5 PNT

Question 1

GNSS refers to what?

Answer 1

Satellite constellations that provide signals from space that transmit positioning and timing data to GNSS receivers in the ground.

Question 2

How many fully operationally capable GNSS constellations are there?

Answer 2

4

Question 3

What are the 4 operational GNSS constellations, and who operates them?

Answer 3

GPS - USA
GLONASS - Russia
Galileo - EU
BeiDou - China

Question 4

What are the name of the 2 regional GNSS constellations?

Answer 4

Navigation Indian Constellation (NavIC) - India

Quasi-Zenith Satellite System (QZSS) - Japan

Question 5

What are the main errors affecting GNSS signals?

Answer 5

Satellite clock errors
Ephimeris errors
Ionospheric time delay

Question 6

What are the 2 systems that correct for errors in GNSS constellations?

Answer 6

GBAS - Ground-based augmentation system

SBAS - Satellite-based augmentation system

Question 7

What is GPS’s three main missions?

Answer 7

Navigation
Timing transfer
Nuclear detonation detection

Question 8

GPS consists of what and how many segments?

Answer 8

3 segments

Space segment
Control segment
User segment

Question 9

What unit is ensures effective delivery of GPS?

Answer 9

2nd Space Operations Squadron (2SOPS)

Question 10

What is the purpose of GPS monitoring sites?

Answer 10

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.

Question 11

What datum does GPS use?

Answer 11

World Geodetic System (WGS) 84

Question 12

What orbit are GPS satellites in?

Answer 12

MEO

Question 13

How many GPS satellites are there?

Answer 13

30

Question 14

What is the US’s commitment with the number and availability of GPS satellites?

Answer 14

At least 24 operational satellites

95% of the time

Question 15

What are the 3 missions of GPS?

Answer 15

Navigation

Time transfer

Nuclear detonation detection

Question 16

What 2 services does GPS provide?

Answer 16

Standard Position Service (SPS) - broadcasts C/A code on L1

Precise Position Service (PPS) - broadcasts P/Y code on L1 and L2

Question 17

What is the greatest source of errors in from GNSS?

Answer 17

Ionospheric Delays

Question 18

Describe the role of the GPS monitoring station

Answer 18

Track satellites as they pass overhead.

Collect navigation signals, range/carrier measurements and atmospheric data.

Feed this back to the Master Control Station.

Question 19

Describe the roles of the Master Control Station

Answer 19

• Provide C2
• Compute precise location of satellites
• Generate navigation message
• Monitor satellite broadcast to ensure health and accuracy
• Perform satellite maintenance and anomaly resolution

Question 20

Describe the role of the GPS ground antenna

Answer 20

• Send commands, navigation date uploads and processor program uploads.
• Collect telemetry.
• S-band ranging to provide anomaly resolution and early orbit support.

Question 21

What 3 codes are available to GPS?

Answer 21

C/A
P(Y)
M

Question 22

Name the benefits that M-Code offers

Answer 22

Jamming resistance
Blue Force electronic attack compatibility
Anti-spoof