問題一覧
1
What is the contributing source for Error Range of ±0.5 m?
Tropospheric Delays
2
What is the contributing source for Error Range of ±5 m?
Ionospheric delays
3
What is the term used for approximation distance between satellite and a GNSS receiver?
Pseudorange
4
How much error range does Receiver * Noise have?
+ 0.3 m
5
What is the inclination angle of GLONASS satellite system?
64.8 degrees
6
What is the meaning of NAVSTAR in GNSS satellite system?
Navigation System using Time and Ranging
7
How many satellite and spares does * GPS satellite system have?
24 Satellites + Spares
8
It is a term used for measuring the distance not angles.
Triangulation
9
In what year does GPS was initially launched for military use, but opened up to civilian use?
1983
10
GPS works through a technique called
trilateration
11
At what speed does GPS satellite travels above the Earth?
8,700 mph
12
In what year does GLONASS satellite system declared fully operational?
1970
13
On what specific date that BeiDou Navigation Satellite System started providing global services?
December 27, 2018
14
What is the meaning of MEO in GNSS?
Medium Earth Orbit
15
What is the accuracy of NAVIC satellite system?
3 m (public); 2 m (encrypted)
16
What is the term used for the point of the orbit closest to Earth?
perigee
17
It is a way of radio signals are transmitted from one point to another inside the Earth's atmosphere or free space.
propagation
18
How much is the altitude of GALILEO satellite system?
23,616km
19
What satellite system provides global search and rescue function?
Galileo
20
What is the meaning of GEO in GNSS?
Geosynchronous Equatorial Orbit
21
Master Station adjust the satellite's orbit parameters and on-board high precision clocks when necessary to maintain accuracy.
True
22
Ground antenna uploads any changes in satellite status back to the satellites.
True
23
nanosecond is equal to 30 cm.
True
24
microsecond is equal * to 10,000 nanoseconds.
False
25
L1C "Fourth Civilian GPS Signal" has a bandwidth of 1575.45 MHz.
False
26
Who develop echo sounder?
Alexander Behm
27
What year Echo sounder develop?
1913
28
Sonar originally an acronym for?
Sound Navigation And Ranging
29
type of Echo sounder
single beam echo-sounder multi-beam echo-sounder chart recording echo sounder electronic echo sounder
30
record depth on a specially treated paper held between 2 rollers moving at a uniform speed over a grounded plate.
chart recording echo sounder
31
used to build up an image of a large area of the sea bed.
multi-beam echo-sounder -
32
measuring the depth to the ocean floor directly underneath the ship.
single beam echo-sounder
33
it uses digital methods in measuring time delay of return pulses and a digital analogue display
electronic echo sounder
34
Consists of GNSS satellites, orbiting about 20,000 km above the earth. Each GNSS has its own constellation of satellites
Space Segment
35
The control segment comprises of a ground-based network of master control stations, data uploading stations, and monitor stations.
Control Segment
36
adjust the satellites' orbit parameters and on-board high-precision clocks when necessary to maintain
Master control stations
37
monitor the satellites' signal and status, and relay this information to the master control station
Monitor stations
38
uploads any change in satellite status back to the satellites
Uploading stations/Ground Antennas
39
User segment consists of GNSS antennas and receivers used to determine information such as position, velocity, and time
User Segment
40
Receivers need at least 4 satellites to obtain a position. If more are available, these additional observations can be used to improve the position solution GNSS signals are modulated by a unique pseudorandom digital sequence, or code. Each satellite uses a different pseudorandom code Receivers know the pseudorandom code for each satellite. This allows receivers to correlate (synchronize) with the GNSS signal to a particular satellite
Reception
41
how many satellite to give us position in gps?
need at least 4 satellites to obtain a position
42
To determine accurate positions, we need to know the range to the satellite. This is the direct path distance from the satellite to the user equipment The signal will "bend" when traveling through the earth's atmosphere. This "bending" increases the amount of time the signal takes to travel from the satellite to the receiver. Since the computed range contains errors and is not exactly equal to the actual range, we refer to it as a "pseudorange"
Propagation
43
A DGPS for GPS can increase accuracy by about a thousandfold, from approximately?
15 meters (49 ft) to 1-3 centimeters
44
Dgps
differential global positioning system
45
The point in the moon's orbit where it is farthest from the earth is called
apogee