# Lesson 7 Flashcards

Click a question to reveal the answer.

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<summary><strong>1. In one sentence, what is an IADS?</strong></summary>
<div class="card-answer"><p>A layered, integrated air-defense system: a cascade of specialized radars, each doing one job and handing its track to the next, that together cover the engagement.</p></div>
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<summary><strong>2. What does an Early Warning (EW) radar do, and in what band?</strong></summary>
<div class="card-answer"><p>Detects inbound air activity at hundreds of km and alerts higher echelons. UHF or L band, large antenna, low PRF, wide fan beam on a slow rotation (2D track only).</p></div>
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<summary><strong>3. What is the job of the ACQ and HF radars?</strong></summary>
<div class="card-answer"><p>Acquisition (ACQ) produces 3D tracks for engagement (typically S band); a height-finder (HF) adds elevation to a 2D ACQ. Together they hand a 3D track to the engagement radars.</p></div>
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<summary><strong>4. What does GCI provide?</strong></summary>
<div class="card-answer"><p>Ground-controlled intercept — the C2 layer that vectors interceptor aircraft using the IADS's 3D track picture.</p></div>
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<summary><strong>5. TTR vs TIR — what is the difference?</strong></summary>
<div class="card-answer"><p>The target-tracking radar (TTR) is the SAM site's fire-control sensor holding the target. The target-illuminating radar (TIR) floods the target with energy so a semi-active missile seeker can home on the reflection.</p></div>
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<summary><strong>6. What band and PRF characterize a TTR?</strong></summary>
<div class="card-answer"><p>X band, narrow slewable pencil beam, medium-to-high PRF (often pulse-Doppler), at tens to a low hundred km.</p></div>
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<summary><strong>7. What sensors operate in the terminal layer?</strong></summary>
<div class="card-answer"><p>The AI (airborne interceptor) radar — X-band AESA fighter fire control; the missile's active seeker — Ka/mmW, very high PRF over the last 5–20 km; and the proximity fuse — short-range CW/high-PRF that triggers the warhead at burst radius.</p></div>
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<summary><strong>8. Match the kill-chain links to radar classes.</strong></summary>
<div class="card-answer"><p>Detect → EW; Track/Identify → ACQ+HF, GCI, ESM; Engage (cue) → TTR/AI; Engage (illuminate) → TIR; Engage (terminal) → active seeker; Kill → proximity fuse.</p></div>
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<summary><strong>9. Why do EW investments tend to attack the early kill-chain rows?</strong></summary>
<div class="card-answer"><p>The early rows (Detect, Track) are cheaper to defeat and have higher payoff — everything downstream depends on them, so breaking a handoff early starves the whole chain.</p></div>
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<summary><strong>10. How does a B-21-class target (≈ −30 dBsm) change detection range?</strong></summary>
<div class="card-answer"><p>Because <span class="math notranslate nohighlight">\(R_{\max}\propto\sigma^{1/4}\)</span>, a <span class="math notranslate nohighlight">\(-30\)</span> dBsm RCS collapses detection range to about 17.8% of the legacy (1 m²) value at every layer.</p></div>
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<summary><strong>11. Where does LO buy the most <em>absolute</em> kilometers, and why?</strong></summary>
<div class="card-answer"><p>At the EW and ACQ layers. The percentage reduction is the same everywhere (<span class="math notranslate nohighlight">\(\sigma^{1/4}\)</span>), so the largest raw shrink happens where the rings start largest — the long-range surveillance layers.</p></div>
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<summary><strong>12. Does LO make the bomber invulnerable?</strong></summary>
<div class="card-answer"><p>No. It shrinks every ring proportionally; the engagement layers still close in. LO buys standoff and time, not invisibility — which is why later blocks add active EW on top.</p></div>
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