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Track-While-Scan (TWS). Naval Weapons Systems. Learning Objectives. Comprehend concepts of TWS system Know the six basic functions of a TWS system Comprehend the concepts of acquisition, tracking, and turning gates. Limitation of Traditional Search Radar:. NO FIRE CONTROL SOLUTION.
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Track-While-Scan(TWS) Naval Weapons Systems
Learning Objectives • Comprehend concepts of TWS system • Know the six basic functions of a TWS system • Comprehend the concepts of acquisition, tracking, and turning gates
Limitation of Traditional Search Radar: NO FIRE CONTROL SOLUTION
Problems • Dedicated FC radar can only track one target. • Systems usually have separate Scanning and Tracking Radars. • The target knows it’s being tracked. • The target can initiate Counter Measures • Weapons home in on FC radar
Concept of TWS • Maintain Target tracks in a computer • Periodic updates from a scanning radar
Functions of TWS • Detection • Correlation • Track Initiation and file generation (if a new target) • Tracking “Gates” • Gate prediction, smoothing and positioning • Predict future target position
Gate Generation • Acquisition gate • Tracking gate • Turning gate
Acquisition Gate 10 degrees 10 degrees 2000 yards
Tracking Gate 1.5 degrees 1.5 degrees 120 yards
tracking gate Turn Detection Gate *Computer determines size of gate
TWS Processing Original Course Turn Detection Gate Tracking Gates Tracking Gates Acquisition Gate
Track Initiation and Track File Generation • Track file • Store position and gate data • Code for acquisition window • Calculations on the return of a target are done by a computer. • Much too slow to maintain a small tracking gate.
Positioning and Smoothing Functions • Repositioning and smoothing must be done within the TWS algorithm. • “Lagging” Target • “Leading” Target • This is done mathematically.
Do parameters match those from previous scan Does track ambiguity exist Resolve ambiguity Yes Scanning radar detects a target Yes NO NO Generate a new track file & store data Generate an acquisition gate Generate Track Gate & indicator in file Compute target tracking parameters Acquisition Target previously in track or acquisition Ready for the next radar scan information Reposition track gate centered on future position Update tracking parameters Recompute track gate Track TWS Diagram
TWS Radar System Advantages • Scan and Track on same system • Tracking information used for computation of a fire control solution. • Immediate Fire Control Solution
Real World Applications • AN/SYS-2 IADT • used on some missile ships • Mk 92 CAS - FFG • AN/SPQ-9 – 5” Gun • Mk 23 TAS – NATO Sea Sparrow • AEGIS C&D • holds track files for AEGIS • dedicated computer
Summary • Radar continues scanning • Computer predicts positions • Track while Scan! • Track information used for fire control solution.