Spectrogram function help needed

I have a radar signal and the problem statement is such that, i have to extract the velocity of the projectile and the distance by which it has missed the target from it. So, with respect to this, I have acquired the data using the data acquisition toolbox of MATLAB with the help of windows sound card at a sampling frequency of 8khz. All my time domain amplitude values are in the range +1v to -1v as the 'winsound' takes amplitude values only between these levels. After data acquisition I have used the signal processing toolbox in MATLAB and have used spectrogram function to plot a freq v/s time plot of my signal. I am correctly able to see the characteristic 'v' curve which signifies the presence of doppler in my signal but I am unable to extract any frequency information from the spectrogram plot. i.e. at a particular time instant, I am unable to find a frequency which belongs to that particular time instant. Can someone pl. help me with this?? I am attaching the spectrogram code for your reference.

fs=8000; y=dop(7000:10000);

figure; windowsize = 128; window = kaiser(windowsize,5); nfft = windowsize; noverlap = windowsize-1; [S,F,T] = spectrogram(y,window,noverlap,nfft,fs); imagesc(T,F,log10(abs(S))) set(gca,'YDir','Normal') xlabel('Time (secs)') ylabel('Freq (Hz)') title('Short-time Fourier Transform spectrum')