Have you tried multiple concurrent ultrasonic source to one ultrasonic sensor?

Suppose there are several ultrasonic sources triggered concurrently, an ultrasonic sensor detects and separates them, is there a way of doing this? (For example, modulating ultrasonic waves)

If you control the sources, you can always ensure that, at any one instant, only one source will be transmitting so, in the event of a detection, you would know which source was active. You’d do a sort of round robin selection of the source and ensure that there was a sufficient gap (milliseconds) between transmissions to ensure no interference.

Maybe say what your application is for other ideas.

Yes, by

For example, modulating ultrasonic waves

You will need custom transmit and receive circuitry, and sophisticated code.

6v6gt: If you control the sources, you can always ensure that, at any one instant, only one source will be transmitting so, in the event of a detection, you would know which source was active. You'd do a sort of round robin selection of the source and ensure that there was a sufficient gap (milliseconds) between transmissions to ensure no interference.

Maybe say what your application is for other ideas.

Ranging system using acoustic signal, but I want it to scale to a large number of users. Basically I want concurrent multiple users

jremington: Yes, by You will need custom transmit and receive circuitry, and sophisticated code.

Somebody told me that he developed an Arduino-based collision avoidance vehicle, he implemented several SRH-04 on the vehicle to detect several directions' obstacles. Based on his words, it seems that such(concurrent ultrasonic sources ranging) functionality has already become a part of the Arduino library, but I am not sure... So I asked here to see if anybody did this.

HC-SR04 sensors must be used in succession, as they will interfere with each other otherwise.

Basically I want concurrent multiple users

Not on an Arduino.