RADAR

Question 1

Radar components

Answer 1

Radar receiver/transmitter (R/T);
• Antenna/pedestal (antenna array and IFF interrogator R/T);
• Radar data processor (RDP);
• Radome;
• IFF Mode 4 crypto;
• Waveguide assembly;
• Waveguide dehydrator.

Question 2

R/T

Answer 2

The receiver/transmitter generates the transmission pulse for the antenna and
converts the received pulse from the antenna into a usable form for the RDP to process

Question 3

Antenna/Pedestal

Answer 3

provides for controllable antenna position and
azimuth drive for the radar and provides the radar and IFF interrogation signals to the planar array for
transmission.

Question 4

A/P Subsystem

Answer 4

Controller

Azimuth drive assembly - speeds of 12, 108, or 154

Radome/IFF array attached to x-band antenna

Question 5

RDP

Answer 5

Radar Data Processor

The RDP processes the raw radar and IFF interrogator data to form tracks
which are presented to the operator on the mission display. The RDP receives digitized antenna azimuth and
IFF replies from the A/P, radar video from the R/T, helicopter position from the EGI, and operator mode
control command via the mission computer. The RDP provides digital pulse compression in selected modes,
radar control, video processing, data communications, tracking and image processing.

Question 6

Radome

Answer 6

The radome provides environmental protection for the antenna/pedestal assembly and is
relatively transparent to RF energy.

Question 7

Crypto Module

Answer 7

The KIV-6 provides the encryption/decryption functions required for secure IFF
Mode 4 operations. It is loaded during preflight with current day/next day (Mode 4A/4B) keylists and is zeroized
after flight. The KIV-6 interfaces with the IFF processor in the RDP

Question 8

Waveguide Assembly

Answer 8

The waveguide assembly transmits the voltage standing wave ratio from the
R/T to the A/P and transmits X-band radiation.

Question 9

Waveguide dehydrator

Answer 9

The waveguide dehydrator is a passive, desiccant-filled cylinder mounted
beneath the mission computer in the SO console avionics rack. The waveguide dehydrator connects to the radar
waveguide for the purpose of moisture removal to prevent waveguide arcing

Question 10

Standby

Answer 10

default power up or after hard init

Question 11

Short Range Search (SRCH SHORT)

Answer 11

Scan Rate: 108

Radar 100yds-16NM
IFF 100yds-75NM

Range Scales (NM): .25, .5, 1, 2, 4, 8, 16, 32, 64, 128, 256

Optimized to detect both
large and small contacts
at short ranges. Used for
low-visibility approaches and
situations requiring display
of closely spaced contacts.

Question 12

Short Range Periscope Detect (PERI SHORT)

Answer 12

Scan Rate: 108

Radar: 100 yds - 16 NM
IFF: 100 yds -75 NM

0.25, 0.5, 1, 2, 4, 8, 16,
32, 64, 128, 256

Optimized to detect small
contacts such as periscopes
at short ranges.

Question 13

Long Range
Periscope Detect
(PERI LONG)

Answer 13

108

Radar: 2-32 NM
IFF: 100 yds -75 NM

2, 4, 8, 16, 32, 64, 128,
256

Optimized to detect small
targets such as periscopes,
submarine snorkels, mines,
or lifeboats in the presence
of sea clutter.

Question 14

Automatic Radar
Periscope
Detection and
Discrimination
(PERI ARPDD)
(APS-153(V)1
only)

Answer 14

154

Radar: 100 yards - 30 NM
IFF: 100 yards - 45 NM

0.25 - 256 NM

Provides for range profile
of a target. High range
resolution tracks closely
separated tracks. Detects
probable periscopes and
presents to the operator
as symbols on the mission
display.

Question 15

Inverse
Synthetic
Aperture Radar
(ISAR ON/OFF)

Answer 15

0

5 - 160 NM

Provides for
two-dimensional image of
designated surface contact
for purpose of identifying
ship class.

Question 16

Surveillance
Search Mode
(SRCH LONG)

Answer 16

12

Radar: 0.25 - 160 NM
IFF: 100 yds - 160 NM

4, 8, 16, 32, 64, 128,
256

Standard long-range
surveillance detection
mode of radar.

Question 17

Coastal Search

SRCH CSTL

Answer 17

12

Radar: 0.25 - 160 NM
IFF: 100 yds - 160 NM

4, 8, 16, 32, 64, 128,
256

Optimized to display
coastline detail.

Question 18

ARPDD mode note about discriminator

Answer 18

100 yards to 2 NM will have video and tracks. Discriminator labels will not display

Question 19

ARPDD Regular Signature

Answer 19

Most useful for periscope detection

Question 20

ESIG (ARPDD)

Answer 20

Extended signature

ESIG size is determined by the discriminator and is most useful for
determining target length and large scale features.

Question 21

A-scan (ARPDD)

Answer 21

Amplitude Scan

Monochrome ESIG with only peak amplitude responses identified.
Most useful for determining target architecture (analogous to ISAR A-scan characteristics).

Question 22

PINT

Answer 22

Periscope detect (PD) integration times used for PERI SHORT/LONG

3 Levels: L/M/H

For higher sea state, select higher PINT to prevent false alarms.

Question 23

STI

Answer 23

Small Target Indicator

Radar tracks that exhibit characteristics of exposed periscope/mast

Standard symbol with “s”

Question 24

LMR

Answer 24

Land Mass Rejection

radar tracks are not displayed on regions defined as land (world vector shoreline map which is stored permanently inside the
RDP, does not include the locations of man-made
objects)

No effect on IFF tracks; fused will drop radar track and continue as IFF

Question 25

ISAR

Answer 25

Inverse Synthetic Aperture Radar

2-d image of surface target for purpose of identifying ship class

Able to freeze images for quadrant format viewing with up to 4 images, one of which can be dynamic

Question 26

IFF

Answer 26

Mode 1, 2, 3/A, 3/C, and 4 (requires crypto); transmitter/receiver are functions of the A/P

Sent to ship via data link

Question 27

IFF Track Showcode

Answer 27

display IFF code responses attached to track symbols

Question 28

ISAR image quality

Answer 28

For low sea states or target speeds, increase integration time

Question 29

Automatic Detection and Tracking

Answer 29

Maximum 320 (APS-147);

2500 for ARPDD beneath AOP. 320 reported to AOP; 256 radar, 64 IFF.