Retaining data within forms if form submission fails

I have a very long form with around 50 different fields. All users of the form are logged in and most will be submitting over a flakey mobile network. If the user submits the form and their connection drops they lose everything submitted so far when they go back. Is there a way of ensuring this is not the case or is it something more likely to be handled on a browser level?

Thanks in advance.

You could use the Partial Entries add-on, which will take a snapshot of the data based on the WordPress heartbeat, but that data would be available only to your, the site administrator. It would not save the user the trouble of entering their data again. That would be handled with local storage at the browser level. Gravity Forms does not currently support that, but we do have an open feature request to add that capability.