Direct path and reflections of ultrasound transmission I am using the following system:
Ultrasonic chirp signals with central frequency 100kHz are being transmitted using ultrasonic sensor. After the transmission through the medium(air/solid/liquid/combination) they are being received with hydrophone. The system is being controled by DSP and signal generation and acquisition is obtained via DAC and ADC. Our aim is to detect the time of arrival between transmission and reception.
My mentor suggested that I could use something with FFT to observe reflections, but I am struggling to find information on the internet about it. Does anyone have a suggestion how that could be done using FFT, or any other method?
That sounds like a usual FMCW sonar.
It's technically identical to FMCW radar. So, multiply your receive with your transmit signal, you get a signal at the beat frequency, which is proportional to the range.
Standard FMCW approaches; there's a wealth of info out there.