GPS Flashcards
How many satellites orbiting earth?
24
What type of signal does it send?
Time signal
What are some similar systems launched by Russia and Europe?
GLONASS (Russia) and Galileo (Europe)
What does GPS technology provide?
Accurate location information
What does GPS rely on?
It relies on a space-based network of satellites
How is accuracy maintained?
By the control system
GPS systems (3)
- Space System
- Control system
- User system
Space system:
24 satellites, 6 orbital tracks so at least 4 satellites per track. Provides a minimum of 5 to 8 satellites anywhere on earth.
Orbit time of a satellite?
11 hours and 58 min
What do GPS receivers convert satellite signals into?
It converts it into position, velocity, and time estimates. XYZ (position, location and velocity) and time.
Control systems: What is the main purpose of control systems?
Is to maintain and update satellites
What is selective availability?
is a system the government can use to degrade public accuracy.
What are the 2 signals produced by the control systems?
SPS: Standard positioning service
and
PPS: Precise positioning service.
User System:
Consists of GPS signal receivers.
How can you improve accuracy?
Removal of selective availability and the use of different GPS receivers.
What signal can consumer receivers not receive.
Consumer receivers cannot detect PPS.
What is the equation the satellites use?
Trilateration
What are some sources of errors of GPS?
- Atmosphere/ionosphere
- Atomic clock deviation on SV’s (small)
- Non-direct signal path between SV and receiver
- Receiver math
- Geometry
- Blocked line of sight (buildings)
Geo-reference:
The act of coordinating collective data to a common global reference, other related topics included Geo-coding and address matching.
Geographic Information Science:
The science related to examining and studying the technology associated with collecting, storing and processing spatial data. Research expands the technology.
Geographic Information Studies:
Studies related to the societial cobntect of geographic information systems.
Geographic information system?
The integrated hardware and software to collect, store and process spatial data.