Official curriculum roadmap, subject/topic distribution, negative marking rules, pacing guidelines, and solved sample questions.
🎯 Mapped Subjects & Topic Question Distribution
Total Question Pool100%
82 MCQs
Combined Active Syllabus
Radar Systems, Remote Sensing & Signal Processing
82 MCQs
Topic Pool
📊 Question Pool Structure
82 MCQs across fundamental, intermediate, and advanced concept tiers.
⚡ Recommended Pacing
45 to 60 seconds per MCQ. Flag complex problems and preserve 10 minutes for final revision.
⚖️ Scoring & Negative Marking
+1 mark per correct answer. In competitive tests with negative marking, -0.25 applies for incorrect guesses.
💡 Strategic Preparation & Exam Hall Guidelines
To maximize your score on Radar Systems, Remote Sensing & Signal Processing, candidates are advised to follow a structured three-pass approach. In the First Pass, solve all direct recall and formula-based questions within 30 seconds each to secure foundational marks. In the Second Pass, tackle multi-step analytical and quantitative reasoning problems. In the Third Pass, review marked questions and verify calculations.
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What is the fundamental Radar Equation for received power ($P_r$) from a point target at range $R$?
A$P_r = (P_t G^2 \lambda^2 \sigma) / ((4\pi)^3 R^4)$, showing that received power is inversely proportional to the fourth power of distance ($R^4$)
B$P_r = P_t / R^2$
C$P_r = P_t imes R^4$
D$P_r = (P_t G \lambda) / (4\pi R)$
✓ Correct Answer:A - $P_r = (P_t G^2 \lambda^2 \sigma) / ((4\pi)^3 R^4)$, showing that received power is inversely proportional to the fourth power of distance ($R^4$)
📖 Step-by-Step Solution & Conceptual Rationale:
Because radar signals travel round-trip (spreading over $R^2$ outgoing and $R^2$ returning), received power drops with $1/R^4$, requiring massive receiver sensitivity.
What determines the fundamental Range Resolution ($\Delta R$) of an unmodulated pulsed radar system?
AThe pulse width ($ au$) or signal bandwidth ($B$): $\Delta R = c \cdot au / 2 = c / (2B)$, where $c$ is the speed of light
BThe physical height of the antenna tower
CThe rotational speed of the antenna dish
DThe transmit carrier frequency only
✓ Correct Answer:A - The pulse width ($ au$) or signal bandwidth ($B$): $\Delta R = c \cdot au / 2 = c / (2B)$, where $c$ is the speed of light
📖 Step-by-Step Solution & Conceptual Rationale:
Wider signal bandwidth ($B$) yields narrower compressed pulses and sharper range resolution, allowing the radar to resolve closely spaced disaster targets.
What is the primary objective of 'Pulse Compression' (Linear Frequency Modulation / Chirp) in radar transmitters?
ATo transmit a long pulse with high average energy (maximizing detection range) while achieving the fine range resolution of a short pulse via matched filter matched filtering
BTo reduce the physical weight of the antenna
CTo make the radar signal invisible to enemies
DTo convert radio waves into sound waves
✓ Correct Answer:A - To transmit a long pulse with high average energy (maximizing detection range) while achieving the fine range resolution of a short pulse via matched filter matched filtering
📖 Step-by-Step Solution & Conceptual Rationale:
Pulse compression solves the classic radar trade-off between energy (long pulse) and range resolution (wide bandwidth chirp).
What is the 'Maximum Unambiguous Range' ($R_{unamb}$) of a pulsed radar with Pulse Repetition Interval ($PRT$) or Pulse Repetition Frequency ($PRF$)?
A$R_{unamb} = c \cdot PRT / 2 = c / (2 \cdot PRF)$
B$R_{unamb} = c \cdot PRF$
C$R_{unamb} = 2c / PRF$
D$R_{unamb} = c / (4 \cdot PRF^2)$
✓ Correct Answer:A - $R_{unamb} = c \cdot PRT / 2 = c / (2 \cdot PRF)$
📖 Step-by-Step Solution & Conceptual Rationale:
If a target echo returns after the next pulse has already been transmitted (beyond $R_{unamb}$), it appears as an ambiguous second-time-around echo at false range.
What is the 'Doppler Dilemma' (Range-Doppler Ambiguity) in pulsed Doppler radar design?
ALow PRF provides long unambiguous range but low unambiguous velocity; High PRF provides high unambiguous velocity but short unambiguous range ($R_{unamb} \cdot v_{unamb} = c \cdot \lambda / 4$)
BRadar can measure only range or only angle, never both
CRadar signals travel slower in rain than in air
DDoppler radars cannot detect moving targets
✓ Correct Answer:A - Low PRF provides long unambiguous range but low unambiguous velocity; High PRF provides high unambiguous velocity but short unambiguous range ($R_{unamb} \cdot v_{unamb} = c \cdot \lambda / 4$)
📖 Step-by-Step Solution & Conceptual Rationale:
Modern radars resolve the Doppler Dilemma by dynamically switching between multiple PRFs (staggered PRF) across consecutive dwell bursts.
What are 'Blind Speeds' in Moving Target Indication (MTI) pulse radar?
ATarget radial velocities where the Doppler shift is an exact integer multiple of the radar's PRF ($f_d = n \cdot PRF$), causing the target echo phase shift to match stationary clutter (cancelling out)
BVelocities exceeding the speed of light
CSpeeds where the radar operator is blinded by glare
DZero velocity only
✓ Correct Answer:A - Target radial velocities where the Doppler shift is an exact integer multiple of the radar's PRF ($f_d = n \cdot PRF$), causing the target echo phase shift to match stationary clutter (cancelling out)
📖 Step-by-Step Solution & Conceptual Rationale:
Staggered PRF (transmitting pulses at varying non-uniform intervals) eliminates blind speed notches in air surveillance and weather radars.
In FMCW (Frequency-Modulated Continuous-Wave) Radar, how is Target Range ($R$) extracted from the intermediate frequency 'Beat Signal' ($f_b$)?
ARange is directly proportional to the beat frequency: $R = (c \cdot T_{sweep} \cdot f_b) / (2 B)$, where $B$ is sweep bandwidth and $T_{sweep}$ is chirp duration
BRange is calculated by counting returned pulses
CRange is measured by signal amplitude only
DRange is calculated from antenna tilt angle
✓ Correct Answer:A - Range is directly proportional to the beat frequency: $R = (c \cdot T_{sweep} \cdot f_b) / (2 B)$, where $B$ is sweep bandwidth and $T_{sweep}$ is chirp duration
📖 Step-by-Step Solution & Conceptual Rationale:
In FMCW radar, mixing the received delayed chirp with the instantaneous transmitted chirp yields a constant low-frequency tone ($f_b$) proportional to range.
What is a '2D Range-Doppler FFT' in FMCW radar signal processing?
AA 1st FFT along fast-time samples (within each chirp) extracts Range; a 2nd FFT along slow-time chirp indices (across the frame) extracts Doppler Velocity
BA 2D photo compression algorithm
CAn image sharpening filter
DA method for calculating radar battery life
✓ Correct Answer:A - A 1st FFT along fast-time samples (within each chirp) extracts Range; a 2nd FFT along slow-time chirp indices (across the frame) extracts Doppler Velocity
📖 Step-by-Step Solution & Conceptual Rationale:
2D FFT generates the Range-Doppler matrix, resolving stationary debris, moving survivors, and rescue vehicles in a single processing frame.
What is 'Radar Cross Section' (RCS, $\sigma$) of a target?
AThe measure of the target's ability to intercept and reflect radar energy back in the direction of the radar receiver, measured in square meters ($m^2$) or $dBsm$
BThe physical cross-sectional surface area measured with a ruler
CThe weight of the target in kilograms
DThe electrical resistance of the target
✓ Correct Answer:A - The measure of the target's ability to intercept and reflect radar energy back in the direction of the radar receiver, measured in square meters ($m^2$) or $dBsm$
📖 Step-by-Step Solution & Conceptual Rationale:
RCS depends on physical geometry, surface material, radar frequency, and viewing aspect angle (e.g. human $pprox 1\ m^2$, small drone $pprox 0.01\ m^2$, airliner $pprox 100\ m^2$).
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