EO-7(2)

Question 1

Why classify radars and signals by function?

Answer 1

Can help sorting through numerous signals to determine if weapons systems are present, allows a platform to preform in different ways based on the environment

Question 2

Identify some examples of “Search Radar” systems:

Answer 2

Early Warning (EW), Height Finder (HF), Surface Search (SS), Navigation (NA), Range Instrumentation (RI), Meteorological Radar (ME), Over-the-Horizon Radar, Synthetic Array (Aperture) Radar (SAR)

Question 3

Identify some examples of “Threat Radar” functions:

Answer 3

Target Acquisition (TA), Target Tracking (TT), Fire Control (FC), Airborne Intercept (AI), Anti-Aircraft Artillery (AA), Multi Function (MF), Missile Guidance (MG)

Question 4

Does early warning detect targets at a close distance or far away?

Answer 4

As far away as possible

Question 5

What system typically uses large PDs and circular scans? (can be air, land, or ship borne platforms)

Answer 5

early warning (EW)

Question 6

what radar is designed to determine altitude of an airborne target

Answer 6

height finder

Question 7

height finders are usually co located with what radar?

Answer 7

EW

Question 8

Surface Search (SS)

Answer 8

Short range system that provides tracking data on ships for coastal defense or vessel movement control.

Question 9

what radar group does harbor search (HS) and coastal search (CS) fall under?

Answer 9

surface search (SS)

Question 10

Primarily used to prevent collisions

Answer 10

navigation (NA)

Question 11

provide terrain surveillance by detecting and identifying targets like tanks, trucks, and people.

Answer 11

Battle field surveillance (BS)

Question 12

Battle field surveillance (BS)

Answer 12

Tend to be low power, man portable systems. larger ones can be mounted on vehicles or aircraft.

Question 13

Acquires and automatically tracks airborne targets to provide trajectory information on objects of interest

Answer 13

range Instrumentation (RI)

Question 14

used to locate precipitation, calculate motion, and estimate its type. (snow, rain ect) (Most use pulsed doppler radars)

Answer 14

meteorological radar (ME)

Question 15

what causes the limitation of line of sight for most radars

Answer 15

the curvature of the earth

Question 16

type of radar used to detect and track targets from beyond the horizon

Answer 16

over the horizon radar (OTH)

Question 17

What are the 2 types of OTH radars?

Answer 17

Sky wave and ground wave systems

Question 18

Explain skywave systems

Answer 18

Uses certain angles and certain RFs (usually 3-30 MHz) to “bounce” radio waves off the ionosphere and back to Earth to targets beyond the horizon.

Question 19

What factors affect the changing ionic densities?

Answer 19

Time of day, time of year, solar activity, weather

Question 20

Explain ground wave

Answer 20

Uses lower frequencies (below 3MHz), uses atmospheric layers as a waveguide “ducting”

Question 21

Explain synthetic array (aperture) radar (SAR)

Answer 21

transmits pulses, adds the returned pulses together to get larger “picture”

Question 22

Which radar does terrain imaging, and ground mapping?

Answer 22

Synthetic Array (Aperture) Radar (SAR)

Question 23

used upon initial detection of a target to refine angle and range measurements

Answer 23

Target acquisition (TA)

Question 24

Used to maintain the location of a target by constantly calculating the targets range, angle, and velocity

Answer 24

Target Tracking (TT)

Question 25

Explain Fire Control (FC)

Answer 25

designed specifically to provide info about a target to a fire control system in order for how to direct weapons to hit the target (identifies target's azimuth, elevation, range, velocity)

Question 26

What is a radar with an air to air role, typically housed in the aircraft's nose cone?

Answer 26

Airborne intercept (AI)

Question 27

Anti-Aircraft Artillery (AA)

Answer 27

used to determine adversary aircrafts angle, and range and projected path to be transmitted to a computer and used to direct weapons to the target

Question 28

Multi Function (MF)

Answer 28

used to perform multiple tasks, can perform different functions. ex. target detection, acquisition, tracking, warheads vs. decoys (sometimes called MPARs)

Question 29

What does MPAR stand for?

Answer 29

Multi-function Phased Array Radar

Question 30

Missile-Guidance Radar (MG)

Answer 30

Used to provide missile guidance and course correction to a missile as it moves toward its target

Question 31

What is a missile?

Answer 31

Self-propelled guided weapon system.

Question 32

Name the main missile system components:

Answer 32

Targeting/guidance, flight system, engine, warhead

Question 33

What are the 3 categories for missile guidance?

Answer 33

homing, beam riding, and command guidance

Question 34

What are the 3 homing guidance types?

Answer 34

active, semi active, and passive

Question 35

What is it when a homing missile contains a radar transceiver. and has the ability to find and track a target autonomously?

Answer 35

active homing

Question 36

What is the main benefit of an active homing missile?

Answer 36

The fire and forget capability

Question 37

What is the main disadvantages of an active homing missile?

Answer 37

Equipment must be small, it's expensive, and is only able to work at relatively short ranges.

Question 38

only has a reciever in the nose come of the missile, which passively detects a radar signal from an external source.

Answer 38

semi-active homing

Question 39

A semi-active homing missile is an example of what kind of radar system?

Answer 39

A bistatic CW radar system

Question 40

Describe the advantage of a semi-active homing missile.

Answer 40

It is not weighed down by a transmitter and, therefore, has greater reach.

Question 41

Describe the disadvantages of a semi-active homing missile.

Answer 41

The target must be "illuminated" during the entire flight, leaving the launch aircraft vulnerable to counter-attack.

Question 42

missile guides itself based on emissions from the target itself instead of reflections from the radar

Answer 42

passive homing

Question 43

Name an example of a passive homing missile.

Answer 43

Infrared homing (i.e. heat seeking)

Question 44

what are the two missile remote guidance types

Answer 44

beam riding and command

Question 45

What is the simplest method of missile guidance?

Answer 45

beam riding

Question 46

a transmit antenna on the ground points a beam at the target. the missile adjusts itself to keep in the center of the beam

Answer 46

beam riding

Question 47

one radar is used to track the target another is used to track the missile

Answer 47

command

Question 48

Command guided missiles can receive what 3 types of information?

Answer 48

1. missile and target location

Question 49

command info for missile: the missile contains an onboard computer that calculates course corrections based on data received

Answer 49

missile and target

Question 50

command info for missile: has to have an internal navigation system to determine it's own location. uses data along with recieved target location to calculate course corrections.

Answer 50

target location only

Question 51

command info for missiles: course calculations made by parent radar, sends commands to missile. (pitch, yaw, roll, as well as arming and detonation commands)

Answer 51

steering commands

Question 52

What are the common methods in relation to encoding schemes for command guidance?

Answer 52

pulse duration (PDM), pulse position (PPM), pulse code modulation (PCM), amplitude modulation (AM)

Question 53

The process in which the duration, or width, of each pulse is varied in proportion to the amplitude of a modulating waveform

Answer 53

pulse duration modulation (PDM)

Question 54

What is the most common use of Pulse Duration Modulation (PDM)?

Answer 54

Used to control servomechanisms inside of missiles.

Question 55

Way to save wasted energy from the PDM but still convey information. Simply transmits the edges of the PDM pulses.

Answer 55

Pulse Postion Modulation

Question 56

Remote Controlled Servos

Answer 56

Used to provide actuation for various mechanical systems (i.e. steering of a car, rudder of a boat)

Question 57

PPM typically uses a consistent timing interval known as?

Answer 57

Frame time

Question 58

What is sent at the beginning of each frame to maintain a timing reference for command guidance?

Answer 58

frame markers (reference pulse group)

Question 59

What is a broad category of modulation that uses pulses to create binary codes?

Answer 59

Pulse code modulation

Question 60

PPM- PCM

Answer 60

uses a series of closely spaced pulses to pass info. reciever decodes as 1 or 0, depending on the presence or lack of in the sequence.

Question 61

FSK-PCM

Answer 61

changes the RF of the pulses in order to convey info. (Higher freq might indicate 1, lower may indicate 0)

Question 62

PSK-PCM

Answer 62

phase shift 180° imparted during the transmission of the pulse, position and duration of the phase shifts translates into binary.