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WorksheetsGNSS Ground Course
Total questions: 32
Worksheet time: 16mins
Select the correct statement:
GPS is one example of a GNSS
GNSS is a different name for GPS
GNSS is the military version of GPS
GNSS is a type of GPS
GPS has the following three major segments:
GPS, GNSS and User
Airborne, Ground and User
Space, Control and User
Civil, Military and Space
The satellite segment consists of a constellation of:
At least 24 Satellites plus 1 operational spare, in 6 orbital planes
At least 24 Satellites plus 3 as operational spares, in 6 orbital planes
At least 24 Satellites including 3 operational spares, in 8 orbital planes
At least 24 Satellites including 3 operational spares, in 8 orbital planes
Every satellite transmits continuously: (select all that apply)
Using the same two L-Band frequencies as other GPS satellites
On different frequencies from other satellites
On L1 for coarse/acquisition codes (civilian) and L2 for precision ranging codes (military)
Every satellite transmission includes the following navigation message data: (select all that apply)
Satellite Ephemeris and Almanac data
System maintenance/health status
GPS time reference and clock corrections
GPS receivers can distinguish between individual satellites using:
Different frequencies for each satellite
Almanac data of the satellites position in space
Directional modulation
Identifying the pseudo-random code unique to each satellite
The function of the control segment in Colorado Springs, USA is:
To track, monitor and manage all GNSS satellites
To track, monitor and manage all GPS satellites
For military use only
For civilian use only
The User segment consists of:
An airborne receiver measuring the distance to the satellites
A two-way UHF receiver
A two-way UHF receiver
Equipment receiving, decoding and processing the GPS satellite codes and message data
In order to provide a 3D navigation solution an aircraft’s GPS receiver must have:
A minimum of four satellites in view
A minimum of five, or if barometric aiding is available four satellites in view
A minimum of two satellites in view
Three satellites in view for a three dimensional solution
Select the correct statement: (select all that apply)
Each GPS receiver contains a very accurate atomic clock
A signal transmitted from the aircraft unit triggers a return signal from the satellites
Triangulation is the basis of GPS navigation
Select all correct statements:
GPS measures distance by measuring travel time of a radio signal from the satellite to the receiver
Each satellite contains its own highly accurate atomic clock
The GPS signal is affected by the earths ionosphere and troposphere
Each satellite transmits data as to its position relative to the centre of the earth, this is called:
Selective availability
Pseudo random code
Ephemeris data
Almanac data
Almanac data provides the following information:
The same as Ephemeris data
Pseudo Random code
Position and orbit information of each satellite within the entire Nav Star constellation
Coefficient for calculating ionospheric delay and UTC
GPS satellite signals are:
High power digital transmission, not susceptible to static interference
Low power digital transmission, susceptible to static interference
High power analogue transmission, not susceptible to static interference
Low power analogue transmission, susceptible to static interference
The GPS uses triangulation to determine position:
A minimum of two satellites are required for a two dimensional fix
A minimum of three satellites are required for a three dimensional fix
A minimum of three satellites are required for a two dimensional fix
A minimum of four satellites are required for a two dimensional fix
The mathematical model of the earth which GPS uses is known as:
Satellite ranging
Worldwide geodetic system 1972 (WGS-72)
Worldwide geodetic system 1984 (WGS-84)
TSO C129
What Civil Aviation Rules contain GPS requirements?
CAR Part 91 & AC Part 91
CAR part 19 Subpart D
AIP RAC 44.1, Subpart D
TSO C-129 Class 1 and 2
For IFR flights using GPS as a primary means of navigation:
The make and model of GPS unit shall be entered in item 10 (nav equipment) of an ICAO flight plan
An ICAO flight plan is not required
“G” shall be entered in item 10 (nav equipment) on an ICAO flight plan
No special entry needs to be made on the ICAO flight plan
When must a RAIM prediction be performed?
Prior to departure for all GPS flights
During flight when a RAIM warning is displayed
Prior to departure if a GPS approach is to be conducted
Prior to commencement of a GPS approach
If a GPS approach is planned at the destination, what must be considered with regards to an alternate?
An alternate must be carried if standby power for runway lighting is not available for the GPS approach
An alternate must be carried if at time of departure a RAIM outage is predicted
If an alternate is required, a suitable GPS approach must be available at the alternate
If an alternate is required, a suitable non-GPS approach must be available at the alternate
Can GPS be used as a sole means navigation system?
Yes
No
Yes, but only within the NZ FIR
Yes, but only within the Auckland Oceanic FIR
What situation would result in a low PDOP?
Many satellites in view, situated close together
Few satellites in view, situated close together
Many satellites in view, spaced far apart
Few satellites in view, spaced far apart
What does RAIM stand for?
Receiver Automatic Identity Monitoring
Receiver Assisted Integrity Monitoring
Receiver Autonomous Identity Monitoring
Receiver Autonomous Integrity Monitoring
What is clock error and how can it be minimised?
Satellite clock is fast or slow, eliminated via corrections sent by master control station in Colorado Springs, USA
Time delays due ionospheric and tropospheric propagation. The receiver compensates for this based on satellite position
Receiver clock is fast or slow. The receiver automatically begins a trimming process until the error is minimized
Satellite and receiver clocks are slightly out of sync. Cannot be eliminated due to unavoidable factors of relativity
If a receiver’s clock is fast, will the distance of the aircraft from the satellite initially be calculated as further or closer than it actually is?
Closer
Further
The same
It depends on the position of the aircraft relative to the satellite
What is the purpose of a masking angle and what is it typically set to?
To ignore satellites in the cone of confusion directly overhead an aircraft, typically set to 7.5°
To ignore satellites low on the horizon because their signals have greater atmosphere to pass through. Typically set to 7.5°
To ignore satellites spaced too closely together. Typically set to 15°
To ignore satellites low on the horizon due to higher relativity and clock errors. Typically set to 7.5°
When might a RAIM warning be displayed?
When there is poor satellite geometry or there aren’t enough satellites in view
When the satellites in view are too low on the horizon and PDOP is too small
When the pilot has failed to obtain a RAIM prediction before departure
When the clock error or Ephemeris error has exceeded limits
What is DGPS and how does it work?
Digital GPS, works as an enhanced version of conventional analogue GPS
Digital GPS, uses a series of ground reference stations to obtain accuracy data which is uploaded to the master control station
Differential GPS, uses a series of ground reference stations to broadcast accuracy corrections to any nearby receivers
Differential GPS, uses a series of additional satellites to improve satellite geometry
What is the expected error of a GNSS system using C/A (civilian) code, with selective availability (SA) turned off?
Max error of 3-5m
Max error of 15-18m, less if SA were turned on
Max error of 1-2 NM
Max error of 15-18m. The US Government still has the option of exercising ‘selective deniability’ or the ‘jamming’ of civilian GPS use
What is the relationship between PBN, RNP and RNAV?
PBN and RNAV are types of RNP. PBN requires on-board integrity monitoring whereas RNAV does not
RNP and RNAV are types of PBN. RNAV requires on-board integrity monitoring whereas RNP does not
PBN and RNAV are types of RNP. RNAV requires on-board integrity monitoring whereas PBN does not
RNP and RNAV are types of PBN. RNP requires on-board integrity monitoring whereas RNAV does not
If an aircraft in NZ is following an RNAV 2 route, what is the tracking accuracy required?
Within 1NM either side of track 90% of the time
Within 2NM either side of track 95% of the time.
Within 1NM either side of track 95% of the time.
Within 2NM either side of track 90% of the time.
If the GPS unit loses integrity, what action must the pilot take? (select all that apply)
Notify ATC and verify position, if RAIM warning displays for more than 10 minutes
Notify ATC and verify position, if GPS operates in DR mode for more than 1 minute
Make a PAN PAN call and operate under VFR if conditions permit
