L4 Pre-flight

L4 Pre-flight#

Block 1: Radar Fundamentals — Lesson 4: Pulse Radars and Ambiguity Work this before L4. 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#

  • L3 wrap-up

  • The Jupyter Book Reading page for L4 — Pulse Radars & Ambiguity — covering pulse width, PRI/PRF, duty cycle, range resolution, and the range-Doppler ambiguity tradeoff.

Quiz questions (5 items, ~5 minutes)#

Q1. (Multiple choice) For a pulse radar, the duty cycle is defined as:

  • [ ] (a) PW \(\cdot\) PRF

  • [ ] (b) PW \(/\) PRF

  • [ ] (c) PRF \(/\) PW

  • [ ] (d) PW \(+\) PRI

Q2. (Multiple choice) A radar transmits a 1 \(\mu\)s pulse. What is its best range resolution?

  • [ ] (a) 1.5 m

  • [ ] (b) 15 m

  • [ ] (c) 150 m

  • [ ] (d) 1.5 km

Q3. (Multiple choice) A radar uses PRF \(= 1\) kHz. What is its maximum unambiguous range?

  • [ ] (a) 1.5 km

  • [ ] (b) 15 km

  • [ ] (c) 150 km

  • [ ] (d) 1500 km

Q4. (Short answer) In one sentence, why can’t a radar achieve both unambiguous range and unambiguous Doppler at the same PRF?

Q5. (Multiple choice) A surveillance radar that needs to see hundreds of kilometers in range but does not care about Doppler is most likely operating at:

  • [ ] (a) Low PRF

  • [ ] (b) Medium PRF

  • [ ] (c) High PRF

  • [ ] (d) Continuous wave

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