L14 Pre-flight

L14 Pre-flight#

Block 2: RF Electronic Warfare — Lesson 14: Triangulation and Fusion Work this before L14. 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#

  • L13 wrap-up

  • The Jupyter Book Reading page for L14 — lines of position and triangulation, the crossing-angle effect on accuracy, multi-receiver fusion, and the RWR signal-processing chain.

Quiz questions (5 items, ~5 minutes)#

Q1. (Multiple choice) A single receiver measures the bearing to an emitter. By itself, that measurement gives you:

  • [ ] (a) The emitter’s exact position

  • [ ] (b) A line of position — the emitter is somewhere along the bearing, near or far

  • [ ] (c) The emitter’s range only

  • [ ] (d) The emitter’s velocity

Q2. (Multiple choice) Two identical receivers cross their bearings on an emitter. What most strongly sets the accuracy of the resulting fix?

  • [ ] (a) The transmit power of the emitter

  • [ ] (b) The crossing (“cut”) angle of the two bearings — the geometry

  • [ ] (c) The color of the display

  • [ ] (d) The pulse repetition interval

Q3. (Multiple choice) An emitter moves far downrange so the two bearings cross at a shallow angle. The position fix:

  • [ ] (a) Becomes more accurate

  • [ ] (b) Is unaffected

  • [ ] (c) Degrades, with the error stretched mainly along the range direction

  • [ ] (d) Rotates 90 degrees but keeps the same size

Q4. (Multiple choice) Why fuse bearings from three or more receivers instead of just two?

  • [ ] (a) Three bearings always meet exactly at one point

  • [ ] (b) It removes the need for any geometry

  • [ ] (c) The fix is overdetermined, so a least-squares solution adds redundancy, better geometry, and a way to spot a bad bearing

  • [ ] (d) It lets each receiver use a narrower bandwidth

Q5. (Short answer) Before you cross two receivers’ bearings into a fix, what must be true about the two measurements, and what do you create if you cross bearings from different emitters?

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