# dopsteeringvec

Doppler steering vector

## Syntax

``DSTV = dopsteeringvec(dopplerfreq,numpulses)``
``DSTV = dopsteeringvec(dopplerfreq,numpulses,PRF)``

## Description

````DSTV = dopsteeringvec(dopplerfreq,numpulses)` returns the temporal (time-domain) Doppler steering vector for a target at a normalized Doppler frequency of `dopplerfreq` in hertz. The pulse repetition frequency is assumed to be 1 Hz. ```

example

````DSTV = dopsteeringvec(dopplerfreq,numpulses,PRF)` specifies the pulse repetition frequency, `PRF`.```

## Examples

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Calculate the steering vector corresponding to a Doppler frequency of 200 Hz. Assume there are 10 pulses and the PRF is 1 kHz.

`dstv = dopsteeringvec(200,10,1000)`
```dstv = 10×1 complex 1.0000 + 0.0000i 0.3090 + 0.9511i -0.8090 + 0.5878i -0.8090 - 0.5878i 0.3090 - 0.9511i 1.0000 - 0.0000i 0.3090 + 0.9511i -0.8090 + 0.5878i -0.8090 - 0.5878i 0.3090 - 0.9511i ```

## Input Arguments

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Doppler frequencies in hertz, specified as a scalar or vector. The normalized Doppler frequency is the Doppler frequency divided by the pulse repetition frequency. Every element of `dopplerfreq` must be smaller than or equal to one-half the pulse repetition frequency `PRF`.

Data Types: `single` | `double`

Number of pulses, specified as a positive integer scalar. The time-domain Doppler steering vector consists of `numpulses` samples taken at intervals of `1/PRF` (slow-time samples).

Data Types: `single` | `double`

Pulse repetition frequency in hertz, specified as a positive scalar. The time-domain Doppler steering vector consists of `numpulses` samples taken at intervals of `1/PRF` (slow-time samples). The normalized Doppler frequency is the Doppler frequency divided by the pulse repetition frequency.

Data Types: `single` | `double`

## Output Arguments

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Temporal Doppler steering vector, returned as a column vector or a matrix. `DSTV` has `numpulses` rows and a number of columns equal to the number of elements of `dopplerfreq`.

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### Temporal Doppler Steering Vector

The temporal (time-domain) steering vector corresponding to a point scatterer is:

`${e}^{j2\pi {f}_{d}{T}_{p}n}$`

where n = 0,1,2, ..., N – 1 are slow-time samples (one sample from each of N pulses), fd is the Doppler frequency, and Tp is the pulse repetition interval. The product of the Doppler frequency and the pulse repetition interval is the normalized Doppler frequency.

## Version History

Introduced in R2011a