FMCW Lidar Range and Velocity
Calculate ideal FMCW lidar range and radial velocity from separated beat frequencies.
Description
Ideal FMCW lidar uses already separated range-beat and Doppler frequencies.
Ideal FMCW lidar uses already separated range-beat and Doppler frequencies. Chirp slope maps one beat to delay while wavelength maps the other to radial velocity.1
Calculate ideal FMCW lidar range and radial velocity from separated beat frequencies.
When to use FMCW Lidar Range and Velocity
Use this tool to calculate ideal FMCW lidar range and radial velocity from separated beat frequencies.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use FMCW Lidar Range and Velocity and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter rangeBeatFrequencyHertz, chirpSlopeHertzPerSecond, dopplerFrequencyHertz, wavelengthMeters using the field table and calculation rules, then run the tool.
- Read rangeMeters, radialVelocityMetersPerSecond. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| rangeBeatFrequencyHertz | Range beat frequency (Hz) | number | Required |
| chirpSlopeHertzPerSecond | Chirp slope (Hz/s) | number | Required |
| dopplerFrequencyHertz | Doppler frequency (Hz) | number | Required |
| wavelengthMeters | Wavelength (m) | number; minimum: 0 | Required |
Enter finite signed frequencies/slope with nonzero slope and positive wavelength. Return signed meters and m/s.
range=c rangeBeat/(2chirpSlope); velocity=λdoppler/2 Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| rangeMeters | FMCW range (m) | number |
| radialVelocityMetersPerSecond | Radial velocity (m/s) | number |
{
"input": {
"rangeBeatFrequencyHertz": 1000000,
"chirpSlopeHertzPerSecond": 1000000000000,
"dopplerFrequencyHertz": 100000,
"wavelengthMeters": 0.00000155
},
"output": {
"rangeMeters": 149.896229,
"radialVelocityMetersPerSecond": 0.0775
}
}Limitations and assumptions
No beat extraction, range–velocity separation, aliasing or refractive-index correction is performed.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Swept-Frequency Distance: Convert swept-frequency phase slope to delay and one-way distance. For a complementary task, use Doppler Lidar Frequency Shift: Calculate monostatic lidar Doppler frequency shift from radial velocity and wavelength.
References
-
FMCW Lidar Range and Velocity — tool.io
Similar or alternative tools
- Swept-Frequency Distance
Convert swept-frequency phase slope to delay and one-way distance.
- Doppler Lidar Frequency Shift
Calculate monostatic lidar Doppler frequency shift from radial velocity and wavelength.