Hi @BORNLOVE_NTIKHA
My thoughts on this suggestion are that it sounds more like an 'intermediary' app that you are needing, to log GNSS data streams and calculate data on demand when requested by ODK Collect. Way beyond my competence! However, something highlighted by @seadowg raises a caution here - you'd need to be able to read data from an unknown range of GNSS devices (so possibly varying standards / language formats), which could limit the practicality of creating a solution that can be used widely.
I suggested in an earlier post a simple way of doing something that starts you on the road to averaged positions - use a geotrace to record a number of points, then process the results to calculate the desired answer. It's probably way more complicated, but if you record the geotrace for a set period (e.g. 2 minutes, recording a point every 10 seconds), you could then adapt the process suggested by @Xiphware in this post: ODK geoshape/geotrace/geopoint to KML to extract the coordinates and calculate an average (and presumably a standard deviation to contribute to your accuracy) which you could then use within your form - take note of the cautions he includes at the bottom of the post! Or process the geotrace field once you've downloaded the instance.
I'm still learning the ropes with my high accuracy GNSS receiver, but one salutary lesson is that the log files are huge. I'm not sure how practical it is store them or even access them from ODK. And as with all data, I am mindful of not getting hung up on accuracy at the expense of meaning - it does matter that I have accuracy of 1m or less for some work (rather than 3-6m which is sufficient in many of my projects) but 5cm accuracy would give a false sense of quality (and probably isn't repeatable anyway, without a tripod, for example, which I never carry in the mountains!). It's a similar argument to people worrying about how many 'significant figures' to present when the underlying data is coarse.
Apologies if that sounds disrespectful of your idea or needs, I'm just a boring pragmatist!