THE AMBIGUITY DIAGRAM  

WHAT IS IT? THE BASIC DEFINITION: An ambiguity diagram is a three-dimensional plot that shows the results of convolving a range of frequency-shifted signals with a fixed reference signal. DETAILED EXPLANATION: The Ambiguity diagram uses the waveform that is sent out by a RADAR as its reference waveform. In order to generate an Ambiguity diagram we use this reference waveform as the impulse response to our matched filter. We then convolve this matched filter with several different frequency-shifted versions of our reference signal, which represent the types of returning waveforms we expect to get from a moving object. For example, we start out with a reference signal which is frequency shifted by -5. We convolve this frequency-shifted signal with our reference signal (which contains no frequency shift). We then keep repeating this process going from -5 all the way to zero and then up to a signal frequency-shifted by 5. Note that at a frequency shift of zero, we are simply convolving the reference signal with itself. This is where the result of the convolution should yield its maximum result. All of the results of these convolutions are plotted alongside one another to form a three dimensional graph called the Ambiguity diagram. ^ back to top ^

MOTIVATION – Why this is important OBJECTIVE – What we hoped to achieve AMBIGUITY DIAGRAM - What it is AMBIGUITY DIAGRAM - How to read it WAVEFORMS – The signals we analyzed RESULTS – Results for CW and PCM CHIRP - A closer look POSSIBLE EXTENTIONS – What’s next CODE - Fascinating stuff ACKNOWLEDGMENTS - Who we have to thank