# dop2speed

Convert Doppler shift to speed

## Syntax

``radvel = dop2speed(dps,lambda)``

## Description

example

````radvel = dop2speed(dps,lambda)` returns the radial velocity in meters per second. This value corresponds to the one-way Doppler shift `dps` for the wavelength `lambda`.```

## Examples

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Calculate the radial velocity of an automobile based on the Doppler shift of a continuous-wave radar. The radar carrier frequency is 24.15 GHz. Assume a doppler shift of 2.880 kHz.

```f0 = 24.15e9; lambda = physconst('LightSpeed')/f0; dopshift = 2.880e3; radvel = dop2speed(dopshift,lambda)```
```radvel = 35.7516 ```

The radial velocity is 35.75 meters per second or 80 miles/hour.

## Input Arguments

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One-way Doppler shift in hertz, specified as a scalar, vector, or matrix.

Data Types: `single` | `double`

Wavelength in meters, specified as a positive scalar.

Data Types: `single` | `double`

## Output Arguments

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Radial velocity in meters per second, returned as a scalar, vector, or matrix.

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The radial velocity of a source relative to a receiver can be computed from the one-way Doppler shift:

`${V}_{s,r}=\Delta f\lambda$`

where Vs,r denotes the radial velocity of the source relative to the receiver, Δf is the Doppler shift in hertz, and λ is the carrier frequency wavelength in meters.

## Version History

Introduced in R2011a