Simple Android app.

We are looking for a freelance android developer who has detailed knowledge about direct access to the GNSS of Android devices. Knowledge of handling time-critical tasks is also important. If you are experienced in these topics, the app will be simple and straightforward for you.

The app to-be-developed is quite simple: All it needs to do is create a short ‘beep’ sound at a given UTC time. The complicated part is that this beep needs to be exactly at a given true UTC, down to a millisecond.
,
Determining the exact UTC and handling of time is crucial for the desired app. For this reason, the app will have to access the exact time via the GNSS, specifically the android.location.GnssClock class.

It is critical that several different devices, which are set to beep at the same UTC time, do in fact beep perfectly synchronous at the same millisecond.(Note: it is not important if that beep is e.g. 3ms late –as long as that delay is the same for all devices –the synchrony is most important

The App needs to includean interface for ‘Tasker’, which is an app suite for the automation of Android devices. Tasker will call the desired app via intents and supply several parameters:
1) the UTC of the beep
2) Characteristics ofthe beep (Volume, length, frequency) and
3) the audio channel (incl. alarm channel).

Java or Kotlin are liekely preferrable, as both are closely supported by the android operating system, so the time critical tasks can be expected work as desired.

We expect a working .apk and commented source code.

A simplified protocol for the app usage could look like this:
1.Tasker will start upthe beep app approx. 2minutesbefore the desired beep.
2.A given time in UTC „Date“ format can be converted to a UTC in “Milliseconds” format viaDate.getTime()
3.The beep app gets the accurate UTC by activatingthe GNSS(satfix) and accessing android.location.GnssClock
4.Calculate the time difference between the desired beep UTC and current UTC, as provided by the GNSS (both in millisecond-format).
5.Set an exact timer at the calculated time difference. Start the beep when the timer runs out. 6.Get another accurate UTC time from Gnss Clock and report it back to a Tasker variable and screen (for control& documentation).
7.The app quits itself after this. (there may be an option for this.)