Test 4 Flashcards
True or False: In order to calculate three-dimensional, vertical position (x,y,z), three GNSS satellites are needed.
False, FOUR GNSS satellites are needed.
True or False: The first GPS satellite launch in 1978, while the full constellation was achieved in 1994.
TRUE
Match the following terms with a correct example of each:
Observation
Triangulation
Trilateration
GPS
Map and Compass
Landmarks
Observation -> Landmarks
Triangulation -> Map and Compass
Trilateration -> GPS
Which of the following locations calculates an unknown position using a previous known position and is used by animals and humans.
Landmarks
Celestial Naviagation
Dead Reckoning
Dead Reckoning calculates an unknown position using a previous known position and is used by animals and humans.
Place the following steps of using triangulation to identify your location in the correct order:
- Repeat process for landmarks 2 and 3 Your position is at the intersection of the three lines
- Sight a field bearing to landmark 1 and transfer bearing line to map
- Align map and compass to north
- Find three landmarks in field and label them 1, 2, 3 on map
- Align map and compass to north
- Find three landmarks in field and label them 1, 2, 3 on map
- Sight a field bearing to landmark 1 and transfer bearing line to map
- Repeat process for landmarks 2 and 3 5. Your position is at the intersection of the three lines
Match the following elements of a GPS position with the correct definition.
Position status
Height Above Ellipsoid (HAE)
Position Averaging
Streaming Position
Position status -> 2D, 3D, differential, etc.
Height Above Ellipsoid (HAE) -> Altitude expressed as height above datum
Position Averaging -> Positions averaged into a single point
Streaming Position -> Logged when moving
An element of a GPS position altitude expressed as height above datum
height above ellipsoid
Elements of a GPS position:
Positions averaged into a single point is called what?
Position averaging
Elements of a GPS position
What does streaming position do?
Logged when moving
Which of the following is NOT an error that degrades the accuracy of a GPS location?
Position Error (PE)
Elevation Mask Altitude
Dilution of Precision (DOP)
Signal to Noise Ratio (SNR)
Elevation Mask Altitude
A ___________ GPS is a correction message transmitted to GPS receivers to account for error.
differential
A ___________ GPS is a correction message transmitted to GPS receivers to account for error.
Name one example of a Satellite Based Augmentation System (SBAS) , or correction computed from base stations and uploaded to geostationary satellites.
WAAS
EGNOS
GAGAN
MSAS
SDCM
T or F In order to collect sub-meter accuracy horizontal coordinates using a GPS receiver, you would need to spend extra money on a Mapping-Grade GPS, not just use a Recreational-Grade GPS.
False -
The Validation step occurs in the ____ stage of the Field Data Workflow
Assimilation
Any field data you collect should be validated on a ___ basis
daily This ensures that you identify any issues in your data schema, collection workflow, or data collected at the beginning of the project, rather than then end.