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Torpedo Proximity Scoring System (TPSS)

Prepared For: International Test and Evaluation Association

Prepared By: Clarence Ching, (NUWC/KPT)Gregory A. Babich (ARL/PSU)Bruce J. Frei (ARL/PSU)Bruce T. Einfalt (ARL/PSU)

21 November 2010

Outline

• Background• Development Process• System Design• System Components• Summary• Acknowledgements

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The Torpedo Proximity Scoring System (TPSS) was developed to provide a previously non-existent Test and Evaluation (T&E) capability to Commander Operational Test and Evaluation Force (COTF) for operational evaluation of an Anti-Torpedo-Torpedo (ATT).

The purpose of TPSS is to provide the ability to accurately measure the Closest Point of Approach (CPA) of an ATT as it engages a torpedo emulator during operational testing.

Current U.S. Navy tracking ranges do not currently have the ability to accurately measure the ATT’s CPA nor do those tracking ranges provide all the acoustic environments required for ATT operational testing.

Background

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Develop a torpedo-based CPA measurement system that willprovide the ability to accurately measure the CPA of an ATT as itengages the torpedo emulator during operational testing.

Design the system to accommodate additional capabilities toenable advanced threat emulation

Utilize open architecture and COTS hardware

Build six Torpedo Proximity Scoring System (TPSS) units

Firewall activities from ATT Developmental Testing efforts

Background:Objectives

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NUWC/KPT—ARL/PSU development process provides quick reaction capability (QRC) to support current and future DoD needs

Close attention paid to end-user’s needsRapid prototypingDeliver systems for use in operational environments

Work closely with end-user throughout development processWelcome and encourage end-user(s) to participate in development processCan generally make changes on the fly throughout the development process with minimal impact to schedule/budget

Emphasize strong engineering standardsStreamlined design reviews (SRR, PDR, CDR, etc.)Open architecture design with COTS hardware Extensive, rigorous testing (deck, acoustic tank, test ranges)

Development Process

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2005April, kickoff and system optionsAugust, system requirements review (SRR)

2006April, system design review (SDR)June, TPSS self-noise test at seaNovember, first use of TPSS with ATT

2007ATT vs. TPSS throughout 2007May, all 6 TPSS units and spares deliveredJuly, closeout briefing with sponsor

2008—2010Three years of ATT vs. TPSS

Development Process:Timeline

20 months from kickoff to use against ATT

28 months from kickoff to Government accep-tance of 6 TPSS units

Nearly 100 shots since 2006

15 months from kickoff to at-sea shakeout

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s1

s2

s3

TIME

RA

NG

E

r1

r2

r3

Discrete Range to ATT

Continuous Range to ATT

Timestamp Approach

r = c·∆t

System Design:Overview

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r = c·∆t rm = (c+ec)·(∆t+e∆t)

= c·∆t + c·e∆t + ec·∆t + e∆t·ec = r + c·e∆t + ec·∆t + e∆t·ec|rm- r| = |r - r + c·e∆t + ec·∆t + e∆t·ec| = |c·e∆t + ec·∆t + e∆t·ec|

= |c·e∆t + (c/c)·ec·∆t + e∆t·ec| = |c·e∆t + r·ec/c + e∆t·ec| ≈ |c·e∆t + r·ec/c| ≤ c·|e∆t| + r·|ec|/c

r is the true range to the ATTrm is the measured range to ATTc is the true speed of soundec is the error term accounting an erroneous speed of sound∆t = true receive time - true transmit time e∆t is the error term accounting for an erroneous time delay

System Design:Error Analysis

Major source of range measurement error is e∆t

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GPS

Disciplining(Connected to GPS)

IRIG-B

. . . . . . . . . . . . . . . . .

Minimal timestamp drift over duration of run

GPSMinimal timestamp drift when compared to GPS time

Time

Power-up Run CompleteLaunch

Start Recording

Recording

Stop Recording

System Design:Timestamp

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System Design:Operations

Data Recording

Data Analysis

Acoustic data and timing info recordedData reordered in MATLAB MAT filesOpen-loop geometry or closed-loop tactics

Analysis softwareEvaluationDocument results

Prepare vehicle for deployment

Record acoustic data during run

Download data from TPSS (data extraction), acquire signal transmit times from ATT, and acquire range data (when available) to augment analysis

Using analysis software, determine ATT’s CPA based on acoustic data

Document results

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System Components:Overview

Hydrophones Record System Analysis Computer

8 hydrophones total

2 hydrophones in nose

2 EFOV shells

3 hydrophones per EFOV shell

Housed in nose

IRIG card w/rubidium clock

COTS processors & drives

COTS A/Ds

Acoustic data recorded in MATLAB MAT files

PC

MATLAB

PSU/ARL-developed MATLAB code

CPA algorithms and GUI

Pre-launch deck checks

Extended Field of View (EFOV)

ShellsRecord System

Hydrophones

X,G,M Test Vehicle (TV)

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System Components:CPAMS

CPA Measurement Software (CPAMS)Example Plots for Fictional Engagement

Range as a function of timeRange calculated for active transmitsCPA is typically extrapolated valueRange at detonation time based on projection

TPSS-centric 3d plotRange decomposed into (x,y,z) relative to TPSSUseful for visualization of engagement

ATT position relative to TPSS at time of

ATT transmit12

Summary

TPSS development process was streamlined resulting in rapid delivery

Six TPSS units were accepted by the Government 28 months after kickoff meeting

TPSS provides accurate range measurements

TPSS has a total of nearly 100 runs since it was delivered

TPSS has proven to be a reliable system with a 94% in-water success rate

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Acknowledgements

TPSS was funded by the Central Test & Evaluation Investment Program (CTEIP) Resource Enhancement Project (REP)

Endorsements and technical direction provided by Commander Operational Test and Evaluation Force (COMOPTEVFOR)

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