L9 Pre-flight

L9 Pre-flight#

Block 1: Radar Fundamentals — Lesson 9: Project 1 Work Day Work this before L9. Pre-flights are never collected — in class, anyone may be cold-called to present any question at the board, and that recitation is the participation grade.

Assumed pre-class reading#

  • The Project 1 handout (B-21 Threat Detection Range Analysis), posted with B21_RCS_Table.csv and L9_Project1Starter.m.

  • L7 and L8 wrap-ups.

This quiz checks that you arrive ready to work, not that you have done the project. Read the handout before class.

Quiz questions (5 items, ~5 minutes)#

Q1. (Multiple choice) In Project 1, each threat radar computes detection range using which RCS column from the B-21 table?

  • [ ] (a) Always the X-band column, since LO is designed against fire control radars

  • [ ] (b) The column matching that radar’s own operating band

  • [ ] (c) The average of all three columns

  • [ ] (d) The worst-case (largest) column

Q2. (Multiple choice) The B-21’s RCS table shows higher (less suppressed) values at UHF than at X-band. The operational consequence is:

  • [ ] (a) The TTR detects the B-21 farther out than the EW radar

  • [ ] (b) The EW radar detects the B-21 farther out, relative to its X-band layers, than RCS suppression alone would suggest

  • [ ] (c) All three classes detect the B-21 at the same range

  • [ ] (d) The RCS table must be wrong, since LO is broadband

Q3. (Multiple choice) A +3 dB error in RCS changes the computed detection range by a factor of:

  • [ ] (a) \(10^{3/10} \approx 2.0\)

  • [ ] (b) \(10^{3/20} \approx 1.4\)

  • [ ] (c) \(10^{3/40} \approx 1.2\)

  • [ ] (d) No change — RCS does not affect detection range

Q4. (Short answer) The EW radar detects the B-21 well before the TTR can. In one sentence, why does that gap matter for the kill chain — that is, why is detection not the same as engagement?

Q5. (Multiple choice) The RCS table covers aspect 0° to 180° and is symmetric about the nose–tail axis. To plot detection range over the full 360° of azimuth, you should:

  • [ ] (a) Set RCS to zero for aspects beyond 180°

  • [ ] (b) Mirror the table: the value at 360° − θ equals the value at θ

  • [ ] (c) Extrapolate linearly past 180°

  • [ ] (d) Re-run the analysis with a second table

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