That new Nexus 7 update slowly rolling out across the Google-sphere does more than patch the touchscreen issues. A Googler has confirmed that JSS15Q also fixes the GPS bug that users began reporting shortly after the device launched.
The bug was causing the 2013 Nexus 7 to lose its GPS lock after prolonged use. Switching between multiple GPS-enabled apps (which is, you know, a lot of them) would accelerate the breakdown. The only fix was a reboot. That should be a thing of the past now with JSS15Q hitting devices.
When is it going to get to your device? No way to know. Probably not longer than a day or two, as long as you have a stock recovery. Otherwise, there will probably be a link to the OTA package at some point. Also note that some users are reporting errors with the update on rooted devices.