Notes on Basic GPS Positioning and Geodetic Concepts

These notes have been prepared for a short course on GPS positioning, with particular reference to land-based applications. They consist of three chapters:

• Introduction to GPS
• GPS Enhancements
• Mapping Issues

You may download them for your personal use. All files are in Adobe Acrobat PDF format.

Chapter 1 (Acrobat PDF file 602kB)

Contents:

1.1 Introduction to the System Components
1.1.1 System Design Considerations
1.1.2 The Space Segment
1.1.3 The Control Segment
1.1.4 The User Segment -- The Applications
1.2 GPS Satellite Constellation and Signals
1.2.1 GPS Constellation Design
1.2.2 GPS Signal Components
1.2.3 The Civilian - Military Relationship
1.2.4 Why is the GPS Signal is so Complicated?
1.2.5 GPS Satellite Ephemerides
1.3 GPS Measurements
1.3.1 The Transmitted Signal
1.3.2 The GPS Range Measurements
1.3.3 The GPS Carrier Phase Measurements
1.3.4 Ranging Using PRN Codes
1.3.5 An Observation Model of the Pseudo-Range
1.3.6 Coping with the Satellite Clock Bias
1.4 GPS Instrumentation
1.4.1 Antennas
1.4.2 Signal Processing Principles for Code-Correlating Receivers
1.4.3 Trends In GPS Instrumentation References

Chapter 2 (Acrobat PDF file 511kB)

Contents:

2.1 Factors Influencing GPS Accuracy
2.1.1 GPS Measurement Biases and Errors
2.1.2 Absolute and Relative Positioning
2.1.3 Satellite - Receiver Geometry
2.1.4 Processing Algorithms, Operational Mode and Other Enhancements
2.2 Relative GPS Techniques
2.2.1 Differential GPS Navigation
2.2.2 Carrier Phase-Based Relative Positioning
2.2.3 Real-Time DGPS Data Correction Transmissions
2.2.4 Real-time DGPS Communication Link Considerations
2.2.5 Real-time DGPS Services
2.3 GPS Augmentation Options
2.3.1 Global GPS System Augmentation
2.3.2 Non-GPS Satellite-Based Navigation Systems
2.3.3 Examples of Software Enhancements
2.3.4 Hardware Augmentation: GPS and Other Sensors References

Chapter 3 (Acrobat PDF file 585kB)

Contents:

3.1 Datums and Coordinate Systems
3.1.1 Introduction to Geodesy: The Figure of the Earth
3.1.2 Geodetic Datums
3.1.3 Datum and Coordinate Transformations
3.1.4 The WGS84 Satellite Datum
3.1.5 The International Terrestrial Reference System
3.2 Spatial Data Capture
3.2.1 The Survey Operation
3.2.2 Accuracy Standards and Specifications
3.2.3 Map Attribute Data
3.2.4 Data Storage, Maintenance and Distribution
3.3 Map Display
3.3.1 Map Projections
3.3.2 Coordinates, Datums and Maps
3.3.3 Map Scales and Accuracies
3.3.4 Map-Aided Positioning References