Fundamental radar principle: is radar essentially an echo-ranging system that measures target range (and often velocity) from reflected signals?
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ATrue
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BFalse
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CTrue only for continuous-wave systems
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DTrue only for pulsed systems
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EFalse for all monostatic radars
Answer
Correct Answer: True
Explanation
Introduction:Radar (Radio Detection and Ranging) operates by transmitting electromagnetic energy and processing the returned echoes from objects. The simplest conceptual model is “echo ranging,” analogous to sonar but using radio waves.
Given Data / Assumptions:
- Monostatic or bistatic radar geometries.
- Pulsed or continuous-wave (CW) techniques.
- Standard free-space propagation assumptions for basic explanation.
Concept / Approach:
In pulsed radar, range R is inferred from round-trip time: R = c * Δt / 2. In CW/FMCW, range and velocity are extracted from frequency modulation and Doppler shifts. In all cases, the radar uses a form of echo measurement to infer target properties.
Step-by-Step Solution:
1) Transmit waveform (pulse or modulated CW) toward the scene.2) Targets scatter energy; a portion returns to the radar antenna.3) Receiver measures time/frequency/phase of echoes.4) Convert observables to range (time delay), velocity (Doppler), angle (antenna pattern/beamforming).Verification / Alternative check:
Radar equation and matched-filter theory formalize echo processing; all common radar classes fundamentally analyze returned signals.
Why Other Options Are Wrong:
- “False” or restricted truths ignore that both pulsed and CW radar rely on echoes.
Common Pitfalls:
Assuming CW radars do not “range.” FMCW and phase-coded CW retrieve range through modulation.
Final Answer:
True