accuracy performance of various DGPS architectures.

Dr. Chris Hegarty
MITRE

DGPS Overview
• Local-area, regional-area, wide-area architectures
• Code vs. carrier-phase based systems
• Pseudolites
• Performance overview

Differential Error Sources
• Satellite ephemeris errors
• Satellite clock errors
• Selective availability
• Ionospheric and tropospheric delay
• Multipath
• Receiver internal noise and biases

Observable Modeling
• Code pseudorange and carrier phase outputs
• Code-minus-carrier observables
• Carrier smoothed code operation
• Double difference operation
• System error budgets

Level: A basic knowledge of GPS, as well as engineering terms and concepts, is assumed. Knowledge provided in Courses 110A&B is assumed. Most attendees proceed to 140B.

1:30 - 5:00, Tuesday, String 1
140B: Differential GPS II

Back to main tutorials page

For technical and scientific professionals and managers who would like an in-depth perspective on the GPS system, its performance and operation. Also, for those entering the field or those specialists desiring a broader view of GPS developments.

Dr. Hegarty

DGPS Design Considerations
• Range vs. navigation domain corrections
• Data links; pseudolites
• Reducing major error components
• Ambiguity resolution

DGPS Case Studies I
• RTCM SC104 message format
• USCG maritime DGPS and Nationwide DGPS (NDGPS)
• Commercial satellite-based systems

DGPS Case Studies II
• Satellite-based Augmentation Systems (SBAS)
• Ground-based Augmentation Systems (GBAS); pseudolites
• RINEX format
• CORS network for precise positioning (survey)
• International GNSS Service (IGS)
• Precise time transfer

Level: A basic knowledge of GPS, as well as engineering terms and concepts, is assumed. Courses 110A&B, and 140A, or equivalent experience are prerequisite.