Design Plan JTLS-0151 ROLANDS & ASSOCIATES Corporation

JTLS-0151 Global Sunrise and Sunset

Ellen Roland, Joel Modisette

1.0 Summary of Model Change Request

Previously JTLS modeled the light conditions of DAY and NIGHT throughout a bounded game box,typically a military theater of operations. Light Condition changed instantly in the game boxaccording to preset database entries for sunrise and sunset time. No representation of lightcondition occurred outside the game box. This ECP provides dynamic and realistic worldwiderepresentation of day or night light conditions according to simulation game time. This designsupports the web-enabled, service-oriented architecture currently used by JTLS and planned forthe future Joint Live Virtual Constructive (JLVC) 2020 project.

2.0 Design Summary

The Global Sunrise and Sunset design calculates the light condition value of DAY or NIGHT as afunction of two inputs: location (latitude and longitude) and time (current or future). Real-worldsunrise/sunset algorithms are employed to determine a light condition using simulation time andlocation. The design replaces the previous versions that relied upon game time and databasevalues for sunrise and sunset. The design impacts JTLS in two areas:

1. The WHIP Map Component projects a daytime/nighttime graphic object, or shadow, over theworld map. The software industry typically refers to this graphic object as "The Terminator", andthis design will employ that term.

2. Model behaviors that previously relied on the static parameter of light condition will now use asimilar dynamic variable. Hence, object behavior that changes according to a DAY or NIGHTcondition will retain the same behavior. However light conditions that determine object behaviornow change over time and location in the same manner as the real world progression of sunlightacross the globe.

3.0 Detailed Design

3.1 Terminator On The Map Component

The Terminator graphic object renders a shadow overlay on the Map Component that emulatesthe shadow of DAY and NIGHT on the earth’s surface. The Terminator functionality is found in theFilter panel, Layers icon of the Map Component. The Terminator is easily toggled on/off tosupport any planning that may be affected by light condition.

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JTLS overarching design philosophy of maximum automation for the user occurs throughout thisECP design. JTLS automatically implements the appropriate light condition in algorithms(Table 3.2.1), including advance planning. The user is never required to determine or enter lightcondition at any time. The Terminator exists only as a visual aid to remind the user of potentialchanges due to light condition.

Figure 1 provides a screen shot of the terminator graphic in the Map Component of the WHIP.expands the Layers portion of the filter panel to show detail. Figure 2 expands the Filter Panel:Layer Icon portion to show the Terminator toggle detail.

FIGURE 1. Map Component Terminator

3.2 Model Behavior Under Dynamic Light Conditions

Light Condition checks at time/location are conducted automatically by JTLS. There is no needfor a user to consult the Terminator graphic in the Map Component to complete any JTLS order.Object behavior modifications due to light condition have existed in all previous versions of JTLS,and this design implements dynamic light condition in existing algorithms. This section providesdetail on enhancements in object behavior that will occur as a result of the design.

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FIGURE 2. Terminator Graphic Layer

3.2.1 Existing Model Behavior Due To Light Condition

Light condition effects in the existing version of JTLS are listed in Table 1. This ECP design retainsall the original functionality in these areas.

Table 1. Light Condition Implementation Areas

AREA RELEVANT DATA STRUCTURE DESCRIPTION

FLP.CS.LC.WC.ATTRITION.FACTOR FIRE LETHALITY PROTOTYPE, COMBAT SYSTEM, LIGHT CONDITION, WEATHER CONDITION permanent entity

Combat System’s efficiency in offensive combat under current light conditions.

AD.DAY.NIGHT.FACTOR AIR DEFENSE CLASS entity Multiplier used to alter the probability that the air defense site can detect and engage an incoming enemy Air Mission under current daylight conditions.

UT.NIGHT.EFFECTIVENESS UNIT entity Multiplier used in Lanchester attrition calculations for combat under night conditions

WDC.NIGHT.FACTOR WEATHER DELIVERY CAPABILITY entity

Modifier to WDC.DELIVER.FACTOR to affect the outcome of weapon delivery under night conditions

TW.DAY.NIGHT.FACTOR TARGETABLE WEAPON entity Multiplier used to adjust probabilities of hit when the weapon is used during night conditions

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3.2.2 Timing Implementation For Dynamic Light Condition

Previous versions of JTLS represented one light condition throughout the game box at asimulation time. The effect of DAY transitioning to NIGHT in the midst of an extended operation,or the effect of operations geographically spanning across the boundary between day and night,was not fully represented.

The new design enhances the representation of light condition by checking for DAY or NIGHT atkey times or locations when the light condition impacts behavior. Table 1 provides the newtiming/location of light condition implementation in the JTLS algorithms.

ST.NIGHT.FACTOR SENSOR TYPE entity multiplier used to adjust a sensor’s probability of effectiveness under night conditions

Air Mission Loads LOAD ASSIGNMENT ARRAY table

Specifies an Air Mission load use for either DAY or NIGHT

Table 2. Timing and Location Implementations of Light Condition

AREA IMPLEMENTATION

FLP.CS.LC.WC.ATTRITION.FACTOR Light Condition determined at combat system location during calculation of Combat System efficiency before and during combat

AD.DAY.NIGHT.FACTOR Light Condition determined at Air Defense Batteries location during the detect and engage sequence

UT.NIGHT.EFFECTIVENESS Light Condition determined at unit location during calculation of Unit Effectiveness during nighttime combat

WDC.NIGHT.FACTOR Light Condition determined at delivery platform time and location for calculation of weapon delivery outcome

TW.DAY.NIGHT.FACTOR Light Condition determined at the impact time and location for probability of hit calculations

ST.NIGHT.FACTOR Light Condition checked at sensor location during probability of detection calculations.

Air Mission Loads Air Mission resourcing algorithm checks load availability for the Light Condition present at mission location at time on top

Table 1. Light Condition Implementation Areas

AREA RELEVANT DATA STRUCTURE DESCRIPTION

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3.2.3 Sunrise And Sunset Computation

The calculation of sunrise and sunset times in JTLS replicate the actual Sunrise Equation used inreal world calculations of sunrise and sunset, such as those used in Google Earth. The equationsimplemented in the CEP and WHIP may be found in the United States Naval Observatory NauticalAlmanac, Section L Notes and References, Ephemeride Theory and Concepts.

4.0 Data Changes

The design required no new variables. The calculation of light condition now uses internalvariables of time and location. The following two existing database variables were removed:

REMOVED VARIABLE NAMES

• SUNRISE.TIME

• SUNSET.TIME

5.0 Order Changes

No order parameter or structure changes are required to implement this design.

6.0 JODA Changes

The design required no JODA Data System parameter, structure, or protocol changes. LightCondition information was removed from the JODA. The WHIP executes an identical but separatesunrise/sunset geospatial algorithm to render the Terminator.

7.0 Test Plan

These test plans address each of the algorithms affected by light condition. During testing ofGlobal Sunrise and Sunset the user should use a reputable source (i.e. NOAA ERSL SunriseSunset Calculator) to determine sunrise and sunset times on a given day at a latitude/longitude.JTLS currently does not support Daylight Savings Time (DST). Any adjustments for DST must beconducted by the user and factored into calculations for DAY or NIGHT.

7.1 FLP.CS.LC.WC.ATTRITION.FACTOR Algorithm Test

Purpose:

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7.2 AD.DAY.NIGHT.FACTOR Algorithm Test

Purpose:

7.3 UT.NIGHT.EFFECTIVENESS Algorithm Test

Purpose:

7.4 WDC.NIGHT.FACTOR Algorithm Test

Purpose:

7.5 TW.DAY.NIGHT.FACTOR Algorithm Test

Purpose: A Targetable Weapon launch with a subsequent NIGHT impact time/location shouldemploy NIGHT probability of hit condition, regardless of DAY or NIGHT condition atweapon launch site.

Step 1:

7.6 ST.NIGHT.FACTOR Algorithm Test

7.7 Air Mission Loads Algorithm Test 1

Purpose: Air missions with a NIGHT Time on Top/Destination should resource with a NIGHT airmission load, regardless of DAY or NIGHT launch time.

Step 1:

7.8 Air Mission Loads Algorithm Test 2

Purpose: Air missions with a DAY Time on Top/Destination should resource with a DAY airmission load, regardless of DAY or NIGHT launch time.

Step 1: Text

Step 2: Text

Expected Results: [Describe the specific model behavior to be observed.]

7.9 Test 2 Targetable Weapon launch in day, weapon probability of kill under nighttime condition

Purpose: Text

Step 1: Text

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Step 2: Text

Step 3: Text

7.10 Text

7.11 Test 2 Targetable Weapon launch at night, weapon probability of kill under daytime condi-tion

Purpose: Text

Step 1: Text

Step 2: Text

Step 3: Text

Expected Results: Text

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