Nav Final Flashcards
aim of basic phase
introduce to ct-142
intro to flight ops & multicrew environment
develop nav and comms call
what is INS
inertial navigation system: a navigation aid that uses a computer and accelerometers to continously calculate via DR the position, orientation and velocity of a moving object w/o external references
generic INS components
accelerometers
computers
cdu
stable platform
advantages of INS (6)
self-contained undetectable unjammable all wx worlwide ops accurate px and very accurate altittude
how INS calculates positions
acceleration = velocity -> velocity = distance
mechanical INS
free moving stable platform that uses gymbals and gyros to maintain a level reference for the accelerometers to sense movement
strapdown INS
all modern INS’s mounted to the a/c frame. the level reference is calculated by computers
advantages of a strapdown system (reduces):
weight/hardware
power consumption
maintenance
cost
advantages of a strapdown system (increases):
reliability
service life
what is an accelerometer
a basic device for measuring accelerations
desired characteristics of an accelerometer (4)
low threshold of sensitivity
wide range of sensitivity
linear output
high resolution
basic part of stable platform (5)
gyros gimbals ac servo motors or DC torque motors resolvers synchros
parts of a simple gyro (3)
rotor
spin axis
gimbal
properties of a gyro
rigidity
precession
two types of precessions
real
apparent
what is the RLG in CT-142
honeywell
what are the parts of the honeywell (7)
cervit block mirrors prism cathode anode inert gas photo cells
how does the honeywell work
uses angular rates of motion (phase difference)
2 types of errors of the RLG
lock in (caused by non-perfect optics = back scatterint) differential path length (Tc diff between cervit caveties)
what is the fix for back scattering
dithering
what are the main advantages to integration/hybridization
improved accuracy
better chance of mission completion
what are the main disadvantages of integration/hybridization
loss of self-containment
loss of covertness
define leveling
no component of gravity sensed by x and y accelerometers
what is azimuth alignment
alignment of the azimuth sensitive axis to True North
what are the 10 initial conditions
2 initial px coordinates (lat/long)
2 inital velocities
3 initial orientations
3 orientation rates
what are the types of alignment (4)
self-alignment (most popular)
reference alignment
moving allignment
in-flight alignment
what is the self-alignment sequence (6)
initialization warm-up coarse leveling coarse alignenment fine leveling fine alignment
what are high latitude alignement problems
undetectable tilt preventing initiation of gyro compassing
inability to accurately resolve True North
types of alignment errors (2)
unbounded: leveling gryo drift, azimuth gyro drift, inital azimuth misalignment
bounded: inital levelling, accelerometers, velocity errors
what is schuler theory
tilt error that tries to self-correct but then applies real gravity in the process. takes 84.4min for the cycle to repeat itself
what are the two components of the honeywell IRS
IRU inertial reference system
MSU mode selector unit
what is contained in the IRU (4)
inertial sensor assembly
microprocessors
power supply
a/c electronic interfaces
What does the MSU provide (3)
inertial mode selection
status indication
remote test initiation
what are the modes of operation of the IRS (4)
off
align
nav
attitude
what is provided to the FMS from the NAV mode of the IRS (8)
a/c altitude body rates body acceleration true heading velocity vectors wind data lat/long inertial altitude
what are the alignment requirements of the IRS
enter present px via FMS
IRU conducts reasonability test of new px
if the new px is >1° of stored value = test fail
entering identical coords twice will override
what does the IRU feed to ATS (6)
true heading true track present lat/long inertial g/s wind velocity & direction system status
what is the system that is most prone to failure during IRS initialization and alignment sequence
emulated INS
how many waypoints can be entered
20
what are the controls and display of the INS
nav sensor selection panel
emulated INS control panel
INS DID display
what is the principle of GPS
measures ranges between receiver and satellites
what are the 2 types of apparent precession
earth rate
transport wander
what are unique capabilities of the GPS
3D velocity and time global coverage continous passive unlimited resistant allows common grid reference (3 very gross children pucked up red ants)
what are the 3 parts of the GPS system
space segment
control segment
user segment
what are the components of the user segment of the GPS
Antenna Computer Signal processing equipment oscillator (ACSO)
what are the 2 navigation services
sps (standard positioning service)
pps (precise positioning service)
what are 3 types of GPS receivers
sequencial
multiplex
continous
what are the type of codes for the GPS
c/a codes (37)
p code
y codes (p codes encrypted)
what are the operating frequencies of L1 and L2
- 42
1227. 6
what is pseudo ranging
3d position could be established with 3 satellites but due to inherent clock errors in the satellite, we need a 4th to resolve px using pseudo ranging
what is contained in nav msg from GPS (5)
clock correction ephemeris data ephemeris data gps NOTAMs Almanac/health status
what are the components of the FMS (7)
2 x CDUs 1 x DTU 2 x ACU 2 x Glareshield Advisorie 2 x GPS antennas config module
what are the FMS inputs (5)
AHRS DADC IRU DTU GPS
what are the FMS outputs (4)
flight instruments
FGC
IRU
DTU
what is the kalman filter
it blends the 2 GPS positions with the IRU in a satistical model to determine the best position
what is in the FMS database
VORs Approaches & Rwy info NDBs En-route intersections SIDs STARS Airports with >4000' hard sfc rwy
what is the GPS process
satellite selection
searching the sky
satellite acquisition
what are two types GPS errors
User Radial Error
Dilution of Precision
what does LAAS and WAAS stand for and what do they do
local area augmentation system
wide area augmentation system
used to eliminate GPS errors
how many waypoints can be stored in the emulated GPS
20
what are the emulated GPS inputs (aircraft gps to emulated) (8)
gps position time satellite info system status altitude g/s ground track TAS
what are the GPS outputs (emulated to user interface) (6)
position & time satellite info altitude ground track g/s TAS
what is the TDS
tactical display system
a visual aid presents user specified information on display system to enhance situational and tactical awareness
what can be displayed on TDS
fly to points contacts reference marks vectors SAR patterns free form graphics range circles
3 sources of the TDS
GPS
INS
DR
what are the functions of the TDS
FTP reference marks lines (fixed vectors) lines (normal vectors) circles radar circle SAR patterns
what are the components of an ADF
adf receiver
antenna
RMI
what are the nav aids that use ADF
NDBs
what is the accuracy of the ADF
±3 degree
what is the range of the ADF
200nm (200kHz)- 50nm (1600kHz) and decreases at night
what is the ADF on the dh8 and what are its components
king 806 ARL radio compass receiver CDU antennas bearing indicators
what are the operating limits of the King 806
190.0 - 1799.0 kHz
what is a VOR
VHF omni directional range
accepted accuracy limitations of the VOR
±2.5 degrees
characteristics of the VOR
affected by echos from hills and bldgs
80° cone of confusion
LOS
capabilites of a TACAN
LOS max 252 users cone of confusion 60° - 110° accuracy ±0.75° 1m slant range
what is the TACAN in dh8
King 709 TACAN
in the second avionics rack
What is an EPL
a line along which the A/C was known to have been at a particular time
what are 3 sources of position line
visual
electronic
celestial
what are the types of EPL
straight
curved
what are the advantages of fuel management
increase safety and efficiency
conservation fuel on ferry flight
optimize payload
saving on fuel in long rage tactical flights
efficiency fuel conservation on a long range flight when max range is required
controls maybe adjusted in flight
what is the definition of cruise control
organized control of A/C in flight to obtain max flight profile efficiency
factors that affect fuel management
en-route weather w/c T°c fuel capacity fuel availability amount of fuel reserve req'd max T/O and Min landing weight payload distance ATC restriction
what is endurance
a specific speed and altitude to achieve the lowest FF -> max time A/B
what is range
specific speed and altitude to achieve max ground range/lb fuel
what is the specific fuel consumption
ratio of fuel used to the amount of thrust produced
Ff/ESHP
why do we manage fuel
ensure enough fuel for mission
detect early fuel leaks
check if fuel consumption matches predicted
be aware of fuel in case of diversion or re-task
what is specific Air Range
measure of efficiency with which an a/c flies through the air SAR=TAS/FF
what is Specific Ground range
mesaur of efficiency with which an a/c flies over the ground SGR= G/S / FF
what factors causes change in planned fuel burn
ISA wind wx avoidance a/c not to spec fuel leak ATC rerouting
what is a radius of action
max ground distance that an a/c can fly from a start point and back to that start point in a specific time. Time out/time back = g/s back / g/s out
what is the point of safe return
a point beyond which an a/c cannot fly and return to it’s own or same place withing a safe limit of endurance. SLE = total endurance - 1500lbs
PSR = (SLE)G/S home / G/S out + G/S home
what is an ETP
a point on the intended track from which it will take the same amount time to fly to either critical point A/D
what are the deisred properties of a map
orthomorphic
conformal
sufficient details
what are the different types of map projections
cylindrical, conical and azymuthal
what are the most common projections used for topographical maps in the CF
lambert conformal
transverse mercator
what are the four ways to integrate INS
ground reference system in which a ground based flying system is intergrated with the INS
GPS
Dopple
Celestial
what is the electrical requirement of the IRU
receives AC and DC power from the a/c 115v AC or 28v DC
what are the four ways to integrate INS
ground reference system in which a ground based flying system is intergrated with the INS
GPS
Dopple
Celestial
what is the electrical requirement of the IRU
receives AC and DC power from the a/c 115v AC or 28v DC
What are characteristics of a Mercator projection
Great circles - curved Rhumb lines - straight Angle - correct Shape - correct Scale - correct and constant Size - correct
What is magnetic dip
Angle between the local horizon and total magnetic field
What is magnetic meridian
Direction of the horizontal component of the earth’s mag field at a point
What is variation
Horizontal angle between true and mag north
