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16 Cards in this Set
- Front
- Back
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Global Navigation Satellite System (GNSS) |
Satellite-based location and navigational system with satellites paired with ground-based receivers. |
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Navigation System Using Timing and Ranging (NAVSTAR) Global Positioning System (GPS) |
Name of the U.S. Department of Defense's GPS initially used for military purpose until made available for civilian use. |
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GLONASS |
Russian system intended for independence from GPS. |
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What are the three main components of a GNSS? |
Satellite segment - sufficient number of satellites Control segment - allows tracking, communications, data gathering, integration, analysis, and control facilities User segment - receivers used by a variety of people and in many applications. |
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What are the differences between carrier signal and coded signal and how are they used? |
Carrier signals are modulated for the purpose of conveying information, whereas coded signals are combinations of frequencies that represent the value of a digit to be transmitted.
Carrier signals can carry C/A and/or P codes, whereas the coded signals contain digits with specific purposes (e.g. C/A code for civilian use and P code for military application) |
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Trilateration |
Determining location through the measurements of ranging or diatances, using the intersection of multiple spheres projected out from a signal source. |
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How can we compensate for the ionosphere and atmosphere? |
By using physical models, dual frequency receivers and limiting satellites to those above 15 degrees |
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Multipath errors |
Errors that result from reflection and refraction of satellite signals, causing them to travel further distances |
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Dilution of Precision (DOP) |
A measure of satellite geometry, with lower values indicating better geometry and lower errors. |
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What would be an ideal satellite geometry? |
For ideal satellite geometry, the satellites must be well distributed and scattered, not closely bunched together or poorly spaced, to provide good DOP. |
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Nationwide Differential GPS System (NDGPS) |
Refers to the use of two or more receivers in order to remove ranging errors. |
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Wide Area Augmentation System (WAAS) |
Satellite-based augmentation system operated by the Federal Aviation Administration (FAA) |
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Continuously Operating Reference Station (CORS) |
A network that archives and distributes GPS data for precise positioning. |
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Global differential GPS (GDGPS) |
A high accuracy GPS augmentation system designed to support real-time positioning, timing, and orbit determination requirements of NASA. |
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International GNSS Service (IGS) |
Network designed to provide the highest quality data and products as the standard for GNSS. |
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What are the characteristics of data generated by a GPS? |
GPS units record location in latitude and longitude, and data is represented as viewing tracks, waypoints on a map require projection. |
