Hi Harshita,
I understand you want to find the Time Delay, the Degree of Arrival and the Time Difference of Arrival of the sound using audio-signals from 4 microphones. You could apply cross-correlation and triangulation on the audio-signals to find these values.
1. You can follow the given steps to find the time delay:
- Load the audio signals and extract the audio data from each microphone.
- Calculate the cross-correlation between each of the microphone pairs. You can use MATLAB’s inbuilt ‘xcorr’ function to find the cross-correlation. You can refer the following documentation for more information: https://www.mathworks.com/help/matlab/ref/xcorr.html
- The maximum (or minimum if the signals are negatively correlated) of the cross-correlation function indicates the point in time where the signals are best aligned, i.e., the time delay between the two signals corresponds to the peak in the cross-correlations found in previous step2. You can use the ‘max’ function to find the peak and its corresponding index.
- You can refer the following documentation on cross-correlation: https://en.wikipedia.org/wiki/Cross-correlation
2. To find the Time Difference of Arrival(TDOA), you can refer the following documentation: https://www.mathworks.com/help/fusion/ug/object-tracking-using-time-difference-of-arrival.html
- You can use the time-delay values along with propagation speed and the length of audio waves to find the TDOA as described in the documentation.
3. Now, based on the TDOA between different pairs, you use triangulation to find the Direction of Arrival for the audio signal. You could refer to the following documentation which explains how to implement triangulation: https://circuitcellar.com/resources/ee-tips/triangulation-trilateration-or-multilateration-ee-tip-125/
I hope this helps.
