GPS/PNT

Question 1

Positioning

Answer 1

Precise positioning. Important for GPS guided munitions

Question 2

Nuclear Detonation Detection (NUDET)

Answer 2

Detection of nuclear detonation

Question 3

Time Transfer

Answer 3

Provides highly accurate timing information for synchornoization

Question 4

Space Segment and Limitations

Answer 4

31 Satellites operational, 41 Satellites on-orbit, need 24, dependent on ground stations and susceptible to jamming, possible errors (ionospheric effects, multi-pathing)

Question 5

Control Segment

Answer 5

Ground antenna, Master Control Station, Satellite TT&c, Monitor Station

Question 6

User Segment

Answer 6

Primary are Military Personnel

Question 7

Vulnerabilities

Answer 7

Susceptible to jamming. Factors – Distance, weak signal, ease of jammer construction, omni-directional antennas, frequencies well known, most military receivers need C/A before access to P(Y).

Question 8

Trilateration

Answer 8

With 3 satellites you still have 2 possible locations.
b) 4 satellites are required to acquire a fixed location on earth including timing.

Question 9

Errors of Probability

Answer 9

Circular Error Probable (CEP) – horizontal or lat/long distribution, Spherical Error Probable (SEP) – 3-dimensional distribution

Question 10

Dilution of Precision (DOP)

Answer 10

Good DOP ➔ results when the angles from the satellites are large.

DOP is typically worse in mountainous or urban terrain because you’re reliant on overhead satellites. (1-6 on GIANT)

Question 11

Which is the code acquisition code?

Answer 11

C/A, transmitted on L1 (civilian), 1575

Question 12

Which is the Precision code?

Answer 12

P(Y), Encrypted, Transmitted on L1 and L2 (military M-Code), 1227

Question 13

Which band contains both C/A and P(Y) codes?

Answer 13

L1 because L2 only carries the P(Y) code (direct acquisition)

Question 14

What is Flex Power?

Answer 14

Flex Power is provided on the M-code subsystem on a GPS satellite for enhanced performance.

Question 15

Which are the additional L bands?

Answer 15

L1C: First launched on GPS III Satellites.
L2C: Civilian signal designed for commercial sector.
L3: NUDET
L4: Ionospheric correction
L5: Designed for transportation/aviation safety services.

Question 16

GPS Tactics, Techniques, and Procedures (TTPs)

Answer 16

Jamming Mitigation – Turn on and Encrypt your DAGR before you SP/LD > Ensure the Joint Restricted Frequency List (JRFL) is adhered to >Block interfering signals >Move out of jamming environment.