Chirp Signal Range Detection Simulator – FMCW Radar Explained

📡

Interactive FMCW Radar Simulator

See how a chirp signal detects an object's range and velocity from the returned echo.

📡 Radar Parameters

Carrier Frequency 77 GHz Chirp Bandwidth 500 MHz Chirp Duration 1 ms

Chirp Slope

5.00 × 10¹¹ Hz/s

🎯 Target Parameters

Target Range 50 m Target Velocity 20 m/s

Interpretation

Target approaching radar

⚙ Simulation

Try this: Move the target range slider. Then move the velocity slider. Watch how the beat frequencies change.

ROUND-TRIP DELAY

333 ns

DOPPLER SHIFT

10.27 kHz

UP-CHIRP BEAT

176.94 kHz

DOWN-CHIRP BEAT

156.40 kHz

🎯 Radar Scene

📡

RADAR

→

🚗

TARGET

📤 Transmitted Chirp

📥 Delayed + Doppler Echo

🔀 Mixer Output — Beat Signal

The mixer compares the transmitted chirp with the delayed received echo. The resulting low-frequency signal contains range and Doppler information.

📊 Beat Frequency Spectrum

The peak in the spectrum is the frequency measured by the radar receiver.

🔄 Up-Chirp / Down-Chirp Method

UP-CHIRP

f_up = f_range + f_D

DOWN-CHIRP

f_down = f_range − f_D

RANGE COMPONENT

166.67 kHz

🎯 Radar Estimate

Estimated Range

50.00 m

Estimated Velocity

20.00 m/s

✓ Radar successfully recovered range and velocity.

🧮 Equations Used in the Simulation

Wavelength

λ = c / f_c

Round-trip delay

τ = 2R / c

Chirp slope

K = B / T

Doppler frequency

f_D = 2v / λ

Range beat frequency

f_R = Kτ

Range

R = c f_R / 2K

🎓 Student Challenge

1. Set the target range to 100 m. Keep velocity at 0 m/s. Observe the beat frequency.

2. Keep the range at 100 m and change velocity from 0 to +30 m/s. What happens to the beat frequency?

3. Change velocity to −30 m/s. Compare the result with +30 m/s.

4. Increase the chirp bandwidth. Observe how the range-related beat frequency changes.

5. Explain why using both up-chirp and down-chirp allows range and velocity to be separated.

Return to Premium Virtual DSP Lab →