ESM System

Question 1

What are the functions of the ESM system?

Answer 1

electronic support (ES), functioning as an electronic warfare (EW) search, surveillance, and corroboration sensor. The second is to provide the aircrew with situational awareness regarding EW threats to the helicopter via the Helicopter Threat Warning (HTW) function.

Question 2

What equipment is a part of the ESM system?

Answer 2

the receiver processor and four antennas

Question 3

What does the Receiver/Processor consist of?

Answer 3

• Two RF baseband down converters;
• Two analog baseband receivers;
• A digital frequency discriminator;
• A pulse processor;
• SBC (Single board computer);
• Synthesizer module.

Question 4

What do the down converters do?

Answer 4

Each down converter provides the necessary antenna switching, preselection, attenuation, and first RF down conversion to an intermediate frequency (IF).

Question 5

What do the baseband receivers do?

Answer 5

Each baseband receiver performs the second and final IF conversion, IF filtering, video filtering, and amplitude/phase measurements.

Question 6

What does the digital frequency discriminator do?

Answer 6

The digital frequency discriminator provides a frequency measurement on each incoming pulse.

Question 7

What does the pulse processor do?

Answer 7

The pulse processor generates descriptor words, called pulse descriptor words (PDW) for each pulse detected.

Question 8

What does the single board computer do?

Answer 8

receives pulse descriptor words from the pulse processor for data processing to correlate specific emitter pulses into pulse trains. PDW data is then
used to form emitters and define their characteristics and to determine emitter parameters such as identification, threat level, bearing, and location.

Question 9

What does the synthesizer module do?

Answer 9

The synthesizer module provides multiple frequency references used for the local oscillator (LO) and built-in test (BIT)/calibration signals. Calibration functions provide correction factors to compensate for amplitude and phase measurement drift.

Question 10

What does the active calibration capability do?

Answer 10

it injects known RF signals from the synthesizer into the antenna RF chains, to correct for system measurement errors. These errors are a function of the system environment and fluctuate over time (mainly due to temperature).

Question 11

Describe the ESM antennas

Answer 11

Each ESM antenna contains four separate, spiral antenna elements, two in low band and two in high band and passive RF electronics. The ESM receiver processor further subdivides the RF operating ranges into six sub-bands.

Question 12

What is the field of view for an individual antenna?

Answer 12

100 degrees, giving us a 360 field of view around the helo with some overlap.

Question 13

What is LBI

Answer 13

Long Baseline Interferometer measurements. The
ESM receiver processor selects two adjacent antenna elements, within a band, to perform LBI which is then used to determine emitter location.

Question 14

What do blanking inputs do?

Answer 14

Blanking input ports are provided to minimize the interference effects of onboard transmitter signals. Four ports are dedicated to the radar, radar altimeter, interference blanker and the Link 16. The interference blanker provides combined blanking from the TACAN, IFF interrogator, and IFF transponder.

Question 15

How long does it take ESM to Initialize?

Answer 15

5-6 minutes after initial power application

Question 16

EOI Function

Answer 16

Choose 4 Emitters from the MDL to be Emitters of Interest (EOIs). Emitters of interest that are detected are displayed with “pointers”. Bearing lines to detected EOI emitters will add the NATO name.

Question 17

How long to the bearing lines to detected EOIs remain illuminated?

Answer 17

15 seconds

Question 18

Emitter (+EMTR 10/20/50/ALL) function

Answer 18

used to selectively declutter the ESM display of symbols by emitter mode. The operator can choose to display all emitters of interest or the top 10, 20 (default), or 50. Contacts are displayed in order of priority to ensure that highest priority emitters are retained on the display.

Question 19

Scan Modulation Analysis

Answer 19

Scan modulation analysis (SMA) is a tool with which the operator can potentially break up ambiguities to precisely identify emitters.

Question 20

What happens when you do a Scan Mod Analysis?

Answer 20

the receiver must “stare” at the emitter of interest for the defined dwell time in order to collect the data required to perform the analysis. During this time, the receiver is dedicated to the scan, monopolizing the receiver in order to collect the required data. Detection of new emitters is inhibited during Scan Mod.

Question 21

Where should the aircraft be during a Scan Mod?

Answer 21

on the beam of the emitter you are trying to identify.

Question 22

Dwell times for Scan Mod

Answer 22

the default is 10 seconds, the max is 300 seconds (5 min)

Question 23

Warning about SMA and HTW

Answer 23

Use of SMA in a high threat environment may result in failure to detect HTW.

Question 24

How to stop a Scan Mod in progress?

Answer 24

re-select the emitter, select the SCAN MOD function, and enter 0 seconds for the dwell time.

Question 25

What can negatively effect LBI measurements?

Answer 25

pairs. Location may not be measured in the aft section due to interference from the tail. When possible, position the aircraft with the emitter to port between 225°- 315° relative or starboard between 45°-135° relative.

Question 26

How can you help LBI find the emitter?

Answer 26

Performing maneuvers to create significant bearing change (i.e. target aspect angle changes) during location can result in improved location accuracy and time to fix the ESM system’s LBI location measurement. Perform alternating standard rate turns (3°/sec) in an S-pattern.

Question 27

Threat Levels of Emitters.

Answer 27

1 = Unknown;
2 = Non-threat;
3 = Warning;
4 = Imminent threat to a surface platform;
5 = Imminent threat to an airborne platform.

Question 28

Max reported confidence of an emitter?

Answer 28

95%

Question 29

What does CLR TRAKS do and when should you do it?

Answer 29

It clears out everything the system had detected and resets the system, starting the process all over again.

trick question, you shouldn’t do it.

Question 30

How many MDLs can we bring to the aircraft?

Answer 30

8

Question 31

How long does it take for the system to come back online after switching MDLs?

Answer 31

5

Question 32

What can we do with the Operator Library?

Answer 32

An air or ship operator can create or modify the operator library. A maximum of 20 operator library
entries can be entered in the air, uplinked by the ship, or a combination of both. In helo control, air operators
can view and modify the library’s parameters for these 20 entries.

Question 33

What is the purpose of the Operator Library?

Answer 33

The operator library is only used for ID purposes; it does not modify the ESM baseline scan strategy. If the MDL does not include dwells in the frequency range defined for the emitter in the operator library, the emitter will not be detected.