track-while-scan (tws) naval weapons systems. learning objectives comprehend concepts of tws system...
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Track-While-ScanTrack-While-Scan(TWS)(TWS)
Naval Weapons SystemsNaval Weapons Systems
Learning ObjectivesLearning Objectives
Comprehend concepts of TWS Comprehend concepts of TWS systemsystem
Know the six basic functions of a Know the six basic functions of a TWS systemTWS system
Comprehend the concepts of Comprehend the concepts of acquisition, tracking, and turning acquisition, tracking, and turning gatesgates
Limitation of Traditional Limitation of Traditional Search Radar:Search Radar:
NO FIRE CONTROL NO FIRE CONTROL SOLUTIONSOLUTION
ProblemsProblems Dedicated FC radar can only track Dedicated FC radar can only track
one target.one target. Systems usually have separate Systems usually have separate
Scanning and Tracking Radars.Scanning and Tracking Radars. The target knows it’s being The target knows it’s being
tracked.tracked. The target can initiate Counter The target can initiate Counter
MeasuresMeasures Weapons home in on FC radarWeapons home in on FC radar
Concept of TWSConcept of TWS
Maintain Target tracks in a Maintain Target tracks in a computercomputer
Periodic updates from a Periodic updates from a scanning radar scanning radar
Functions of TWSFunctions of TWS DetectionDetection CorrelationCorrelation Track Initiation and file generation (if Track Initiation and file generation (if
a new target)a new target) Tracking “Gates”Tracking “Gates” Gate prediction, smoothing and Gate prediction, smoothing and
positioningpositioning Predict future target positionPredict future target position
Gate GenerationGate Generation
Acquisition gateAcquisition gate
Tracking gateTracking gate
Turning gateTurning gate
Acquisition GateAcquisition Gate
10 degrees
10 degrees
2000 yards
Tracking GateTracking Gate
1.5 degrees
1.5 degrees
120 yards
Turn Detection GateTurn Detection Gate
*Computer determines size of gate
tracking gate
TWS ProcessingTWS Processing
Acquisition Gate
Tracking Gates
Turn Detection Gate
Tracking Gates
Original Course
Track Initiation and Track File GenerationTrack Initiation and Track File Generation
Track fileTrack file• Store position and gate dataStore position and gate data
Code for acquisition windowCode for acquisition window Calculations on the Calculations on the returnreturn of a of a
target are done by a computer.target are done by a computer.• Much too slow to maintain a small Much too slow to maintain a small
tracking gate.tracking gate.
Positioning and Smoothing Positioning and Smoothing FunctionsFunctions
Repositioning and smoothing must Repositioning and smoothing must be done within the TWS algorithm.be done within the TWS algorithm.
““Lagging” TargetLagging” Target ““Leading” TargetLeading” Target
• This is done mathematically.This is done mathematically.
TWS DiagramTWS DiagramScanning radardetects a target
Do parameters matchthose from previous scan
NO
Yes Doestrack ambiguity exist
NO
Yes
Generate a new track file & store data
Generate anacquisition gate
Resolveambiguity
Targetpreviously in track or acquisition
Compute target tracking parameters
Acquisition
Track
Generate Track Gate & indicator in file
Update trackingparameters
Reposition trackgate centered onfuture position
Ready for the next radar scan information
Recompute track gate
TWS Radar System AdvantagesTWS Radar System Advantages Scan and Track on same systemScan and Track on same system Tracking information used for Tracking information used for
computation of a fire control solution. computation of a fire control solution.
Immediate Fire Control SolutionImmediate Fire Control Solution
Real World ApplicationsReal World Applications• AN/SYS-2 IADTAN/SYS-2 IADT
used on some missile shipsused on some missile ships
• Mk 92 CAS - FFGMk 92 CAS - FFG• AN/SPQ-9 – 5” GunAN/SPQ-9 – 5” Gun• Mk 23 TAS – NATO Sea SparrowMk 23 TAS – NATO Sea Sparrow• AEGIS C&D AEGIS C&D
holds track files for AEGISholds track files for AEGIS dedicated computer dedicated computer
SummarySummary
Radar continues scanningRadar continues scanning Computer predicts positionsComputer predicts positions Track while Scan!Track while Scan! Track information used for fire Track information used for fire
control solution.control solution.
Questions?Questions?