5 PNT Flashcards
GNSS refers to what?
Satellite constellations that provide signals from space that transmit positioning and timing data to GNSS receivers in the ground.
How many fully operationally capable GNSS constellations are there?
4
What are the 4 operational GNSS constellations, and who operates them?
GPS - USA
GLONASS - Russia
Galileo - EU
BeiDou - China
What are the name of the 2 regional GNSS constellations?
Navigation Indian Constellation (NavIC) - India
Quasi-Zenith Satellite System (QZSS) - Japan
What are the main errors affecting GNSS signals?
Satellite clock errors
Ephimeris errors
Ionospheric time delay
What are the 2 systems that correct for errors in GNSS constellations?
GBAS - Ground-based augmentation system
SBAS - Satellite-based augmentation system
What is GPS’s three main missions?
Navigation
Timing transfer
Nuclear detonation detection
GPS consists of what and how many segments?
3 segments
Space segment
Control segment
User segment
What unit is ensures effective delivery of GPS?
2nd Space Operations Squadron (2SOPS)
What is the purpose of GPS monitoring sites?
Track the GPS satellites as they pass overhead and collect navigation signals, range/carrier measurements and atmospheric data.
Then pass this to the Master Control Station.
What datum does GPS use?
World Geodetic System (WGS) 84
What orbit are GPS satellites in?
MEO
How many GPS satellites are there?
30
What is the US’s commitment with the number and availability of GPS satellites?
At least 24 operational satellites
95% of the time
What are the 3 missions of GPS?
Navigation
Time transfer
Nuclear detonation detection
What 2 services does GPS provide?
Standard Position Service (SPS) - broadcasts C/A code on L1
Precise Position Service (PPS) - broadcasts P/Y code on L1 and L2
What is the greatest source of errors in from GNSS?
Ionospheric Delays
Describe the role of the GPS monitoring station
Track satellites as they pass overhead.
Collect navigation signals, range/carrier measurements and atmospheric data.
Feed this back to the Master Control Station.
Describe the roles of the Master Control Station
- Provide C2
- Compute precise location of satellites
- Generate navigation message
- Monitor satellite broadcast to ensure health and accuracy
- Perform satellite maintenance and anomaly resolution
Describe the role of the GPS ground antenna
- Send commands, navigation date uploads and processor program uploads.
- Collect telemetry.
- S-band ranging to provide anomaly resolution and early orbit support.
What 3 codes are available to GPS?
C/A
P(Y)
M
Name the benefits that M-Code offers
Jamming resistance
Blue Force electronic attack compatibility
Anti-spoof
