slide 19

Two received signals can still be observed even if two objects are closer than half of light speed times pulse width. Correlation peaks can be detected when the whole pattern of the received signal overlaps with the temporary signal, despite the presence of other signals like noise. By detecting these peaks, two objects can be distinguished. Range compression increases range resolution, independent of pulse width. Then, we look at a case of two received signals. You can see, even if two objects are closer than half of light speed times pulse width, which leads to the overlap of their signals, we still can observe the peaks of the correlation peak, because correlation only becomes higher when the whole pattern of the received signal overlaps with the temporary signal. However, the whole received signals include other signals, such as noise, doesn't matter. With the detection of peaks, we can distinguish two objects. Through the range compression, the range resolution no longer depends on the pulse width and largely increases.