Unclassified

Suppression and the Efficiency of Infantry Soldiers

Dr. Eylam Gofer, Ben Levav, Yohay Gerafi

Unclassified

Background Combat models tend to focus on:

The battlefield The weapons

Both factors are physical and quantifiable The soldier is less emphasized

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Unclassified

Background cont.

Soldiers are expected to perform different tasks on the battlefield and operate various weapons

They are also affected by:• Physiological factors• Psychological factors• Human-weapons system interface• …

Most of these influences are subjective and therefore vary from one soldier to the other

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Fear results from the

obvious threat to one’s life

Subjective and varied between soldiersIs the basis to the

phenomenon called suppression

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Suppression - Definition

Time-limited degradation of combat efficiency of a unit or an individual subjected to enemy fire

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Quantitative Approach “Macro” approach: Marshall, Wigram, and

Rowland Mainly define degradation measures to combat

efficiency We tried to use a “Micro” approach that

focuses on the soldiers activities in combat and how they are affected by suppression

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Unclassified

Objective Describing, Quantifying and Analyzing Fire

Suppression Effect on Infantry Soldiers in Combat

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Unclassified

Soldier in a “foxhole” or behind a temporary

cover

General Suppression Model

Soldier advancing

Method

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Unclassified

1st

2nd3rd

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Unclassified

9

Down Hill

Unclassified

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Scanning The Field

of Fire

Target Acquisition

Aiming Firing “BDA”

Unclassified

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Scanning The Field

of Fire

Target Acquisition

Aiming Firing “BDA”

1t 4t3t2t 5t

Soldier Activity Cycle: Length: Rate:

54321 tttttTw

ww T/1 Fire Rate in Training0.66( shots/sec)

Nominal Fire Rate 0.1( shots/sec)

Combat condition degradation[Rowland, 1986]

Unclassified

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Down Hill

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Effect of Suppression

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Scanning The Field

of Fire

Target Acquisition

Aiming Firing “BDA”

Suppressing Event

Direct Fire

Indirect Fire

Suppressing events: Time between events: Rate: Duration of suppression:

ss T/1sT

t

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Suppression Duration Approximate duration: Seconds Not deterministic, variance sources:

• Between soldiers• Between events, for the same soldier• Between the weapons or ammunition that

cause the suppression - mainly caliber Therefore we regard t as a random variable

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t~Gamma),1/|cal(

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Direct Fire Gamma Distributions

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0

0.01

0.02

0.03

0.04

0.05

0.06

משך הדיכוי מתחמושת קליעית )שניות(

תפו

פיהצ

קליע 0.5'

קליע 7.62 מ"מ

קליע 5.56 מ"מ

Suppression Duration (Seconds)

Den

sity

12.7 mm (50 cal.) 7.62 mm 5.56 mm

Unclassified

General Model

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Suppression Model

The Soldier Activity CycleLength - Tw Rate - w=1/ Tw

Suppressing EventLength - Ts Rate - s=1/ Ts

The Soldier Suppressed Activity

Rate - ’w

Degradation rate

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Results Simulation:

On-going soldier activity cycle A sequence of suppressing events - each

with a random duration “Disturbing” the soldier activity cycle Measuring the activity rate with the

disturbance

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Unclassified

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Direct Fire - Fire Rate Under Suppression

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0 0.05 0.1 0.15 0.2 0.25

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Fire Rate Enemy (shots/sec)

Fir

e R

ate

Fro

m F

oxho

le (

shot

s/se

c)

5.56 mm

7.62 mm

12.7 mm (50 cal.)

Unclassified

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Direct Fire - Degradation Rate)%(

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 0.02 0.04 0.06 0.08 0.1 0.12

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Fire Rate Enemy (shots/sec)

5.56 mm 7.62 mm 12.7 mm (50 cal.)

Deg

rada

tion

Rat

e(%

)

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Indirect Artillery Fire Direct fire is usually more accurate due to

range and system accuracy - It is reasonable to assume the majority of the shots fired will hit the vicinity of the post close surrounding, therefore suppressing the soldier in it

Indirect fire is statistical - Not every round will cause suppression

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Unclassified

Probability of Suppression [Mueller & Pietsch, 1978] - empirical study Ammunition calibers examined: 155mm, 81mm The main result: formulation of the probability of

suppression when the ammunition caliber (D) and impact distance (r) are given: P)suppression|r,D(

We have transformed that into P)suppression|R,D( R - the distance of the position from the aiming

point (assuming artillery fire CEP is 30 meters)

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Unclassified

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02.0108exp89.0)|( 25 RRuppressionP s

81 mm

155 mm

Distance of the Artillery Aiming Point from the Post (meters)

Pro

babi

lity

of

Sup

pres

sion

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Suppression Duration [Mueller & Pietsch, 1978] give a rather low

empirically-based estimate This, we assume, is due to the absence of real

danger to the subjects during the experiment Again, based on [Rowland, 1986], it is

reasonable to assume figures are about ten times larger

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Unclassified

Indirect Fire - Fire Rate Under Suppression

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Position Distance From Aiming Point (meters)

Time Betweenrounds (seconds)

Position Fire Rate)shots/minute(

Unclassified

Concluding Remarks The suppression model is one of the building

blocks of the methodology for comparing force configurations based on operational efficiency

The mathematical results can be, and already have been, incorporated in different models, modules and combat simulators

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Unclassified

Thank you!

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