ECE 495 — Electromagnetic Warfare and Survivability

Block 3: IR EW and Signature Management
Lesson 29: Project 3 Work Day

Juan Jurado, Col, USAF, Ph.D.
Permanent Professor and Head
Electrical and Computer Engineering
Fall 2026

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Block 3 · Lesson 29 · The Ask

Project 3: The Ask

Your group is the B-21 signature-management cell.

Product

A prioritized package of signature investments that buys the most survivability against a three-band threat, chosen inside a fixed budget.

Everything you need is in L21–L28: the loudest-band rule, RCS scaling, IR intensity
Handout, signature CSV, investment menu, and starter are posted
Results presentations at L30 — 10 minutes, 5 of Q&A, everyone speaks

You cannot buy every band. Spend where the limiter is.

Block 3 · Lesson 29 · Scenario

The Scenario: Three Bands, One Aircraft

The target area is watched in three bands at once:

Threat	Detects	Band
Surveillance radar (EWR)	$2~\text{m}^2$ at 90 km	VHF
Fire-control radar (TTR)	$0.03~\text{m}^2$ at 45 km	X
MANPADS seeker (IR)	$300~\text{W/sr}$ at 8 km (lethal 6)	MWIR

Baseline B-21, nose-on

$$\sigma_{\rm VHF}=2~\text{m}^2 \qquad \sigma_{\rm X}=0.032~\text{m}^2 \qquad J_{\rm stern}=300~\text{W/sr}$$

Radars illuminate you nose-on; the MANPADS engages tail-on. No threat positions, no routes: ingress and egress are shorthand for aspect. The full pattern is in the CSV.

Block 3 · Lesson 29 · Method

Signatures to Detection to the Loudest Band

Each threat turns a signature into a detection range through a Block-3 law:

Radar — fourth power

$$R_{\rm radar} = R_{\rm ref}\left(\frac{\sigma}{\sigma_{\rm ref}}\right)^{1/4}$$

IR — square root

$$R_{\rm IR} = R_{\rm ref}\sqrt{\frac{J}{J_{\rm ref}}}$$

The defender needs only one band, so detection is the largest: $R_{\rm det} = \max_b R_b$
Reducing a quiet band does nothing until it becomes the limiter
The fourth root is harsh: it takes $\sim$12 dB of RCS just to halve a radar's range

This is L28 made operational: find the limiter, then spend on it.

Block 3 · Lesson 29 · The Budget

The Budget — and the Tension

Seven investments on the menu, and a budget that cannot buy them all.

Your package must satisfy

$$\textstyle\sum \text{cost} \le 10 \qquad \textstyle\sum \text{weight} \le 5$$

The decibels you buy add within each band — and every row on the menu cuts some bands and not others. IR intensity is two contributors, skin and hot parts + plume: each IR treatment cuts only one.

So the question is never how much reduction you bought. It is which band you bought it in.

Block 3 · Lesson 29 · The Budget

The Budget — and the Tension

Your package must satisfy

$$\textstyle\sum \text{cost} \le 10 \qquad \textstyle\sum \text{weight} \le 5$$

Where the limiter is

Score the baseline before you spend a point.

Which band is loudest — and which rows on the menu touch it at all?

Where the lethality is

Spend it all on the limiter and the MANPADS is still lethal at the target.

Buying it down spends budget you wanted for the radars.

The whole project lives in that trade. Defend your package.

Block 3 · Lesson 29 · Tasking

Your Tasks

1 · Signature-to-detection pipeline — signature plus package to three ranges to $R_{\rm det}$; verify on the starter
2 · Budget search — score every package that fits the caps and minimize $R_{\rm det}$
3 · The terminal threat — plot every feasible package, $R_{\rm det}$ against MANPADS range, and defend your pick
4 · Aspect — turn the aircraft: nose, beam, tail; a full sweep earns the bonus
5 · Recommendation — one slide: what to buy first, and what you left on the table

Block 3 · Lesson 29 · Starter

Starting Point

The starter gives you a working pipeline for the simplest case:

Reads B21_SignaturePattern.csv and the SignatureMenu.csv
Scores one example package (X-band RAM + plume) with the loudest-band rule
Plots the fourth-power trade: what a decibel of RCS actually buys

Example File: L29_Project3Starter.m

The example is an example, not a recommendation. Sample AI prompts are on the Project 3 page.

Block 3 · Lesson 29 · Battle Rhythm

Today's Battle Rhythm

Clock	What happens
First 10 min	Groups assigned, claim a whiteboard, read the handout together
Next 30 min	Divide the work: pipeline + budget search, terminal-threat plot, aspect, recommendation
Last 10 min	Regroup: what's done, what's blocked, who owns what before L30

I am floating between groups — pitch me your loudest band and your package early.

Name the limiter before you spend a single point.

Block 3 · Lesson 29 · Wrap-Up

Wrap-Up

Before you leave

Pipeline verified against the starter's baseline ($R_{\rm det}\approx 90$ km)
A first package chosen — and checked against the cost and weight caps
Task owners assigned through L30

Next lesson

L30: Project 3 results presentations — slides and code due before class
HW3 due at the start of L30
Quiz 3 (open book) in class, tied to your project work