GPS/RNAV Systems Flashcards

1
Q

Give a BRIEF explanation about how the GPS system works generally (Segments, Basic function, RAIM/WAAS)

A

3 Segments:
Space - Satellites
Control - Ground Stations
User - GPS receivers

Satellites TRILATERATE your location using accurate ATOMIC CLOCKS to measure the time it takes for a signal to move between it and the receiver

RAIM - Monitors signal integrity
WAAS - eliminates any major ATOMIC CLOCK ERROR via ground stations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

If your GPS is only RAIM capable, what considerations need to be taken concerning the choice of alternate airport filed?

A

Either your Destination or your Alternate must have a ground based approach available

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does having a WAAS capable GPS enable us to do concerning the choice of alternate airport filed?

A

Having a WAAS capable GPS enables us to choose an Alternate Airport that ONLY has an RNAV IAP available.

*This is because WAAS enables us to use GPS as our primary means of navigation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain the WAAS system and how it functions.

A

38 Ground Reference Stations

3 Master stations - Correct for atomic clock error

6 Uplink stations

3 Geostationary Sats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many Satellites are needed for RAIM to function properly?

A
  • 5 Sats
  • 4 Sats, if you have Barometric Aiding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many Satellites are needed for RAIM to be able to isolate a corrupted signal?

A

6 Sats

  • 5 Sats, If you have Barometric Aiding

*This is the Exclusion element in ‘Fault detection and exlusion’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Does our aircraft have DME?

A

No, we have GPS in lieu of DME

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

On a GPS approach, what are the following CDI sensitivity changes:
- Enroute
- Terminal
- Approach

A

Enroute
+- 2 NM (with RAIM, 5nm without)

Terminal
+- 1 NM, within 30 NM of the airport

Approach
+- 0.3 NM, when within 2 NM of the FAF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens when Approach Mode is NOT armed prior to at least 2 NM from the FAF? (3 things)

A
  1. Approach Mode will not automatically activate
  2. Sensitivity will not drop to Terminal levels of +- 0.3 NM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many Satellites are required for the following GPS dimensions:
- 2D location
- 3D location
- RAIM
- RAIM + Exclusion

A

2D = 3
3D = 4
RAIM = 5 + Baro-Aiding (6 without BA), 6 Sats for Exclusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which is WAAS and which is RAIM only?

TSO 129/196
TSO 145/146

A

TSO 129/196 = Non-WAAS (RAIM only)

TSO 145/146 = WAAS equipped GPS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Explain how RNAV CDI sensitivity changes as we leave the Enroute environment

A

Enroute (ENR) = +- 2NM with WAAS (RAIM = 5NM)

Terminal (TRM) = +- 1NM when within 30NM from the airport

Approach (APP) = +- 0.3 NM within 2NM of the FAF with RAIM only, WAAS will continue scaling down starting AT the FAF to +- 700ft for LPV approaches

Missed Approach = +- 1NM once you pass the MAP and activate the missed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is required to fly an LPV approach?

A

You MUST be WAAS equipped
- Baro-Aiding or RAIM are not enough to fly LPV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is required to fly an LNAV/VNAV approach?

A

WAAS or a Baro-Aided GPS
- RAIM only is not enough to fly LNAV/VNAV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What enables the GPS to go down to the 350ft (700ft total width) full deflection accuracy in the approach environment?

A

WAAS.
- This enables us to perform ILS ‘like’ LPV approaches
- Without WAAS, the accuracy will not step down, and we cannot fly down to LPV mins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is required to fly an LP approach?

A

You MUST have WAAS in order to fly an LPV approach
- RAIM (basic IFR GPS) or Baro-Aiding is not enough to fly an LP approach.

17
Q

Are we able to fly approaches with ‘(RNP)’ in the title?

A

No,
- Requires a letter of authorization from the FAA and special equipment/training to fly.
- They are similar to CAT II & III ILS approaches

18
Q

What should you do if you encounter a RAIM failure while on an RNAV approach?

A
  1. Go missed
  2. Report to failure to ATC (required)
  3. Switch to Ground based navaids
19
Q

How will you know if your WAAS or RAIM issues a failure?

A

You will see a yellow ‘LOI’ (Loss of Integrity) annunciation appear on the HSI.

20
Q

What happens at 2 NM from the FAF in regards to GPS integrity?

A

The GPS will perform a RAIM prediction and notify you with ‘LOI’ if there are any issues with the GPS

21
Q

How do you know your aircraft is IFR certified to perform LPV approaches?

A

The G1000 Supplement to the AFM states that our aircraft is TSO-146 and approved for GPS approaches

22
Q

How does ADS-B work?

A
  1. Satellites communicate with the aircraft to determine position
  2. ADS-B OUT sends that GPS derived information to ground stations
  3. Ground stations send the location information to ATC and aircraft with ADS-B IN
23
Q

How often does ADS-B GPS information update a location position?

A

About once per second

24
Q

What does TIS-B add to ADS-B?

A

Traffic Information Service Broadcast (TIS-B) completes the ADS-B IN traffic display picture by adding aircraft equipped with a Transponder only, and not ADS-B OUT.