L19 — Project 2 Work Day

L19 — Project 2 Work Day#

No new theory today. Your group is the B-21 mission-planning cell, and the period belongs to Project 2: geolocate the IADS emitters defending a target area — passively, from RWR bearings — precisely enough to cue a weapon, while the aircraft stays outside every threat's lethal range.

The ask#

Produce weapon-quality locations for the emitters defending a target area, found passively from RWR bearings while the B-21 stays on a standoff orbit outside every threat ring. Everything you need is in L13–L14: angle of arrival, lines of position, and crossing bearings into a fix. A bearing is a line — the fix, and its precision, is the product.

The scenario#

A notional IADS sector near the grid origin (km, North/East). The priors are coarse ELINT (\(\pm 5\) km) — good enough to plan against, not to shoot:

ID

Class

Band

Prior (N, E)

Keep-out

E1

EW

UHF (0.5 GHz)

(0, 0)

20 km

E2

ACQ

S (3 GHz)

(10, −8)

45 km

E3

TTR

X (10 GHz)

(−6, 6)

40 km

Your entire flight path must stay outside all three keep-out circles.

Bearings to a fix to an ellipse#

Each RWR cut is a bearing with noise \(\sigma_\theta = 0.5^\circ\). Cross cuts taken from different points along your path and the lines meet at a fix — with an error ellipse set by geometry and noise. A wide cut and a long baseline shrink the ellipse; a shallow cut or long range stretch it. Summarize each fix by its \(\mathrm{CEP} \approx 0.59(a+b)\) from the \(1\sigma\) semi-axes. This is L14 made operational: geometry, not receiver quality, sets your accuracy.

The spec — and the tension#

The standoff weapon’s seeker acquires within a 1 km basket, so to cue it confidently you need

\[ \mathrm{CEP} \le \tfrac{1}{2}(1\ \text{km}) = 0.5\ \text{km} \]

for the lethal emitters (ACQ and TTR at least). Accuracy wants you close and on a long baseline; survivability wants you far, outside every keep-out. The whole project lives in that tension — defend your geometry.

Your tasks#

  1. Geolocation pipeline — bearings to a fix to a \(1\sigma\) ellipse; verify on the starter.

  2. Collection design — choose standoff, baseline, heading, and cuts; stay outside every keep-out.

  3. Execute and geolocate — run the simulator along your path; report fixes and CEP.

  4. Meet the spec — who passes, who doesn’t, and the accuracy–standoff trade.

  5. Visualization — emitters, keep-outs, path, fixes, and ellipses, to scale.

  6. Recommendation — one slide to the strike cell.

Materials#

Project 2 handout (PDF)

IADS_Scenario.csv

MATLAB · code/L19_Project2Starter.m↓

The starter reads IADS_Scenario.csv, flies a two-waypoint sample leg, calls rwr_collection_sim.m to collect noisy bearings, and cross-fixes one emitter with its \(1\sigma\) ellipse and CEP. The true emitter positions are hidden inside the simulator — estimating them is the job. Verify the two-point case first, then add cuts, emitters, and geometry. (The simulator and CSV are bundled in the code zip beside the starter, which reads them from the current folder.)

How to use the work day#

  • First 10 minutes — groups assigned; read the handout together and sketch the geometry.

  • Next 30 minutes — divide the work: pipeline, collection design, execution, visualization, story.

  • Last 10 minutes — regroup: what’s done, what’s blocked, who owns what before L20.

Plan the presentation first — it tells you what to compute. Next lesson: L20 — Project 2 presentations. Slides and code due before class, HW2 due at the start of class, and Quiz 2 in class.

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