GNSS

Question 1

what does GNSS stand for

Answer 1

global navigation satellite systems

Question 2

what kind of wave does GNSS transmit

Answer 2

UHF, around 1,600MHz

Question 3

what are the components of GNSS

Answer 3

space segment
control segment
user segment

Question 4

describe space segment

Answer 4

satellite systems managed by ground

Question 5

describe control segment

Answer 5

control system

Question 6

describe user segment

Answer 6

GNSS receiver detects signals from satellites

Question 7

how many satellites are used for a position fix

Answer 7

4

Question 8

how do satellites get a position fix

Answer 8

each satellite has an atomic clock on board
GNSS receiver detects how long a satellite signal takes to reach it –> this is distance from satellite

Question 9

what is the accuracy of a position fix

Answer 9

10-30m

Question 10

what is differential GNSS

Answer 10

error correction – a ground station of fixed position transmits known error to GNSS receiver

Question 11

what is the accuracy of differential GNSS

Answer 11

5m

Question 12

what is SBAS

Answer 12

satellite based augmentation system - ICAO generic term

Question 13

true or false – all GNSS receivers are capable of picking up correction signal

Answer 13

false

Question 14

what is DOP

Answer 14

dilution of precision - position accuracy depends on satellite positions

Question 15

what is RAIM

Answer 15

receiver autonomous integrity monitoring
ensures receiver can see correct number of satellites

Question 16

how many satellites are needed for fault detection

Answer 16

5

Question 17

how many satellites are needed for fault detection and exclusion

Answer 17

6