# Doppler Velocity from I&Q channel

23 views (last 30 days)
Muhammad Fayyaz on 20 Aug 2018
Commented: Aicha Sow on 12 Aug 2021
I am new to this field and struggling to find doppler velocity from pure Doppler RADAR. I have I&Q channel, which I beleive is used to find doppler velocity by finding their phase difference ? Any sort of help would be much appreciated
##### 4 CommentsShow 3 older commentsHide 3 older comments
Aicha Sow on 12 Aug 2021
Hi @Muhammad Fayyaz I was indeed hoping for another answear. But thanks for taking the time to reply.

Sign in to comment.

### Answers (3)

Honglei Chen on 20 Aug 2018
There is a Doppler estimation example in Phased Array System Toolbox. You can find it at
HTH
##### 2 CommentsShow 1 older commentHide 1 older comment
Honglei Chen on 20 Aug 2018
Edited: Honglei Chen on 20 Aug 2018

Sign in to comment.

Muhammad Fayyaz on 20 Aug 2018
Thanks for the quick response. But I had already seen this example, which is for FREQUENCY MODULATED CW Radar system. I have purely CW system with no such information as required for FMCW or Pulse.
##### 0 CommentsShow -1 older commentsHide -1 older comments

Sign in to comment.

Honglei Chen on 20 Aug 2018
If you are using a pure CW system, you cannot derive the range information. In that case you just mix the received signal with the transmitted signal, like what is done for range in the FMCW radar example. However, this time all frequency shifts are caused by Doppler shift. So just as shown in the FMCW radar example, once you get the beat frequency, that is your Doppler shift and you can then translate that to speed.
HTH
##### 2 CommentsShow 1 older commentHide 1 older comment
Honglei Chen on 20 Aug 2018
If you have FFT output, you can just locate the peak and get the corresponding frequency. To translate that frequency to speed, you can use dop2spped
Note that this is for one way propagation. Since you are using a radar, you probably have two way propagation so you need to divide the result by 2 to get the correct speed.
HTH

Sign in to comment.

### Categories

Find more on Detection, Range and Doppler Estimation in Help Center and File Exchange

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!