This video show several blocks in the digital signal processing chain that allow to enhance the visibility and tracking of moving targets. We show CFAR, Moving Targete Detection with Doppler Filtering, a Heatmap and the I and Q signals.

We recorded the following video during one of our training sessions at a customer location. We recorded radar raw data with SkyRadar's 8 GHz NextGen Pulse Radar. To do the digital signal processing we used our DSP and visualisation environment FreeScopes (the setting includes the modules FreeScopes Basic I, FreeScopes Basic II and FreeScopes ATC I).

In the DSP we first cleaning the raw data of the reflection by the source. Then we visualized raw data in an A-Scope and compared it with raw data, prefiltered by a CFAR-block. The prefiltered A-Scope gives a much cleaner image of the situation.

We also visualized the rawdata (suppressed source, but no CFAR) in a PPI.
Next to it, we placed a PPI which visualizes data prefiltered with a Moving Target Detection Block MTD, which makes use of a Doppler filter (MTD DF). 

My colleague Arnold moves in front of the radar. The difference of the radar image with and without MTD is striking (even without CFAR).

We also look at the I and the Q part of the signal separately (just with suppressed source).

The last block in the video show a heatmap of Arnold's movement. To get there we first create a matrix of the radar vector (radar raw data is a vector of range cell amplitudes at a given moment in time). The burst block aggregates several radar sweeps into a matrix (meaning several subsequent frames), so that a subsequent FFT-block can apply a Fourrer transform. This can be nicely displayed in a heatmap. An approaching movement compresses the wave, it will hence be displayed above the normal frequency. Distancing from the radar will expand the wave's frequency. As it gets smaller it is displayed below the normal frequency.

Here some links to learn more about CFAR, Moving Targete Detection with Doppler Filtering, a Heatmap and the I and Q signals.

SkyRadar produces the training radar and FreeScopes for aviation academies and universities. The system can be used by many students concurrently and can be accessed remotely. Talk to us to learn more.

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