Unit 2 Flashcards
What does the Doppler system measure
Ground speed and drift
This is known as the transmitted energy that undergoes a perceived shift and frequency as the distance between the source and observer changes
Doppler effect theory
When transmitter or receiver is in motion
Single Doppler shift
When both transmitter and receiver are in motion. This is used in aircraft
Double Doppler shift
How many antenna(s) does the Doppler system have
single antenna
How many forward beams and rear beams are there
Two forward beams (positive)
Two rear beams (negative)
If there is an increase in groundspeed what will happen to the forward and rear beams
Increase in positive shift in forward beams and increase in negative shifting rear beams
If there is a decrease in groundspeed what will happen to the forward beams and rear beams
Decrease in positive shift in the forward beams and decrease in negative shift in the rear beams
What affects groundspeed
Headwinds/tailwinds
What affects drift angle
Crosswinds
What navigation system do we use for Doppler
APN–218 Doppler navigation system
At what speed does the APN – 218 lock on
96 knotts
What is the maximum altitude of the APN– 218
70,000 feet
What is the transmit frequency of the APN – 218
 13.325 +/- 0.015 GHz
What LRU controls DVS functions and displays current ground speed and drift angle information. Also has the land/sea switch
Ground speed drift indicator GSDI
What LRU contains the receiver/transmitter, the antenna, all DVS related component circuitry and a dehydrator
Doppler velocity sensor DVS
What calculates three unstable aircraft reference velocities
DVS
What are the three external connectors on the DVS and what are they for
J1 - Aircraft wiring
J2 - Backshop
J3 - Program plug/cap
What are the three unstable A/C velocities calculated by the DVS
Vva, Vha, Vda
What develops velocities into earth-referenced stabilized velocities
External navigation computer
What do the unstable aircraft reference velocities convert to
Vv, Vh, Vd
What uses information from Doppler radar antenna in the direction of the actual track of the aircraft
Radar System
What uses information supplied by Doppler to determine the actual track of the aircraft and make corrections to the flight path
Autopilot
How does the Doppler system communicate with other systems
1553B Data Bus and ARINC 429
