ASAR Reference Guide

Arrowsmith Search & Rescue - Works Offline

SAR Manager Calculators

Probability, coverage, and effort calculators for search planning and management.

Jump to Calculator

Formulas Reference

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Symbol Definitions

SymbolNameUnit
AAreakm²
CCoverageratio
STrack Spacingm
TTime Spent Searchinghours
VVelocity (Speed of Search)km/h
WEffective Sweep Width (Rd)m
ZArea Effectively Sweptkm²
TTLTotal Track Length (Total Effort)km
POAProbability of Area%
PdenProbability Density%/km²
PODProbability of Detection%
PSRProbable Success RatePOS/Searcher Hour
POSProbability of Success%
POScumCumulative POS%
OPOScumOverall Cumulative POS%
RdRange of Detectionm

Key Formulas

Theoretical Search Area

Area = π × r²    (r = speed × elapsed time)

Probability

Segment POA = (Seg Area / Region Area) × Region POA
Pden = POA / A

Total Track Length

TTL = V × T
TTL = V × T × (# Searchers)
TTL = (A × 1000) / S
TTL = (Z × 1000) / W

Area Swept & Coverage

Z = (W × TTL) / 1000    or    Z = C × A
C = Z / A    or    C = (W × TTL) / (A × 1000)
S = W / C    (spacing from desired coverage)

Detection & Success

POD = 1 − e−C    (random coverage)
POS = POA × POD
POScum = ∑ POS (all regions)
Adjusted POA = POA × (1 − POD) / (1 − POS_total)

Area Calculator

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Circular Area from Travel Time

Range (radius)
6.0
km
Search Area
113.1
km²

r = speed × time  |  A = πr²

Circular Area from Radius

Area
78.5
km²

A = π × r²

Triangle Area (Heron's Formula)

Area
6.0
km²

s = (a+b+c)/2  |  A = √(s(s-a)(s-b)(s-c))

Rd (Range of Detection) and Effective Sweep Width Calculator

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Paces Conversion

Metres per pace = 100 / paces per 100m

Rd Test Walks (enter paces per leg)

Leg Test 1 (paces) Test 1 (m) Test 2 (paces) Test 2 (m) Test 3 (paces) Test 3 (m) Test 4 (paces) Test 4 (m)
Rd (avg, m) - - - -
Overall Avg Rd (m) -

Effective Sweep Width W from Rd

W = Rd × visibility correction factor

High Visibility (×1.8)
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m
Medium Visibility (×1.6)
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m
Low Visibility (×1.1)
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m

M242 Ecoregion Reference (Marine Mountains, Mixed Forest, Summer)

Object / VisibilityEffective Sweep Width (W)
Person-sized, White/Orange (High)36 m
Person-sized, Blue (Medium)32 m
Person-sized, Green (Low)17 m
Glove-sized Clue (High)8 m

Mattson Consensus POA Calculator

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Rate the most likely region as 10 and all others in proportion to it. Calculates consensus POA, Pden, and PSR rankings.

Team Members

Region Ratings (0-10)

Team Member

Region Parameters

Parameter
Area (km²)
Speed (km/hr)
Sweep Width (m)

Coverage, Effort, Z, and POD Calculator

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Enter segment area, sweep width, and desired track spacing to calculate coverage and POD.

Seg Area A (km²) Sweep W (m) Spacing S (m) Coverage C TTL (km) Z (km²) POD
Total - - - - - - -

Enter segment area, sweep width, and desired coverage to calculate track spacing and POD.

Seg Area A (km²) Sweep W (m) Desired C Spacing S (m) TTL (km) Z (km²) POD
Total - - - - - - -

Total Effort (TTL) Calculator

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A. From Track Count

TTL
10.0
km

TTL = tracks × length

B. From Speed / Time

TTL
24.0
km

TTL = V × T × searchers

C. From Area / Spacing

TTL
50.0
km

TTL = (area(ha) / 100) × 1000 / spacing(m)

D. From Z and W

TTL
100.0
km

TTL = (Z × 1000) / W

Effort, Z, and Coverage Per Segment

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Segment Parameters

Searcher Track Lengths

Enter track length directly, OR velocity + time (track length will auto-calculate).

Searcher Velocity (km/h) Time (hrs) Track Length (km)
TTL (Total) - - 0.0 km

Z and Coverage by Visibility Level

Visibility W (m) TTL (km) Z (km²) Coverage C POD
High 36 - - - -
Medium 32 - - - -
Low 17 - - - -
Clue 8 - - - -

Planning Sweep Search Calculator

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Segment Inputs

If "Number of Parallel Tracks" is left blank, it will be calculated from baseline and derived track spacing. Enter a number to override.

Results

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Overall Cumulative POS Calculator

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Enter initial POA as decimal (e.g. 0.30 = 30%), then enter coverage C for each search round. POD and adjusted POA are calculated automatically.

Overall Cumulative POS
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%
Sum of Adjusted POA
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(should = 1.0)

OPOScum = sum of all POS values across all regions and all search rounds. The sum of final adjusted POA values should equal 1.0 as a check.