Cant find Doppler shift with LFM signal Im stuck on this one. I hope someone helps me! 

Problem: I need to find Dopler shift with array of reflected chirps.

I have bursts of chirps which then i sampled, and calculated fft. 
Im suposed to calculate Doppler shift using just spectrum. I see it's shifted but have no idea how to calculate the shift. I tried with boxcars in hope it will  be easier and i will notice something, but it's the same thing. Also i find some really useful article and also stuck understanding it. 


  "Unless the target is moving at an extremely high speed relative to
  the speed of light, the Doppler shift will be small and very difficult
  to detect from one pulse. The solution to this problem is to transmit
  a burst waveform containing repeated pulses. Initially, for
  simplicity, boxcars were used as the pulse so that some insight into
  how the parameters of the pulse affect the Doppler shift might be
  gained."
  source
The resulting spectrum appears to be your Doppler shift (possibly as a ratio to half the sampling rate, depending on what the horizontal axis on your plot represents). Without seeing all the processing that was done to generate the "Filtered Chirp Sequence" I cannot be certain but I assume it is a complex result from the subsequent plots, which would rotate in phase at the rate of the Doppler offset. To confirm this, run the test or simulation with known 0 Doppler or Clock offset and confirm that the resulting phase is constant from sample to sample.