No new theory today. Your group is the survivability analysis cell supporting B-21 mission planning, and the period belongs to Project 1: detection range versus aspect and band, with uncertainty a planner can actually use.
## The ask Produce the range at which each threat radar class first detects the B-21, as a function of **aspect angle** and **operating band** — with uncertainty. Everything you need is in L1–L8: the range equation, RCS, the IADS taxonomy, and $S_{\min}$. Detection range is not a number — it's a *shape*. ## The scenario A notional adversary IADS sector defends the target area with the three radar classes from L7 — the same notional parameters as the L7 type-along, so your old code works here: | Class | Band | $f$ | $P_t$ | $G_t = G_r$ | $S_{\min}$ | | --- | --- | --- | --- | --- | --- | | EW | UHF | 0.5 GHz | 2 MW | 25 dBi | $-140$ dBW | | ACQ | S | 3 GHz | 1 MW | 30 dBi | $-130$ dBW | | TTR | X | 10 GHz | 100 kW | 35 dBi | $-140$ dBW | Free space, monostatic, detect at $S \geq S_{\min}$. The full tasking, deliverables, and grading live in the handout — it is the authoritative document. ## The RCS model `B21_RCS_Table.csv` gives notional B-21 RCS in dBsm at $5^\circ$ aspect steps, nose to tail, in all three threat bands. Three rules: - **Band matching.** Each radar uses its own band's column: EW → UHF, ACQ → S, TTR → X. - **Symmetry.** The table is symmetric about the nose–tail axis, so it covers the full circle. - **Uncertainty.** Every value is the center of a $\pm 3$ dB interval. How you carry that interval into kilometers is your call to defend. Note where LO works hardest — and where it doesn't. The bands disagree, and that disagreement is the story. ## Your five tasks 1. **Detection range vs aspect** — $R_{\max}(\theta)$ per class, in band. Justify your binning. 2. **Uncertainty** — propagate $\pm 3$ dB of RCS into kilometers. 3. **Visualization** — one picture that tells the whole story. 4. **Ingress implications** — which class, which aspects, by how much. With numbers. 5. **Recommendation** — one slide to the mission planning cell. ## Materials Project 1 handout (PDF) B21_RCS_Table.csv MATLAB · code/L9_Project1Starter.m↓ The starter skeleton handles the plumbing — it loads the CSV, converts dBsm to m², defines all three threat classes as a table, and computes one worked $R_{\max}$ so you can verify your pipeline. Your analysis begins at the `TODO` blocks. **Verify the worked number first. Then build.** (The CSV is bundled inside the zip next to the starter, which reads it from the current folder.) ## How to use the work day - **First 10 minutes** — groups assigned, claim a whiteboard, read the handout together. - **Next 30 minutes** — divide the work: pipeline, uncertainty, visualization, story. - **Last 10 minutes** — regroup: what's done, what's blocked, who owns what before L10. The instructor floats between groups — pitch your approach early. And plan the presentation *first*: it tells you what to compute. ## Before you leave - Pipeline verified against the skeleton's worked number. - Task owners assigned through L10. - Questions for the instructor in writing tonight, not at 0700 before class. Next lesson: **L10 — Project 1 results presentations.** Slides and code due before class, HW1 due at the start of class, and Quiz 1 in class.